The Pennsylvanian-early permian bird spring carbonate shelf, Southeastern California: Fusulinid biostratigraphy, paleogeographic evolution, and tectonic implications

USGS Publications Warehouse

Stevens, C.H.; Stone, P.

2007-01-01

The Bird Spring Shelf in southeastern California, along with coeval turbidite basins to the west, records a complex history of late Paleozoic sedimentation, sea-level changes, and deformation along the western North American continental margin. We herein establish detailed correlations between deposits of the shelf and the flanking basins, which we then use to reconstruct the depositional history, paleogeography, and deformational history, including Early Permian emplacement of the regionally significant Last Chance allochthon. These correlations are based on fusulinid faunas, which are numerous both on the shelf and in the adjoining basins. Study of 69 fusulinid species representing all major fusulinid-bearing Pennsylvanian and Lower Permian limestone outcrops of the Bird Spring Shelf in southeastern California, including ten new species of the genera Triticites, Leptotriticites, Stewartina, Pseudochusenella, and Cuniculinella, forms the basis for our correlations. We group these species into six fusulinid zones that we correlate with fusulinid-bearing strata in east-central and southern Nevada, Kansas, and West Texas, and we propose some regional correlations not previously suggested. In addition, we utilize recent conodont data from these areas to correlate our Early Permian fusulinid zones with the standard Global Permian Stages, strengthening their chronostratigraphic value. Our detailed correlations between the fusulinid-bearing rocks of the Bird Spring Shelf and deep-water deposits to the northwest reveal relationships between the history of shelf sedimentation and evolution of basins closer to the continental margin. In Virgilian to early Asselian (early Wolfcampian) time (Fusulinid Zones 1 and 2), the Bird Spring Shelf was flanked on the west by the deep-water Keeler Basin in which calcareous turbidites derived from the shelf were deposited. In early Sakmarian (early middle Wolfcampian) time (Fusulinid Zone 3), the Keeler Basin deposits were uplifted and

Permian of Southeast Asia: an overview

NASA Astrophysics Data System (ADS)

Fontaine, Henri

2002-08-01

Permian rocks are widely distributed throughout Southeast Asia. Because of the tropical-equatorial climate the rocks are commonly deeply weathered and covered by dense vegetation over much of the region. Elsewhere, Permian rocks are well exposed and easy to access, particularly where limestone outcrops have weathered to form spectacular, castellated, tower karst. Many limestone outcrops, containing abundant fusulinaceans, were early recognized to be of Permian age, but many outcrops without fusulinaceans, erroneously assigned to the Permian, were found subsequently to be of Triassic age, and more careful studies have established the Permian age of rocks of other lithologies. It is now recognized that different depositional environments are represented by the Permian deposits in various parts of the region. Massive limestones, widespread throughout the region, represent extensive carbonate platforms; local occurrences of thick bedded cherts indicate deposition in deep marine environments, coal, bauxite and clastic sediments with vertebrate remains in North Vietnam and Laos indicate deposition in a continental environment, and pebbly mudstones in Myanmar, Peninsular Thailand, northwest Malaysia and Sumatra, are considered to have been formed in a glacial environment. Volcanic rocks are absent in northwest Peninsular Malaysia and Peninsular Thailand, but are extensively developed in North Vietnam, Sumatra, the eastern Malay Peninsula and Timor. Fossils, representing many fossil groups, are often prolific in Permian sediments, with fusulinaceans, for example, occurring in astronomical numbers in many limestone outcrops. Age-diagnostic fossils demonstrate that the whole of the Permian is represented in different areas of Southeast Asia. Fossil faunal and floral assemblages have been used to establish climatic conditions and environments of deposition, to define distinct crustal blocks and to provide the basis for reconstructing the palaeogeography during Permian times.

Evolution of a complex behavior: the origin and initial diversification of foliar galling by Permian insects

NASA Astrophysics Data System (ADS)

Schachat, Sandra R.; Labandeira, Conrad C.

2015-04-01

A central notion of the early evolution of insect galling is that this unique behavior was uncommon to rare before the diversification of angiosperms 135 to 125 m.yr. ago. However, evidence accumulated during recent years shows that foliar galls were diverse and locally abundant as early as the Permian Period, 299 to 252 m.yr. ago. In particular, a diversity of leaf galling during the Early Permian has recently been documented by the plant-damage record of foliar galls and, now, our interpretation of the body-fossil record of culprit insect gallers. Small size is a prerequisite for gallers. Wing-length measurements of Permian insects indicate that several small-bodied hemipteroid lineages originated early during the Permian, some descendant lineages of which gall the leaves of seed plants to the present day. The earliest foliar gallers likely were Protopsyllidiidae (Hemiptera) and Lophioneuridae (Thripida). Much of the Early Permian was a xeric interval, and modern galls are most common in dry, extra-tropical habitats such as scrubland and deserts. Plant-damage, insect body fossils, and the paleoclimate record collectively support the ecological expansion of foliar galling during the Early Permian and its continued expansion through the Late Permian.

Permian biogeography of the Indian subcontinent with special reference to the marine fauna

NASA Astrophysics Data System (ADS)

Singh, Trilochan

Permian biogeography of the Indian subcontinent is discussed in the light of brachiopods and associated fossils from different localities. The discussion is based primarily on the Permian "biome" concept of Waterhouse and Bonham-Carter (1975), wherein three biomes are proposed: group A of subpolar, group B of temperate, and group C of tropical character. Data on the occurrence of Permian brachiopods and associated fossils are given for the Salt Range, Karakoram, and Himalayan regions of India, Nepal, Bhutan, Tibet, and Peninsular India with respect to the age of the fauna. Marine Permian localities of the Himalayan region include those of Ladakh, Zanskar, Lahaul and Spiti, Kashmir, Bhadarwah-Bhallesh-Chamba, Kinnaur, Garhwal, Kumaun, Darjeeling, Sikkim, and Arunachal Pradesh. Permian marine localities of Peninsular India, which forms a part of central Gondwanaland, include those of Bap, Badhaura, Umaria, Manendragarh, and Daltonganj, where marine transgression occurred in Early Permian time. The faunas of these localities are discussed with respect to their age, which falls into two groups, Early and Late Permian. It is suggested that widespread colder climatic conditions prevailed in the Indian subcontinent during the early Early Permian. Similar conditions continued in most of the localities until the late Early Permian, except at west Karakoram (Shaksgam valley), Zanskar, north Tibet (central and western part), and the Salt Range. However, during the Late Permian, climatic conditions were varied. Cold climatic conditions prevailed in north Tibet (central part), Kumaun Tethyan Himalaya, and south Tibet; temperate conditions occurred in west Karakoram (Shaksgam valley), Zanskar, Lahaul and Spiti, Bhadarwah-Bhallesh-Chamba, north Nepal, and north Sikkim; and tropical conditions occurred in the Salt Range, east Karakoram, Ladakh, Kashmir, and north Tibet (western and eastern parts). At a few localities there appear to be some anomalies that might be due to lack of

Evolution of a complex behavior: the origin and initial diversification of foliar galling by Permian insects.

PubMed

Schachat, Sandra R; Labandeira, Conrad C

2015-04-01

A central notion of the early evolution of insect galling is that this unique behavior was uncommon to rare before the diversification of angiosperms 135 to 125 m.yr. ago. However, evidence accumulated during recent years shows that foliar galls were diverse and locally abundant as early as the Permian Period, 299 to 252 m.yr. ago. In particular, a diversity of leaf galling during the Early Permian has recently been documented by the plant-damage record of foliar galls and, now, our interpretation of the body-fossil record of culprit insect gallers. Small size is a prerequisite for gallers. Wing-length measurements of Permian insects indicate that several small-bodied hemipteroid lineages originated early during the Permian, some descendant lineages of which gall the leaves of seed plants to the present day. The earliest foliar gallers likely were Protopsyllidiidae (Hemiptera) and Lophioneuridae (Thripida). Much of the Early Permian was a xeric interval, and modern galls are most common in dry, extra-tropical habitats such as scrubland and deserts. Plant-damage, insect body fossils, and the paleoclimate record collectively support the ecological expansion of foliar galling during the Early Permian and its continued expansion through the Late Permian.

Permian depositional history, Leach Mountains, northeastern Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martindale, S.G.

1993-04-01

The 4,000 m thick Permian sequence in the Leach Mountains consists of carbonate rock, chert, terrigenous clastic rock and phosphatic rock. These rocks, in ascending order, comprise the Third Fork Fm., Badger Gulch Fm., Trapper Creek Fm., Grandeur Fm., Meade Peak Phosphatic Shale Tongue of the Phosphoria Fm., Murdock Mountain Fm. and Gerster Limestone. This sequence disconformably overlain by Triassic strata. Initial Permian deposition, represented by the late Wolfcampian to early Leonardian Third Fork Fm., was on a slope, at a water depth of about 50 m. Subsequently, a shallowing trend occurred during the early Leonardian to late Leonardian withmore » deposition of the Badger Gulch, Trapper Creek and Grandeur Fms. The Trapper Creek and Grandeur Fms. were deposited on the shelf, in very shallow subtidal to supratidal environments. The shelf persisted through the remainder of the Permian. In the late leonardian, the Meade Peak Tongue was deposited in very shallow subtidal and intertidal environments. A supratidal environment was re-established in latest Leonardian( ) to early Guadalupian with deposition of the lower Murdock Mountain Fm. The upper Murdock Mountain Fm. was deposited in very shallow subtidal to supratidal environments. Later during the early Guadalupian, intertidal to shallow subtidal deposition of the Gerster Limestone occurred. Angular phosphatic pebbles that were derived from phosphatic strata at the top of the Gerster Limestone are contained in the Triassic basal conglomerate. These pebbles indicate that the last Permian event was probably emergence and erosion of the top of the Gerster Limestone.« less

The armoured dissorophid Cacops from the Early Permian of Oklahoma and the exploitation of the terrestrial realm by amphibians.

PubMed

Reisz, Robert R; Schoch, Rainer R; Anderson, Jason S

2009-07-01

Cacops, one of the most distinctive Paleozoic amphibians, is part of a clade of dissorophoid temnospondyls that diversified in the equatorial region of Pangea during the Late Carboniferous and Early Permian, persisting into the Late Permian in Central Russia and China. Dissorophids were a successful group of fully terrestrial, often spectacularly armoured predators, the only amphibians apparently able to coexist with amniotes when the latter started to dominate terrestrial ecosystems. In this paper, we describe excellent new skulls from the Early Permian of Oklahoma attributed to Cacops, Cacops morrisi sp. nov. and provide for the first time detailed information about this iconic dissorophid. These specimens show anatomical and ontogenetic features that will impact on future studies on the evolution of terrestriality in tetrapods. For example, the large, posteriorly closed tympanic embayment has fine striations on an otherwise smooth surface, documenting the oldest known clear evidence for the presence of a tympanic membrane in the fossil record, a structure that is used for hearing airborne sound in extant tetrapods. The skull of C. morrisi also has several features associated with predatory behaviour, indicating that this dissorophid may have been one of the top terrestrial predators of its time.

Stratigraphy and paleogeographic significance of a Late Pennsylvanian to Early Permian channeled slope sequence in the Darwin Basin, southern Darwin Hills, east-central California

USGS Publications Warehouse

Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.; Ritter, Scott M.

2015-01-01

The complex stratigraphy of late Paleozoic rocks in the southern Darwin Hills consists of regionally extensive Mississippian and Early to Middle Pennsylvanian rocks overlain by latest Pennsylvanian to Early Permian rocks, herein called the Darwin Hills sequence. Deposition of this latter sequence marked the beginning of the Darwin Basin. In Mississippian time, a carbonate platform prograded westward over slightly older slope deposits. In the Late Mississippian this platform was exposed to erosion and siliciclastic sediments were deposited. In Early to Middle Pennsylvanian time the area subsided, forming a west-facing ramp that was subjected to deformation and erosion in Middle or early Late Pennsylvanian time. Later this area was tilted westward and deep-water sediments were deposited on this slope. In latest Pennsylvanian to earliest Permian time, a major channel was cut through the older Pennsylvanian rocks and into the Upper Mississippian strata. This channel was gradually filled with increasingly finer grained, deep-water sediment as the area evolved into a basin floor by Early Permian (Sakmarian) time. Expansion of the Darwin Basin in Artinskian time led to a second phase of deposition represented by strata of the regionally extensive Darwin Canyon Formation. The geology in this small area thus documents tectonic events occurring during the early development of the Darwin Basin.

Carboniferous - Early Permian magmatic evolution of the Bogda Range (Xinjiang, NW China): Implications for the Late Paleozoic accretionary tectonics of the SW Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

Wali, Guzalnur; Wang, Bo; Cluzel, Dominique; Zhong, Linglin

2018-03-01

The Late Paleozoic magmatic evolution of the Bogda Range (Chinese North Tianshan) is important for understanding the accretionary history of the Central Asian Orogenic Belt. We investigated the Carboniferous and Lower Permian volcanic and sedimentary sequences of the Daheyan section, southern Bogda Range, and present new zircon U-Pb ages and whole-rock geochemical data for the volcanic rocks. One Carboniferous rhyolite is dated at 298 ± 8 Ma; a Permian basalt yielded many Proterozoic zircon xenocrysts, and its maximum age (∼297 Ma) is constrained by the detrital zircon ages of the sandstone that stratigraphically underlies it. These volcanic rocks belong to calc-alkaline series. We further synthesize previous geochronological, geochemical and isotopic data of magmatic and sedimentary rocks in the Bogda Range. The available data indicate that the magmatism occurred continuously from 350 Ma to 280 Ma. A comprehensive analysis allows us to propose that: (1) the Carboniferous to Early Permian magmatic rocks of the Bogda Range generally show consistent arc-type features; (2) increasing mantle input through time suggests intra-arc extension in a supra-subduction zone; (3) the localized occurrence of Early Permian alkaline pillow basalts and deep water sediments close to the major shear zone advocate a transtensional crustal thinning during the transition from Carboniferous convergence to Early Permian transcurrent tectonics; (4) occurrence of a large number of Proterozoic zircon xenocrysts in the Late Paleozoic magmatic rocks, and Proterozoic detrital zircons in the coeval clastic sediments suggest a continental or transitional basement of the Bogda Arc; (5) subduction in the Bogda area terminated prior to the deposition of Middle Permian terrestrial sediments.

Sedimentological constraints on the initial uplift of the West Bogda Mountains in Mid-Permian.

PubMed

Wang, Jian; Cao, Ying-Chang; Wang, Xin-Tong; Liu, Ke-Yu; Wang, Zhu-Kun; Xu, Qi-Song

2018-01-23

The Late Paleozoic is considered to be an important stage in the evolution of the Central Asian Orogenic Belt (CAOB). The Bogda Mountains, a northeastern branch of the Tianshan Mountains, record the complete Paleozoic history of the Tianshan orogenic belt. The tectonic and sedimentary evolution of the west Bogda area and the timing of initial uplift of the West Bogda Mountains were investigated based on detailed sedimentological study of outcrops, including lithology, sedimentary structures, rock and isotopic compositions and paleocurrent directions. At the end of the Early Permian, the West Bogda Trough was closed and an island arc was formed. The sedimentary and subsidence center of the Middle Permian inherited that of the Early Permian. The west Bogda area became an inherited catchment area, and developed a widespread shallow, deep and then shallow lacustrine succession during the Mid-Permian. At the end of the Mid-Permian, strong intracontinental collision caused the initial uplift of the West Bogda Mountains. Sedimentological evidence further confirmed that the West Bogda Mountains was a rift basin in the Carboniferous-Early Permian, and subsequently entered the Late Paleozoic large-scale intracontinental orogeny in the region.

Redox chemistry changes in the Panthalassic Ocean linked to the end-Permian mass extinction and delayed Early Triassic biotic recovery

NASA Astrophysics Data System (ADS)

Zhang, Guijie; Zhang, Xiaolin; Hu, Dongping; Li, Dandan; Algeo, Thomas J.; Farquhar, James; Henderson, Charles M.; Qin, Liping; Shen, Megan; Shen, Danielle; Schoepfer, Shane D.; Chen, Kefan; Shen, Yanan

2017-02-01

The end-Permian mass extinction represents the most severe biotic crisis for the last 540 million years, and the marine ecosystem recovery from this extinction was protracted, spanning the entirety of the Early Triassic and possibly longer. Numerous studies from the low-latitude Paleotethys and high-latitude Boreal oceans have examined the possible link between ocean chemistry changes and the end-Permian mass extinction. However, redox chemistry changes in the Panthalassic Ocean, comprising ˜85-90% of the global ocean area, remain under debate. Here, we report multiple S-isotopic data of pyrite from Upper Permian-Lower Triassic deep-sea sediments of the Panthalassic Ocean, now present in outcrops of western Canada and Japan. We find a sulfur isotope signal of negative Δ33S with either positive δ34S or negative δ34S that implies mixing of sulfide sulfur with different δ34S before, during, and after the end-Permian mass extinction. The precise coincidence of the negative Δ33S anomaly with the extinction horizon in western Canada suggests that shoaling of H2S-rich waters may have driven the end-Permian mass extinction. Our data also imply episodic euxinia and oscillations between sulfidic and oxic conditions during the earliest Triassic, providing evidence of a causal link between incursion of sulfidic waters and the delayed recovery of the marine ecosystem.

Permian scorpions from the Petrified Forest of Chemnitz, Germany.

PubMed

Dunlop, Jason A; Legg, David A; Selden, Paul A; Fet, Victor; Schneider, Joerg W; Rößler, Ronny

2016-04-07

Paleozoic scorpions (Arachnida: Scorpiones) have been widely documented from the Carboniferous Period; which hosts a remarkable assemblage of more than sixty species including both putative stem- and crown-group fossils. By contrast the succeeding Permian Period is almost completely devoid of records, which are currently restricted to a trace fossil from the early Permian of New Mexico, USA and some limb fragments from the late Permian of the Vologda Region, Russia. ?Opsieobuthus tungeri sp. nov. from the Petrified Forest of Chemnitz, Germany represents the first complete body fossils of scorpions from the Permian. Explosive volcanism preserved these remarkable specimens in situ as part of the palaeosol horizon and bedrock of the Petrified Forest, immediately beneath the Zeisigwald tuff horizon. This dates to the early Permian (Sakmarian) or ca. 291 Ma. Intriguingly, the specimens were obtained from a palaeosol horizon with a compacted network of different-sized woody roots and thus have been preserved in situ in their likely life position, even within their original burrows. Differences in the structure of the comb-like pectines in the two fossils offer evidence for sexual dimorphism, and permit further inferences about the ecology and perhaps even the reproductive biology of these animals. As putative members of a Coal Measures genus, these fossils suggest that at least some Carboniferous scorpion lineages extended their range further into the Permian. This contributes towards a picture of scorpion evolution in which both basal and derived (orthostern) forms coexisted for quite some time; probably from the end of the Carboniferous through to at least the mid Triassic.

Late Pennsylvanian and early permian chondrichthyan microremains from San Salvador Patlanoaya (Puebla, Mexico)

USGS Publications Warehouse

Derycke-Khatir, C.; Vachard, D.; Degardin, J.-M.; Flores de Dios, A.; Buitron, B.; Hansen, M.

2005-01-01

The San Salvador Patlanoaya section (Puebla State, Mexico) is known for its richness of many fossil groups. Among them, the calcareous shells have been principally investigated. This paper deals with Missourian-Virgilian (Late Pennsylvanian) and Leonardian (late Early Permian) Mexican fish remains. A discussion about Helicoprion and related genera, is followed by the systematic description of the revised or discovered taxa: Cooperella typicalis, Moreyella cf. M. typicalis, M. (?) sp., "Sturgeonella" quinqueloba, Hybodontidae gen. sp. 1 and 2, scale indet. Palaeobiogeographic implications are suggested. ?? 2005 Elsevier SAS. All rights reserved.

A large aberrant stem ichthyosauriform indicating early rise and demise of ichthyosauromorphs in the wake of the end-Permian extinction

PubMed Central

Jiang, Da-Yong; Motani, Ryosuke; Huang, Jian-Dong; Tintori, Andrea; Hu, Yuan-Chao; Rieppel, Olivier; Fraser, Nicholas C.; Ji, Cheng; Kelley, Neil P.; Fu, Wan-Lu; Zhang, Rong

2016-01-01

Contrary to the fast radiation of most metazoans after the end-Permian mass extinction, it is believed that early marine reptiles evolved slowly during the same time interval. However, emerging discoveries of Early Triassic marine reptiles are questioning this traditional view. Here we present an aberrant basal ichthyosauriform with a hitherto unknown body design that suggests a fast radiation of early marine reptiles. The new species is larger than coeval marine reptiles and has an extremely small head and a long tail without a fluke. Its heavily-built body bears flattened and overlapping gastral elements reminiscent of hupehsuchians. A phylogenetic analysis places the new species at the base of ichthyosauriforms, as the sister taxon of Cartorhynchus with which it shares a short snout with rostrally extended nasals. It now appears that ichthyosauriforms evolved rapidly within the first one million years of their evolution, in the Spathian (Early Triassic), and their true diversity has yet to be fully uncovered. Early ichthyosauromorphs quickly became extinct near the Early-Middle Triassic boundary, during the last large environmental perturbation after the end-Permian extinction involving redox fluctuations, sea level changes and volcanism. Marine reptile faunas shifted from ichthyosauromorph-dominated to sauropterygian-dominated composition after the perturbation. PMID:27211319

Paleomagnetic data support Early Permian age for the Abor Volcanics in the lower Siang Valley, NE India: Significance for Gondwana-related break-up models

NASA Astrophysics Data System (ADS)

Ali, Jason R.; Aitchison, Jonathan C.; Chik, Sam Y. S.; Baxter, Alan T.; Bryan, Scott E.

2012-05-01

Confusion exists as to the age of the Abor Volcanics of NE India. Some consider the unit to have been emplaced in the Early Permian, others the Early Eocene, a difference of ˜230 million years. The divergence in opinion is significant because fundamentally different models explaining the geotectonic evolution of India depend on the age designation of the unit. Paleomagnetic data reported here from several exposures in the type locality of the formation in the lower Siang Valley indicate that steep dipping primary magnetizations (mean = 72.7 ± 6.2°, equating to a paleo-latitude of 58.1°) are recorded in the formation. These are only consistent with the unit being of Permian age, possibly Artinskian based on a magnetostratigraphic argument. Plate tectonic models for this time consistently show the NE corner of the sub-continent >50°S; in the Early Eocene it was just north of the equator, which would have resulted in the unit recording shallow directions. The mean declination is counter-clockwise rotated by ˜94°, around half of which can be related to the motion of the Indian block; the remainder is likely due local Himalayan-age thrusting in the Eastern Syntaxis. Several workers have correlated the Abor Volcanics with broadly coeval mafic volcanic suites in Oman, NE Pakistan-NW India and southern Tibet-Nepal, which developed in response to the Cimmerian block peeling-off eastern Gondwana in the Early-Middle Permian, but we believe there are problems with this model. Instead, we suggest that the Abor basalts relate to India-Antarctica/India-Australia extension that was happening at about the same time. Such an explanation best accommodates the relevant stratigraphical and structural data (present-day position within the Himalayan thrust stack), as well as the plate tectonic model for Permian eastern Gondwana.

Astronomical tuning of the end-Permian extinction and the Early Triassic Epoch of South China and Germany

NASA Astrophysics Data System (ADS)

Li, Mingsong; Ogg, James; Zhang, Yang; Huang, Chunju; Hinnov, Linda; Chen, Zhong-Qiang; Zou, Zhuoyan

2016-05-01

The timing of the end-Permian mass extinction and subsequent prolonged recovery during the Early Triassic Epoch can be established from astronomically controlled climate cycles recorded in continuous marine sedimentary sections. Astronomical-cycle tuning of spectral gamma-ray logs from biostratigraphically-constrained cyclic stratigraphy through marine sections at Meishan, Chaohu, Daxiakou and Guandao in South China yields an integrated time scale for the Early Triassic, which is consistent with scaling of magnetostratigraphy from climatic cycles in continental deposits of the Germanic Basin. The main marine mass extinction interval at Meishan is constrained to less than 40% of a 100-kyr (kilo-year) cycle (i.e., <40 kyr) and the sharp negative excursion in δ13C is estimated to have lasted <6 kyr. The sharp positive shift in δ13C from - 2 ‰ to 4‰ across the Smithian-Spathian boundary at Chaohu was completed in 50 kyr. The earliest marine reptiles in the Mesozoic at Chaohu that are considered to represent a significant recovery of marine ecosystems did not appear until 4.7 myr (million years) after the end-Permian extinction. The durations of the Griesbachian, Dienerian, Smithian and Spathian substages, including the uncertainty in placement of widely used conodont biostratigraphic datums for their boundaries, are 1.4 ± 0.1, 0.6 ± 0.1, 1.7 ± 0.1 and 1.4 ± 0.1 myr, implying a total span for the Early Triassic of 5.1 ± 0.1 myr. Therefore, relative to an assigned 251.902 ± 0.024 Ma for the Permian-Triassic boundary from the Meishan GSSP, the ages for these substage boundaries are 250.5 ± 0.1 Ma for base Dienerian, 249.9 ± 0.1 Ma for base Smithian (base of Olenekian stage), 248.2 ± 0.1 Ma for base Spathian, and 246.8 ± 0.1 Ma for the base of the Anisian Stage. This astronomical-calibrated timescale provides rates for the recurrent carbon isotope excursions and for trends in sedimentation accumulation through the Early Triassic of studied sections in South

Mantle contribution and tectonic transition in the Aqishan-Yamansu Belt, Eastern Tianshan, NW China: Insights from geochronology and geochemistry of Early Carboniferous to Early Permian felsic intrusions

NASA Astrophysics Data System (ADS)

Du, Long; Long, Xiaoping; Yuan, Chao; Zhang, Yunying; Huang, Zongying; Wang, Xinyu; Yang, Yueheng

2018-04-01

Late Paleozoic is a key period for the accretion and collision of the southern Central Asian Orogenic Belt (CAOB). Here, we present new zircon U-Pb ages, whole-rock geochemistry and Sr-Nd isotopic compositions for four Late Paleozoic felsic plutons in Eastern Tianshan (or Tienshan in some literatures) in order to constrain the tectonic evolution of the southern CAOB. The granodioritic pluton and its dioritic enclaves were synchronously formed in the Early Carboniferous (336 ± 3 Ma and 335 ± 2 Ma, respectively). These rocks are depleted in Nb, Ta and Ti, and enriched in Rb, Ba, Th and U related to the primitive mantle, which show typical features of arc rocks. They both have similar Sr-Nd isotopic ratios to those granitic rocks from the eastern Central Tianshan Block and have the latest Mesoproterozoic two stage Nd model ages (TDM2) (1111-1195 Ma for the granodioritic pluton and 1104-1108 Ma for the enclaves, respectively), indicating that their source magmas may have been derived from the Mesoproterozoic crust. The albitophyric pluton was also emplaced in the Early Carboniferous (333 ± 3 Ma). Rocks of this pluton have similar εNd(t) values (-0.69 to -0.37) and TDM2 ages (1135-1161 Ma) to those of the granodioritic rocks, suggest similar crustal source for both types of rocks. In contrast, the K-feldspar granitic and monzonitic plutons were emplaced in the Early Permian (292 ± 3 Ma and 281 ± 2 Ma, respectively). Samples of the K-feldspar granitic pluton have high K2O + Na2O, FeO/MgO, Ga/Al, HFSE (e.g., Zr and Hf) and low CaO, Sr and Ba, exhibiting characteristics of A2-type granites, which probably emplaced in a post-collisional extension environment. They have higher εNd(t) values (+2.77 to +3.27) and more juvenile TDM2 ages (799-841 Ma) than the Early Carboniferous plutons, suggesting that they were derived from relatively younger crustal sources. The monzonitic granites are metaluminous to weakly peraluminous with A/CNK ranging from 0.93 to 1.05, and have

Late Permian to Early Oligocene granitic magmatism of the Phan Si Pan uplift area, NW Vietnam: their relationship to Phanerozoic crustal evolution of Southwest China

NASA Astrophysics Data System (ADS)

Pham, T. T.; Shellnutt, G.

2015-12-01

The Phan Si Pan uplift area of NW Vietnam is a part of the Archean to Paleoproterozoic Yangtze Block, Southwest China. This area is of particular interest because it experienced a number of Phanerozoic crustal building events including the Emeishan Large Igneous Province, the India-Eurasia collision and Ailaoshan - Red River Fault displacement. In the Phan Si Pan uplift area, there are at least three different geochronological complexes, including: (1) Late Permian, (2) Eocene and (3) Early Oligocene. (1) The Late Permian silicic rocks are alkali ferroan A1-type granitic rocks with U/Pb ages of 251 ± 3 to 254 ± 3 Ma. The Late Permian silicic rocks of Phan Si Pan uplift area intrude the upper to middle crust and are considered to be part of the ELIP that was displaced during the India-Eurasian collision along the Ailaoshan-Red River Fault shear zone and adjacent structures (i.e. Song Da zone). Previous studies suggest the Late Permian granitic rocks were derived by fractional crystallization of high - Ti basaltic magma. (2) The Eocene rocks are alkali ferroan A1-type granites (U/Pb ages 49 ± 0.9 Ma) and are spatially associated with the Late Permian granitic rocks. The trace element ratios of this granite are similar to the Late Permian rocks (Th/Nb=0.2, Th/Ta = 2.5, Nb/U = 24, Nb/La =1.2, Sr/Y=1). The origin of the Eocene granite is uncertain but it is possible that it formed by fractional crystallization of a mafic magma during a period of extension within the Yangtze Block around the time of the India-Eurasia collision. (3) The Early Oligocene granite is characterized as a peraluminous within-plate granite with U/Pb ages of 31.3 ± 0.4 to 34 ± 1 Ma. The Early Oligocene granite has trace element ratios (Th/Nb = 2.1, Th/Ta = 22.6, Nb/U = 4.4, Nb/La = 0.4, Sr/Y = 60.4) similar to crust melts. The high Sr/Y ratio (Sr/Y = 20 - 205) indicates a lower crust source that was garnet-bearing. The Phan Si Pan uplift was neither a subduction zone nor an arc environment

Response of Late Carboniferous and Early Permian Plant Communities to Climate Change

NASA Astrophysics Data System (ADS)

Dimichele, William A.; Pfefferkorn, Hermann W.; Gastaldo, Robert A.

Late Carboniferous and Early Permian strata record the transition from a cold interval in Earth history, characterized by the repeated periods of glaciation and deglaciation of the southern pole, to a warm-climate interval. Consequently, this time period is the best available analogue to the Recent in which to study patterns of vegetational response, both to glacial-interglacial oscillation and to the appearance of warm climate. Carboniferous wetland ecosystems were dominated by spore-producing plants and early gymnospermous seed plants. Global climate changes, largely drying, forced vegetational changes, resulting in a change to a seed plant-dominated world, beginning first at high latitudes during the Carboniferous, reaching the tropics near the Permo-Carboniferous boundary. For most of this time plant assemblages were very conservative in their composition. Change in the dominant vegetation was generally a rapid process, which suggests that environmental thresholds were crossed, and involved little mixing of elements from the wet and dry floras.

Early Permian mafic dikes in the Nagqu area, central Tibet, China, associated with embryonic oceanic crust of the Meso-Tethys Ocean

NASA Astrophysics Data System (ADS)

Chen, S. S.; Fan, W. M.; Shi, R. D.; Gong, X. H.

2017-12-01

During the latest Carboniferous to early Permian, a mantle plume initiated continental rifting along the northern Gondwana margin, which subsequently developed into the Meso-Tethys Ocean. However, the nature and timing of the embryonic oceanic crust of the Meso-Tethys Ocean remains poorly understood. Here, we present for the first time a combined analysis of petrological, geochronological, geochemical, and Sr-Nd isotopic data for mafic rocks from the Nagqu area, central Tibet. Zircons from the mafic rocks yield a concordant age of ca. 277.8±1.8 Ma, which is slightly younger than the age of mantle plume activity (ca. 300-279 Ma), as represented by the large igneous province (LIP) on the northern Gondwana margin. Geochemical features suggest that the Nagqu mafic rocks, which display normal mid ocean ridge basalt (N-MORB) affinities, are different from those of the LIP, which display oceanic island basalt (OIB)-type affinities. The Nagqu mafic rocks result from a relatively high degree of melting of depleted asthenospheric mantle. Combined with observations from previous studies, we suggest that the late early Permian Nagqu magmatism fully records processes of early stage rifting and incipient formation of oceanic crust. Moreover, the patterns of magmatism are consistent with patterns of rift-related sedimentation that records the transition from predominantly continental to marine deposition in the region during the Carboniferous-Permian. We therefore suggest that rifting of the eastern Cimmerian and northern Gondwana continents started at ca. 277.8 Ma, and the rifting culminated in the opening of the Meso-Tethys Ocean.

The Permian antitropical fusulinoidean genus Monodiexodina: Distribution, taxonomy, paleobiogeography and paleoecology

NASA Astrophysics Data System (ADS)

Ueno, Katsumi

2006-03-01

to be a rather long-ranging taxon from the late Yakhtashian (=Artinskian) to the early Midian (=Capitanian). It is, therefore, concluded that Monodiexodina had an opportunistic character, occurring repeatedly only when favorable, high-energy conditions, such as sand shoal, appeared in warm temperate climatic belts in both hemispheres. Monodiexodina originated in the Southern Transitional Zone from an elongated Eoparafusulina stock at late Early Permian (around late Artinskian) time. It flourished in southern middle latitudinal areas in latest Early and early Middle Permian time. The genus then migrated to the northern hemisphere (Northern Transitional Zone) by some dispersion mechanism at around the early Middle Permian, and prevailed there during the remaining period of the Middle Permian.

Prolonged Permian Triassic ecological crisis recorded by molluscan dominance in Late Permian offshore assemblages.

PubMed

Clapham, Matthew E; Bottjer, David J

2007-08-07

The end-Permian mass extinction was the largest biotic crisis in the history of animal life, eliminating as many as 95% of all species and dramatically altering the ecological structure of marine communities. Although the causes of this pronounced ecosystem shift have been widely debated, the broad consensus based on inferences from global taxonomic diversity patterns suggests that the shift from abundant brachiopods to dominant molluscs was abrupt and largely driven by the catastrophic effects of the end-Permian mass extinction. Here we analyze relative abundance counts of >33,000 fossil individuals from 24 silicified Middle and Late Permian paleocommunities, documenting a substantial ecological shift to numerical dominance by molluscs in the Late Permian, before the major taxonomic shift at the end-Permian mass extinction. This ecological change was coincident with the development of fluctuating anoxic conditions in deep marine basins, suggesting that numerical dominance by more tolerant molluscs may have been driven by variably stressful environmental conditions. Recognition of substantial ecological deterioration in the Late Permian also implies that the end-Permian extinction was the climax of a protracted environmental crisis. Although the Late Permian shift to molluscan dominance was a pronounced ecological change, quantitative counts of 847 Carboniferous-Cretaceous collections from the Paleobiology Database indicate that it was only the first stage in a stepwise transition that culminated with the final shift to molluscan dominance in the Late Jurassic. Therefore, the ecological transition from brachiopods to bivalves was more protracted and complex than their simple Permian-Triassic switch in diversity.

An overview of the Permian (Karoo) coal deposits of southern Africa

NASA Astrophysics Data System (ADS)

Cairncross, B.

2001-08-01

The coal deposits of southern Africa (Botswana, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe) are reviewed. The coal seams formed during two periods, the Early Permian (Artinskian-Kungurian) and the Late Permian (Ufimian-Kazanian). The coals are associated with non-marine terrestrial clastic sedimentary sequences, most commonly mudrock and sandstones, assigned to the Karoo Supergroup. The Early Permian coals are most commonly sandstone-hosted while the younger coals typically occur interbedded with mudstones. The sediments were deposited in varying tectono-sedimentary basins such as foreland, intracratonic rifts and intercratonic grabens and half-grabens. The depositional environments that produced the coal-bearing successions were primarily deltaic and fluvial, with some minor shoreline and lacustrine settings. Coals vary in rank from high-volatile bituminous to anthracite and characteristically have a relatively high inertinite component, and medium- to high-ash content. In countries where coal is mined, it is used for power generation, coking coal, synfuel generation, gasification and for (local) domestic household consumption.

The earliest Permian shark fossils from Texas and their implications for later marine faunas

NASA Astrophysics Data System (ADS)

Shell, R.; Ciampaglio, C. N.

2017-12-01

Complex marine vertebrate faunas from lower Permian rocks are incredibly rare. Recent research suggests that the composition of what few communities can be found varied wildly, especially in regard to the presence or absence of Hybodontiform sharks. Early Permian marine faunas in Texas are generally richer in Hybodont sharks than similarly aged communities in Russia and Bolivia, but the cause of this variation is unknown. A fossil hybodont spine fragment from just above the Pennsylvanian/Permian boundary in Texas, however, suggests that that regional climatic events allowed Hybodont sharks to migrate into the Permian Basin at the outset of the Permian itself. As the Basin evolved tectonically and sedimentologically, these sharks likely evolved to fill new niches as they opened up- which may have resulted in the increased number of Hybodont species in the Permian of Texas: a major factor to consider in the faunal evolution of the Western Interior Seaway during the Mesozoic and beyond.

An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa

PubMed Central

Smith, Roger M.H.

2017-01-01

Based on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Zone (early Lopingian) of the Beaufort Group. Bulbasaurus can be distinguished from Tropidostoma by an array of characters including the presence of a tall, sharp premaxillary ridge, large, rugose, nearly-confluent nasal bosses, a nasofrontal ridge, massive tusks, robust pterygoids, prominently twisted subtemporal bar, and absence of a distinct postfrontal. Inclusion of Bulbasaurus in a phylogenetic analysis of anomodont therapsids recovers it as a member of Geikiidae, a clade of otherwise later Permian dicynodonts such as Aulacephalodon and Pelanomodon. Bulbasaurus exhibits many of the characters typical of adult Aulacephalodon, but at substantially smaller skull size (these characters are absent in comparably-sized Aulacephalodon juveniles), suggesting that the evolution of typical geikiid morphology preceded gigantism in the clade. Bulbasaurus is the earliest known geikiid and the only member of the group known from the Tropidostoma Assemblage Zone; discovery of this taxon shortens a perplexing ghost lineage and indicates that abundant clades from the later Permian of South Africa (e.g., Geikiidae, Dicynodontoidea) may have originated as rare components of earlier Karoo assemblage zones. PMID:28168104

Structural changes of marine communities over the Permian-Triassic transition: Ecologically assessing the end-Permian mass extinction and its aftermath

NASA Astrophysics Data System (ADS)

Chen, Zhong-Qiang; Tong, Jinnan; Liao, Zhuo-Ting; Chen, Jing

2010-08-01

The Permian/Triassic (P/Tr) transition is ecologically assessed based on examining 23 shelly communities from five shallow platform, ramp and shelf basin facies Permian-Triassic boundary (PTB) sections in South China. The shelly communities have undergone two major collapses coinciding with the two episodes of the end-Permian mass extinction. The first P/Tr extinction event devastated shelly communities in all types of settings to some extent. The basin communities have been more severely impacted than both platform and ramp communities. The survival faunas have rebounded more rapidly in shallow niches than in relatively deep habitats. The second P/Tr crisis destroyed the survival communities in shallow setting and had little impact on the basin communities in terms of community structures. The early Griesbachian communities are overall low-diversity and high-dominance. The governorship switch from brachiopods to bivalves in marine communities has been facilitated by two pulses of the end-Permian mass extinction and the whole takeover process took about 200 ka across the P/Tr boundary. Bivalve ecologic takeover initially occurred immediately after the first P/Tr extinction in shallow water habitats and was eventually completed in all niches after the second P/Tr event. Some post-extinction communities have the irregular rarefaction curves due to the unusual community structures rather than sampling intensities.

Paleogeographic changes across the Pennsylvanian-Permian boundary within the Mid-Continent (USA) inferred from detrital zircon geochronology of continental deposits

NASA Astrophysics Data System (ADS)

Soreghan, M. J.; Soreghan, G. S.

2017-12-01

The Permo-Pennsylvanian was characterized by intense orogenesis associated with Pangaean assembly, and profound climate shifts as earth transitioned from full icehouse conditions in the Pennsylvanian-early Permian to collapse into greenhouse conditions by latest Permian time. The modern U.S. Midcontinent was part of equatorial western Pangaea (North America) sandwiched between a continental-scale orogenic zone to the east and south (Appalachian-Ouachita-Marathon orogenic belt) and a series of basement-cored, intra-plate uplifts along western Pangaea (Ancestral Rocky Mountains). Here, we present a compilation of detrital zircon geochronology data from the Permo-Pennsylvanian of the Midcontinent as well as coeval strata of the east and west to explore sediment dispersal and potential tectonic and climatic influences on these provenance signatures. Zircon provenance data come from mostly eolian and fluvial silt- and sandstones of Early Pennsylvanian through Mid Permian age, although some data include marine sandstones. Our new data were acquired by LA-ICPMS at the University of Arizona Laserchron, and predominant age groups include >2500 Ma (Archean), 1600-1800 Ma (Yavapai-Matzatzal), 1300-900 Ma (Grenville), 790-570 Ma (Neoproterozoic), and 480-360 (E-M Paleozoic). However, the relative distributions of these populations exhibit distinctive temporal differences, especially across the Pennsylvanian-Permian boundary, but also spatially in comparison to published data from the Appalachian-Ouachita-Marathon basin, Ancestral Rocky Mountain basins, and the western Pangaean margin. Although the Central Pangaean Mountains, and in particular the Grenville-age basement rocks, were a dominant source of sediment to the Midcontinent, the data suggest an abrupt introduction of Neoproterozoic zircons in the early Permian. This signature also appears within the Ancestral Rocky Mountains region, but is rare along the western margin and the Appalachian basin in the early Permian. This

Early Triassic alternative ecological states driven by anoxia, hyperthermals, and erosional pulses following the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Pietsch, C.; Petsios, E.; Bottjer, D. J.

2015-12-01

The end-Permian mass extinction, 252 million years ago, was the most devastating loss of biodiversity in Earth's history. Massive volcanic eruptions of the Siberian Traps and the concurrent burning of coal, carbonate, and evaporite deposits emplaced greenhouse and toxic gasses. Hyperthermal events of the surface ocean, up to 40°C, led to reduced gradient-driven ocean circulation which yielded extensive equatorial oxygen minimum zones. Today, anthropogenic greenhouse gas production is outpacing carbon input modeled for the end-Permian mass extinction, which suggests that modern ecosystems may yet experience a severe biotic crisis. The Early Triassic records the 5 million year aftermath of the end-Permian mass extinction and is often perceived as an interval of delayed recovery. We combined a new, high resolution carbon isotope record, sedimentological analysis, and paleoecological collections from the Italian Werfen Formation to fully integrate paleoenvironmental change with the benthic ecological response. We find that the marine ecosystem experienced additional community restructuring events due to subsequent hyperthermal events and pulses of erosion. The benthic microfauna and macrofauna both contributed to disaster communities that initially rebounded in the earliest Triassic. 'Disaster fauna' including microbialites, microconchids, foraminifera, and "flat clams" took advantage of anoxic conditions in the first ~500,000 years, dominating the benthic fauna. Later, in the re-oxygenated water column, opportunistic disaster groups were supplanted by a more diverse, mollusc-dominated benthic fauna and a complex ichnofauna. An extreme temperature run-up beginning in the Late Dienerian led to an additional hyperthermal event in the Late-Smithian which co-occurred with increased humidity and terrestrial run-off. Massive siliciclastic deposits replaced carbonate deposition which corresponds to the infaunalization of the benthic fauna. The disaster taxa dominated

Provincialization of terrestrial faunas following the end-Permian mass extinction.

PubMed

Sidor, Christian A; Vilhena, Daril A; Angielczyk, Kenneth D; Huttenlocker, Adam K; Nesbitt, Sterling J; Peecook, Brandon R; Steyer, J Sébastien; Smith, Roger M H; Tsuji, Linda A

2013-05-14

In addition to their devastating effects on global biodiversity, mass extinctions have had a long-term influence on the history of life by eliminating dominant lineages that suppressed ecological change. Here, we test whether the end-Permian mass extinction (252.3 Ma) affected the distribution of tetrapod faunas within the southern hemisphere and apply quantitative methods to analyze four components of biogeographic structure: connectedness, clustering, range size, and endemism. For all four components, we detected increased provincialism between our Permian and Triassic datasets. In southern Pangea, a more homogeneous and broadly distributed fauna in the Late Permian (Wuchiapingian, ∼257 Ma) was replaced by a provincial and biogeographically fragmented fauna by Middle Triassic times (Anisian, ∼242 Ma). Importantly in the Triassic, lower latitude basins in Tanzania and Zambia included dinosaur predecessors and other archosaurs unknown elsewhere. The recognition of heterogeneous tetrapod communities in the Triassic implies that the end-Permian mass extinction afforded ecologically marginalized lineages the ecospace to diversify, and that biotic controls (i.e., evolutionary incumbency) were fundamentally reset. Archosaurs, which began diversifying in the Early Triassic, were likely beneficiaries of this ecological release and remained dominant for much of the later Mesozoic.

Provincialization of terrestrial faunas following the end-Permian mass extinction

PubMed Central

Sidor, Christian A.; Vilhena, Daril A.; Angielczyk, Kenneth D.; Huttenlocker, Adam K.; Nesbitt, Sterling J.; Peecook, Brandon R.; Steyer, J. Sébastien; Smith, Roger M. H.; Tsuji, Linda A.

2013-01-01

In addition to their devastating effects on global biodiversity, mass extinctions have had a long-term influence on the history of life by eliminating dominant lineages that suppressed ecological change. Here, we test whether the end-Permian mass extinction (252.3 Ma) affected the distribution of tetrapod faunas within the southern hemisphere and apply quantitative methods to analyze four components of biogeographic structure: connectedness, clustering, range size, and endemism. For all four components, we detected increased provincialism between our Permian and Triassic datasets. In southern Pangea, a more homogeneous and broadly distributed fauna in the Late Permian (Wuchiapingian, ∼257 Ma) was replaced by a provincial and biogeographically fragmented fauna by Middle Triassic times (Anisian, ∼242 Ma). Importantly in the Triassic, lower latitude basins in Tanzania and Zambia included dinosaur predecessors and other archosaurs unknown elsewhere. The recognition of heterogeneous tetrapod communities in the Triassic implies that the end-Permian mass extinction afforded ecologically marginalized lineages the ecospace to diversify, and that biotic controls (i.e., evolutionary incumbency) were fundamentally reset. Archosaurs, which began diversifying in the Early Triassic, were likely beneficiaries of this ecological release and remained dominant for much of the later Mesozoic. PMID:23630295

Closure of the Mongol-Okhotsk Ocean as Constrained by Late Permian to Early Cretaceous Paleomagnetic Data from the Suture Zone

NASA Astrophysics Data System (ADS)

Cogne, J.; Kravchinsky, V.; Gilder, S.; Hankard, F.

2005-12-01

The Paleozoic Mongol-Okhotsk Ocean separated the Siberian craton to the north from a landmass composed of Amuria, Tarim, Qaidam, Tibet and the North and South China blocks to the south. Based on a comparison of paleomagnetic data from the NCB with the Eurasian apparent polar wander path, this ocean closed by the beginning of the Cretaceous. We present here a review of recent paleomagnetic studies of Late Permian to Early Cretaceous formations from the Transbaikal area of south Siberia, coming from localities situated on both sides of the Mongol-Okhotsk suture zone. The main conclusions that we draw from these studies are as follows. (1) A Late Permian ~4500 km latitude difference indeed existed between Amuria and the Siberia blocks at 110°E longitude. (2) In Middle-Late Jurassic times, a 1700 to 2700 km paleolatitudinal gap still existed between the two blocks. This contradicts geological interpretations of a Middle Jurassic closure of the ocean at this longitude. (3) Consistency of Early Cretaceous paleolatitudes from both sides of the suture demonstrates the closure of the ocean at that time. Altogether, these suggest a quite fast closure between the Middle Jurassic and the Early Cretaceous, at about 15±11 cm/yr. Finally, all pre-Late Cretaceous paleomagnetic poles appear to be distributed along small-circles centered on site localities. We think this is due to continued deformation acting in the Mongol-Okhotsk suture region related to suturing. Conversely, the post-Early Cretaceous rotations may be related to Tertiary deformation under the effect of the India-Asia collision.

Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea

NASA Astrophysics Data System (ADS)

Cisneros, Juan Carlos; Abdala, Fernando; Atayman-Güven, Saniye; Rubidge, Bruce S.; Celâl Şengör, A. M.; Schultz, Cesar L.

2012-01-01

The medial Permian (∼270-260 Ma: Guadalupian) was a time of important tetrapod faunal changes, in particular reflecting a turnover from pelycosaurian- to therapsid-grade synapsids. Until now, most knowledge on tetrapod distribution during the medial Permian has come from fossils found in the South African Karoo and the Russian Platform, whereas other areas of Pangaea are still poorly known. We present evidence for the presence of a terrestrial carnivorous vertebrate from the Middle Permian of South America based on a complete skull. Pampaphoneus biccai gen. et sp. nov. was a dinocephalian "mammal-like reptile" member of the Anteosauridae, an early therapsid predator clade known only from the Middle Permian of Russia, Kazakhstan, China, and South Africa. The genus is characterized, among other features, by postorbital bosses, short, bulbous postcanines, and strongly recurved canines. Phylogenetic analysis indicates that the Brazilian dinocephalian occupies a middle position within the Anteosauridae, reinforcing the model of a global distribution for therapsids as early as the Guadalupian. The close phylogenetic relationship of the Brazilian species to dinocephalians from South Africa and the Russian Platform suggests a closer faunistic relationship between South America and eastern Europe than previously thought, lending support to a Pangaea B-type continental reconstruction.

Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea.

PubMed

Cisneros, Juan Carlos; Abdala, Fernando; Atayman-Güven, Saniye; Rubidge, Bruce S; Şengörc, A M Celâl; Schultz, Cesar L

2012-01-31

The medial Permian (~270-260 Ma: Guadalupian) was a time of important tetrapod faunal changes, in particular reflecting a turnover from pelycosaurian- to therapsid-grade synapsids. Until now, most knowledge on tetrapod distribution during the medial Permian has come from fossils found in the South African Karoo and the Russian Platform, whereas other areas of Pangaea are still poorly known. We present evidence for the presence of a terrestrial carnivorous vertebrate from the Middle Permian of South America based on a complete skull. Pampaphoneus biccai gen. et sp. nov. was a dinocephalian "mammal-like reptile" member of the Anteosauridae, an early therapsid predator clade known only from the Middle Permian of Russia, Kazakhstan, China, and South Africa. The genus is characterized, among other features, by postorbital bosses, short, bulbous postcanines, and strongly recurved canines. Phylogenetic analysis indicates that the Brazilian dinocephalian occupies a middle position within the Anteosauridae, reinforcing the model of a global distribution for therapsids as early as the Guadalupian. The close phylogenetic relationship of the Brazilian species to dinocephalians from South Africa and the Russian Platform suggests a closer faunistic relationship between South America and eastern Europe than previously thought, lending support to a Pangaea B-type continental reconstruction.

Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea

PubMed Central

Cisneros, Juan Carlos; Abdala, Fernando; Atayman-Güven, Saniye; Rubidge, Bruce S.; Şengör, A. M. Celâl; Schultz, Cesar L.

2012-01-01

The medial Permian (∼270–260 Ma: Guadalupian) was a time of important tetrapod faunal changes, in particular reflecting a turnover from pelycosaurian- to therapsid-grade synapsids. Until now, most knowledge on tetrapod distribution during the medial Permian has come from fossils found in the South African Karoo and the Russian Platform, whereas other areas of Pangaea are still poorly known. We present evidence for the presence of a terrestrial carnivorous vertebrate from the Middle Permian of South America based on a complete skull. Pampaphoneus biccai gen. et sp. nov. was a dinocephalian “mammal-like reptile” member of the Anteosauridae, an early therapsid predator clade known only from the Middle Permian of Russia, Kazakhstan, China, and South Africa. The genus is characterized, among other features, by postorbital bosses, short, bulbous postcanines, and strongly recurved canines. Phylogenetic analysis indicates that the Brazilian dinocephalian occupies a middle position within the Anteosauridae, reinforcing the model of a global distribution for therapsids as early as the Guadalupian. The close phylogenetic relationship of the Brazilian species to dinocephalians from South Africa and the Russian Platform suggests a closer faunistic relationship between South America and eastern Europe than previously thought, lending support to a Pangaea B-type continental reconstruction. PMID:22307615

Marine anoxia and delayed Earth system recovery after the end-Permian extinction.

PubMed

Lau, Kimberly V; Maher, Kate; Altiner, Demir; Kelley, Brian M; Kump, Lee R; Lehrmann, Daniel J; Silva-Tamayo, Juan Carlos; Weaver, Karrie L; Yu, Meiyi; Payne, Jonathan L

2016-03-01

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and (238)U/(235)U isotopic compositions (δ(238)U) of Upper Permian-Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ(238)U across the end-Permian extinction horizon, from ∼3 ppm and -0.15‰ to ∼0.3 ppm and -0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans-characterized by prolonged shallow anoxia that may have impinged onto continental shelves-global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe.

Permian (Leonardian) brachiopods from Paso Hondo Formation, Chiapas, southern Mexico. Paleobiogeographical implications

NASA Astrophysics Data System (ADS)

Torres-Martínez, Miguel A.; Sour-Tovar, Francisco; Barragán, Ricardo

2016-11-01

One of the most important marine sequences of calcareous rocks from the Paleozoic of Mexico outcrops in southern Chiapas. It is composed by different units from Early Permian, being the Paso Hondo Formation the youngest with a Leonardian age. Different groups of marine invertebrates as corals, bivalves, gastropods, bryozoans, brachiopods and crinoids have been previously reported of this unit. Five brachiopod species of the orders Productida, Athyridida, Spiriferida and Spiriferinida from the Barrio Allende section of this unit are herein described. The new species Dyoros (Lissosia) maya and Hustedia shumardi are proposed. Sedimentology and paleoecology of the Paso Hondo Formation, suggest a well-lighted shallow lagoon environment with continuous terrigenous input. The subgenus Dyoros (Lissosia), the genus Paucispinifera and the species Hustedia shumardi, Spiriferella propria and Spiriferellina tricosa are typical taxa from Permian localities of Texas, New Mexico and Coahuila. Their presence in the studied area suggests that during Early Permian there was a geographic connection between the different localities of the biotic Grandian Province (southern USA, northern Mexico and Venezuela) and southeastern Chiapas.

Permian and Triassic microfloral assemblages from the Blue Nile Basin, central Ethiopia

NASA Astrophysics Data System (ADS)

Dawit, Enkurie L.

2014-11-01

Palynological investigation was carried out on surface samples from up to 400 m thick continental siliciclastic sediments, here referred to as “Fincha Sandstone”, in the Blue Nile Basin, central Ethiopia. One hundred sixty species were identified from 15 productive samples collected along a continuous road-cut exposure. Six informal palynological assemblage zones have been identified. These assemblage zones, in ascending order, are: “Central Ethiopian Permian Assemblage Zone - CEPAZ I”, earliest Permian (Asselian-Sakmarian); “CEPAZ II”, late Early Permian (Artinskian-Kungurian); CEPAZ III - Late Permian (Kazanian-Tatarian); “CETAZ IV”, Lower Triassic (Olenekian Induan); “CETAZ V”, Middle Triassic (Anisian Ladinian); “CETAZ VI”, Late Triassic (Carnian Norian). Tentative age ranges proposed herein are compared with faunally calibrated palynological zones in Gondwana. The overall composition and vertical distribution of miospores throughout the studied section reveals a wide variation both qualitatively and quantitatively. The high frequency of monosaccate pollen in CEPAZ I may reflect a Glossopterid-dominated upland flora in the earliest Permian. The succeeding zone is dominated by straite/taeniate disaccate pollen and polyplicates, suggesting a notable increase in diversity of glossopterids. The decline in the diversity of taeniate disaccate pollen and the concomitant rise in abundance of non-taeniate disaccates in CEPAZ III may suggest the decline in Glossopteris diversity, though no additional evidence is available to equate this change with End-Permian extinction. More diverse and dominant non-taeniate, disaccate, seed fern pollen assignable to FalcisporitesAlisporites in CETAZ IV may represent an earliest Triassic recovery flora. The introduction of new disaccate forms with thick, rigid sacci, such as Staurosaccites and Cuneatisporites, in CETAZ V and VI may indicate the emergence of new gymnospermous plants that might have favourably

Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia

NASA Astrophysics Data System (ADS)

Beard, J. Andrew; Ivany, Linda C.; Runnegar, Bruce

2015-09-01

Oxygen isotope compositions of marine carbonates are commonly employed for understanding ancient temperatures, but this approach is complicated in the very distant past due to uncertainties about the effects of diagenesis and the isotopic composition of seawater, both locally and globally. Microsampled accretionary calcite from two species of the fossil bivalve Eurydesma Sowerby and Morris 1845 collected from sediments of Cisuralian age in high latitude marine sediments along the SE coast of Australia records cyclic seasonal fluctuations in shell δ18O values during growth, demonstrating the primary nature of the isotope signal and thus allowing investigation of early Permian seawater isotopic composition and water temperature in the high southern latitudes. The mean and seasonal range of δ18Ocarb decreases poleward across about 10° of paleolatitude (∼67°S-77°S). The presence of co-occurring dropstones and stratigraphically associated glendonites constrains winter temperatures across the region to near-freezing, thus permitting calculation of realistic estimates of water composition and summer temperatures. Summer δ18Ocarb values indicate water temperatures between 5 °C and 12 °C, with warmer values at lower latitudes. The decrease in both mean sea surface temperature and seasonal amplitude with increasing latitude on the Gondwanan coast is much like that observed along high-latitude coastlines today. Calculated δ18Owater decreases toward the pole, likely associated with an increasing contribution of isotopically light fresh water derived from summer snow-melt. The gradient in δ18Owater is similar to that documented over a similar span of latitude on the modern SE Greenland coast. We infer the presence of a north-flowing coastal current of cold, O18-depleted water that entrains progressively greater amounts of more typical seawater as it moves away from the pole. δ18O values in SE Australia, however, are about 3‰ lower than those off Greenland

Post-Variscan basin evolution in the central Pyrenees: Insights from the Stephanian-Permian Anayet Basin

NASA Astrophysics Data System (ADS)

Rodríguez-Méndez, Lidia; Cuevas, Julia; Tubía, José María

2016-03-01

The Anayet Basin, in the central Pyrenees, records a Stephanian-Permian continental succession including three Permian volcanic episodes. The absolute chronology of these rocks has allowed us to better constrain the early post-Variscan evolution of the Pyrenees. The transtensional regime responsible for the formation of the pull-apart Anayet Basin began at least in Stephanian times, the age of the first post-Variscan deposits in the area, and lasted until Late Permian. During Middle Eocene times, the Alpine Orogeny inverted the Anayet Basin and led to the formation of south-vergent chevron folds and axial plane penetrative cleavage.

Late Early Permian continental ichnofauna from Lake Kemp, north-central Texas, USA

USGS Publications Warehouse

Lucas, S.G.; Voigt, S.; Lerner, A.J.; Nelson, W.J.

2011-01-01

Continental trace fossils of Early Permian age are well known in the western United States from Wolfcampian (~. Asselian to Artinskian) strata, but few examples are known from Leonardian (~. Kungurian) deposits. A substantial ichnofauna from strata of the lower part of the Clear Fork Formation at Lake Kemp, Baylor County, Texas, augments the meager North American record of Leonardian continental trace fossil assemblages. Ichnofossils at Lake Kemp occur in the informally-named Craddock dolomite member of the Clear Fork Formation, which is 12-15. m above the local base of the Clear Fork. The trace-bearing stratum is an up-to-0.3. m thick, laminated to flaser-bedded, dolomitic siltstone that also contains mud cracks, raindrop impressions, microbially induced mat structures, and some land-plant impressions. We interpret the Craddock dolomite member as the feather-edge of a marine transgressive carbonate deposit of an irregular coastline marked by shallow bays or estuaries on the eastern shelf of the Midland basin, and the trace-fossil-bearing stratum at Lake Kemp is an unchannelized flow deposit on a muddy coastal plain. The fossil site at Lake Kemp yields a low to moderately diverse fauna of invertebrate and vertebrate traces. A sparse invertebrate ichnofauna consists of arthropod feeding and locomotion traces assigned to Walpia cf. W. hermitensis White, 1929 and Diplichnites gouldi Gevers in Gevers et al., 1971. Tetrapod footprints are most common and assigned to Batrachichnus salamandroides (Geinitz, 1861), cf. Amphisauropus kablikae (Geinitz and Deichm??ller, 1882), and Dromopus lacertoides (Geinitz, 1861), which represent small temnospondyl, seymouriamorph, and basal sauropsid trackmakers. Both the traces and sedimentary features of the fossil horizon indicate a freshwater setting at the time of track formation, and the trace assemblage represents the Scoyenia ichnofacies and the Batrachichnus ichnofacies in an overbank environment with sheet flooding and shallow

Appalachian Piedmont landscapes from the Permian to the Holocene

USGS Publications Warehouse

Cleaves, E.T.

1989-01-01

Between the Potomac and Susquehanna Rivers and from the Blue Ridge to the Fall Zone, landscapes of the Piedmont are illustrated for times in the Holocene, Late Wisconsin, Early Miocene, Early Cretaceous, Late Triassic, and Permian. Landscape evolution took place in tectonic settings marked by major plate collisions (Permian), arching and rifting (Late Triassic) and development of the Atlantic passive margin by sea floor spreading (Early Cretaceous). Erosion proceeded concurrently with tectonic uplift and continued after cessation of major tectonic activity. Atlantic Outer Continental Shelf sediments record three major erosional periods: (1) Late Triassic-Early Jurassic; (2) Late Jurassic-Early Cretaceous; and (3) Middle Miocene-Holocene. The Middle Miocene-Holocene pulse is related to neotectonic activity and major climatic fluctuations. In the Piedmont upland the Holocene landscape is interpreted as an upland surface of low relief undergoing dissection. Major rivers and streams are incised into a landscape on which the landforms show a delicate adjustment to rock lithologies. The Fall Zone has apparently evolved from a combination of warping, faulting, and differential erosion since Late Miocene. The periglacial environment of the Late Wisconsin (and earlier glacial epochs) resulted in increased physical erosion and reduced chemical weathering. Even with lowered saprolitization rates, geochemical modeling suggests that 80 m or more of saprolite may have formed since Late Miocene. This volume of saprolite suggests major erosion of upland surfaces and seemingly contradicts available field evidence. Greatly subdued relief characterized the Early Miocene time, near the end of a prolonged interval of tropical morphogenesis. The ancestral Susquehanna and Potomac Rivers occupied approximately their present locations. In Early Cretaceous time local relief may have been as much as 900 m, and a major axial river draining both the Piedmont and Appalachians flowed southeast

An Early-Middle Guadalupian (Permian) isotopic record from a mid-oceanic carbonate buildup: Akiyoshi Limestone, Japan

NASA Astrophysics Data System (ADS)

Musashi, Masaaki; Isozaki, Yukio; Kawahata, Hodaka

2010-08-01

In order to understand the oceanographic changes before the Guadalupian-Lopingian (Permian) boundary mass extinction event, we investigated the isotopic compositions of the inorganic carbon and the oxygen ( δ13C carb and δ18O carb) of the Guadalupian (Middle Permian) shallow marine carbonates deposited on a seamount-top in the superocean Panthalassa. The drilled samples were obtained at Kaerimizu in the Akiyoshi area, SW Japan. We focused on the Roadian-Wordian (Middle Guadalupian) interval that spans over 7 fusuline zones; i.e. the Parafusulina kaerimizuensis Zone ( Pk Z.), Afghanella ozawai Zone ( Ao Z.), Neoschwagerina craticulifera robusta Zone ( Ncr Z.), Verbeekina verbeeki-Afghanella schenki Zone ( Vv-As Z.), Neoschwageina fusiformis Zone ( Nf Z.), Verbeekina verbeeki Zone ( Vv Z.), and Colania douvillei Zone ( Cd Z.), in ascending order. Analytical results showed that the δ13C carb values stayed almost constant around + 3.0‰ PDB in the Pk Z., Ao Z. and the lower half of the Ncr Z., and those in the upper-section gradually decreased down to -2.0‰, of which the lowest was found in the Cd Z. We statistically extracted the samples with presumably better preserved δ13C carb values in the Kaerimizu section ranged between + 0.5 and + 4.0‰ with average values of δ13C carb of + 2.7 ± 1.0‰, on the basis of δ13C carb- δ18O carb characterization. This interval shows a monotonous decrease in δ13C carb values from ca + 4.0‰ to + 2.0‰. This indicates that the primary productivity might be generally high in the Wordian mid-oceanic domain but slightly declined in the Late Wordian. The studied Early-Middle Guadalupian interval is chemostratigraphically correlated with the other mid-Pansalassan paleo-atoll limestone e.g. Iwato Formation in Japan, suggesting that the relatively high δ13C carb (over + 3.0‰) of seawater predominated in shallow mid-superocean during the middle Middle Permian.

A new stem group echinoid from the Triassic of China leads to a revised macroevolutionary history of echinoids during the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Thompson, Jeffrey R.; Hu, Shi-xue; Zhang, Qi-Yue; Petsios, Elizabeth; Cotton, Laura J.; Huang, Jin-Yuan; Zhou, Chang-yong; Wen, Wen; Bottjer, David J.

2018-01-01

The Permian-Triassic bottleneck has long been thought to have drastically altered the course of echinoid evolution, with the extinction of the entire echinoid stem group having taken place during the end-Permian mass extinction. The Early Triassic fossil record of echinoids is, however, sparse, and new fossils are paving the way for a revised interpretation of the evolutionary history of echinoids during the Permian-Triassic crisis and Early Mesozoic. A new species of echinoid, Yunnanechinus luopingensis n. sp. recovered from the Middle Triassic (Anisian) Luoping Biota fossil Lagerstätte of South China, displays morphologies that are not characteristic of the echinoid crown group. We have used phylogenetic analyses to further demonstrate that Yunnanechinus is not a member of the echinoid crown group. Thus a clade of stem group echinoids survived into the Middle Triassic, enduring the global crisis that characterized the end-Permian and Early Triassic. Therefore, stem group echinoids did not go extinct during the Palaeozoic, as previously thought, and appear to have coexisted with the echinoid crown group for at least 23 million years. Stem group echinoids thus exhibited the Lazarus effect during the latest Permian and Early Triassic, while crown group echinoids did not.

Paleomagnetic results from Late Pennsylvanian marls and Early Permian red paleosols of the Dunkard group, Ohio and West Virginia, U.S.A.

NASA Astrophysics Data System (ADS)

Abrajevitch, A.; Oliva, B.; Peters, S.; Beehr, A.; van der Voo, R.

2006-12-01

Sediments of the Dunkard Gr. were deposited in the Appalachian foreland basin during the Pennsylvanian and Early Permian, an interval encompassing the long reverse polarity Kiaman chron. Lithofacies in the Dunkard Gr. in eastern Ohio and western West Virginia include lenticular and sheet-form cross-bedded micaceous sandstones, coal, mottled red and purple mudstones, gray laminated mudstones and argillaceous lime mudstones. They are indicative of deposition on a low-gradient, tropical wet-dry fluvial plain. Few lithofacies are laterally persistent over sufficiently long distances, so that correlation schemes are based largely on coal horizons, partly for historical economic reasons and partly because coal beds appear to be more laterally persistent than most other lithofacies. Magnetostratigraphy would therefore provide a powerful additional correlation tool in the Dunkard Gr, A short normal polarity interval has been reported in the Dunkard Gr. (Helsley, 1965), but to date such a change in magnetic field polarity has not been confirmed by later studies. To confirm the presence of the normal polarity subchron and to explore the possibility of using it as a correlation tool in the Dunkard Gr., we sampled 5 sections thought to straddle the Late Pennyslvanian-Early Permian boundary. Sampled lithofacies include red and mottled red-purple paleosols, grey mudstones containing siderite concretions, micaceous sandstones, and dark gray argillaceous limestones. Samples were demagnetized thermally and by AF. The remanent magnetic directions agree with those expected for the Early Permian. A change in polarity was detected in three of the studied sections. Magnetization is carried by several different magnetic minerals, mostly hematite in paleosols and iron sulfides in combination with magnetite in sandstones, marls and limestones. Although we have found good evidence for the normal polarity interval within Kiaman age rocks of the Dunkard Gr., additional magnetostratigraphic

Permian plate margin volcanism and tuffs in adjacent basins of west Gondwana: Age constraints and common characteristics

NASA Astrophysics Data System (ADS)

López-Gamundí, Oscar

2006-12-01

Increasing evidence of Permian volcanic activity along the South American portion of the Gondwana proto-Pacific margin has directed attention to its potential presence in the stratigraphic record of adjacent basins. In recent years, tuffaceous horizons have been identified in late Early Permian-through Middle Permian (280-260 Ma) sections of the Paraná Basin (Brazil, Paraguay, and Uruguay). Farther south and closer to the magmatic tract developed along the continental margin, in the San Rafael and Sauce Grande basins of Argentina, tuffs are present in the Early to Middle Permian section. This tuff-rich interval can be correlated with the appearance of widespread tuffs in the Karoo Basin. Although magmatic activity along the proto-Pacific plate margin was continuous during the Late Paleozoic, Choiyoi silicic volcanism along the Andean Cordillera and its equivalent in Patagonia peaked between the late Early Permian and Middle Permian, when extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region. The San Rafael orogenic phase (SROP) interrupted sedimentation along the southwestern segment of the Gondwana margin (i.e., Frontal Cordillera, San Rafael Basin), induced cratonward thrusting (i.e., Ventana and Cape foldbelts), and triggered accelerated subsidence in the adjacent basins (Sauce Grande and Karoo) located inboard of the deformation front. This accelerated subsidence favored the preservation of tuffaceous horizons in the syntectonic successions. The age constraints and similarities in composition between the volcanics along the continental margin and the tuffaceous horizons in the San Rafael, Sauce Grande, Paraná, and Karoo basins strongly suggest a genetic linkage between the two episodes. Radiometric ages from tuffs in the San Rafael, Paraná, and Karoo basins indicate an intensely tuffaceous interval between 280 and 260 Ma.

A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China.

PubMed

Reisz, Robert R; Liu, Jun; Li, Jin-Ling; Müller, Johannes

2011-05-01

Captorhinids, a clade of Paleozoic reptiles, are represented by a rich fossil record that extends from the Late Carboniferous into the Late Permian. Representatives of this clade dispersed from the equatorial regions of Laurasia into the temperate regions of Pangea during the Middle and Late Permian. This rich fossil record shows that there was an evolutionary trend from faunivorous to omnivorous and herbivorous feeding habits within this clade. The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp. nov, is a member of Moradisaurinae, a clade of captorhinids with multiple tooth rows arranged in parallel. The presence of this moradisaurine in the Middle Permian of south central Asia leads us to suggest that paleogeographic changes during the Permian, with part of what is today China becoming a large peninsula of Pangea, allowed these early reptiles as well as other terrestrial vertebrates to extend their geographic ranges to this region of the Late Paleozoic supercontinent.

Multiple episodes of extensive marine anoxia linked to global warming and continental weathering following the latest Permian mass extinction.

PubMed

Zhang, Feifei; Romaniello, Stephen J; Algeo, Thomas J; Lau, Kimberly V; Clapham, Matthew E; Richoz, Sylvain; Herrmann, Achim D; Smith, Harrison; Horacek, Micha; Anbar, Ariel D

2018-04-01

Explaining the ~5-million-year delay in marine biotic recovery following the latest Permian mass extinction, the largest biotic crisis of the Phanerozoic, is a fundamental challenge for both geological and biological sciences. Ocean redox perturbations may have played a critical role in this delayed recovery. However, the lack of quantitative constraints on the details of Early Triassic oceanic anoxia (for example, time, duration, and extent) leaves the links between oceanic conditions and the delayed biotic recovery ambiguous. We report high-resolution U-isotope (δ 238 U) data from carbonates of the uppermost Permian to lowermost Middle Triassic Zal section (Iran) to characterize the timing and global extent of ocean redox variation during the Early Triassic. Our δ 238 U record reveals multiple negative shifts during the Early Triassic. Isotope mass-balance modeling suggests that the global area of anoxic seafloor expanded substantially in the Early Triassic, peaking during the latest Permian to mid-Griesbachian, the late Griesbachian to mid-Dienerian, the Smithian-Spathian transition, and the Early/Middle Triassic transition. Comparisons of the U-, C-, and Sr-isotope records with a modeled seawater PO 4 3- concentration curve for the Early Triassic suggest that elevated marine productivity and enhanced oceanic stratification were likely the immediate causes of expanded oceanic anoxia. The patterns of redox variation documented by the U-isotope record show a good first-order correspondence to peaks in ammonoid extinctions during the Early Triassic. Our results indicate that multiple oscillations in oceanic anoxia modulated the recovery of marine ecosystems following the latest Permian mass extinction.

Juvenile-adult habitat shift in permian fossil reptiles and amphibians.

PubMed

Bakker, R T

1982-07-02

Among extant large reptiles, juveniles often occupy different habitats from those of adults or subadults and thus avoid competition with and predation from the older animals; small juveniles often choose cryptic habitats because they are vulnerable to a wide variety of predators. Evidence from fossil humeri and femora of Early Permian reptiles collected from sediments of several distinct habitats indicate that similar shifts in habitat occurred. Juvenile Dimetrodon seem to have favored cryptic habitats around swamp and swampy lake margins; adults favored open habitats on the floodplains. Similar patterns of habitat shift seem to be present in the reptile Ophiacodon and the amphibian Eryops and may have been common in fossil tetrapods of the Permian-Triassic.

The terminal Permian in European Russia: Vyaznikovian Horizon, Nedubrovo Member, and Permian-Triassic boundary

NASA Astrophysics Data System (ADS)

Lozovsky, V. R.; Balabanov, Yu. P.; Karasev, E. V.; Novikov, I. V.; Ponomarenko, A. G.; Yaroshenko, O. P.

2016-07-01

The comprehensive analysis of the data obtained on terrestrial vertebrata, ostracods, entomologic fauna, megaflora, and microflora in deposits of the Vyaznikovian Horizon and Nedubrovo Member, as well as the paleomagnetic data measured in enclosing rocks, confirms heterogeneity of these deposits. Accordingly, it is necessary to distinguish these two stratons in the terminal Permian of the East European Platform. The combined sequence of Triassic-Permian boundary deposits in the Moscow Syneclise, which is considered to be the most complete sequence in the East European Platform, is as follows (from bottom upward): Vyatkian deposits; Vyaznikovian Horizon, including Sokovka and Zhukovo members; Nedubrovo Member (Upper Permian); Astashikha and Ryabi members of the Vokhmian Horizon (Lower Triassic). None of the sequences of Permian-Triassic boundary deposits known in the area of study characterizes this sequence in full volume. In the north, the Triassic deposits are underlain by the Nedubrovo Member; in the south (the Klyazma River basin), the sections are underlain by the Vyaznikovian Horizon. The Permian-Triassic boundary adopted in the General Stratigraphic Scale of Russia for continental deposits of the East European platform (the lower boundary of the Astashikha Member) is more ancient than the one adopted in the International Stratigraphic Chart. The same geological situation is observed in the German Basin and other localities where Triassic continental deposits are developed. The ways of solving this problem are discussed in this article.

Inferred Early Permian Arc Rifting in Bogda Mountain, Southernmost of the Central Asia Orogenic Belt: Evidence from a Peperite Bearing Volcano-Sedimentary Succession

NASA Astrophysics Data System (ADS)

Memtimin, M.; Guo, Z.

2017-12-01

Late Paleozoic tectonic history, especially Carboniferous-Permian periods, of the Central Asia Orogenic Belt (CAOB) is considered to be the turning point for the termination of terrane amalgamation and closure of the Paleoasian Ocean. However, the debate about the paleoenvironment and tectonic setting of the region during the period is still not resolved. In this study, we report a set of volcano-sedimentary sequence in the Bogda Mountain of the southernmost of CAOB, which is associated with contemporaneous subaqueous emplacement of and interaction between mafic lava and carbonate sediments. The succession contains four distinct facies including closely packed pillow basalts, pillow basalts with interstitial materials, hyaloclastites and peperites. We discuss their formation and emplacement mechanism, interaction between hot magma-water/unconsolidated sediments and thermal metamorphism during the interaction. Textural features of the sequence, especially hyaloclastites and peperites, provide clear evidence for in situ autofragmentation of lava flows, synvolcanic sedimentation of carbonates, fuel coolant interaction when hot magma bulldozed into wet unconsolidated sediments, and represent autochthonous origin of the succession. Lateral transition of the lithofacies indicate a progressively deepening subaqueous environment, resembling a stepwise evolution from early stage of volcanic intrusion with lower lava flux in shallower water level to increasingly subsiding basin with more lava flux in greater depth. Previous studies determined that the mafic magma was intruded around the Carboniferous-Permian boundary ( 300Ma), and geochemical studies showed the magma was originated from dry depleted mantle with little crustal contamination. Nevertheless, the succession was thought to be fault related allochthones formation which was transferred in as part of a Carboniferous intraplate arc. Combining our findings with the previous study results, we propose a new model to

Tectono-stratigraphy and low-grade metamorphism of Late Permian and Early Jurassic accretionary complexes within the Kurosegawa belt, Southwest Japan: Implications for mechanisms of crustal displacement within active continental margin

NASA Astrophysics Data System (ADS)

Hara, Hidetoshi; Kurihara, Toshiyuki; Mori, Hiroshi

2013-04-01

We characterize the tectono-stratigraphic architecture and low-grade metamorphism of the accretionary complex preserved in the Kurosegawa belt of the Kitagawa district in eastern Shikoku, Southwest Japan, in order to understand its internal structure, tectono-metamorphic evolution, and assessments of displacement of continental fragments within the complex. We report the first ever documented occurrence of an Early Jurassic radiolarian assemblage within the accretionary complex of the Kurosegawa belt that has been previously classified as the Late Permian accretionary complex, thus providing a revised age interpretation for these rocks. The accretionary complex is subdivided into four distinct tectono-stratigraphic units: Late Permian mélange and phyllite units, and Early Jurassic mélange and sandstone units. The stratigraphy of these four units is structurally repeated due to an E-W striking, steeply dipping regional fault. We characterized low-grade metamorphism of the accretionary complex via illite crystallinity and Raman spectroscopy of carbonaceous material. The estimated pattern of low-grade metamorphism showed pronounced variability within the complex and revealed no discernible spatial trends. The primary thermal structure in these rocks was overprinted by later tectonic events. Based on geological and thermal structure, we conclude that continental fragments within the Kurosegawa belt were structurally translated into both the Late Permian and Early Jurassic accretionary complexes, which comprise a highly deformed zone affected by strike-slip tectonics during the Early Cretaceous. Different models have been proposed to explain the initial structural evolution of the Kurosegawa belt (i.e., micro-continent collision and klippe tectonic models). Even if we presuppose either model, the available geological evidence requires a new interpretation, whereby primary geological structures are overprinted and reconfigured by later tectonic events.

Silicified wood from the Permian and Triassic of Antarctica: Tree rings from polar paleolatitudes

USGS Publications Warehouse

Ryberg, P.E.; Taylor, E.L.

2007-01-01

The mass extinction at the Permian-Triassic boundary produced a floral turnover in Gondwana in which Paleozoic seed ferns belonging to the Glossopteridales were replaced by corystosperm seed ferns and other seed plant groups in the Mesozoic. Secondary growth (wood production) in both plant groups provides information on plant growth in relation to environment in the form of permineralized tree rings. Techniques utilized to analyze extant wood can be used on fossil specimens to better understand the climate from both of these periods. Late Permian and early Middle Triassic tree rings from the Beardmore Glacier area indicate an environment where extensive plant growth occurred at polar latitudes (~80–85°S, Permian; ~75°S, Triassic). A rapid transition to dormancy in both the Permian and Triassic woods suggests a strong influence of the annual light/dark cycle within the Antarctic Circle on ring production. Latewood production in each ring was most likely triggered by the movement of the already low-angled sun below the horizon. The plants which produced the wood have been reconstructed as seasonally deciduous, based on structural and sedimentologic evidence. Although the Late Permian climate has been reconstructed as cold temperate and the Middle Triassic as a greenhouse, these differences are not reflected in tree ring anatomy or wood production in these plant fossils from the central Transantarctic Mountains.

Delayed recovery of non-marine tetrapods after the end-Permian mass extinction tracks global carbon cycle

PubMed Central

Irmis, Randall B.; Whiteside, Jessica H.

2012-01-01

During the end-Permian mass extinction, marine ecosystems suffered a major drop in diversity, which was maintained throughout the Early Triassic until delayed recovery during the Middle Triassic. This depressed diversity in the Early Triassic correlates with multiple major perturbations to the global carbon cycle, interpreted as either intrinsic ecosystem or external palaeoenvironmental effects. In contrast, the terrestrial record of extinction and recovery is less clear; the effects and magnitude of the end-Permian extinction on non-marine vertebrates are particularly controversial. We use specimen-level data from southern Africa and Russia to investigate the palaeodiversity dynamics of non-marine tetrapods across the Permo-Triassic boundary by analysing sample-standardized generic richness, evenness and relative abundance. In addition, we investigate the potential effects of sampling, geological and taxonomic biases on these data. Our analyses demonstrate that non-marine tetrapods were severely affected by the end-Permian mass extinction, and that these assemblages did not begin to recover until the Middle Triassic. These data are congruent with those from land plants and marine invertebrates. Furthermore, they are consistent with the idea that unstable low-diversity post-extinction ecosystems were subject to boom–bust cycles, reflected in multiple Early Triassic perturbations of the carbon cycle. PMID:22031757

Upper Permian vertebrates and their sedimentological context in the South Urals, Russia

NASA Astrophysics Data System (ADS)

Tverdokhlebov, Valentin P.; Tverdokhlebova, Galina I.; Minikh, Alla V.; Surkov, Mikhail V.; Benton, Michael J.

2005-02-01

Fossil fishes and tetrapods (amphibians and reptiles) have been discovered at 81 localities in the Upper Permian of the Southern Urals area of European Russia. The first sites were found in the 1940s, and subsequent surveys have revealed many more. Broad-scale stratigraphic schemes have been published, but full documentation of the rich tetrapod faunas has not been presented before. The area of richest deposits covers some 900,000 km 2 of territory between Samara on the River Volga in the NW, and Orenburg and Sakmara in the SW. A continental succession, some 3 km thick, of mudstones, siltstones, and sandstones, deposited on mudflats and in small rivers flowing off the Ural Mountain chain, span the last two stages of the Permian (Kazanian, Tatarian). The succession is divided into seven successive units of Kazanian (Kalinovskaya, Osinovskaya, and Belebey svitas, in succession) and Tatarian age, which is further subdivided into the early Tatatian Urzhumian Gorizont (Bolshekinelskaya and Amanakskaya svitas, in succession), and the late Tatarian Severodvinian (Vyazovskaya and Malokinelskaya svitas, of equivalent age) and Vyatkian gorizonts (Kulchumovskaya and Kutulukskaya svitas, of equivalent age). This succession documents major climatic changes, with increasing aridity through the Late Permian. The climate changes are manifested in changing sedimentation and the spread of dryland plants, and peak aridity was achieved right at the Permo-Triassic (PTr) boundary, coincident with global warming. Uplift of the Urals and extinction of land plants led to stripping of soils and massive run-off from the mountains; these phenomena have been identified at the PTr boundary elsewhere (South Africa, Australia) and this may be a key part of the end-Permian mass extinction. The succession of Late Permian fish and tetrapod faunas in Russia documents their richness and diversity before the mass extinction. The terminal Permian Kulchomovskaya and Kutulukskaya svitas have yielded

Regional implications of new chronostratigraphic and paleogeographic data from the Early Permian Darwin Basin, east-central California

USGS Publications Warehouse

Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.

2015-01-01

The Darwin Basin developed in response to episodic subsidence of the western margin of the Cordilleran continental shelf from Late Pennsylvanian (Gzhelian) to Early Permian (late Artinskian) time. Subsidence of the basin was initiated in response to continental truncation farther to the west and was later augmented by thrust emplacement of the Last Chance allochthon. This deep-water basin was filled by voluminous fine-grained siliciclastic turbidites and coarse-grained limestone-gravity-flow deposits. Most of this sediment was derived from the Bird Spring carbonate shelf and cratonal platform to the northeast or east, but some came from an offshore tectonic ridge (Conglomerate Mesa Uplift) to the west that formed at the toe of the Last Chance allochthon. At one point in the late Artinskian the influx of extrabasinal sediment was temporarily cut off, resulting in deposition of a unique black limestone that allows precise correlation throughout the basin. Deep-water sedimentation in the Darwin Basin ended by Kungurian time when complex shallow-water to continental sedimentary facies spread across the region. Major expansion of the Darwin Basin occurred soon after the middle Sakmarian emplacement of the Last Chance allochthon. This tectonic event was approximately coeval with deformation in northeastern Nevada that formed the deep-water Dry Mountain Trough. We herein interpret the two basins to have been structurally continuous. Deposition of the unique black limestone is interpreted to mark a eustatic sea level rise that also can be recognized in Lower Permian sections in east-central Nevada and central Arizona.

Marine anoxia and delayed Earth system recovery after the end-Permian extinction

PubMed Central

Lau, Kimberly V.; Maher, Kate; Altiner, Demir; Kelley, Brian M.; Kump, Lee R.; Lehrmann, Daniel J.; Silva-Tamayo, Juan Carlos; Weaver, Karrie L.; Yu, Meiyi; Payne, Jonathan L.

2016-01-01

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and 238U/235U isotopic compositions (δ238U) of Upper Permian−Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ238U across the end-Permian extinction horizon, from ∼3 ppm and −0.15‰ to ∼0.3 ppm and −0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans—characterized by prolonged shallow anoxia that may have impinged onto continental shelves—global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe. PMID:26884155

Architecture and evolution of an Early Permian carbonate complex on a tectonically active island in east-central California

USGS Publications Warehouse

Stevens, Calvin H.; Magginetti, Robert T.; Stone, Paul

2015-01-01

The newly named Upland Valley Limestone represents a carbonate complex that developed on and adjacent to a tectonically active island in east-central California during a brief interval of Early Permian (late Artinskian) time. This lithologically unique, relatively thin limestone unit lies within a thick sequence of predominantly siliciclastic rocks and is characterized by its high concentration of crinoidal debris, pronounced lateral changes in thickness and lithofacies, and a largely endemic fusulinid fauna. Most outcrops represent a carbonate platform and debris derived from it and shed downslope, but another group of outcrops represents one or possibly more isolated carbonate buildups that developed offshore from the platform. Tectonic activity in the area occurred before, probably during, and after deposition of this short-lived carbonate complex.

Circum-Pacific accretion of oceanic terranes to continental blocks: accretion of the Early Permian Dun Mountain ophiolite to the E Gondwana continental margin, South Island, New Zealand

NASA Astrophysics Data System (ADS)

Robertson, Alastair

2016-04-01

Accretionary orogens, in part, grow as a result of the accretion of oceanic terranes to pre-existing continental blocks, as in the circum-Pacific and central Asian regions. However, the accretionary processes involved remain poorly understood. Here, we consider settings in which oceanic crust formed in a supra-subduction zone setting and later accreted to continental terranes (some, themselves of accretionary origin). Good examples include some Late Cretaceous ophiolites in SE Turkey, the Jurassic Coast Range ophiolite, W USA and the Early Permian Dun Mountain ophiolite of South Island, New Zealand. In the last two cases, the ophiolites are depositionally overlain by coarse clastic sedimentary rocks (e.g. Permian Upukerora Formation of South Island, NZ) that then pass upwards into very thick continental margin fore-arc basin sequences (Great Valley sequence, California; Matai sequence, South Island, NZ). Field observations, together with petrographical and geochemical studies in South Island, NZ, summarised here, provide evidence of terrane accretion processes. In a proposed tectonic model, the Early Permian Dun Mountain ophiolite was created by supra-subduction zone spreading above a W-dipping subduction zone (comparable to the present-day Izu-Bonin arc and fore arc, W Pacific). The SSZ oceanic crust in the New Zealand example is inferred to have included an intra-oceanic magmatic arc, which is no longer exposed (other than within a melange unit in Southland), but which is documented by petrographic and geochemical evidence. An additional subduction zone is likely to have dipped westwards beneath the E Gondwana margin during the Permian. As a result, relatively buoyant Early Permian supra-subduction zone oceanic crust was able to dock with the E Gondwana continental margin, terminating intra-oceanic subduction (although the exact timing is debatable). The amalgamation ('soft collision') was accompanied by crustal extension of the newly accreted oceanic slab, and

A multistratigraphic approach to pinpoint the Permian-Triassic boundary in continental deposits: The Zechstein-Lower Buntsandstein transition in Germany

NASA Astrophysics Data System (ADS)

Scholze, Frank; Wang, Xu; Kirscher, Uwe; Kraft, Johannes; Schneider, Jörg W.; Götz, Annette E.; Joachimski, Michael M.; Bachtadse, Valerian

2017-05-01

The Central European Basin is very suitable for high-resolution multistratigraphy of Late Permian to Early Triassic continental deposits. Here the well exposed continuous transition of the lithostratigraphic Zechstein and Buntsandstein Groups of Central Germany was studied for isotope-chemostratigraphy (δ13Corg, δ13Ccarb, δ18Ocarb), major and trace element geochemistry, magnetostratigraphy, palynology, and conchostracan biostratigraphy. The analysed material was obtained from both classical key sections (abandoned Nelben clay pit, Caaschwitz quarries, Thale railway cut, abandoned Heinebach clay pit) and a recent drill core section (Caaschwitz 6/2012) spanning the Permian-Triassic boundary. The Zechstein-Buntsandstein transition of Central Germany consists of a complex sedimentary facies comprising sabkha, playa lake, aeolian, and fluvial deposits of predominantly red-coloured siliciclastics and intercalations of lacustrine oolitic limestones. The new data on δ13Corg range from - 28.7 to - 21.7 ‰ showing multiple excursions. Most prominent negative shifts correlate with intercalations of oolites and grey-coloured clayey siltstones, while higher δ13Corg values correspond to an onset of palaeosol overprint. The δ13Ccarb values range from - 9.7 to - 1.3 ‰ with largest variations recorded in dolomitic nodules from the Zechstein Group. In contrast to sedimentary facies shifts across the Zechstein-Buntsandstein boundary, major element values used as a proxy (CIA, CIA*, CIA-K) for weathering conditions indicate climatic stability. Trace element data used for a geochemical characterization of the Late Permian to Early Triassic transition in Central Germany indicate a decrease in Rb contents at the Zechstein-Buntsandstein boundary. New palynological data obtained from the Caaschwitz quarry section reveal occurrences of Late Permian palynomorphs in the Lower Fulda Formation, while Early Triassic elements were recorded in the upper part of the Upper Fulda Formation

Implications of latest Pennsylvanian to Middle Permian paleontological and U-Pb SHRIMP data from the Tecomate Formation to re-dating tectonothermal events in the Acatlán Complex, Southern Mexico

USGS Publications Warehouse

Keppie, J. Duncan; Sandberg, Charles A.; Miller, B.V.; Sanchez-Zavala, J. L.; Nance, R.D.; Poole, Forrest G.

2004-01-01

Limestones in the highly deformed Tecomate Formation, uppermost unit of the Acatla??n Complex, are latest Pennsylvanian-earliest Middle Permian in age rather than Devonian, the latter based on less diagnostic fossils. Conodont collections from two marble horizons now constrain its age to range from latest Pennsylvanian to latest Early Permian or early Middle Permian. The older collection contains Gondolella sp., Neostreptognathodus sp., and Streptognathodus sp., suggesting an oldest age limit close to the Pennsylvanian-Permian time boundary. The other collection contains Sweet-ognathus subsymmetricus, a short-lived species ranging only from Kungurian (latest Leonardian) to Wordian (earliest Guadelupian: 272 ?? 4 to 264 ?? 2 Ma). A fusilinid, Parafusulina c.f. P. antimonioensis Dunbar, in a third Tecomate marble horizon is probably Wordian (early Guadelupian, early Middle Permian). Furthermore, granite pebbles in a Tecomate conglomerate have yielded ???320-264 Ma U-Pb SHRIMP ages probably derived from the ???288 Ma, arc-related Totoltepec pluton. Collectively, these data suggest a correlation with two nearby units: (1) the Missourian-Leonardian carbonate horizons separated by a Wolfcampian(?) conglomerate in the upper part of the less deformed San Salvador Patlanoaya Formation; and (2) the clastic, Westphalian-Leonardian Matzitzi Formation. This requires that deformation in the Tecomate Formation be of Early-Middle Permian age rather than Devonian. These three formations are re-interpreted as periarc deposits with deformation related to oblique subduction. The revised dating of the Tecomate Formation is consistent with new data, which indicates that the unconformity between the Tecomate and the Piaxtla Group is mid-Carboniferous and corresponds to a tectonothermal event. ?? 2004 by V. H. Winston and Son, Inc. All rights reserved.

Far-travelled permian chert of the North Fork terrane, Klamath mountains, California

USGS Publications Warehouse

Mankinen, E.A.; Irwin, W.P.; Blome, C.D.

1996-01-01

Permian chert in the North Fork terrane and correlative rocks of the Klamath Mountains province has a remanent magnetization that is prefolding and presumably primary. Paleomagnetic results indicate that the chert formed at a paleolatitude of 8.6?? ?? 2.5?? but in which hemisphere remains uncertain. This finding requires that these rocks have undergone at least 8.6?? ?? 4.4?? of northward transport relative to Permian North America since their deposition. Paleontological evidence suggests that the Permian limestone of the Eastern Klamath terrane originated thousands of kilometers distant from North America. The limestone of the North Fork terrane may have formed at a similar or even greater distance as suggested by its faunal affinity to the Eastern Klamath terrane and more westerly position. Available evidence indicates that convergence of the North Fork and composite Central Metamorphic-Eastern Klamath terranes occurred during Triassic or Early Jurassic time and that their joining together was a Middle Jurassic event. Primary and secondary magnetizations indicate that the new composite terrane containing these and other rocks of the Western Paleozoic and Triassic belt behaved as a single rigid block that has been latitudinally concordant with the North American craton since Middle Jurassic time.

Comparative Earth history and Late Permian mass extinction

NASA Technical Reports Server (NTRS)

Knoll, A. H.; Bambach, R. K.; Canfield, D. E.; Grotzinger, J. P.

1996-01-01

The repeated association during the late Neoproterozoic Era of large carbon-isotopic excursions, continental glaciation, and stratigraphically anomalous carbonate precipitation provides a framework for interpreting the reprise of these conditions on the Late Permian Earth. A paleoceanographic model that was developed to explain these stratigraphically linked phenomena suggests that the overturn of anoxic deep oceans during the Late Permian introduced high concentrations of carbon dioxide into surficial environments. The predicted physiological and climatic consequences for marine and terrestrial organisms are in good accord with the observed timing and selectivity of Late Permian mass extinction.

Petrography and geochemistry of the Permian-Triassic boundary interval, Yangou section, South China: Implications for early Griesbachian seawater δ13CDIC gradient with depth

NASA Astrophysics Data System (ADS)

Li, Rong

2017-04-01

The carbon isotopic composition (δ13Ccarb) recorded in shelf carbonates has been widely used as a proxy for the isotopic composition (δ13CDIC) of surface ocean water to establish paleocean chemistry and circulation patterns. However, δ13Ccarb values do not necessarily preserve the δ13CDIC, due to post-depositional diagenetic alteration. In order to examine the early Griesbachian surface-to-deep δ13CDIC gradient with depth, the diagenetic features of the Permian-Triassic boundary interval (beds 18 to 35) from Yangou section, located in the Yangtze carbonate platform interior, South China, are delineated to compare with those of the slope GSSP Meishan section. The petrographic and geochemical observations show that the early Griesbachian carbonates in the Yangou section underwent pervasive dolomitization in its early diagenetic history. Three types of early replacement dolomites and one type of dolomite cement are present. The dolomite crystals display internal zonation, with high-Ca calcian dolomite (HCD) core being encased successively by calcite and an outermost Fe-rich HCD cortex. The initial dolomitization took place in anoxic seawater, and underwent subsequent diagenetic system involved with meteoric water. The two most negative δ13C values in claystones of Beds 21-3 and 35 are probably related to meteoric diagenesis. Above and/or below the meteorically influenced beds, the dolomite and calcite have uniformly positive δ13C values. The primary carbon isotopic compositions are probably preserved in the early Griesbachian carbonate from the platform Yangou section, which could probably be related to the poor formation of the outermost Fe-rich HCD cortex. Compared to the slope carbonate from the Meishan section, the platform carbonate from the Yangou section has lower primary δ13Ccarb values. It is estimated that the δ13CDIC gradient with depth between Yangou and Meishan is less than the previously suggested. The results highlight the need for evaluation

Contrasting microbial community changes during mass extinctions at the Middle/Late Permian and Permian/Triassic boundaries

NASA Astrophysics Data System (ADS)

Xie, Shucheng; Algeo, Thomas J.; Zhou, Wenfeng; Ruan, Xiaoyan; Luo, Genming; Huang, Junhua; Yan, Jiaxin

2017-02-01

Microbial communities are known to expand as a result of environmental deterioration during mass extinctions, but differences in microbial community changes between extinction events and their underlying causes have received little study to date. Here, we present a systematic investigation of microbial lipid biomarkers spanning ∼20 Myr (Middle Permian to Early Triassic) at Shangsi, South China, to contrast microbial changes associated with the Guadalupian-Lopingian boundary (GLB) and Permian-Triassic boundary (PTB) mass extinctions. High-resolution analysis of the PTB crisis interval reveals a distinct succession of microbial communities based on secular variation in moretanes, 2-methylhopanes, aryl isoprenoids, steranes, n-alkyl cyclohexanes, and other biomarkers. The first episode of the PTB mass extinction (ME1) was associated with increases in red algae and nitrogen-fixing bacteria along with evidence for enhanced wildfires and elevated soil erosion, whereas the second episode was associated with expansions of green sulfur bacteria, nitrogen-fixing bacteria, and acritarchs coinciding with climatic hyperwarming, ocean stratification, and seawater acidification. This pattern of microbial community change suggests that marine environmental deterioration was greater during the second extinction episode (ME2). The GLB shows more limited changes in microbial community composition and more limited environmental deterioration than the PTB, consistent with differences in species-level extinction rates (∼71% vs. 90%, respectively). Microbial biomarker records have the potential to refine our understanding of the nature of these crises and to provide insights concerning possible outcomes of present-day anthropogenic stresses on Earth's ecosystems.

Regional analysis of spiculite faunas in the permian phosphoria basin: Implications for paleoceanography

USGS Publications Warehouse

Murchey, Benita L.

2004-01-01

During the Permian, the relative abundance and apparent diversity of siliceous sponges expanded over a wide range of depths in the basins from Nevada and Idaho to the open ocean. Radiolarian preservation and apparent diversity increased in the deeper Cordilleran basins as well. In the Arctic regions, significant sponge spiculites were deposited in epicratonic basins. At the same time that siliceous sponge populations expanded along the northwestern margin of Pangea, warm-water carbonate producers disappeared. Suppression of carbonate-producing organisms along the margin was critical to the accu- mulation and preservation of both the demosponge spiculites in the Eastern Belt and the spicule-rich argillites of the Central Belt. Vigorous thermohaline circulation was the major control on the paleobiogeography of the late Early, Middle, and early Late Permian along northwest Pangea. It was driven by cold, nutrient- and oxygen-rich northern waters and it produced a coastal current that swept down the margin of the supercontinent. The upwelling associated with deposition of world-class phosphorites in the Phosphoria basin was a part of this larger oceanographic system.

Permian paleoclimate data from fluid inclusions in halite

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.

1999-01-01

This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

The Origin and Early Radiation of Archosauriforms: Integrating the Skeletal and Footprint Record.

PubMed

Bernardi, Massimo; Klein, Hendrik; Petti, Fabio Massimo; Ezcurra, Martín D

2015-01-01

We present a holistic approach to the study of early archosauriform evolution by integrating body and track records. The ichnological record supports a Late Permian-Early Triassic radiation of archosauriforms not well documented by skeletal material, and new footprints from the Upper Permian of the southern Alps (Italy) provide evidence for a diversity not yet sampled by body fossils. The integrative study of body fossil and footprint data supports the hypothesis that archosauriforms had already undergone substantial taxonomic diversification by the Late Permian and that by the Early Triassic archosauromorphs attained a broad geographical distribution over most parts of Pangea. Analysis of body size, as deduced from track size, suggests that archosauriform average body size did not change significantly from the Late Permian to the Early Triassic. A survey of facies yielding both skeletal and track record indicate an ecological preference for inland fluvial (lacustrine) environments for early archosauromorphs. Finally, although more data is needed, Late Permian chirotheriid imprints suggest a shift from sprawling to erect posture in archosauriforms before the end-Permian mass extinction event. We highlight the importance of approaching palaeobiological questions by using all available sources of data, specifically through integrating the body and track fossil record.

Permian age from radiolarites of the Hawasina nappes, Oman Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wever, P.D.; Grissac C.B.; Bechennec, F.

1988-10-01

The Hawasina napper of the Oman Mountains yielded Permian radiolarians from cherts stratigraphically overlying a thick volcanic basement (Al Jil Formation) at the base of the Hamrat Duru Group. This fauna represents the first Permian radiolarians and radiolarites in the central and western Tethyan realm. A Permain age for pelagic sequences within the Hawasina Complex of Oman has major significance for regional paleogeographic reconstruction. A clear differentiation between platform (reefal sediments) and basin (radiolarites) from the base of the Late Permian (255 Ma) is implied. It suggests a flexure of the platform during Permian time; the present data implies thatmore » a zone of rifting was already developed adjacent to the northeast Gondwana platform margin during the Late Permian. The Hamrat Duru Basin corresponds to an opening intracontinental rift area (sphenochasm) between Arabia and northeast Gondwana, a reentrant of the paleo-Tethys.« less

Late Permian wood-borings reveal an intricate network of ecological relationships.

PubMed

Feng, Zhuo; Wang, Jun; Rößler, Ronny; Ślipiński, Adam; Labandeira, Conrad

2017-09-15

Beetles are the most diverse group of macroscopic organisms since the mid-Mesozoic. Much of beetle speciosity is attributable to myriad life habits, particularly diverse-feeding strategies involving interactions with plant substrates, such as wood. However, the life habits and early evolution of wood-boring beetles remain shrouded in mystery from a limited fossil record. Here we report new material from the upper Permian (Changhsingian Stage, ca. 254-252 million-years ago) of China documenting a microcosm of ecological associations involving a polyphagan wood-borer consuming cambial and wood tissues of the conifer Ningxiaites specialis. This earliest evidence for a component community of several trophically interacting taxa is frozen in time by exceptional preservation. The combination of an entry tunnel through bark, a cambium mother gallery, and up to 11 eggs placed in lateral niches-from which emerge multi-instar larval tunnels that consume cambium, wood and bark-is ecologically convergent with Early Cretaceous bark-beetle borings 120 million-years later.Numerous gaps remain in our knowledge of how groups of organisms interacted in ancient ecosystems. Here, Feng and colleagues describe a late Permian fossil wood-boring beetle microcosm, with the oldest known example of complex tunnel geometry, host tissue response, and the presence of fungi within.

Permian Tethyan Fusulinina from the Kenai Peninsula, Alaska

USGS Publications Warehouse

Stevens, C.H.; Davydov, V.I.; Bradley, D.

1997-01-01

Two samples from a large, allochthonous limestone block in the McHugh Complex of the Chugach terrane on the Kenai Peninsula, Alaska, contain species of 12 genera of Permian Fusulinina including Abadehella, Kahlerina, Pseudokahlerina?, Nankinella, Codonofusiella, Dunbarula, Parafusulina?, Chusenella, Verbeekina, Pseudodoliolina, Metadoliolina?, Sumatrina?, and Yabeina, as well as several other foraminiferans and one alga. The assemblage of fusulinids is characteristically Tethyan, belonging to the Yabeina archaica zone of early Midian (late Wordian) age. Similar faunas are known from the Pamirs, Transcaucasia, and Japan, as well as from allochthonous terranes in British Columbia, northwestern Washington, and Koryakia in eastern Siberia.

Tectonic implications of facies patterns, Lower Permian Dry Mountain trough, east-central Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallegos, D.M.; Snyder, W.S.; Spinosa, C.

1991-02-01

Paleozoic tectonism is indicated by a study of a west-east facies analysis transect across the northern portion of the Lower Permian Dry Mountain trough (DMT). In an attempt to characterize the Early Permian basin-filling sequences, three broadly recognizable facies packages have been identified across the DMT: the western margin facies and the central basin facies of the DMT and an eastern shelf facies. In the western margin facies of the basin, pulses of tectonic activity are recorded at McCloud Spring in the Sulphur Springs Range. Here, shallow open-marine carbonate overlies eroded Vinini Formation and, in turn, is unconformably overlain bymore » basinal marine carbonate. An unconformity also marks the contact with the overriding prograding coarse clastic facies. These abrupt transitions suggest the sediments were deposited in a tectonically active area where they preservation of Waltherian sequences is unlikely to occur. Similarly abrupt transitions are evident in the western part of the central basin facies. At Portuguese Springs n the Diamond Range, a thin basal marine conglomerate delineates Lower Permian sedimentation over the Pennsylvanian Ely Formation. Coarsening-upward basinal carbonate strata of pelagic, hemipelagic, and turbidite components overlie the basal conglomerate. this progression of sediments is unconformably overlain by a subaerial sequence of coarse clastic deposits. Within the eastern part of the central basin facies in the Maverick Spring Range, the Lower Permian sediments are open-marine siltstone, wackestone, packstone, and grainstone. The sediments are assigned to a gradually sloping ramp, indicating the effects of tectonism on this margin of the basin were subdued.« less

Olson's Extinction and the latitudinal biodiversity gradient of tetrapods in the Permian

PubMed Central

Day, Michael O.; Rubidge, Bruce S.; Fröbisch, Jörg

2017-01-01

The terrestrial vertebrate fauna underwent a substantial change in composition between the lower and middle Permian. The lower Permian fauna was characterized by diverse and abundant amphibians and pelycosaurian-grade synapsids. During the middle Permian, a therapsid-dominated fauna, containing a diverse array of parareptiles and a considerably reduced richness of amphibians, replaced this. However, it is debated whether the transition is a genuine event, accompanied by a mass extinction, or whether it is merely an artefact of the shift in sampling from the palaeoequatorial latitudes to the palaeotemperate latitudes. Here we use an up-to-date biostratigraphy and incorporate recent discoveries to thoroughly review the Permian tetrapod fossil record. We suggest that the faunal transition represents a genuine event; the lower Permian temperate faunas are more similar to lower Permian equatorial faunas than middle Permian temperate faunas. The transition was not consistent across latitudes; the turnover occurred more rapidly in Russia, but was delayed in North America. The argument that the mass extinction is an artefact of a latitudinal biodiversity gradient and a shift in sampling localities is rejected: sampling correction demonstrates an inverse latitudinal biodiversity gradient was prevalent during the Permian, with peak diversity in the temperate latitudes. PMID:28381616

Aridification across the Carboniferous-Permian transition in central equatorial Pangea: The Catalan Pyrenean succession (NE Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Mujal, Eudald; Fortuny, Josep; Marmi, Josep; Dinarès-Turell, Jaume; Bolet, Arnau; Oms, Oriol

2018-01-01

The Carboniferous-Permian terrestrial successions record a global climatic shift from icehouse to hothouse conditions. Our multidisciplinary study documents an aridification trend throughout the 1000 m thick composite terrestrial succession of the western Catalan Pyrenees (NE Iberian Peninsula), representing this time period. The detailed stratigraphic framework integrates sedimentology, paleopedology, biochronology (plant fossils and tetrapod footprints) and geochronology (paleomagnetism). Additional absolute age correlation is also carried out. The new and reviewed data show that the late Carboniferous wet environments (with short drought periods) progressively changed to a strong seasonal semi-arid and arid climate (with short humid periods) through the early Permian. This paleoclimatic trend supports the previously suggested aridification of the Pangean pan-tropical belt, and supports the hypothesis of the influence of the recurrent climatic fluctuations in Central Pangea, being tentatively correlated to the Southern Gondwanan glaciation-deglaciation periods. Therefore, the Carboniferous-Permian terrestrial succession from the Catalan Pyrenees emerges as a continuous record that can help to constrain late Paleozoic paleoenvironmental events.

Aerobic Marine Habitat Loss During the Late Permian Extinction

NASA Astrophysics Data System (ADS)

Penn, J. L.; Deutsch, C.; Payne, J.; Sperling, E. A.

2016-12-01

Rapid climate change at the end of the Permian is thought to have triggered the most severe mass extinction in Earth's history, but the precise mechanism of biodiversity loss is unknown. Geological evidence points to lethally hot equatorial temperatures and an expansion of anoxic ocean waters as likely culprits. However, previous climate model simulations of the warm Early Triassic exhibit weak tropical warming, and anoxic conditions require a massive and unconstrained increase in the ocean nutrient reservoir. Reconciling model predictions with the geologic record remains a key challenge to identifying the kill-mechanism, which must also take into account the role of animal physiology. Here we apply a recently developed index for the metabolic scope of marine animals to the first global climate simulations of the Permian-Triassic transition to quantify the effects of ocean warming and oxygen (O2) depletion on aerobic habitat availability. Forcing with extreme CO2 concentrations warms the surface ocean by over 10oC, consistent with paleoproxies for upper ocean temperature change. Warming depletes global O2, with greatest losses occuring in tropical deep waters as a result of their reduced ventilation. Together warming and deoxygenation would have constricted the occurrence of marine habitat by 80% globally, by decreasing the metabolic index of the Permian ocean. These changes are most pronounced in the tropics where the fossil record suggests recovery was severely inhibited. Fossil deposits also record changes in animal body size across the extinction. We find that adaptation via body size reductions can compensate for increasing hypoxia at high latitudes, and even prevent extinction there, but cannot maintain the habitability of the tropics.

Stratigraphy and lithofacies of Lisburne Group carbonate rocks (Carboniferous - Permian) in the National Petroleum Reserve - Alaska

USGS Publications Warehouse

Dumoulin, Julie A.; Bird, Kenneth J.; Houseknecht, David W.

2001-01-01

Carbonate rocks of the Lisburne Group (Carboniferous-Permian) occur widely throughout northern Alaska. In the NPRA, seismic mapping and well penetrations show that the Lisburne occurs throughout the subsurface except in northernmost NPRA where it is missing by depositional onlap. Lisburne strata encountered in 11 exploratory wells in the northern part of the NPRA are essentially undeformed, consist of limestone and lesser dolostone, sandstone, siltstone, and shale, encompass a wide array of chiefly shallow-water facies, and range in age from Early Mississippian to Permian. Basins and platforms that formed during Mississippian (and possibly Devonian) time greatly affected depositional patterns of the Lisburne. Total thickness of the Lisburne in northern NPRA wells varies from almost 4000 ft in the Ikpikpuk-Umiat Basin to 300 ft on the north edge of the Fish Creek Platform. Lisburne strata of Mississippian age are found in northeastern NPRA, comprise three subunits (lower limestone, middle dolostone, and upper limestone) and are oldest (Osagean) in the Ikpikpuk-Umiat Basin. All wells that penetrated the Lisburne in northern NPRA encountered rocks of Pennsylvanian age; these intervals are mainly limestone and characterized by decameter-scale shallowing-upward sequences. Lisburne sections of prob-able Early-middle Permian age range from thin (≤60 ft) intervals of dolostone and limestone in the Fish Creek Platform area to thick (500-1000 ft) successions of interbedded limestone and siliciclastic sediment in the Ikpikpuk-Umiat Basin and northwestern NPRA. Abundant non-carbonate detritus, primarily quartz and chert with locally notable plagioclase feldspar and metamorphic lithic clasts, occurs throughout the Lisburne Group in northern NPRA. Per-mian strata and a persistent non-carbonate detrital component are also seen in the Lisburne in subsurface beneath the Chukchi Sea (Hanna Trough) to the northwest, but are not found in Lisburne successions elsewhere in Alaska.

Restoration of marine ecosystems following the end-Permian mass extinction: pattern and dynamics

NASA Astrophysics Data System (ADS)

Chen, Z.

2013-12-01

Life came closest to complete annihilation during the end-Permian mass extinction (EPME). Pattern and cause of this great dying have long been disputed. Similarly, there is also some debate on the recovery rate and pattern of marine organisms in the aftermath of the EPME. Some clades recovered rapidly, within the first 1-3 Myr of the Triassic. For instance, foraminiferal recovery began 1 Myr into the Triassic and was not much affected by Early Triassic crises. Further, some earliest Triassic body and trace fossil assemblages are also more diverse than predicted. Others, ie. Brachiopods, corals etc., however, did not rebound until the Middle Triassic. In addition, although ammonoids recovered fast, reaching a higher diversity by the Smithian than in the Late Permian, much of this Early Triassic radiation was within a single group, the Ceratitina, and their morphological disparity did not expand until the end-Spathian. Here, I like to broaden the modern ecologic network model to explore the complete trophic structure of fossilized ecosystems during the Permian-Triassic transition as a means of assessing the recovery. During the Late Permian and Early Triassic, primary producers, forming the lowest trophic level, were microbes. The middle part of the food web comprises primary and meso-consumer trophic levels, the former dominated by microorganisms such as foraminifers, the latter by opportunistic communities (i.e. disaster taxa), benthic shelly communities, and reef-builders. They were often consumed by invertebrate and vertebrate predators, the top trophic level. Fossil record from South China shows that the post-extinction ecosystems were degraded to a low level and typified by primary producers or opportunistic consumers, which are represented by widespread microbialites or high-abundance, low-diversity communities. Except for some opportunists, primary consumers, namely foraminifers, rebounded in Smithian. Trace-makers recovered in Spathian, which also saw

End-Permian mass extinction and palaeoenvironmental changes in Neotethys: Evidence from an oceanic carbonate section in southwestern Tibet

NASA Astrophysics Data System (ADS)

Shen, Shu-zhong; Cao, Chang-qun; Zhang, Yi-chun; Li, Wen-zhong; Shi, G. R.; Wang, Yue; Wu, Ya-sheng; Ueno, K.; Henderson, C. M.; Wang, Xiang-dong; Zhang, Hua; Wang, Xiao-juan; Chen, Jun

2010-08-01

This paper documents a new Permian-Triassic carbonate sequence which recorded the end-Permian mass extinction in the isolated oceanic setting of Neotethys in southwestern Tibet, China. The sequence is over 350 m thick and consists of the Gyanyima and the Lower Lanchengquxia formations in ascending order. The Lopingian (Late Permian) Gyanyima Formation is composed of fossiliferous reddish carbonates dominated by Colaniella grainstone and reef facies including fenestrate/sponge/coral framestone and bafflestone. 156 species are recognized from the Lopingian Gyanyima Formation. Composite ranges of brachiopods, ostracods, rugose corals and foraminifers at the Gyanyima Section suggest that evolution and diversification of Permian marine organisms continued to the end-Permian preceding a major faunal extinction close to the Permian-Triassic boundary (PTB), coincident with a 2-3‰ negative shift of δ13C carb. The timing and accelerating extinction pattern and the negative δ13C carb excursion are largely comparable with those reported from many previously-documented sections on continental shelf environments. Based on a detailed lithofacies analysis, the latest Permian reefal facies is sharply replaced by ostracod/crinoid packstone/grainstone with abrupt abundant occurrences of Early Triassic conodonts at the Gyanyima Section. This is then followed by thrombolitic microbialite, stromatolite, packstone containing abundant spherical microbes, and bivalve/ammonoid packstone of tidal and intertidal facies. This distinct lithofacies and biofacies shift would, therefore, suggest a dramatic faunal community and environmental change across the PTB. Distinct palaeoclimate fluctuations through the P- T interval are also indicated by the alternation of warm- and cool-water faunas through the uppermost part of the succession. The lower part of the Gyanyima Formation is characterized by a warm condition as indicated by Cathaysian-dominated fossils. This was then followed by a mild

The Origin and Early Radiation of Archosauriforms: Integrating the Skeletal and Footprint Record

PubMed Central

Bernardi, Massimo; Klein, Hendrik; Petti, Fabio Massimo; Ezcurra, Martín D.

2015-01-01

We present a holistic approach to the study of early archosauriform evolution by integrating body and track records. The ichnological record supports a Late Permian–Early Triassic radiation of archosauriforms not well documented by skeletal material, and new footprints from the Upper Permian of the southern Alps (Italy) provide evidence for a diversity not yet sampled by body fossils. The integrative study of body fossil and footprint data supports the hypothesis that archosauriforms had already undergone substantial taxonomic diversification by the Late Permian and that by the Early Triassic archosauromorphs attained a broad geographical distribution over most parts of Pangea. Analysis of body size, as deduced from track size, suggests that archosauriform average body size did not change significantly from the Late Permian to the Early Triassic. A survey of facies yielding both skeletal and track record indicate an ecological preference for inland fluvial (lacustrine) environments for early archosauromorphs. Finally, although more data is needed, Late Permian chirotheriid imprints suggest a shift from sprawling to erect posture in archosauriforms before the end-Permian mass extinction event. We highlight the importance of approaching palaeobiological questions by using all available sources of data, specifically through integrating the body and track fossil record. PMID:26083612

Conodont succession and reassessment of major events around the Permian-Triassic boundary at the Selong Xishan section, southern Tibet, China

NASA Astrophysics Data System (ADS)

Yuan, Dong-Xun; Zhang, Yi-Chun; Shen, Shu-Zhong

2018-02-01

A major discrepancy for the age of the Selong Group from middle Cisuralian (Early Permian) to Changhsingian resulted from previous reports of Sakmarian, Kungurian and Guadalupian (Middle Permian) conodonts and Lopingian (Late Permian) brachiopods. Recently, Cisuralian and Guadalupian conodonts were reported again from the Selong Group and the basal part of the Kangshare Formation at the Selong section, but the age discrepancy remains. We present our conodont materials based on large samples collected from the Selong Group and our interpretation based on identifications using a sample population approach. Three conodont zones are recognized in our re-investigation of the upper part of the Selong Group. They include the Vjalovognathus sp., the Mesogondolella hendersoni, and the M. sheni zones, in ascending order. These zones are overlain by the basal Triassic Hindeodus parvus Zone and the Otoceras woodwardi Zone. Our reassessment of conodonts reported by previous studies from Selong and nearby sections suggest that all specimens consistently point to a Lopingian age; the upper part of the Selong Group is latest Changhsingian in age based on the presence of Clarkina orchardi and Mesogondolella sheni. Previously reported early Cisuralian and Guadalupian conodonts are misidentified using a form species concept. A hiatus may be present at the erosional surface between the Selong Group and the Waagenites Bed of the basal part of the Kangshare Formation. However, the hiatus is minimal because conodont and brachiopod assemblages above and below this surface are very similar, and it results from a latest Changhsingian transgression just before the extinction that follows a global latest Changhsingian regression. There is a distinct rapid end-Permian mass extinction at Selong within the Waagenites Bed, as indicated by the disappearances of all benthic brachiopods, rugose corals and Permian bryozoans. The burst of Clarkina species in the Waagenites Bed and throughout the

Permian vegetational Pompeii from Inner Mongolia and its implications for landscape paleoecology and paleobiogeography of Cathaysia

PubMed Central

Wang, Jun; Pfefferkorn, Hermann W.; Zhang, Yi; Feng, Zhuo

2012-01-01

Plant communities of the geologic past can be reconstructed with high fidelity only if they were preserved in place in an instant in time. Here we report such a flora from an early Permian (ca. 298 Ma) ash-fall tuff in Inner Mongolia, a time interval and area where such information is filling a large gap of knowledge. About 1,000 m2 of forest growing on peat could be reconstructed based on the actual location of individual plants. Tree ferns formed a lower canopy and either Cordaites, a coniferophyte, or Sigillaria, a lycopsid, were present as taller trees. Noeggerathiales, an enigmatic and extinct spore-bearing plant group of small trees, is represented by three species that have been found as nearly complete specimens and are presented in reconstructions in their plant community. Landscape heterogenity is apparent, including one site where Noeggerathiales are dominant. This peat-forming flora is also taxonomically distinct from those growing on clastic soils in the same area and during the same time interval. This Permian flora demonstrates both similarities and differences to floras of the same age in Europe and North America and confirms the distinct character of the Cathaysian floral realm. Therefore, this flora will serve as a baseline for the study of other fossil floras in East Asia and the early Permian globally that will be needed for a better understanding of paleoclimate evolution through time. PMID:22355112

Permian vegetational Pompeii from Inner Mongolia and its implications for landscape paleoecology and paleobiogeography of Cathaysia.

PubMed

Wang, Jun; Pfefferkorn, Hermann W; Zhang, Yi; Feng, Zhuo

2012-03-27

Plant communities of the geologic past can be reconstructed with high fidelity only if they were preserved in place in an instant in time. Here we report such a flora from an early Permian (ca. 298 Ma) ash-fall tuff in Inner Mongolia, a time interval and area where such information is filling a large gap of knowledge. About 1,000 m(2) of forest growing on peat could be reconstructed based on the actual location of individual plants. Tree ferns formed a lower canopy and either Cordaites, a coniferophyte, or Sigillaria, a lycopsid, were present as taller trees. Noeggerathiales, an enigmatic and extinct spore-bearing plant group of small trees, is represented by three species that have been found as nearly complete specimens and are presented in reconstructions in their plant community. Landscape heterogenity is apparent, including one site where Noeggerathiales are dominant. This peat-forming flora is also taxonomically distinct from those growing on clastic soils in the same area and during the same time interval. This Permian flora demonstrates both similarities and differences to floras of the same age in Europe and North America and confirms the distinct character of the Cathaysian floral realm. Therefore, this flora will serve as a baseline for the study of other fossil floras in East Asia and the early Permian globally that will be needed for a better understanding of paleoclimate evolution through time.

Global Evidence for an End-Permian Mass Extinction Event

NASA Astrophysics Data System (ADS)

Becker, L.; Nicholson, C.; Poreda, R.; Basu, A.; Acampo, A.

2003-04-01

We will present the global evidence for a Permian-Triassic impact event and re-examine some of the structural, seismic, gravity and well data for a proposed impact crater, the Bedout High, offshore northwestern Australia (Gorter, PESA News pp. 33--34, 1996). Gorter (1996) speculates that the Bedout High is the uplifted core (30 km) of a circular feature, some 220 km across, formed by the impact of a large bolide (comet or asteroid) with the earth near the end-Permian (K-Ar dating of volcanics ˜253 +/- 5 Ma). Accepting a possible impact origin for the Bedout structure, with the indicated dimensions, would have had profound effects on global climate and significant changes in lithotratigraphic, biostratigraphic and chemo-stratigraphic indicators as seen in several Permian-Triassic locations worldwide. Evidence for an impact of extraterrestrial origin is based upon several impact tracers including shocked metamorphosed grains, productivity collapse, helium-3, Mossbauer spectroscopy on nanophase Fe material, noble gases in magnetic fines and fullerenes with trapped noble gases from some end-Permian sites. These findings suggest that the Bedout structure and a possible newly discovered (˜100 km) secondary crater may be good candidates for an oceanic/continental impact(s) at the end Permian, triggering the most severe mass extinction in the history of life on the Earth.

Floral Assemblages and Patterns of Insect Herbivory during the Permian to Triassic of Northeastern Italy.

PubMed

Labandeira, Conrad C; Kustatscher, Evelyn; Wappler, Torsten

2016-01-01

) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian-Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant-insect interactions remain unknown.

Strangelove Ocean and Deposition of Unusual Shallow-Water Carbonates After the End-Permian Mass Extinction

NASA Technical Reports Server (NTRS)

Rampino, Michael R.; Caldeira, Ken

2003-01-01

The severe mass extinction of marine and terrestrial organisms at the end of the Permian Period (approx. 251 Ma) was accompanied by a rapid negative excursion of approx. 3 to 4 per mil in the carbon-isotope ratio of the global surface oceans and atmosphere that persisted for some 500,000 into the Early Triassic. Simulations with an ocean-atmosphere/carbon-cycle model suggest that the isotope excursion can be explained by collapse of ocean primary productivity (a Strangelove Ocean) and changes in the delivery and cycling of carbon in the ocean and on land. Model results also suggest that perturbations of the global carbon cycle resulting from the extinctions led to short-term fluctuations in atmospheric pCO2 and ocean carbonate deposition, and to a long-term (>1 Ma) decrease in sedimentary burial of organic carbon in the Triassic. Deposition of calcium carbonate is a major sink of river-derived ocean alkalinity and for CO2 from the ocean/atmosphere system. The end of the Permian was marked by extinction of most calcium carbonate secreting organisms. Therefore, the reduction of carbonate accumulation made the oceans vulnerable to a build-up of alkalinity and related fluctuations in atmospheric CO2. Our model results suggest that an increase in ocean carbonate-ion concentration should cause increased carbonate accumulation rates in shallow-water settings. After the end-Permian extinctions, early Triassic shallow-water sediments show an abundance of abiogenic and microbial carbonates that removed CaCO3 from the ocean and may have prevented a full 'ocean-alkalinity crisis' from developing.

Response of carbon isotopic compositions of Early-Middle Permian coals in North China to palaeo-climate change

NASA Astrophysics Data System (ADS)

Ding, Dianshi; Liu, Guijian; Sun, Xiaohui; Sun, Ruoyu

2018-01-01

To investigate the magnitude to which the carbon isotopic ratio (δ13C) varies in coals in response to their contemporary terrestrial environment, the Early-Middle Permian Huainan coals (including coals from the Shanxi Formation, Lower Shihezi Formation and Upper Shihezi Formation) in North China were systematically sampled. A 2.5‰ variation range of δ13C values (-25.15‰ to -22.65‰) was observed in Huainan coals, with an average value of -24.06‰. As coal diagenesis exerts little influence on carbon isotope fractionation, δ13C values in coals were mainly imparted by those of coal-forming flora assemblages which were linked to the contemporary climate. The δ13C values in coals from the Shanxi and Lower Shihezi Formations are variable, reflecting unstable climatic oscillations. Heavy carbon isotope is enriched in coals of the Capitanian Upper Shihezi Formation, implying a shift to high positive δ13C values of coeval atmospheric CO2. Notably, our study provides evidence of the Kamura event in the terrestrial environment for the first time.

Permian arc evolution associated with Panthalassa subduction along the eastern margin of the South China block, based on sandstone provenance and U-Pb detrital zircon ages of the Kurosegawa belt, Southwest Japan

NASA Astrophysics Data System (ADS)

Hara, Hidetoshi; Hirano, Miho; Kurihara, Toshiyuki; Takahashi, Toshiro; Ueda, Hayato

2018-01-01

We have studied the petrography, geochemistry, and detrital zircon U-Pb ages of sandstones from shallow-marine forearc sediments, accretionary complexes (ACs), and metamorphosed accretionary complexes (Meta-ACs) within the Kurosegawa belt of Southwest Japan. Those rocks formed in a forearc region of a Permian island arc associated with subduction of the Panthalassa oceanic crust along the eastern margin of the South China block (Yangtze block). The provenance of the shallow-marine sediments was dominated by basaltic to andesitic volcanic rocks and minor granitic rocks during the late Middle to Late Permian. The ACs were derived from felsic to andesitic volcanic rocks during the Late Permian. The provenance of Meta-ACs was dominated by andesitic volcanic rocks in the Middle Permian. The provenance, source rock compositions, and zircon age distribution for the forearc sediments, ACs and Meta-ACs have allowed us to reconstruct the geological history of the Permian arc system of the Kurosegawa belt. During the Middle Permian, the ACs were accreted along the eastern margin of the South China block. The Middle Permian arc was an immature oceanic island arc consisting of andesitic volcanic rocks. During the Late Permian, the ACs formed in a mature arc, producing voluminous felsic to andesitic volcanic rocks. A forearc basin developed during the late Middle to Late Permian. Subsequently, the Middle Permian ACs and part of the Late Permian AC underwent low-grade metamorphism in the Late to Early Jurassic, presenting the Meta-ACs.

Endangered plant-parrot mutualisms: seed tolerance to predation makes parrots pervasive dispersers of the Parana pine

PubMed Central

Tella, José L.; Dénes, Francisco V.; Zulian, Viviane; Prestes, Nêmora P.; Martínez, Jaime; Blanco, Guillermo; Hiraldo, Fernando

2016-01-01

Parrots are largely considered plant antagonists as they usually destroy the seeds they feed on. However, there is evidence that parrots may also act as seed dispersers. We evaluated the dual role of parrots as predators and dispersers of the Critically Endangered Parana pine (Araucaria angustifolia). Eight of nine parrot species predated seeds from 48% of 526 Parana pines surveyed. Observations of the commonest parrot indicated that 22.5% of the picked seeds were dispersed by carrying them in their beaks. Another five parrot species dispersed seeds, at an estimated average distance of c. 250 m. Dispersal distances did not differ from those observed in jays, considered the main avian dispersers. Contrary to jays, parrots often dropped partially eaten seeds. Most of these seeds were handled by parrots, and the proportion of partially eaten seeds that germinated was higher than that of undamaged seeds. This may be explained by a predator satiation effect, suggesting that the large seeds of the Parana pine evolved to attract consumers for dispersal. This represents a thus far overlooked key plant-parrot mutualism, in which both components are threatened with extinction. The interaction is becoming locally extinct long before the global extinction of the species involved. PMID:27546381

Endangered plant-parrot mutualisms: seed tolerance to predation makes parrots pervasive dispersers of the Parana pine.

PubMed

Tella, José L; Dénes, Francisco V; Zulian, Viviane; Prestes, Nêmora P; Martínez, Jaime; Blanco, Guillermo; Hiraldo, Fernando

2016-08-22

Parrots are largely considered plant antagonists as they usually destroy the seeds they feed on. However, there is evidence that parrots may also act as seed dispersers. We evaluated the dual role of parrots as predators and dispersers of the Critically Endangered Parana pine (Araucaria angustifolia). Eight of nine parrot species predated seeds from 48% of 526 Parana pines surveyed. Observations of the commonest parrot indicated that 22.5% of the picked seeds were dispersed by carrying them in their beaks. Another five parrot species dispersed seeds, at an estimated average distance of c. 250 m. Dispersal distances did not differ from those observed in jays, considered the main avian dispersers. Contrary to jays, parrots often dropped partially eaten seeds. Most of these seeds were handled by parrots, and the proportion of partially eaten seeds that germinated was higher than that of undamaged seeds. This may be explained by a predator satiation effect, suggesting that the large seeds of the Parana pine evolved to attract consumers for dispersal. This represents a thus far overlooked key plant-parrot mutualism, in which both components are threatened with extinction. The interaction is becoming locally extinct long before the global extinction of the species involved.

Evidence for Late Permian-Upper Triassic ocean acidification from calcium isotopes in carbonate of the Kamura section in Japan

NASA Astrophysics Data System (ADS)

Ye, F.; Zhao, L., Sr.; Chen, Z. Q.; Wang, X.

2017-12-01

Calcium and carbon cycles are tightly related in the ocean, for example, through continental weathering and deposition of carbonate, thus, very important for exploring evolutions of marine environment during the earth history. The end-Permian mass extinction is the biggest biological disaster in the Phanerozoic and there are several studies talking about variations of calcium isotopes across the Permian-Triassic boundary (PTB). However, these studies are all from the Tethys regions (Payne et al., 2010; Hinojosa et al., 2012), while the Panthalassic Ocean is still unknown to people. Moreover, evolutions of the calcium isotopes during the Early to Late Triassic is also poorly studied (Blattler et al., 2012). Here, we studied an Uppermost Permian to Upper Triassic shallow water successions (Kamura section, Southwest Japan) in the Central Panthalassic Ocean. The Kamura section is far away from the continent without any clastic pollution, therefore, could preserved reliable δ44/40Cacarb signals. Conodont zonation and carbonate carbon isotope also provide precious time framework which is necessary for the explaining of the δ44/40Cacarb profile. In Kamura, δ44/40Cacarb and δ13Ccarb both exhibit negative excursions across the PTB, the δ44/40Cacarb value in the end-Permian is 1.0398‰ then abrupt decrease to the minimum value of 0.1524‰. CO2-driven global ocean acidification best explains the coincidence of the δ44/40Cacarb excursion with negative excursions in the δ13Ccarb of carbonates until the Early Smithian(N1a, N1b, N1c, P1, N2, P2). In the Middle and the Late Triassic, the δ44/40 Cacarb average approximately 1.1‰. During the Middle and Late Triassic, strong relationships between δ44/40Cacarb and δ13Ccarb are collapsed, indicating a normal pH values of the seawater in those time. The Siberian Trap volcanism probably played a significant role on the δ44/40Cacarb until the late Early Triassic. After that, δ44/40Cacarb was mostly controlled by carbonate

Sandstone provenance and U-Pb ages of detrital zircons from Permian-Triassic forearc sediments within the Sukhothai Arc, northern Thailand: Record of volcanic-arc evolution in response to Paleo-Tethys subduction

NASA Astrophysics Data System (ADS)

Hara, Hidetoshi; Kunii, Miyuki; Miyake, Yoshihiro; Hisada, Ken-ichiro; Kamata, Yoshihito; Ueno, Katsumi; Kon, Yoshiaki; Kurihara, Toshiyuki; Ueda, Hayato; Assavapatchara, San; Treerotchananon, Anuwat; Charoentitirat, Thasinee; Charusiri, Punya

2017-09-01

Provenance analysis and U-Pb dating of detrital zircons in Permian-Triassic forearc sediments from the Sukhothai Arc in northern Thailand clarify the evolution of a missing arc system associated with Paleo-Tethys subduction. The turbidite-dominant formations within the forearc sediments include the Permian Ngao Group (Kiu Lom, Pha Huat, and Huai Thak formations), the Early to earliest Late Triassic Lampang Group (Phra That and Hong Hoi formations), and the Late Triassic Song Group (Pha Daeng and Wang Chin formations). The sandstones are quartzose in the Pha Huat, Huai Thak, and Wang Chin formations, and lithic wacke in the Kiu Lom, Phra That, Hong Hoi and Pha Daeng formations. The quartzose sandstones contain abundant quartz, felsic volcanic and plutonic fragments, whereas the lithic sandstones contain mainly basaltic to felsic volcanic fragments. The youngest single-grain (YSG) zircon U-Pb age generally approximates the depositional age in the study area, but in the case of the limestone-dominant Pha Huat Formation the YSG age is clearly older. On the other hand, the youngest cluster U-Pb age (YC1σ) represents the peak of igneous activity in the source area. Geological evidence, geochemical signatures, and the YC1σ ages of the sandstones have allowed us to reconstruct the Sukhothai arc evolution. The initial Sukhothai Arc (Late Carboniferous-Early Permian) developed as a continental island arc. Subsequently, there was general magmatic quiescence with minor I-type granitic activity during the Middle to early Late Permian. In the latest Permian to early Late Triassic, the Sukhothai Arc developed in tandem with Early to Middle Triassic I-type granitic activity, Middle to Late Triassic volcanism, evolution of an accretionary complex, and an abundant supply of sediments from the volcanic rocks to the trench through a forearc basin. Subsequently, the Sukhothai Arc became quiescent as the Paleo-Tethys closed after the Late Triassic. In addition, parts of sediments of

Euxinia prior to end-Permian main extinction at Xiaojiaba section, Sichuan Province, South China

NASA Astrophysics Data System (ADS)

Wei, H.; Algeo, T. J.; Chen, D.; Yu, H.

2013-12-01

Redox conditions in the global ocean prior to, during, and following the end-Permian mass extinction at 252.28 Ma remain contentious. Previous studies in western Australia, South China, and East Greenland have shown that photic-zone euxinia was present at least intermittently from the early Changhsingian through the Dienerian1-3. Here we report a study of organic carbon isotopes, pyrite sulfur isotopes, TOC, pyritic sulfur content, REE, and major and trace elements from the Upper Permian Xiaojiaba section in the Chaotian district of Guangyuan City, Sichuan Province, China. During the Permian-Triassic transition, this section was located on the northwestern margin of the South China Block, facing the Paleo-Tethys Ocean. Our results indicate that suboxic conditions prevailed during the Wuchiapingian and suboxic to anoxic conditions with several pulses of euxinia during the Changhsingian. δ13Corg values are mostly -28‰ to -26‰ but show three positive excursions (to -22‰) prior to the end-Permian mass extinction horizon. These positive excursions are associated with higher Spy concentrations (to ~1%). δ34Spy values are variable (from -41‰ to +5‰) but show a sharp negative excursion in the late Changhsingian (to -43.4‰) that coincided with the most positive δ13Corg values. This horizon is also associated with increases in Eu/Eu*, Baxs, ∑REE, Si, and redox-sensitive metals such as V. These patterns reflect linkage of the C and S cycles during the latest Permian, possibly in response to redox controls. The observed positive excursions in δ13Corg may be due to organic inputs from green sulfur bacteria, which exhibit a smaller photosynthetic fractionation (-12.5‰4) than eukaryotic algae. The pronounced negative excursion of δ34Spy corresponds to a sulfate-sulfide S isotope fractionation of about -60‰, suggesting a large flux of syngenetic framboidal pyrite, which would be indicative of euxinic water-column conditions. We infer that the euxinia prior

An Early Permian epithermal gold system in the Tulasu Basin in North Xinjiang, NW China: Constraints from in situ oxygen-sulfur isotopes and geochronology

NASA Astrophysics Data System (ADS)

Dong, Leilei; Wan, Bo; Deng, Chen; Cai, Keda; Xiao, Wenjiao

2018-03-01

The Axi and Jingxi-Yelmand gold deposits, being the largest gold deposits in the Chinese North Tianshan, NW China, are located ca. l0 km apart in the Tulasu Basin, and are hosted by the Late Devonian - Early Carboniferous Dahalajunshan Formation. In situ LA-ICP-MS titanium analyses on quartz from the Axi and Jingxi-Yelmand deposits are broadly identical. Accordingly, the calculated ore-forming temperatures by Ti-in-quartz thermometer give average temperatures of 279 °C and 294 °C, respectively. Results of in situ SIMS analyses of oxygen and sulfur isotopes on quartz and pyrite from these two deposits are similar. Temperature-corrected fluids of the Axi deposit have δ18O values of 2.6-8.1‰ and δ34S values of 0.8-2.4‰, whereas the fluids of the Jingxi-Yelmand deposit have δ18O of 6.4-8.9‰ and δ34S of -0.4 to 4.0‰. The oxygen and sulfur isotopes from the two deposits indicate a magmatic origin. LA-ICP-MS zircon U-Pb ages of Aqialehe Formation sandstone provided a lower limit for the mineralization timing of the Axi deposit (288 Ma). In situ SIMS U-Pb analyses on entrapped zircon (297 Ma) and newly recognized 284.5 Ma columnar rhyolite implies that the Jingxi-Yelmand deposit formed in the Early Permian. Based on the magmatic affinity of the ore fluids, similar age and ore-formation temperatures, we propose that the Axi and Jingxi-Yelmand deposits comprise an epithermal gold system, which was driven by the same Permian magma in the Tulasu Basin. The ore geological features together with our new results indicate that the Axi and Jingxi-Yelmand deposits are intermediate and high sulfidation type epithermal deposits, respectively.

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

PubMed Central

Baresel, Björn; Bucher, Hugo; Bagherpour, Borhan; Brosse, Morgane; Guodun, Kuang; Schaltegger, Urs

2017-01-01

New high-resolution U-Pb dates indicate a duration of 89 ± 38 kyr for the Permian hiatus and of 14 ± 57 kyr for the overlying Triassic microbial limestone in shallow water settings of the Nanpanjiang Basin, South China. The age and duration of the hiatus coincides with the Permian-Triassic boundary (PTB) and the extinction interval in the Meishan Global Stratotype Section and Point, and strongly supports a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate as indicated by terrestrial plants. Our model of the Permian-Triassic boundary mass extinction (PTBME) hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO2 induced a transient cool climate whose early phase saw the deposition of the microbial limestone. PMID:28262815

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

NASA Astrophysics Data System (ADS)

Baresel, Björn; Bucher, Hugo; Bagherpour, Borhan; Brosse, Morgane; Guodun, Kuang; Schaltegger, Urs

2017-03-01

New high-resolution U-Pb dates indicate a duration of 89 ± 38 kyr for the Permian hiatus and of 14 ± 57 kyr for the overlying Triassic microbial limestone in shallow water settings of the Nanpanjiang Basin, South China. The age and duration of the hiatus coincides with the Permian-Triassic boundary (PTB) and the extinction interval in the Meishan Global Stratotype Section and Point, and strongly supports a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate as indicated by terrestrial plants. Our model of the Permian-Triassic boundary mass extinction (PTBME) hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO2 induced a transient cool climate whose early phase saw the deposition of the microbial limestone.

Trace fossil evidence for late Permian shallow water condition in Guryul ravine, Kashmir, India

NASA Astrophysics Data System (ADS)

Parcha, Suraj; Horacek, Micha; Krystyn, Leopold; Pandey, Shivani

2015-04-01

The present study is focused on the Late Permian (Changhsingian) succession, present in the Guryul ravine, Kashmir Basin. The basin has a complete Cambro-Triassic sequence and thus contains a unique position in the geology of Himalaya. The Guryul Ravine Permian mainly comprises of mixed siliciclastic-carbonate sediments deposited in a shallow-shelf or ramp setting. The present assemblage of Ichnofossils is the first significant report of trace fossils in the Guryul ravine since early reports in the 1970s. The Ichnofossils reported from this section include: Diplichnites, Dimorphichnus, Monomorphichnus, Planolites, Skolithos along with burrow, scratch marks and annelid worm traces?. The ichnofossils are mainly preserved in medium grain sandstone-mudstone facies. The Ichnofossils are widely distributed throughout the section and are mostly belonging to arthropods and annelid origin, showing behavioral activity, mainly dwelling and feeding, and evidence the dominant presence of deposit feeders. The vertical to slightly inclined biogenic structures are commonly recognized from semi-consolidated substrate which are characteristic features of the near shore/foreshore marine environment, with moderate to high energy conditions. The topmost layer of silty shale contains trace fossils like Skolithos and poorly preserved burrows. The burrow material filled is same as that of host rock. The studied Zewan C and D sequence represents the early to late part of the Changhsingian stage, from 40 to 5 m below the top of Zewan D member with bioturbation still evident in some limestone layers till 2 metres above. No trace fossils could be recognized in the topmost 3 m beds of Zewan D due to their gliding related amalgamated structure. The widespread distribution of traces and their in situ nature will be useful for interpretation of the paleoecological and paleoenvironmental conditions during the late Permian in the Guryul ravine of Kashmir.

Palaeoenvironments and palaeotectonics of the arid to hyperarid intracontinental latest Permian- late Triassic Solway basin (U.K.)

NASA Astrophysics Data System (ADS)

Brookfield, Michael E.

2008-10-01

The late Permian to late Triassic sediments of the Solway Basin consist of an originally flat-lying, laterally persistent and consistent succession of mature, dominantly fine-grained red clastics laid down in part of a very large intracontinental basin. The complete absence of body or trace fossils or palaeosols indicates a very arid (hyperarid) depositional environment for most of the sediments. At the base of the succession, thin regolith breccias and sandstones rest unconformably on basement and early Permian rift clastics. Overlying gypsiferous red silty mudstones, very fine sandstones and thick gypsum were deposited in either a playa lake or in a hypersaline estuary, and their margins. These pass upwards into thick-bedded, multi-storied, fine- to very fine-grained red quartzo-felspathic and sublithic arenites in which even medium sand is rare despite channels with clay pebbles up to 30 cm in diameter. Above, thick trough cross-bedded and parallel laminated fine-grained aeolian sandstones (deposited in extensive barchanoid dune complexes) pass up into very thick, multicoloured mudstones, and gypsum deposited in marginal marine or lacustrine sabkha environments. The latter pass up into marine Lower Jurassic shales and limestones. Thirteen non-marine clastic lithofacies are arranged into five main lithofacies associations whose facies architecture is reconstructed where possible by analysis of large exposures. The five associations can be compared with the desert pavement, arid ephemeral stream, sabkha, saline lake and aeolian sand dune environments of the arid to hyperarid areas of existing intracontinental basins such as Lake Eyre and Lake Chad. The accommodation space in such basins is controlled by gradual tectonic subsidence moderated by large fluctuations in shallow lake extent (caused by climatic change and local variation) and this promotes a large-scale layer-cake stratigraphy as exemplified in the Solway basin. Here, the dominant fine-grained mature

Structure and regional significance of the Late Permian(?) Sierra Nevada - Death Valley thrust system, east-central California

USGS Publications Warehouse

Stevens, C.H.; Stone, P.

2005-01-01

An imbricate system of north-trending, east-directed thrust faults of late Early Permian to middle Early Triassic (most likely Late Permian) age forms a belt in east-central California extending from the Mount Morrison roof pendant in the eastern Sierra Nevada to Death Valley. Six major thrust faults typically with a spacing of 15-20 km, original dips probably of 25-35??, and stratigraphic throws of 2-5 km compose this structural belt, which we call the Sierra Nevada-Death Valley thrust system. These thrusts presumably merge into a de??collement at depth, perhaps at the contact with crystalline basement, the position of which is unknown. We interpret the deformation that produced these thrusts to have been related to the initiation of convergent plate motion along a southeast-trending continental margin segment probably formed by Pennsylvanian transform truncation. This deformation apparently represents a period of tectonic transition to full-scale convergence and arc magmatism along the continental margin beginning in the Late Triassic in central California. ?? 2005 Elsevier B.V. All rights reserved.

Pennsylvanian-Permian tectonism in the Great Basin: The Dry Mountain trough and related basins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, W.S.; Spinosa, C.; Gallegos, D.M.

1991-02-01

Pennsylvanian-Permian tectonism affected the continental margin of western North America from the Yukon to the Mojave Desert. Specific signatures of this tectonism include local angular unconformities, regional disconformities, renewed outpouring of clastic debris from a reactivated Antler and related highlands, and development of deeper water basins with anoxic sediments deposited below wave base. The basins formed include Ishbel trough (Canada), the Wood River basin (Idaho), Cassia basin, Ferguson trough, Dry Mountain trough (all Nevada), and unnamed basins in Death Valley-Mojave Desert region. The Dry Mountain trough (DMT) was initiated during early Wolfcampian and received up to 1,200 m of sedimentmore » by the late Leonardian. The lower contact is a regional unconformity with the Ely Limestone, or locally with the Diamond Peak or Vinini formations. Thus, following a period of localized regional uplift that destroyed the Ely basin, portions of the uplifted and exposed shelf subsided creating the Dry Mountain trough. Evidence suggesting a tectonic origin for the DMT includes (1) high subsidence rates (60-140 m/m.y.); (2) renewed influx of coarse clastic debris from the Antler highlands: (3) possible pre-Early Permian folding, thrusting, and tilting within the highlands; and (4) differential subsidence within the Dry Mountain trough, suggesting the existence of independent fault blocks.« less

Conodont and fusulinid biostratigraphy and history of the Pennsylvanian to Lower Permian Keeler Basin, east-central California

USGS Publications Warehouse

Stevens, C.H.; Stone, P.; Ritter, S.M.

2001-01-01

The Pennsylvanian-Lower Permian Keeler Canyon Formation and lower part of the Lower Permian Lone Pine Formation in east-central California were deposited in a deep-water basin that originated in the Morrowan (Early Pennsylvanian), was fully established by the Desmoinesian (Middle Pennsylvanian), and lasted into the Sakmarian (Early Permian). Stratigraphic studies indicate that the Keeler Canyon Formation can be divided into members recognizable throughout the area of our detailed mapping. From older to younger they are the Tinemaha Reservoir, Tihvipah Limestone, Cerro Gordo Spring, and Salt Tram Members. Rocks in this basin, here referred to as the Keeler basin, contain numerous fusulinid and conodont faunas most of which were deposited by sediment-gravity flows probably originating at the margin of the Bird Spring carbonate platform to the northeast. Sixty-one species of Atokan to Sakmarian fusulinids and 38 species of Desmoinesian to Sakmarian conodonts are recognized. These, in addition to four species of Morrowan conodonts previously reported, show that every stage from the Morrowan to Sakmarian is represented in the basin. The fusulinid faunas are composed largely of taxa of the North American craton, especially the south-central USA, with important endemic constituents and some McCloud Limestone forms, representing the Eastern Klamath terrane. Conodonts are closely similar to species in the Ural Mountains region of Russia and Kazakhstan, as well as the American midcontinent. The co-occurrence of fusulinids and conodonts in the Keeler basin results in a better correlation of zones based on these two groups of fossils than generally is possible.

40Ar/ 39Ar dating of Late Permian evaporites, southeastern New Mexico, USA

NASA Astrophysics Data System (ADS)

Renne, Paul R.; Sharp, Warren D.; Montañez, Isabel P.; Becker, Tim A.; Zierenberg, Robert A.

2001-12-01

40Ar/ 39Ar dating of the potassium-magnesium sulfate mineral langbeinite from Permian evaporites of the Salado formation near Carlsbad, New Mexico, provides quantitative evidence that some salts in these deposits have not recrystallized for 251 Myr since deposition. Survival of Permian salts supports the possibility that Bacillus bacteria recovered from nearby halite was isolated in a closed system and represents a sample of uncontaminated Permian life. Local recrystallization of langbeinite and other nearby minerals is also indicated by the dating, suggesting both the need and the opportunity to document closed system behavior more rigorously. The shoaling and desiccation event recorded by the Salado formation began at least 1 Myr before the Permian-Triassic boundary. Temporal correlation of the Salado with the Zechstein evaporites of north-central Europe supports previously inferred regression models for the origin of these deposits. Significant paleoenvironmental change at the Permian-Triassic boundary thus occurred on a time scale more protracted than that implied by geologically instantaneous events such as bolide impacts.

Prolonged Permian–Triassic ecological crisis recorded by molluscan dominance in Late Permian offshore assemblages

PubMed Central

Clapham, Matthew E.; Bottjer, David J.

2007-01-01

The end-Permian mass extinction was the largest biotic crisis in the history of animal life, eliminating as many as 95% of all species and dramatically altering the ecological structure of marine communities. Although the causes of this pronounced ecosystem shift have been widely debated, the broad consensus based on inferences from global taxonomic diversity patterns suggests that the shift from abundant brachiopods to dominant molluscs was abrupt and largely driven by the catastrophic effects of the end-Permian mass extinction. Here we analyze relative abundance counts of >33,000 fossil individuals from 24 silicified Middle and Late Permian paleocommunities, documenting a substantial ecological shift to numerical dominance by molluscs in the Late Permian, before the major taxonomic shift at the end-Permian mass extinction. This ecological change was coincident with the development of fluctuating anoxic conditions in deep marine basins, suggesting that numerical dominance by more tolerant molluscs may have been driven by variably stressful environmental conditions. Recognition of substantial ecological deterioration in the Late Permian also implies that the end-Permian extinction was the climax of a protracted environmental crisis. Although the Late Permian shift to molluscan dominance was a pronounced ecological change, quantitative counts of 847 Carboniferous–Cretaceous collections from the Paleobiology Database indicate that it was only the first stage in a stepwise transition that culminated with the final shift to molluscan dominance in the Late Jurassic. Therefore, the ecological transition from brachiopods to bivalves was more protracted and complex than their simple Permian–Triassic switch in diversity. PMID:17664426

Palynofloral associations before and after the Permian-Triassic mass extinction, Kap Stosch, East Greenland

NASA Astrophysics Data System (ADS)

Schneebeli-Hermann, Elke; Hochuli, Peter A.; Bucher, Hugo

2017-08-01

The Permian-Triassic boundary (PTB) interval is known to document a major biodiversity crisis in the history of life. It is generally accepted that this crisis had a significant impact on marine invertebrates. The consequences for terrestrial ecosystems are still controversially discussed. Based on palynological analysis we present a high time resolution microfloral succession of the expanded Late Permian (Wuchiapingian)-Early Triassic (Dienerian) section from Kap Stosch, East Greenland. The quantitative distribution of palynomorphs (range charts and relative abundance data) allows for the differentiation of six distinct palynofloral associations. Ammonoids and conodonts provide independent age control for these assemblages. The Wuchiapingian association I, documented from the Ravnefjeld Formation, shows a typical Late Permian assemblage dominated by bisaccate and monosaccate pollen grains and Vittatina spp. It is separated from association II, present in the basal part of the Wordie Creek Formation, by an important hiatus. This association of Changhsingian or earliest Griesbachian age is characterised by the common occurrence of Ephedripites spp. and reduced abundance and diversity of Vittatina spp. Association III, dated as Griesbachian by the presence of ammonoids, is marked by high relative abundances of taeniate bisaccate pollen grains and high spore diversity. A distinct floral break occurs between the gymnosperm dominated Permian and Griesbachian floras and the lycopsid spore dominated Dienerian associations IV-VI. Ammonoid occurrences verify a Dienerian age for the latter associations. Association V is marked by the absence of non-taeniate bisaccate, striate monosaccate pollen grains, and Vittatina spp. Aratrisporites spp. a typical Triassic lycopsid spore occur consistently from this level onwards. Association VI is characterised by highest lycopsid spore abundances. Cluster analysis demonstrates that Griesbachian assemblages (associations II?-III) are

Stratigraphy and paleontology of Lower Permian rocks north of Cananea, northern Sonora, Mexico

USGS Publications Warehouse

Blodgett, R.B.; Moore, Thomas E.; Gray, F.

2002-01-01

Lower Permian carbonate and overlying red bed clastic rocks are present in a 2 km2 stratigraphic window in the vicinity of Rancho La Cueva, Santa Cruz sheet (scale 1:50,000), northern Sonora, Mexico. This exposure lies unconformably beneath predominantly intermediate Upper Cretaceous volcanics yielding 40Ar/39Ar ages of 73.4?? 0.18 and 71.1 ?? 0.35 Ma. The lower part of the Permian succession consists of light- to medium-gray colored limestones of the Colina Limestone, with a minimum thickness of 235 m. Sedimentary features suggest shallow water, slightly restricted depositional environments. Although lacking observable fossils for the most part, two intervals of richly fossiliferous, silicified shell beds are present near the base and top of the Colina Limestone. The lower fauna consist mostly of gastropods and bivalves. The presence of a new microdomatid gastropod species. Glyptospira sonorensis n. sp., close to Glytospira arelela Plas, suggests a late Wolfcampian age for this horizon. The upper fauna are predominantly molluscan dominated (gastropods and bivalves), but some brachiopods (productids and the rhynchonellid genus Pontisia) are also present. Gastropod genera include Bellerophon, Warthia, Euomphalus (represented by the species, Euomphalus kaibabensis Chronic), Baylea, Worthenia, Naticopsis, Goniasma, Kinishbia, Cibecuia, and Glyptospira. The gastropods suggest a Leonardian (late Early Permian) age for this horizon, and many of the species have previously been recorded from the Supai Group and Kaibab Formation of northern and central Arizona. The Colina Limestone is conformably overlain by 11.2 m of light-gray lime mudstone and dolostone, assigned here to the Epitaph Dolomite, which in turn is succeeded by 58.8 m of red-colored sandstone and gray lime mudstone, assigned here to the Scherrer Formation. This Lower Permian succession is significant because it further strengthens the stratigraphic ties of southeastern Arizona rocks with those of northern

A new U-Pb zircon age and a volcanogenic model for the early Permian Chemnitz Fossil Forest

NASA Astrophysics Data System (ADS)

Luthardt, Ludwig; Hofmann, Mandy; Linnemann, Ulf; Gerdes, Axel; Marko, Linda; Rößler, Ronny

2018-04-01

The Chemnitz Fossil Forest depicts one of the most completely preserved forest ecosystems in late Paleozoic Northern Hemisphere of tropical Pangaea. Fossil biota was preserved as a T0 taphocoenosis resulting from the instantaneous entombment by volcanic ashes of the Zeisigwald Tuff. The eruption depicts one of the late magmatic events of post-variscan rhyolitic volcanism in Central Europe. This study represents a multi-method evaluation of the pyroclastic ejecta encompassing sedimentological and (isotope) geochemical approaches to shed light on magmatic and volcanic processes, and their role in preserving the fossil assemblage. The Zeisigwald Tuff pyroclastics (ZTP) reveal a radiometric age of 291 ± 2 Ma, pointing to a late Sakmarian/early Artinskian (early Permian) stratigraphic position for the Chemnitz Fossil Forest. The initial eruption was of phreatomagmatic style producing deposits of cool, wet ashes, which deposited from pyroclastic fall out and density currents. Culmination of the eruption is reflected by massive hot and dry ignimbrites. Whole-rock geochemistry and zircon grain analysis show that pyroclastic deposits originated from a felsic, highly specialised magma, which underwent advanced fractionation, and is probably related to post-Carboniferous magmatism in the Western Erzgebirge. The ascending magma recycled old cadomic crust of the Saxo-thuringian zone, likely induced by a mantle-derived heat flow during a phase of post-variscan crustal delamination. Geochemical trends within the succession of the basal pyroclastic horizons reflect inverse zonation of the magma chamber and provide evidence for the continuous eruption and thus a simultaneous burial of the diverse ecosystem.

Importance of carbon isotopic data of the Permian-Triassic boundary layers in the Verkhoyansk region for the global correlation of the basal Triassic layer

NASA Astrophysics Data System (ADS)

Zakharov, Yu. D.; Biakov, A. S.; Richoz, S.; Horacek, M.

2015-01-01

This paper is dedicated to a global correlation of marine Permian-Triassic boundary layers on the basis of partially published and original data on the δ13Corg and δ13Ccarb values of the Suol section (Setorym River, South Verkhoyansk region). The section consists of six carbon isotopic intervals, which are easily distinguishable in the carbon isotopic curves for a series of Permian-Triassic reference sections of Eurasia and Northern America, including paleontologically described sections of Central Iran, Kashmir, and Southern China. This suggests that the Permian-Triassic boundary in the Suol section is close to the carbon isotopic minimum of interval IV. In light of new data, we suggest considering the upper part of the Late Permian Changhsingian Stage and the lower substage of the Early Triassic Induan Stage of Siberia in the volumes of the rank Otoceras concavum zone and the Tompophiceras pascoei and Wordieoceras decipiens zones, respectively. The O. concavum zone of the Verkhoyansk region probably corresponds to the Late Changhsingian Hypophiceras triviale zone of Greenland. The carbon isotopic intervals II, III, IV, and V in the Permian-Triassic boundary layers of the Verkhoyansk region traced in a series of the reference sections of Eurasia correspond, most likely, to intensification of volcanic activity at the end of the Late Changhsingian and to the first massive eruptions of Siberian traps at the end of the Changhsingian and the beginning of the Induan Stages. New data indicate the possible survival of ammonoids of the Otoceratoidea superfamily at the species level after mass extinction of organisms at the end of the Permian.

An early bird from Gondwana: Paleomagnetism of Lower Permian lavas from northern Qiangtang (Tibet) and the geography of the Paleo-Tethys

NASA Astrophysics Data System (ADS)

Song, Peiping; Ding, Lin; Li, Zhenyu; Lippert, Peter C.; Yue, Yahui

2017-10-01

The origin of the northern Qiangtang block and its Late Paleozoic-Early Mesozoic drift history remain controversial, largely because paleomagnetic constraints from pre-Mesozoic units are sparse and of poor quality. In this paper, we provide a robust and well-dated paleomagnetic pole from the Lower Permian Kaixinling Group lavas on the northern Qiangtang block. This pole suggests that the northern Qiangtang block had a paleolatitude of 21.9 ± 4.7 °S at ca. 296.9 ± 1.9 Ma. These are the first volcanic-based paleomagnetic results from pre-Mesozoic rocks of the Qiangtang block that appear to average secular variation accurately enough to yield a well-determined paleolatitude estimate. This new pole corroborates the hypothesis, first noted on the basis of less rigorous paleomagnetic data, the presence of diamictites, detrital zircon provenance records, and faunal assemblages, that the northern Qiangtang block rifted away from Gondwana prior to the Permian. Previous studies have documented that the northern Qiangtang block accreted to the Tarim-North China continent by Norian time. We calculate a total northward drift of ca. 7000 km over ca. 100 myr, which corresponds to an average south-north plate velocities of ∼7.0 cm/yr. Our results do not support the conclusion that northern Qiangtang has a Laurasian affinity, nor that the central Qiangtang metamorphic belt is an in situ Paleo-Tethys suture. Our analysis, however, does not preclude paleogeographies that interpret the central Qiangtang metamorphic belt as an intra-Qiangtang suture that developed at southernly latitudes outboard of the Gondwanan margin. We emphasize that rigorous paleomagnetic data from Carboniferous units of northern Qiangtang and especially upper Paleozoic units from southern Qiangtang can test and further refine these paleogeographic interpretations.

Permian Minimum and the Following Major Rise in Seawater 87Sr/86Sr Linked to the Glaciation/Deglaciation and Resultant Change in Weathering Rate

NASA Astrophysics Data System (ADS)

Kani, T.; Isozaki, Y.

2014-12-01

We report a detailed secular change of the middle Middle to early Late Permian seawater 87Sr/86Sr ratio for and Akasaka and Kamura carbonates (Japan) deposited on mid-Pansalassan seamounts and for Shizipo carbonates (South China) deposited on the shallow marine shelf. In these coeval sections, extremely low values (<0.7069; the lowest values of the Phanerozoic) continued from upper Wordian (middle Middle Permian) to the topmost Capitanian (upper Middle Permian) barren interval immediately below the Middle-Late Permian boundary characterized by the major crisis of large-tested fusulines and rugose corals. Immediately after ca. 5 m.y.-long minimum interval, the major rise in 87Sr/86Sr was started and the rate of the rise (0.00007/m.y.) continued in period of time containing 21 m.y. until early Triassic (~239 Ma), that is faster than the Cenozoic major rise (0.00003/m.y.).　The most significant shift through Phanerozoic in Sr isotope trend can be explained by the remarkable changes in continental erosion/weathering rate; in particular, by the onset of glaciation and the following deglaciation, that is supported by global sea level change, in addition to the initial doming/rifting of Pangea. After the Capitanian cooling, the long-term climatic regime shifted to a warmer one during which inland ice sheet was removed to expose old crustal silicates for to erosion/weathering. A mantle plume impingiment might lead a domal uplift that accelerate weathering. Highly radiogenic continental Sr could enter the ocean along the new drainage systems developed with the rifting.

Permian macro- and miofloral diversity, palynodating and palaeoclimate implications deduced from the coal-bearing sequences of Singrauli coalfield, Son-Mahanadi Basin, central India

NASA Astrophysics Data System (ADS)

Singh, Kamal Jeet; Murthy, Srikanta; Saxena, Anju; Shabbar, Husain

2017-03-01

The coal-bearing sequences of Barakar and Raniganj formations exposed in Bina and Jhingurdah open-cast collieries, respectively, are analysed for their macro- and miofloral content. The sediment successions primarily comprise of sandstones, shales, claystones and coal seams. In addition to the diverse glossopterid assemblage, four palynoassemblage zones, namely Zones I and II in Bina Colliery and Zones III and IV in Jhingurdah Colliery, have also been recorded in the present study. The megafossil assemblage from the Barakar strata of Bina Colliery comprises of three genera, namely Gangamopteris, Glossopteris and cf. Noeggerathiopsis. Palynoassemblage-I is characterised by the dominance of non-striate bisaccate pollen genus Scheuringipollenites and subdominance of striate bisaccate Faunipollenites and infers these strata to be of Early Permian (Artinskian) age (Lower Barakar Formation). The palynoassemblage has also yielded a large number of naked fossil spore tetrads, which is the first record of spore tetrads from any Artinskian strata in the world and has a significant bearing on the climatic conditions. The palynoassemblage-II is characterised with the dominance of Faunipollenites over Scheuringipollenites and is indicative of Kungurian age (Upper Barakar Formation). The megafossil assemblage from the Raniganj Formation of Jhingurdah Colliery comprises of five genera with 26 species representing four orders, viz., Equisetales, Cordaitales, Cycadales and Glossopteridales. The order Glossopteridales is highly diversified with 23 taxa and the genus Glossopteris, with 22 species, dominates the flora. The mioflora of this colliery is represented by two distinct palynoassemblages. The palynoassemblage-III is correlatable with the palynoflora of Early Permian (Artinskian) Lower Barakar Formation. The assemblage suggests the continuity of older biozones into the younger ones. The palynoassemblage-IV equates the beds with composition V: Striatopodocarpites

Late Permian Forest Composition And Climate Revealed From High-Resolution Carbon Isotopes In Fossil Tree Rings

NASA Astrophysics Data System (ADS)

Gulbranson, E.; Isbell, J. L.; Taylor, E. L.; Ryberg, P. E.; Taylor, T. N.

2012-12-01

Late Permian forests from Antarctica are one of a few examples of polar forest biomes in Earth history. We present a paleoforestry and geochemical study of three contemporaneous Late Permian fossil forests and geochemical analysis of fossil wood specimens from the Permian-Triassic contact in Antarctica. Late Permian paleoforestry analysis suggests that these forests responded to disturbance in exactly the opposite manner as compared to modern boreal forests, with forest thinning and loss of understory vegetation occurring towards areas of disturbance. New high-resolution carbon isotope data from 6 permineralized stumps, 32 tree rings studied in total, indicate that these forests were mixed evergreen and deciduous, but dominated by deciduous trees. Moreover, intra-tree ring and ring-to-ring variation of δ13C values suggest that the Late Permian polar climate maintained wet winters, with precipitation in the austral winter being a factor of three greater than the austral summer. Such seasonality in precipitation implies the development of a temperate-like climate at polar latitudes following the demise of the late Paleozoic ice age. High-resolution carbon isotopes in tree rings in a stratigraphic succession of Late Permian fossil wood to fossil wood at the Permian-Triassic contact indicates that Antarctica experienced a change in precipitation patterns around the time of the Permian-Triassic boundary, marked by intervals of pronounced drying juxtaposed against wetter conditions.

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

NASA Astrophysics Data System (ADS)

Baresel, Bjoern; Bucher, Hugo; Bagherpour, Borhan; Brosse, Morgane; Guodun, Kuang; Schaltegger, Urs

2017-04-01

High-precision U-Pb dating of single-zircon crystals by chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) is applied to volcanic beds that are intercalated in sedimentary sequences across the Permian-Triassic boundary (PTB). By assuming that the zircon crystallization age closely approximate that of the volcanic eruption and subsequent deposition, U-Pb zircon geochronology is the preferred approach for dating abiotic and biotic events, such as the formational PTB and the Permian-Triassic boundary mass extinction (PTBME). We will present new U-Pb zircon dates for a series of volcanic ash beds in shallow-marine Permian-Triassic sections in the Nanpanjiang Basin, South China. These high-resolution U-Pb dates indicate a duration of 90 ± 38 kyr for the Permian sedimentary hiatus and a duration of 13 ± 57 kyr for the overlying Triassic microbial limestone in the shallow water settings of the Nanpanjiang pull apart Basin. The age and duration of the hiatus coincides with the formational PTB and the extinction interval in the Meishan Global Stratotype Section and Point, thus strongly supporting a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate during the Griesbachian as indicated by terrestrial plants. Our model of the PTBME hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase likely released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO2 induced this transient cool

Refining the chronostratigraphy of the Karoo Basin, South Africa: magnetostratigraphic constraints support an early Permian age for the Ecca Group

NASA Astrophysics Data System (ADS)

Belica, Mercedes E.; Tohver, Eric; Poyatos-Moré, Miquel; Flint, Stephen; Parra-Avila, Luis A.; Lanci, Luca; Denyszyn, Steven; Pisarevsky, Sergei A.

2017-12-01

The Beaufort Group of the Karoo Basin, South Africa provides an important chrono- and biostratigraphic record of vertebrate turnovers that have been attributed to the end-Permian mass extinction events at ca. 252 and 260 Ma. However, an unresolved controversy exists over the age of the Beaufort Group due to a large data set of published U-Pb SHRIMP (Sensitive High Resolution Ion Microprobe) zircon results that indicate a ca. 274-250 Ma age range for deposition of the underlying Ecca Group. This age range requires the application of a highly diachronous sedimentation model to the Karoo Basin stratigraphy and is not supported by published palaeontologic and palynologic data. This study tested the strength of these U-Pb isotopic data sets using a magnetostratigraphic approach. Here, we present a composite ∼1500 m section through a large part of the Ecca Group from the Tanqua depocentre, located in the southwestern segment of the Karoo Basin. After the removal of two normal polarity overprints, a likely primary magnetic signal was isolated at temperatures above 450 °C. This section is restricted to a reverse polarity, indicating that it formed during the Kiaman Reverse Superchron (ca. 318-265 Ma), a distinctive magnetostratigraphic marker for early-middle Permian rocks. The Ecca Group has a corresponding palaeomagnetic pole at 40.8°S, 77.4°E (A95 = 5.5°). U-Pb SHRIMP ages on zircons are presented here for comparison with prior isotopic studies of the Ecca Group. A weighted mean U-Pb age of 269.5 ± 1.2 Ma was determined from a volcanic ash bed located in the uppermost Tierberg Formation sampled from the O + R1 research core. The age is interpreted here as a minimum constraint due to a proposed Pb-loss event that has likely influenced a number of published results. A comparison with the Geomagnetic Polarity Time Scale as well as published U-Pb TIMS ages from the overlying Beaufort Group supports a ca. 290-265 Ma age for deposition of the Ecca Group.

An integrated perspective on the Permian-Triassic "Great Dying"

NASA Astrophysics Data System (ADS)

Algeo, T. J.

2017-12-01

The 252-Ma end-Permian mass extinction (EPME), marked by the loss of 90% of marine invertebrate species, was the largest biocrisis in Earth history. Intensive study of this "Great Dying" has led to major insights and a broad consensus regarding many aspects of this event. The ultimate trigger is regarded as eruption of the Siberian Traps Large Igneous Province (STLIP), which released large quantities of greenhouse gases (CO2 and CH4) and sulfate aerosols, triggering a catastrophic global warming of 10°C and acidification of both land surfaces and the surface ocean. On land, a massive die-off of vegetation led to a transient episode of rapid soil erosion and a longer-term increase in weathering rates linked to elevated temperatures. In the ocean, widespread anoxia developed concurrently with the EPME, triggered by ocean-surface warming that reduced dissolved oxygen solubility in seawater and that intensified vertical stratification. Expanded anoxia led to massive burial of organic matter and reduced sulfur, although the evidence for this is indirect (C, U and S isotopes); few organic-rich deposits of Early Triassic age have been found, suggesting that organic sedimentation occurred mainly on continental slopes or in the deep ocean. Other aspects of the end-Permian crisis remain under debate. For example, there is no consensus regarding changes in marine productivity levels in the aftermath of the EPME, which would have been stimulated by enhanced subaerial weathering but depressed by reduced overturning circulation-the evidence to date may favor localized positive and negative changes in productivity. Also under scrutiny is evidence for volcanic eruptions and environmental perturbations during the 100 kyr prior to the EPME, which are likely to have occurred but remain poorly dated and quantified. The greatest uncertainty, however, may surround the nature of the proximate kill mechanism(s) during the EPME. Many hypotheses have been advanced including mechanisms

Continuity of Permian Mengkareng formation through GPR interpretation in Merangin Geopark

NASA Astrophysics Data System (ADS)

Hanif, F.; Syahputra, R.; Kristyanto, T. H. W.; Tempessy, A. S.; Rokhmatuloh

2017-07-01

The Permian Mengkarang Formation was a part of the continental margin (Gondwana Land) which separated in the Devon Period. In this period, Gondwana Land experienced glaciation at the Paleo South Pole. However, the fossils found in Mengkarang Formation were tropical flora, had made the Merangin to be certified as one of the national geoparks. It also shows that the geological process (stratigraphy and tectonic) in the Merangin has occurred before the Indonesian archipelago was formed: namely the Permian to Triassic period. Ground Penetrating Radar (GPR) was chosen as an effective geophysical method to study shallow subsurface geology. GPR and seismic reflection method have the same common principle to identify the facies and sub-sequence stratigraphy but they are different in implementation. Therefore, this study aims to deliver the vertical continuity of the Permian Mengkarang Formation in high resolution unit. The GPR result showing the subsurface image is based on dielectric of the rock layers. The GPR sections show the absence of the unconformity delivered in the intercalation between mudstone, sandstone, and tuff. Thus, it can be concluded that the Permian Mengkareng Formation continues up to 20 m depth.

Tectono-sedimentary evolution of the Permian-Triassic extension event in the Zagros basin (Iran): results from analogue modelling

NASA Astrophysics Data System (ADS)

Madani-kivi, M.; Zulauf, G.

2015-12-01

Since the 1970s, the largest oil and gas reservoirs have been discovered in the Permian-Early Triassic formationsin Saudi Arabia. Thus, this time period is important for the discovery of new oil reserves in Iran. The Arabian passivecontinental margin has undergone lithospheric extension during the Permian-Triassic, which led to the formation of theNeo-Tethys. The aim of this paper is to describe the development of the continental rift basin in the Zagros region basedon the tectono-sedimentological evolution. We have studied well-log data to specify the distribution of synrift depositsin the Zagros and have related this information to the modelling. Environmental changes indicated by various sedimentarysequences, from a siliciclastic basin to a carbonate platform setting, are described. The Cambrian Hormuz salt, whichoverlies the metamorphosed Precambrian basement, becomes effective as a basal detachment layer influencing the styleof overburden deformation during the Permian-Triassic extension event. We have investigated the formation of variousstructures linked to the presence or absence of the Hormuz layer by analogue modelling and relating these structures to theLate Palaeozoic sedimentation. Based on results of the analogue modelling, we argue that the basal detachment layer (Hormuzseries) has contributed to the various structural styles of the extensional basin development in the Fars domain and theLorestan domain.

Anomalous carbonate precipitates: is the Precambrian the key to the Permian?

NASA Technical Reports Server (NTRS)

Grotzinger, J. P.; Knoll, A. H.

1995-01-01

Late Permian reefs of the Capitan complex, west Texas; the Magnesian Limestone, England; Chuenmuping reef, south China; and elsewhere contain anomalously large volumes of aragonite and calcite marine cements and sea-floor crusts, as well as abundant microbial precipitates. These components strongly influenced reef growth and may have been responsible for the construction of rigid, open reefal frames in which bryozoans and sponges became encrusted and structurally reinforced. In some cases, such as the upper biostrome of the Magnesian Limestone, precipitated microbialites and inorganic crusts were the primary constituents of the reef core. These microbial and inorganic reefs do not have modern marine counterparts; on the contrary, their textures and genesis are best understood through comparison with the older rock record, particularly that of the early Precambrian. Early Precambrian reefal facies are interpreted to have formed in a stratified ocean with anoxic deep waters enriched in carbonate alkalinity. Upwelling mixed deep and surface waters, resulting in massive seafloor precipitation of aragonite and calcite. During Mesoproterozoic and early Neoproterozoic time, the ocean became more fully oxidized, and seafloor carbonate precipitation was significantly reduced. However, during the late Neoproterozoic, sizeable volumes of deep ocean water once again became anoxic for protracted intervals; the distinctive "cap carbonates" found above Neoproterozoic tillites attest to renewed upwelling of anoxic bottom water enriched in carbonate alkalinity and 12C. Anomalous late Permian seafloor precipitates are interpreted as the product, at least in part, of similar processes. Massive carbonate precipitation was favored by: 1) reduced shelf space for carbonate precipitation, 2) increased flux of Ca to the oceans during increased continental erosion, 3) deep basinal anoxia that generated upwelling waters with elevated alkalinities, and 4) further evolution of ocean water in

Synthrusting deposition of the Pennsylvanian and Permian Strathearn Formation, Northern Carlin Trend, Nevada

USGS Publications Warehouse

Theodore, T.G.; Berger, V.I.; Singer, D.A.; Harris, A.G.; Stevens, C.H.

2004-01-01

fragments actually breaking away from an immediately subjacent source. Ordovocian quartzarenite, which forms a tectonically uplifted wedge with the Coyote thrust at its base, became a source region for much of the quartzarenite detritus deposited preferentially in the upper parts of the Strathearn Formation. The conglomerate units of the Strathearn Formation temporally bracket emplacement of the Coyote thrust. Thrusting related to contractional reactivation of the Robert Mountains thrust system largely was completed by middle Early Permian. ?? 2004 Published by Elsevier B.V.

Vitrinite reflectance data for the Permian Basin, west Texas and southeast New Mexico

USGS Publications Warehouse

Pawlewicz, Mark; Barker, Charles E.; McDonald, Sargent

2005-01-01

This report presents a compilation of vitrinite reflectance (Ro) data based on analyses of samples of drill cuttings collected from 74 boreholes spread throughout the Permian Basin of west Texas and southeast New Mexico (fig. 1). The resulting data consist of 3 to 24 individual Ro analyses representing progressively deeper stratigraphic units in each of the boreholes (table 1). The samples, Cambrian-Ordovician to Cretaceous in age, were collected at depths ranging from 200 ft to more than 22,100 ft.The R0 data were plotted on maps that depict three different maturation levels for organic matter in the sedimentary rocks of the Permian Basin (figs. 2-4). These maps show depths at the various borehole locations where the R0 values were calculated to be 0.6 (fig. 2), 1.3 (fig. 3), and 2.0 (fig. 4) percent, which correspond, generally, to the onset of oil generation, the onset of oil cracking, and the limit of oil preservation, respectively.The four major geologic structural features within the Permian Basin–Midland Basin, Delaware Basin, Central Basin Platform, and Northwest Shelf (fig. 1) differ in overall depth, thermal history and tectonic style. In the western Delaware Basin, for example, higher maturation is observed at relatively shallow depths, resulting from uplift and eastward basin tilting that began in the Mississippian and ultimately exposed older, thermally mature rocks. Maturity was further enhanced in this basin by the emplacement of early and mid-Tertiary intrusives. Volcanic activity also appears to have been a controlling factor for maturation of organic matter in the southern part of the otherwise tectonically stable Northwest Shelf (Barker and Pawlewicz, 1987). Depths to the three different Ro values are greatest in the eastern Delaware Basin and southern Midland Basin. This appears to be a function of tectonic activity related to the Marathon-Ouachita orogeny, during the Late-Middle Pennsylvanian, whose affects were widespread across the Permian

Carbon isotope evidence for a vigorous biological pump in the wake of end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Meyer, K. M.; Yu, M.; Jost, A. B.; Payne, J.

2009-12-01

Ocean anoxia and euxinia have long been linked to the end-Permian mass extinction and the subsequent Early Triassic interval of delayed biotic recovery. This anoxic, sulfidic episode has been ascribed to both low- and high-productivity states in the marine water column, leaving the causes of euxinia and the mechanisms underlying delayed recovery poorly understood. To examine the nature of the end-Permian and Early Triassic biological production, we measured the carbon isotopic composition of carbonates from an exceptionally preserved carbonate platform in the Nanpanjiang Basin of south China. 13C of limestones from 5 stratigraphic sections displays a gradient of approximately 4‰ from shallow to deep water within the Lower Triassic. The limestones are systematically enriched in the platform interior relative to coeval slope and basin margin deposits by 2-4‰ at the peaks of correlative positive and negative δ13C excursions. This gradient subsequently collapses to less than 1‰ in the Middle Triassic, coincident with accelerated biotic recovery and cessation of δ13C excursions. Based on the relationship between δ18O and δ13C, trace metal analyses, and lithostratigraphic context, we conclude that the carbon isotope gradient is unlikely to reflect meteoric diagenesis, organic matter remineralization, or changes in the mixing ratio of sediment sources and minerals across the platform. Instead, we interpret the relatively depleted δ13C values toward the basin as reflecting DIC input from 13C-depleted deep waters during early diagenesis in a nutrient-rich, euxinic ocean. These observations suggest that a vigorous prokaryote-driven biological pump sustained Early Triassic ocean anoxia and inhibited recovery of animal ecosystems.

Floral Assemblages and Patterns of Insect Herbivory during the Permian to Triassic of Northeastern Italy

PubMed Central

Labandeira, Conrad C.; Kustatscher, Evelyn

2016-01-01

) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian–Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant–insect interactions remain unknown. PMID:27829032

Evidence for an Alleghanian (Early Carboniferous to Late Permian) tectonothermal event in the New Jersey Coastal Plain basement from 40Ar/39Ar biotite data, geochemistry and gravity modeling

USGS Publications Warehouse

Maguire, T.J.; Volkert, R.A.; Swisher, C. C.; Sheridan, R.E.

2009-01-01

40Ar/39Ar dating of biotite from felsic orthogneiss recovered from the -3890-foot level of the Island Beach State Park (IBSP) well beneath the outer New Jersey Coastal Plain was accomplished using CO2 laser incremental-heating techniques. Over 75% of the Ar released from the incremental-heating experiment form a well-behaved plateau with a calculated age of 243.98 ?? 0.10 Ma. The new 244 Ma biotite age reported here is a cooling age younger than the metamorphic event that crystallized or reheated the biotite. We consider reheating of older biotite to be unlikely because the concordant 40Ar/39Ar spectrum upon repeated incremental laser heating showed a well-developed plateau. Thus, biotites from the IBSP gneiss are interpreted as having crystallized during a single thermal event, followed by cooling to below 300 ??C. The IBSP well falls on a structural and geophysical anomaly trend that is along strike with rocks of the Bronson Hill anticlinorium to the north of the IBSP gneiss. Locally graphitic metasedimentary schists and gneisses recovered from New Jersey wells inboard of the IBSP well gneiss correlate to similar lithologies of the Connecticut Valley synclinorium west of the Hartford basin. Our reinterpretation of the IBSP gneiss as metamorphosed dacite or dacitic tuff is consistent with a correlation to some rocks of the Bronson Hill magmatic arc east of the Hartford basin. If correct, this would imply a Late Ordovician age for the protolith of the IBSP gneiss. Reported 40Ar/39Ar biotite ages of 235-253 Ma from southwestern Rhode Island, and of 238-247 Ma from southeastern Connecticut, are interpreted as cooling ages following a tectonothermal event associated with the Alleghanian orogeny (Early Carboniferous to Late Permian). Cooling ages of Alleghanian age (Early Carboniferous to Late Permian) are not recognized west of the Bronson Hill volcanic arc in either central Connecticut or in Massachusetts. Therefore, the 244 Ma cooling age presented here, and the

Permian tetrapods from the Sahara show climate-controlled endemism in Pangaea.

PubMed

Sidor, Christian A; O'Keefe, F Robin; Damiani, Ross; Steyer, J Sébastien; Smith, Roger M H; Larsson, Hans C E; Sereno, Paul C; Ide, Oumarou; Maga, Abdoulaye

2005-04-14

New fossils from the Upper Permian Moradi Formation of northern Niger provide an insight into the faunas that inhabited low-latitude, xeric environments near the end of the Palaeozoic era (approximately 251 million years ago). We describe here two new temnospondyl amphibians, the cochleosaurid Nigerpeton ricqlesi gen. et sp. nov. and the stem edopoid Saharastega moradiensis gen. et sp. nov., as relicts of Carboniferous lineages that diverged 40-90 million years earlier. Coupled with a scarcity of therapsids, the new finds suggest that faunas from the poorly sampled xeric belt that straddled the Equator during the Permian period differed markedly from well-sampled faunas that dominated tropical-to-temperate zones to the north and south. Our results show that long-standing theories of Late Permian faunal homogeneity are probably oversimplified as the result of uneven latitudinal sampling.

Petrogenesis of Permian A-type granitoids in the Cihai iron ore district, Eastern Tianshan, NW China: Constraints on the timing of iron mineralization and implications for a non-plume tectonic setting

NASA Astrophysics Data System (ADS)

Zheng, Jiahao; Mao, Jingwen; Chai, Fengmei; Yang, Fuquan

2016-09-01

The geochronology and geochemistry of granitoids in the Eastern Tianshan, NW China provide important constraints on the timing of iron mineralization, as well as in understanding evolution history of the southern Central Asian Orogenic Belt (CAOB). Here we present results from a detailed study on granitoid rocks from the Cihai iron ore district in the Beishan region, southern part of the Eastern Tianshan. The granitoid rocks are composed of granodiorite, quartz monzonite, granite, and monzonite. Zircon U-Pb analyses yielded the ages of 294.1 ± 2.2 Ma, 286.5 ± 0.7 Ma, 284.3 ± 3.3 Ma, and 265.6 ± 3.0 Ma, respectively, suggesting they were formed in Early-Middle Permian. Among these granitoid rocks, the ages of quartz monzonite and granite are close to the timing of iron mineralization ( 282 Ma), indicating they may provide a source of iron in the Cihai ore district. Geochemically, the granodiorite, granite, and quartz monzonite samples are characterized by high FeOt/(FeOt + MgO) and Ga/Al ratios (0.84-0.94 and 2.28-3.27, respectively), as well as high zircon saturation temperatures (781-908 °C), similar to those of typical A-type granitoids. Isotopically, they display consistently depleted Hf isotopic compositions (εHf(t) = + 1.18 to + 15.37). Geological, geochemical, and isotopic data suggest that the Cihai A-type granitoids were derived from melting of juvenile lower crust. Some Early Permian A-type granitoids were recently identified in the Tarim and Eastern Tianshan with the ages between 294 and 269 Ma. The A-type granitoids in the Eastern Tianshan formed earlier between 294-284 Ma and exhibit characteristics of A2 type granitoids, whereas the A-type granitoids in the Tarim formed later between 277-269 Ma and show A1 granitoids affinity. We suggest that the Permian Tarim mantle plume does not account for the formation of the A-type granitoids in the Eastern Tianshan area, and the Eastern Tianshan was in a non-plume tectonic setting during Early Permian time

Biostratigraphy and structural setting of the Permian Coyote Butte Formation of central Oregon.

USGS Publications Warehouse

Wardlaw, B.R.; Nestell, M.K.; Dutro, J.T.

1982-01-01

Larger isolated outcrops of the limestones of the Coyote Butte Formation consistently contain younger over older faunas that range through most of the Leonardian Series of the Early Permian. The outcrops of the Coyote Butte Formation are interpreted as right- side up blocks probably introduced into the area as one massive exotic unit. The Coyote Butte Formation is very similar to the Lower Permain limestone near Quinn River Crossing, Nevada, and both are suggested to have a similar origin. The Coyote Butte Formation was probably introduced during a late-stage event to deforming Mesozoic oceanic sediments in Mesozoic time. -Authors

A sudden end-Permian mass extinction (Invited)

NASA Astrophysics Data System (ADS)

Shen, S.

2013-12-01

The end-Permian mass extinction is the largest of the Phanerozoic. In the immediate aftermath the marine ecosystem was dominated by microbial and communities with disaster taxa. Plausible kill mechanism includes an extremely rapid, explosive release of gases such as carbon dioxide, methane and hydrogen sulfide. Siberian flood volcanism has been suggested as the most possible mechanism to trigger the massive release of greenhouse gases from volcanic eruptions and interaction of magmas with carbon from thick organic-rich deposits or rapid venting of coal-derived methane or massive combustion of coal. A sharp δ13C isotopic excursion, rapid disappearance of carbonate benthic communities and δ18O data from conodont apatite suggest rapid global warming. The end-Permian mass extinction occurred in less than 200,000 years. This extinction interval is constrained by two ash beds (Beds 25 and 28) at the Meishan section. However, the extinction patterns remain controversial largely due to the condensed nature of the Meishan sections. Geochemical signals and their interpretations are also contentious. Thus, the level of achievable stratigraphic resolution becomes crucial to determine the nature of the event and a detailed study of the extinction interval is essential to unravel the extinction pattern, chemostratigraphy, and the causes. However, the extinction interval at Meishan is only 26 cm thick and contains distinct gaps at the Permian-Triassic boundary (PTB) and possibly the base of Bed 25. Thus, it is impossible to resolve a detailed extinction pattern. Studying expanded sections is crucial to understand the detailed events before, during and after the main extinction. In this report, we show a highly-expanded Permian-Triassic boundary section in Guangxi Province, South China. The last 4.5 m between beds 22 and 28 of the Meishan sections is represented by a sequence of ~560 m at the section and the extinction interval between beds 24e and 28 at Meishan is represented

Zoonoses in humans from small rural properties in Jataizinho, Parana, Brazil

PubMed Central

Gonçalves, Daniela Dib; Benitez, Aline; Lopes-Mori, Fabiana Maria Ruiz; Alves, Lucimara Aparecida; Freire, Roberta Lemos; Navarro, Italmar Teodorico; Santana, Maria Aparecida Zanella; dos Santos, Luís Roberto Alves; Carreira, Teresa; Vieira, Maria Luísa; de Freitas, Julio Cesar

2013-01-01

The aim of this study was to conduct a serological survey for Lyme diseases, brucellosis, leptospirosis and toxoplasmosis and identify the risk variables related to these zoonoses in humans living in the rural area of Jataizinho, state of Parana, Brazil. A total of 63 rural properties were surveyed. Additionally, 207 serum samples collected from these rural area inhabitants were tested for indirect immunofluorescence (IFI) and western blots (WB) were performed to detect Borrelia burgdorferi (sensu lato); a tamponated acidified antigen test (AAT) and 2-mercaptoethanol (2-ME) were used to detect antibodies of Brucella abortus; the microscopic agglutination test (MAT) was carried out to detect antibodies anti-Leptospira spp. and IFI was used to find antibodies of Toxoplasma gondii. Two of the samples (0.96%) were reactive for Lyme borreliosis, three (1.4%) for brucellosis, 25 (12.1%) for leptospirosis and 143 (69.1%) for toxoplasmosis. Although the town of Jataizinho has a human development index (IDH) that was considered to be average (0.733) in the state of Parana, the low social, economic and cultural conditions of the population from small rural properties have resulted in lack of basic information on animal health and direct or indirect contact with the various species of domestic animals, wildlife and ticks have probably contributed to the prevalence levels found. These results show the need for additional regional studies in order to determine the epidemiological characteristics of these diseases as well as their respective vectors and reservoirs so that effective prophylaxis can be administered in the human population. PMID:24159294

Tectonics, basin analysis and organic geochemical attributes of Permian through Mesozoic deposits and their derivative oils of the Turpan-Hami basin, northwestern China

NASA Astrophysics Data System (ADS)

Greene, Todd Jeremy

The Turpan-Hami basin is a major physiographic and geologic feature of northwest China, yet considerable uncertainty exists as to the timing of its inception, its late Paleozoic and Mesozoic tectonic history, and the relationship of its petroleum systems to those of the nearby Junggar basin. Mesozoic sedimentary fades, regional unconformities, sediment dispersal patterns, and sediment compositions within the Turpan-Hami and southern Junggar basins suggest that these basins were initially separated between Early Triassic and Early Jurassic time. Prior to separation, Upper Permian profundal lacustrine and fan-delta fades and Triassic coarse-grained braided-fluvial/alluvial fades were deposited across a contiguous Junggar-Turpan-Hami basin. Permian through Triassic fades were derived mainly from the Tian Shan to the south as indicated by northward-directed paleocurrent directions and geochemical provenance of granitoid cobbles. Lower through Middle Jurassic strata begin to reflect ponded coal-forming, lake-plain environments within the Turpan-Hami basin. A sharp change in sedimentary-lithic-rich Lower Jurassic sandstone followed by a return to lithic volcanic-rich Middle Jurassic sandstone points to the initial uplift and unroofing of the largely andesitic Bogda Shan range, which first shed its sedimentary cover as it emerged to become the partition between the Turpan-Hami and southern Junggar basins. In Turpan-Hami, source rock age is one of three major statistically significant discriminators of effective source rocks in the basin. A newly developed biomarker parameter appears to track conifer evolution and can distinguish Permian rocks and their correlative oils from Jurassic coals and mudrocks, and their derivative oils. Source fades is a second key control on petroleum occurrence and character. By erecting rock-to-oil correlation models, the biomarker parameters separate oil families into end-member groups: Group 1 oils---Lower/Middle Jurassic peatland

Bioessential element-depleted ocean following the euxinic maximum of the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Takahashi, Satoshi; Yamasaki, Shin-ichi; Ogawa, Yasumasa; Kimura, Kazuhiko; Kaiho, Kunio; Yoshida, Takeyoshi; Tsuchiya, Noriyoshi

2014-05-01

We describe variations in trace element compositions that occurred on the deep seafloor of palaeo-superocean Panthalassa during the end-Permian mass extinction based on samples of sedimentary rock from one of the most continuous Permian-Triassic boundary sections of the pelagic deep sea exposed in north-eastern Japan. Our measurements revealed low manganese (Mn) enrichment factor (normalised by the composition of the average upper continental crust) and high cerium anomaly values throughout the section, suggesting that a reducing condition already existed in the depositional environment in the Changhsingian (Late Permian). Other redox-sensitive trace-element (vanadium [V], chromium [Cr], molybdenum [Mo], and uranium [U]) enrichment factors provide a detailed redox history ranging from the upper Permian to the end of the Permian. A single V increase (representing the first reduction state of a two-step V reduction process) detected in uppermost Changhsingian chert beds suggests development into a mildly reducing deep-sea condition less than 1 million years before the end-Permian mass extinction. Subsequently, a more reducing condition, inferred from increases in Cr, V, and Mo, developed in overlying Changhsingian grey siliceous claystone beds. The most reducing sulphidic condition is recognised by the highest peaks of Mo and V (second reduction state) in the uppermost siliceous claystone and overlying lowermost black claystone beds, in accordance with the end-Permian mass extinction event. This significant increase in Mo in the upper Changhsingian led to a high Mo/U ratio, much larger than that of modern sulphidic ocean regions. This trend suggests that sulphidic water conditions developed both at the sediment-water interface and in the water column. Above the end-Permian mass extinction horizon, Mo, V and Cr decrease significantly. On this trend, we provide an interpretation of drawdown of these elements in seawater after the massive element precipitation event

Lower permian reef-bank bodies’ characterization in the pre-caspian basin

NASA Astrophysics Data System (ADS)

Wang, Zhen; Wang, Yankun; Yin, Jiquan; Luo, Man; Liang, Shuang

2018-02-01

Reef-bank reservoir is one of the targets for exploration of marine carbonate rocks in the Pre-Caspian Basin. Within this basin, the reef-bank bodies were primarily developed in the subsalt Devonian-Lower Permian formations, and are dominated by carbonate platform interior and margin reef-banks. The Lower Permian reef-bank present in the eastern part of the basin is considered prospective. This article provides a sequence and sedimentary facies study utilizing drilling and other data, as well as an analysis and identification of the Lower Permian reef-bank features along the eastern margin of the Pre-Caspian Basin using sub-volume coherence and seismic inversion techniques. The results indicate that the sub-volume coherence technique gives a better reflection of lateral distribution of reefs, and the seismic inversion impedance enables the identification of reef bodies’ development phases in the vertical direction, since AI (impedance) is petrophysically considered a tool for distinguishing the reef limestone and the clastic rocks within the formation (limestone exhibits a relatively high impedance than clastic rock). With this method, the existence of multiple phases of the Lower Permian reef-bank bodies along the eastern margin of the Pre-Caspian Basin has been confirmed. These reef-bank bodies are considered good subsalt exploration targets due to their lateral connectivity from south to north, large distribution range and large scale.

Structure of the Anayet Permian basin (Axial Zone, Central Pyrenees)

NASA Astrophysics Data System (ADS)

Rodriguez, L.; Cuevas, J.; Tubía, J. M.

2012-04-01

The Anayet Permian basin was generated by strike-slip tectonics that opened subsident basins with pull-apart geometries in the western Spanish Axial Zone (between the Aragon and Tena valleys). A continental succession of Permian age, that represents the first post-variscan deposits in the area, fills the basin and covers discordantly Devonian to Carboniferous limestones, sandstones and slates. Permian deposits have been classically divided in four main detrital groups, with three basic volcanic episodes interbedded (Gisbert, 1984, Bixel, 1987): the Grey Unit (50-120 m, Estefanian to Kungurian) with slates, conglomerates, tobaceous slates, coal and pyroclastic deposits, the Transition Unit (50 m maximum) showing grey and red sandstones and lutites with oolitic limestones intercalated, the Lower Red Unit (250 m) composed of cross-bedded red sandstones and andesitic volcanic rocks at the top, and finally the Upper Red Unit (400 m minimum, top eroded) formed by three fining up megasequences of carbonates, red sandstones and lutites with lacustrine carbonates intercalated and alkali basalts at the top. Increasingly older rocks are found towards the western part of the basin, where its depocenter is located. South-vergent angular folds deform the Permian sedimentary succession. Fold axes are N115 °E-trending, almost horizontal and are characterized by a remarkably constant orientation. Folds exhibit a long limb dipping slightly to the north and a short vertical limb, occasionally reversed. In the Anayet basin four main folds, with a wavelength of 400 m, can be distinguished, two anticlines and two synclines, with minor folds associated. Related to the angular folds an axial plane foliation, E-trending and dipping 40 to 60° to the north, is developed in the lutites. The more competent rocks, conglomerates and breccias, only locally show a spaced fracture cleavage. No main thrusts have been detected in Permian rocks. However, minor scale decollements, usually low angle

Siberian gas venting and the end-Permian environmental crisis

NASA Astrophysics Data System (ADS)

Svensen, Henrik; Planke, Sverre; Polozov, Alexander G.; Schmidbauer, Norbert; Corfu, Fernando; Podladchikov, Yuri Y.; Jamtveit, Bjørn

2009-01-01

The end of the Permian period is marked by global warming and the biggest known mass extinction on Earth. The crisis is commonly attributed to the formation of the Siberian Traps Large Igneous Province although the causal mechanisms remain disputed. We show that heating of Tunguska Basin sediments by the ascending magma played a key role in triggering the crisis. Our conclusions are based on extensive field work in Siberia in 2004 and 2006. Heating of organic-rich shale and petroleum bearing evaporites around sill intrusions led to greenhouse gas and halocarbon generation in sufficient volumes to cause global warming and atmospheric ozone depletion. Basin scale gas production potential estimates show that metamorphism of organic matter and petroleum could have generated > 100,000 Gt CO 2. The gases were released to the end-Permian atmosphere partly through spectacular pipe structures with kilometre-sized craters. Dating of a sill intrusion by the U-Pb method shows that the gas release occurred at 252.0 ± 0.4 million years ago, overlapping in time with the end-Permian global warming and mass extinction. Heating experiments to 275 °C on petroleum-bearing rock salt from Siberia suggests that methyl chloride and methyl bromide were significant components of the erupted gases. The results indicate that global warming and ozone depletion were the two main drivers for the end-Permian environmental crisis. We demonstrate that the composition of the heated sedimentary rocks below the flood basalts is the most important factor in controlling whether a Large Igneous Provinces causes an environmental crisis or not. We propose that a similar mechanism could have been responsible for the Triassic-Jurassic (~ 200 Ma) global warming and mass extinction, based on the presence of thick sill intrusions in the evaporite deposits of the Amazon Basin in Brazil.

Siberian Gas Venting and the End-Permian Environmental Crisis

NASA Astrophysics Data System (ADS)

Planke, S.; Svensen, H.; Polozov, A. G.; Schmidbauer, N.; Corfu, F.; Podladchikov, Y. Y.; Jamtveit, B.

2008-12-01

The end of the Permian period is marked by global warming and the largest known mass extinction on Earth. The crisis is commonly attributed to the formation of the Siberian Traps Large Igneous Province although the causal mechanisms remain disputed. We show that heating of Tunguska Basin sediments by the ascending magma played a key role in triggering the crisis. Our conclusions are based on extensive field work in Siberia in 2004 and 2006. Heating of organic-rich shale and petroleum bearing evaporites led to greenhouse gas and halocarbon generation in sufficient volumes to cause global warming and atmospheric ozone depletion. Basin scale gas production potential estimates show that metamorphism of organic matter and petroleum could have generated >50,000 Gt CO2. The greenhouse gases were released to the end-Permian atmosphere partly through spectacular pipe structures with kilometre-sized craters. Dating of a sill intrusion by the U-Pb method shows that the gas release occurred 252.0 ± 0.4 million years ago, overlapping in time with the end-Permian global warming and mass extinction. Heating experiments to 275°C on petroleum-bearing rock salt from Siberia suggests that methyl chloride and methyl bromide were significant components of the erupted gases. The results suggest that global warming and ozone depletion were the two main drivers for the end-Permian environmental crisis. We demonstrate that the composition of the heated sedimentary rocks below the flood basalts is the most important factor in controlling whether a Large Igneous Provinces causes an environmental crisis or not. We propose that a similar mechanism could have been responsible for the Triassic-Jurassic (~200 Ma) global warming and mass extinction, based on the presence of thick sill intrusions in the evaporite deposits of the Amazon Basin in Brazil.

Proliferation of MISS-related microbial mats following the end-Permian mass extinction in terrestrial ecosystems: Evidence from the Lower Triassic of the Yiyang area, Henan Province, North China

NASA Astrophysics Data System (ADS)

Tu, Chenyi; Chen, Zhong-Qiang; Retallack, Gregory J.; Huang, Yuangeng; Fang, Yuheng

2016-03-01

Microbially induced sedimentary structures (MISSs) are commonly present in siliciclastic shallow marine settings following the end-Permian mass extinction, but have been rarely reported in the post-extinction terrestrial ecosystems. Here, we present six types of well-preserved MISSs from the upper Sunjiagou Formation and lower Liujiagou Formation of Induan (Early Triassic) age in the Yiyang area, Henan Province, North China. These MISSs include: polygonal sand cracks, worm-like structures, wrinkle structures, sponge pore fabrics, gas domes, and leveled ripple marks. Microanalysis shows that these MISSs are characterized by thin clayey laminae and filamentous mica grains arranged parallel to bedding plane as well as oriented matrix supported quartz grains, which are indicative of biogenic origin. Facies analysis suggests that the MISS-hosting sediments were deposited in a fluvial sedimentary system during the Early Triassic, including lake delta, riverbeds/point bars, and flood plain paleoenvironments. Abundant MISSs from Yiyang indicate that microbes also proliferated in terrestrial ecosystems in the aftermath of the Permian-Triassic (P-Tr) biocrisis, like they behaved in marine ecosystems. Microbial blooms, together with dramatic loss of metazoans, may reflect environmental stress and degradation of terrestrial ecosystems or arid climate immediately after the severe Permian-Triassic ecologic crisis.

Microbialites and global environmental change across the Permian-Triassic boundary: a synthesis.

PubMed

Kershaw, S; Crasquin, S; Li, Y; Collin, P-Y; Forel, M-B; Mu, X; Baud, A; Wang, Y; Xie, S; Maurer, F; Guo, L

2012-01-01

Permian-Triassic boundary microbialites (PTBMs) are thin (0.05-15 m) carbonates formed after the end-Permian mass extinction. They comprise Renalcis-group calcimicrobes, microbially mediated micrite, presumed inorganic micrite, calcite cement (some may be microbially influenced) and shelly faunas. PTBMs are abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents but are rare in higher latitudes, likely inhibited by clastic supply on Pangaea margins. PTBMs occupied broadly similar environments to Late Permian reefs in Tethys, but extended into deeper waters. Late Permian reefs are also rich in microbes (and cements), so post-extinction seawater carbonate saturation was likely similar to the Late Permian. However, PTBMs lack widespread abundant inorganic carbonate cement fans, so a previous interpretation that anoxic bicarbonate-rich water upwelled to rapidly increase carbonate saturation of shallow seawater, post-extinction, is problematic. Preliminary pyrite framboid evidence shows anoxia in PTBM facies, but interbedded shelly faunas indicate oxygenated water, perhaps there was short-term pulsing of normally saturated anoxic water from the oxygen-minimum zone to surface waters. In Tethys, PTBMs show geographic variations: (i) in south China, PTBMs are mostly thrombolites in open shelf settings, largely recrystallised, with remnant structure of Renalcis-group calcimicrobes; (ii) in south Turkey, in shallow waters, stromatolites and thrombolites, lacking calcimicrobes, are interbedded, likely depth-controlled; and (iii) in the Middle East, especially Iran, stromatolites and thrombolites (calcimicrobes uncommon) occur in different sites on open shelves, where controls are unclear. Thus, PTBMs were under more complex control than previously portrayed, with local facies control playing a significant role in their structure and composition. © 2011 Blackwell Publishing Ltd.

Trophic network models explain instability of Early Triassic terrestrial communities

PubMed Central

Roopnarine, Peter D; Angielczyk, Kenneth D; Wang, Steve C; Hertog, Rachel

2007-01-01

Studies of the end-Permian mass extinction have emphasized potential abiotic causes and their direct biotic effects. Less attention has been devoted to secondary extinctions resulting from ecological crises and the effect of community structure on such extinctions. Here we use a trophic network model that combines topological and dynamic approaches to simulate disruptions of primary productivity in palaeocommunities. We apply the model to Permian and Triassic communities of the Karoo Basin, South Africa, and show that while Permian communities bear no evidence of being especially susceptible to extinction, Early Triassic communities appear to have been inherently less stable. Much of the instability results from the faster post-extinction diversification of amphibian guilds relative to amniotes. The resulting communities differed fundamentally in structure from their Permian predecessors. Additionally, our results imply that changing community structures over time may explain long-term trends like declining rates of Phanerozoic background extinction PMID:17609191

Jurassic cooling ages in Paleozoic to early Mesozoic granitoids of northeastern Patagonia: 40Ar/39Ar, 40K-40Ar mica and U-Pb zircon evidence

NASA Astrophysics Data System (ADS)

Martínez Dopico, Carmen I.; Tohver, Eric; López de Luchi, Mónica G.; Wemmer, Klaus; Rapalini, Augusto E.; Cawood, Peter A.

2017-10-01

U-Pb SHRIMP zircon crystallization ages and Ar-Ar and K-Ar mica cooling ages for basement rocks of the Yaminué and Nahuel Niyeu areas in northeastern Patagonia are presented. Granitoids that cover the time span from Ordovician to Early Triassic constitute the main outcrops of the western sector of the Yaminué block. The southern Yaminué Metaigneous Complex comprises highly deformed Ordovician and Permian granitoids crosscut by undeformed leucogranite dikes (U-Pb SHRIMP zircon age of 254 ± 2 Ma). Mica separates from highly deformed granitoids from the southern sector yielded an Ar-Ar muscovite age of 182 ± 3 Ma and a K-Ar biotite age of 186 ± 2 Ma. Moderately to highly deformed Permian to Early Triassic granitoids made up the northern Yaminué Complex. The Late Permian to Early Triassic (U-Pb SHRIMP zircon age of 252 ± 6 Ma) Cabeza de Vaca Granite of the Yaminué block yielded Jurassic mica K-Ar cooling ages (198 ± 2, 191 ± 1, and 190 ± 2 Ma). At the boundary between the Yaminué and Nahuel Niyeu blocks, K-Ar muscovite ages of 188 ± 3 and 193 ± 5 Ma were calculated for the Flores Granite, whereas the Early Permian Navarrete granodiorite, located in the Nahuel Niyeu block, yielded a K-Ar biotite age of 274 ± 4 Ma. The Jurassic thermal history is not regionally uniform. In the supracrustal exposures of the Nahuel Niyeu block, the Early Permian granitoids of its western sector as well as other Permian plutons and Ordovician leucogranites located further east show no evidence of cooling age reset since mica ages suggest cooling in the wake of crystallization of these intrusive rocks. In contrast, deeper crustal levels are inferred for Permian-Early Triassic granitoids in the Yaminué block since cooling ages for these rocks are of Jurassic age (198-182 Ma). Jurassic resetting is contemporaneous with the massive Lower Jurassic Flores Granite, and the Marifil and Chon Aike volcanic provinces. This intraplate deformational pulse that affected northeastern

The new Permian-Triassic paleomagnetic pole for the East European Platform corrected for inclination shallowing

NASA Astrophysics Data System (ADS)

Fetisova, A. M.; Veselovskiy, R. V.; Scholze, F.; Balabanov, Yu. P.

2018-01-01

The results of detailed paleomagnetic studies in seven Upper Permian and Lower Triassic reference sections of East Europe (Middle Volga and Orenburg region) and Central Germany are presented. For each section, the coefficient of inclination shallowing f (King, 1955) is estimated by the Elongation-Inclination (E-I) method (Tauxe and Kent, 2004) and is found to vary from 0.4 to 0.9. The paleomagnetic directions, corrected for the inclination shallowing, are used to calculate the new Late Permian-Early Triassic paleomagnetic pole for the East European Platform (N = 7, PLat = 52.1°, PLong = 155.8°, A95 = 6.6°). Based on this pole, the geocentric axial dipole hypothesis close to the Paleozoic/Mesozoic boundary is tested by the single plate method. The absence of the statistically significant distinction between the obtained pole and the average Permian-Triassic (P-Tr) paleomagnetic pole of the Siberian Platform and the coeval pole of the North American Platform corrected for the opening of the Atlantic (Shatsillo et al., 2006) is interpreted by us as evidence that 250 Ma the configuration of the magnetic field of the Earth was predominantly dipolar; i.e., the contribution of nondipole components was at most 10% of the main magnetic field. In our opinion, the hypothesis of the nondipolity of the geomagnetic field at the P-Tr boundary, which has been repeatedly discussed in recent decades (Van der Voo and Torsvik, 2001; Bazhenov and Shatsillo, 2010; Veselovskiy and Pavlov, 2006), resulted from disregarding the effect of inclination shallowing in the paleomagnetic determinations from sedimentary rocks of "stable" Europe (the East European platform and West European plate).

Permian paleomagnetism of the Tien Shan fold belt, Central Asia: post-collisional rotations and deformation

NASA Astrophysics Data System (ADS)

Bazhenov, Mikhail L.; S. Burtman, Valentin; Dvorova, Ariadna V.

1999-11-01

Permian volcanic and sedimentary rocks were sampled from eight localities in the western and central parts of the Tien Shan fold belt. High-temperature, sometimes intermediate-temperature components isolated from these rocks at seven localities after stepwise thermal demagnetization are shown either to predate folding or be acquired during deformation; the conglomerate test at some localities is positive. The observed inclinations fit rather well with the Eurasian reference data, whereas the declinations are strongly deflected westward; westerly declinations have already been observed from the other parts of the Tien Shan (from the Turan plate in the west to the northern rim of Tarim and the Urumque area in the east). Our analysis shows that a considerable counterclockwise rotation of the Tien Shan fold belt as a rigid body is geologically improbable. We hypothesize that a sinistral shear zone existed over the fold belt thus accounting for systematically westerly declinations. This zone is about 300 km wide and is traced along the Tien Shan fold belt for 2500 km. A large area of Permian alkali magmatism in the West and Central Tien Shan is interpreted as an extensional domain conjugated with the shear zone. This shear zone can be accounted for by translation of the Kara Kum and Tarim blocks along the Eurasian boundary after their oblique collision in the Late Carboniferous. Two phases of rotation are recognized in the Tien Shan. The earlier rotation took place under shear strain during the D3 stage of deformation in the Artinskian-Ufimian. The later rotation is connected with transpression (D4 stage of deformation) and could occur from the Late Permian to Early Jurassic.

Early Permian transgressive-regressive cycles: Sequence stratigraphic reappraisal of the coal-bearing Barakar Formation, Raniganj Basin, India

NASA Astrophysics Data System (ADS)

Bhattacharya, Biplab; Bhattacharjee, Joyeeta; Bandyopadhyay, Sandip; Banerjee, Sudipto; Adhikari, Kalyan

2018-03-01

The present research is an attempt to assess the Barakar Formation of the Raniganj Gondwana Basin, India, in the frame of fluvio-marine (estuarine) depositional systems using sequence stratigraphic elements. Analysis of predominant facies associations signify deposition in three sub-environments: (i) a river-dominated bay-head delta zone in the inner estuary, with transition from braided fluvial channels (FA-B1) to tide-affected meandering fluvial channels and flood plains (FA-B2) in the basal part of the succession; (ii) a mixed energy central basin zone, which consists of transitional fluvio-tidal channels (FA-B2), tidal flats, associated with tidal channels and bars (FA-B3) in the middle-upper part of the succession; and (iii) a wave-dominated outer estuary (coastal) zone (FA-B4 with FA-B3) in the upper part of the succession. Stacked progradational (P1, P2)-retrogradational (R1, R2) successions attest to one major base level fluctuation, leading to distinct transgressive-regressive (T-R) cycles with development of initial falling stage systems tract (FSST), followed by lowstand systems tract (LST) and successive transgressive systems tracts (TST-1 and TST-2). Shift in the depositional regime from regressive to transgressive estuarine system in the early Permian Barakar Formation is attributed to change in accommodation space caused by mutual interactions of (i) base level fluctuations in response to climatic amelioration and (ii) basinal tectonisms (exhumation/sagging) related to post-glacial isostatic adjustments in the riftogenic Gondwana basins.

Molecular carbon isotope variations in core samples taken at the Permian-Triassic boundary layers in southern China

NASA Astrophysics Data System (ADS)

Wang, Ruiliang; Zhang, Shuichang; Brassell, Simon; Wang, Jiaxue; Lu, Zhengyuan; Ming, Qingzhong; Wang, Xiaomei; Bian, Lizeng

2012-07-01

Stable carbon isotope composition (δ13C) of carbonate sediments and the molecular (biomarker) characteristics of a continuous Permian-Triassic (PT) layer in southern China were studied to obtain geochemical signals of global change at the Permian-Triassic boundary (PTB). Carbonate carbon isotope values shifted toward positive before the end of the Permian period and then shifted negative above the PTB into the Triassic period. Molecular carbon isotope values of biomarkers followed the same trend at and below the PTB and remained negative in the Triassic layer. These biomarkers were acyclic isoprenoids, ranging from C15 to C40, steranes (C27 dominates) and terpenoids that were all significantly more abundant in samples from the Permian layer than those from the Triassic layer. The Triassic layer was distinguished by the dominance of higher molecular weight (waxy) n-alkanes. Stable carbon isotope values of individual components, including n-alkanes and acyclic isoprenoids such as phytane, isop-C25, and squalane, are depleted in δ13C by up to 8-10‰ in the Triassic samples as compared to the Permian. Measured molecular and isotopic variations of organic matter in the PT layers support the generally accepted view of Permian oceanic stagnation followed by a massive upwelling of toxic deep waters at the PTB. A series of large-scale (global) outgassing events may be associated with the carbon isotope shift we measured. This is also consistent with the lithological evidence we observed of white thin-clay layers in this region. Our findings, in context with a generally accepted stagnant Permian ocean, followed by massive upwelling of toxic deep waters might be the major causes of the largest global mass extinction event that occurred at the Permian-Triassic boundary.

Environmental mutagenesis during the end-Permian ecological crisis

PubMed Central

Visscher, Henk; Looy, Cindy V.; Collinson, Margaret E.; Brinkhuis, Henk; van Konijnenburg-van Cittert, Johanna H. A.; Kürschner, Wolfram M.; Sephton, Mark A.

2004-01-01

During the end-Permian ecological crisis, terrestrial ecosystems experienced preferential dieback of woody vegetation. Across the world, surviving herbaceous lycopsids played a pioneering role in repopulating deforested terrain. We document that the microspores of these lycopsids were regularly released in unseparated tetrads indicative of failure to complete the normal process of spore development. Although involvement of mutation has long been hinted at or proposed in theory, this finding provides concrete evidence for chronic environmental mutagenesis at the time of global ecological crisis. Prolonged exposure to enhanced UV radiation could account satisfactorily for a worldwide increase in land plant mutation. At the end of the Permian, a period of raised UV stress may have been the consequence of severe disruption of the stratospheric ozone balance by excessive emission of hydrothermal organohalogens in the vast area of Siberian Traps volcanism. PMID:15282373

Recovery and diversification of marine communities following the late Permian mass extinction event in the western Palaeotethys

NASA Astrophysics Data System (ADS)

Foster, William J.; Sebe, Krisztina

2017-08-01

The recovery of benthic invertebrates following the late Permian mass extinction event is often described as occurring in the Middle Triassic associated with the return of Early Triassic Lazarus taxa, increased body sizes, platform margin metazoan reefs, and increased tiering. Most quantitative palaeoecological studies, however, are limited to the Early Triassic and the timing of the final phase of recovery is rarely quantified. Here, quantitative abundance data of benthic invertebrates were collected from the Middle Triassic (Anisian) succession of the Mecsek Mountains (Hungary), and analysed with univariate and multivariate statistics to investigate the timing of recovery following the late Permian mass extinction. These communities lived in a mixed siliciclastic-carbonate ramp setting on the western margin of the Palaeotethys Ocean. The new data presented here is combined with the previously studied Lower Triassic succession of the Aggtelek Karst (Hungary), which records deposition of comparable facies and in the same region of the Palaeotethys Ocean. The Middle Triassic benthic fauna can be characterised by three distinct ecological states. The first state is recorded in the Viganvár Limestone Formation representing mollusc-dominated communities restricted to above wave base, which are comparable to the lower and mid-Spathian Szin Marl Formation faunas. The second state is recorded in the Lapis Limestone Formation and records extensive bioturbation that is not limited to wave base and is comparable to the upper Spathian Szinpetri Limestone Formation. The third ecological state occurs in the Zuhánya Limestone Formation which was deposited in the Pelsonian Binodosus Zone, and has a more 'Palaeozoic' structure with sessile brachiopods dominating assemblages for the first time in the Mesozoic. The return of community-level characteristics to pre-extinction levels and the diversification of invertebrates suggests that the final stages of recovery and the radiation

Large Early Permian eruptive complexes in northern Saxony, Germany: Volcanic facies analysis and geochemical characterization

NASA Astrophysics Data System (ADS)

Hübner, Marcel; Breitkreuz, Christoph; Repstock, Alexander; Heuer, Franziska

2017-04-01

In the course of formation of extensional basins during the Early Permian a widespread volcanic activity led to the deposition of volcanic and volcanosedimentary units in Saxony (Walter 2006, Hoffmann et al. 2013). Situated east of Leipzig, the North Saxonian Volcanic Complex (NSVC) hosts two large caldera complexes, the Rochlitz and Wurzen Volcanic Systems, with diameters of 90 and 52 km, respectively. Volume estimates (> 1000 km3) qualify these as supereruptions according to Mason et al. (2004). In addition to the large caldera systems, the NSVC hosts several small pyroclastic flow deposits ranging from crystal-poor (e.g. Cannewitz and vitrophyric Ebersbach ignimbrites) to crystal-rich units (Wermsdorf and Dornreichenbach ignimbrites). Additionally rhyolitic lava and subvolcanic units are present. The Chemnitz basin (Schneider et al. 2012), located to the south of the NSVC, harbours caldera-outflow facies deposits of the Rochlitz eruption (Fischer 1991), i.e. the partially vitrophyric Planitz ignimbrite. The Rochlitz and Wurzen caldera-fill ignimbrites exhibit relatively high crystal contents with maxima up to 52 and 58 vol.-%, for corresponding 66 and 68 wt.-% SiO2. This is comparable with the 'monotonous intermediates' (Hildreth 1981) in the Cenozoic western USA investigated by Huber et al. (2012). In contrast, the Planitz ignimbrite in the Chemnitz basin reveals predominantly crystal-poor pyroclastics (<10 vol.-%) with higher SiO2-contents (from 67 to 79 wt.-%). For the comparative study of the NSVC and the Planitz ignimbrite, we use detailed investigation of the volcanosedimentary facies, whole rock geochemical data (> 70 analyses), and mineral geochemistry to reconstruct the eruption history and magma genesis of this large Late Paleozoic magmatic complex in Central Europe. Volcanic textures and geochemical trends indicate magma mingling and mixing to have been important during the formation of the Wurzen caldera system. Geothermometric and -barometric

Starting a Business in the Permian Basin.

ERIC Educational Resources Information Center

Harrison, Danny

The business and economic development center of Midland College provides assistance to small businesses. Written for use by future and current small business owners and entrepreneurs living in a 17-county area of the Permian Basin of Texas, this guidebook describes the procedures for developing a business plan and for successfully starting and…

Environmental mutagenesis during the end-Permian ecological crisis.

PubMed

Visscher, Henk; Looy, Cindy V; Collinson, Margaret E; Brinkhuis, Henk; van Konijnenburg-van Cittert, Johanna H A; Kürschner, Wolfram M; Sephton, Mark A

2004-08-31

During the end-Permian ecological crisis, terrestrial ecosystems experienced preferential dieback of woody vegetation. Across the world, surviving herbaceous lycopsids played a pioneering role in repopulating deforested terrain. We document that the microspores of these lycopsids were regularly released in unseparated tetrads indicative of failure to complete the normal process of spore development. Although involvement of mutation has long been hinted at or proposed in theory, this finding provides concrete evidence for chronic environmental mutagenesis at the time of global ecological crisis. Prolonged exposure to enhanced UV radiation could account satisfactorily for a worldwide increase in land plant mutation. At the end of the Permian, a period of raised UV stress may have been the consequence of severe disruption of the stratospheric ozone balance by excessive emission of hydrothermal organohalogens in the vast area of Siberian Traps volcanism. Copyright 2004 The National Academy of Sciencs of the USA

Gondwana's Apparent Polar Wander Path during the Permian-new insights from South America.

PubMed

Tomezzoli, Renata N; Tickyj, Hugo; Rapalini, Augusto E; Gallo, Leandro C; Cristallini, Ernesto O; Arzadún, Guadalupe; Chemale, Farid

2018-05-31

A long-standing debate regarding the configuration of Pangea during the Late Paleozoic has been going on among the paleomagnetic community concerning the validity of one of two significantly different Pangea reconstructions (Pangea A vs Pangea B) since the proposal of Pangea B. Although, Pangea B avoids any continental overlap marring classical Pangea A configuration (Wegener's type), it requires a Carboniferous-Permian megashear of up to 1500 km to achieve the pre-Jurassic configuration. The existence of this megashear is controversial and has led to a wide range of hypotheses, in order to avoid Pangea A continental overlaps and consequently the need for major intra-Pangea movements and to accommodate the paleomagnetic database within a Pangea A reconstruction. We present paleomagnetic results from Permian volcanic rocks of the El Centinela, La Pampa, Argentina. Undeformed volcanic rocks are not affected by any inclination bias and are, therefore, ideal to test different paleogeographic models. The presence of two different paleopole positions, at the base and the top of the same stratigraphic sequence, makes this location optimal to constrain the track of the Gondwana's path during the Late Paleozoic, which shows the transition from Pangea B during the Carboniferous-Permian, to Pangea A at the Permian - Triassic boundary.

Genetic polymorphisms of human platelet antigens in Euro-African and Japanese descendants from Parana, Southern Brazil.

PubMed

Silvestre, Ana Paula Avenia; Zacarias, Joana Maira Valentini; Guelsin, Gláucia Andréia Soares; Visentainer, Jeane Eliete Laguila; Sell, Ana Maria

2017-09-01

The frequency distributions of HPA-1 to HPA-6 and HPA-15 were evaluated in two Brazilian populations from Parana: a mixed population of predominantly Caucasians and a population of Japanese descendants. Genotyping was performed by PCR-SSP in 364 unrelated individuals. Differences in the distribution of HPA highlight diversity in Brazilian miscegenation and the importance of formation of the HPA panel composed of regional blood donors.

Kerogen morphology and geochemistry at the Permian-Triassic transition in the Meishan section, South China: Implication for paleoenvironmental variation

NASA Astrophysics Data System (ADS)

Sawada, Ken; Kaiho, Kunio; Okano, Kazuki

2012-08-01

Detailed fluorescent microscopic observations and organic geochemical analyses for insoluble sedimentary organic matter (kerogens) are conducted on the end-Permian to earliest Triassic sediments in the Meishan section A of South China. The main objectives of the present study are to reconstruct variations of marine and terrestrial environments, and to evaluate bulk characteristics of terrestrial input in the palaeo-Tethys ocean for the Permian-Triassic boundary (PTB). Most of kerogens in the Meishan section are mainly composed of marine algae-derived amorphous organic matter, while terrestrial plant-derived amorphous organic matter is remarkably dominant in the mass extinction horizon reported previously. The relative abundances of marine organic matter may vary depending on marine production rather than terrestrial input in the palaeo-Tethys associated with changing terrestrial vegetation. We also identified aromatic furans as major compounds in kerogen pyrolysate of all layers. It is possible that sources of aromatic furans with alkyl group, fungi and lichen, proliferated as disaster biota in terrestrial ecosystem through the PTB. Higher abundances of herbaceous organic matter are observed in the layers above the mass extinction horizon. However, the conifer biomarker retene can be identified in kerogen pyrolysates of all layers. These results imply that the productions of herbaceous plants increased as dominant pioneer biota in early stage of recovery for terrestrial ecosystem after its collapse, but also that woody plant potentially continued to be produced in land area throughout the end-Permian and earliest-Triassic.

Triassic actinopterygian fishes: the recovery after the end-Permian crisis.

PubMed

Tintori, Andrea; Hitij, Tomaž; Jiang, Dayong; Lombardo, Cristina; Sun, Zuoyu

2014-08-01

In the last 15 years, the discovery of several new actinopterygian fish faunas from the Early and Middle Triassic of the Tethys, cast new light on the timing, speed and range of their recovery after the end-Permian crisis. In addition to several new taxa having been described, the stratigraphical and geographical record of many others have been greatly extended. In fact, most of the new fossiliferous sites are in southern China, thus at the Eastern end of the Tethys, and furthermore a few are somewhat older (Chaohu, Panxian, Luoping) than the major classical Western Tethys sites (Monte San Giorgio). Following these new finds, it is possible to have a better definition of the Triassic recovery stages. Indeed, after a quite short phase till the end of the Smithian (Olenekian, Early Triassic) in which a rather consistent fauna was present all around the Pangea coasts, a major radiation occurred in the Early-Middle Anisian after the new Middle Triassic fish fauna already appeared in the late Early Triassic, thus occuring well before what was previously supposed from the Alps localities. Furthermore, the new assemblages from southern China point to an early broader differentiation among the basal neopterygians rather than in the 'subholosteans', the group that was then dominant in the Western Tethys since the Late Anisian. It stands that during the Norian a new basal neopterygian radiation gave rise to several new branches that dominated the remaining part of the Mesozoic. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Peronosporomycetes (Oomycota) from a Middle Permian Permineralised Peat within the Bainmedart Coal Measures, Prince Charles Mountains, Antarctica

PubMed Central

Slater, Ben J.; McLoughlin, Stephen; Hilton, Jason

2013-01-01

The fossil record of Peronosporomycetes (water moulds) is rather sparse, though their distinctive ornamentation means they are probably better reported than some true fungal groups. Here we describe a rare Palaeozoic occurrence of this group from a Guadalupian (Middle Permian) silicified peat deposit in the Bainmedart Coal Measures, Prince Charles Mountains, Antarctica. Specimens are numerous and comprise two morphologically distinct kinds of ornamented oogonia, of which some are attached to hyphae by a septum. Combresomyces caespitosus sp. nov. consists of spherical oogonia bearing densely spaced, long, hollow, slender, conical papillae with multiple sharply pointed, strongly divergent, apical branches that commonly form a pseudoreticulate pattern under optical microscopy. The oogonia are attached to a parental hypha by a short truncated stalk with a single septum. Combresomyces rarus sp. nov. consists of spherical oogonia bearing widely spaced, hollow, broad, conical papillae that terminate in a single bifurcation producing a pair of acutely divergent sharply pointed branches. The oogonium bears a short truncate extension where it attaches to the parental hypha. We propose that similarities in oogonium shape, size, spine morphology and hyphal attachment between the Permian forms from the Prince Charles Mountains and other reported Peronosporomycetes from Devonian to Triassic strata at widely separated localities elsewhere in the world delimit an extinct but once cosmopolitan Palaeozoic to early Mesozoic branch of the peronosporomycete clade. We name this order Combresomycetales and note that it played an important role in late Palaeozoic and early Mesozoic peatland ecosystems worldwide. PMID:23936465

Widespread inclination shallowing in Permian and Triassic paleomagnetic data from Laurentia: Support from new paleomagnetic data from Middle Permian shallow intrusions in southern Illinois (USA) and virtual geomagnetic pole distributions

USGS Publications Warehouse

Domeier, M.; Van Der Voo, R.; Denny, F.B.

2011-01-01

Recent paleomagnetic work has highlighted a common and shallow inclination bias in continental redbeds. The Permian and Triassic paleomagnetic records from Laurentia are almost entirely derived from such sedimentary rocks, so a pervasive inclination error will expectedly bias the apparent polar wander path of Laurentia in a significant way. The long-standing discrepancy between the apparent polar wander paths of Laurentia and Gondwana in Permian and Triassic time may be a consequence of such a widespread data-pathology. Here we present new Middle Permian paleomagnetic data from igneous rocks and a contact metamorphosed limestone from cratonic Laurentia. The exclusively reversed Middle Permian magnetization is hosted by low-Ti titanomagnetite and pyrrhotite and yields a paleomagnetic pole at 56.3??S, 302.9??E (A95=3.8, N=6). This pole, which is unaffected by inclination shallowing, suggests that a shallow inclination bias may indeed be present in the Laurentian records. To further consider this hypothesis, we conduct a virtual geomagnetic pole distribution analysis, comparing theoretical expectations of a statistical field model (TK03.GAD) against published data-sets. This exercise provides independent evidence that the Laurentian paleomagnetic data is widely biased, likely because of sedimentary inclination shallowing. We estimate the magnitude of this error from our model results and present and discuss several alternative corrections. ?? 2011 Elsevier B.V.

New Paleomagnetic Data from Upper Permian and Lower Triassic Volcanic Sequences from Hua Binh, Quynh Nhai, and Thuan Chau Localities, Northwest Veitnam and Their Bearing on the Accretion History of Southeast Asia

NASA Astrophysics Data System (ADS)

Geissman, J. W.; Chi, C. T.

2015-12-01

New paleomagnetic data from Upper Permian to Lower Triassic volcanic rocks sampled in NW Vietnam provide more quantitative constraints on the paleogeographic setting of crustal elements that comprise the Song Da Terrane, east of the Song Ma suture, between the South China block (SCB) and north Indochina. These include results from 12 sites (125 samples) from basalts of the Vien Nam Formation, exposed at Hoa Binh Dam; eight sites (74 samples) from basalts of the Cam Thuy Formation near Thuan Chau; and 19 sites (198 samples) from andesites and basalts of the Vien Nam Formation near Quynh Nhai. The collection is limited by the quality of exposures and quantity of independent flows. Most sites yield interpretable magnetizations in progressive demagnetization, and the response implies that characteristic remanent magnetization (ChRM) components are carried by low-titanium magnetite or hematite, or a combination of both; these are isolated from secondary components. Rock magnetic data and petrography support the retention of an early-acquired thermoremanent magnetization in most sites. The Vien Nam Formation mafic volcanic rocks yield a grand mean, in geographic coordinates, of D=33.8o, I=-28.4o ( a95 = 9.5o, k =30.3, N=9 accepted sites), and a pole position at Lat=41.1N, Long=239.8E and a paleolatitude at ~15o S during the Late Permian to Early Triassic. Permian basalts of the Cam Thuy Formation provide a grand mean, corrected for structural tilt, of D=216.1o, I=+10.5o, a95=8.9o, k=107.8, and N= 4, with a pole position at Lat=45.6N, Long=226.8E. Volcanic rocks at the Quynh Nhai locality likely yield the most robust paleofield determination, as the data set is of dual polarity and passes a reversal test. The tilt corrected grand mean (normal polarity) is D=48.3o, I=-10.0o, a95=8.0o, k=27.7, N = 13, and this in turn yields an inferred paleomagnetic pole at Lat=35.7N, Long=217.4E, and a paleolatitude of 5.1oS for the late Permian. Compared with the Late Permian-Early

Late Permian Tsunamites in Guryul Ravine (Kashmir, India) - revisited and rejected

NASA Astrophysics Data System (ADS)

Krystyn, Leopold; Horacek, Micha; Brandner, Rainer; Parcha, Suraj

2014-05-01

Recent claims for tsunami-related event beds induced by the Siberian Trap basalts in this section (Brookfield et al., 2013) have to be questioned. Identical storm generated carbonate beds occur not only during a short interval close to the Permian-Triassic (P-T) boundary but through a major part of the late Permian (Changhsingian) succession there - as low as 26 m below the so-called tsunami beds. Moreover, during our recent study in a closely neighbouring place called Mandakpal (less than 10 km to the southeast), no signs of tsunamites have been detected in time-correlative finegrained sediments. Based on sedimentary and trace fossil evidence we interpret the late Permian of Guryul as relatively shallow, neritic and delta-influenced. The so-called tsunamites are shelly-enriched discontinuous carbonate lenses fed downslope through local channels. Judging from the distinct facies change from the storm related "tsunamites" to thinly bedded mud turbidites above, the sudden deepening may be explained by local and still rift-related tectonics along the NIM (North-Indian Gondwana Margin) which led to episodic seismic induced sediment redeposition in the area of Guryul. Synsedimentary tectonic activity with tilting and eventual Horst and Graben structure building along the large NIM is indicated by margin inversion during the P-T boundary interval leading to sedimentary breaks and 20 times thinner, condensed limestone deposits far offshore from Guryul in Spiti (Krystyn et al., 2004) and Tibet (Orchard et al., 1994). Thus, local seismic activity seems to be a far more logic explanation of the Guryul "tsunamites" than the eruption of the Siberian Traps more than 6000 km away. References Brookfield, M. E., Algeo, T. J., Hannigan, R., Williams, J and Bhat, G. M., 2013: Shaken and Stirred: Seismites and Tsunamites at the Permian-Triassic boundary, Guryul Ravine, Kashmir, India. Palaios, v. 28, 568-582. Krystyn, L., Balini, M. and Nicora, A., 2004: Lower and Middle Triassic

Paleomagnetism and dating of a thick lava pile in the Permian Bakaly formation of eastern Kazakhstan: Regularities and singularities of the paleomagnetic record in thick lava series

NASA Astrophysics Data System (ADS)

Bazhenov, Mikhail L.; Van der Voo, Rob; Menzo, Zachary; Dominguez, Ada R.; Meert, Joseph G.; Levashova, Natalia M.

2016-04-01

Paleomagnetic results on thick lava series are among the most important sources of information on the characteristics of ancient geomagnetic fields. Most paleo-secular variation data from lavas (PSVL) are of late Cenozoic age. There are far fewer results from lavas older than 5 Ma. The Central Asia Orogenic Belt that occupies several million square kilometers in Asia is probably the world's largest area of Paleozoic volcanism and is thus an attractive target for PSVL studies. We studied a ca. 1700 m thick lava pile in eastern Kazakhstan of Early Permian age. Magmatic zircons, successfully separated from an acid flow in this predominantly basaltic sequence, yielded an Early Permian age of 286.3 ± 3.5 Ma. Oriented samples were collected from 125 flows, resulting in 88 acceptable quality flow-means (n ⩾ 4 samples, radius of confidence circle α95 ⩽ 15°) of the high-temperature magnetization component. The uniformly reversed component is pre-tilting and arguably of a primary origin. The overall mean direction has a declination = 242.0° and an inclination = -56.2° (k = 71.5, α95 = 1.8°; N = 88 sites; pole at 44.1°N, 160.6°E, A95 = 2.2°). Our pole agrees well with the Early Permian reference data for Baltica, in accord with the radiometric age of the lava pile and geological views on evolution of the western part of the Central Asia Orogenic Belt. The new Early Permian result indicates a comparatively low level of secular variation especially when compared to PSVL data from intervals with frequent reversals. Still, the overall scatter of dispersion estimates that are used as proxies for SV magnitudes, elongation values and elongation orientations for PSVL data is high and cannot be fitted into any particular field model with fixed parameters. Both observed values and numerical simulations indicate that the main cause for the scatter of form parameters (elongation values and elongation orientations) is the too small size of collections. Dispersion estimates

Insect mimicry of plants dates back to the Permian

PubMed Central

Garrouste, Romain; Hugel, Sylvain; Jacquelin, Lauriane; Rostan, Pierre; Steyer, J.-Sébastien; Desutter-Grandcolas, Laure; Nel, André

2016-01-01

In response to predation pressure, some insects have developed spectacular plant mimicry strategies (homomorphy), involving important changes in their morphology. The fossil record of plant mimicry provides clues to the importance of predation pressure in the deep past. Surprisingly, to date, the oldest confirmed records of insect leaf mimicry are Mesozoic. Here we document a crucial step in the story of adaptive responses to predation by describing a leaf-mimicking katydid from the Middle Permian. Our morphometric analysis demonstrates that leaf-mimicking wings of katydids can be morphologically characterized in a non-arbitrary manner and shows that the new genus and species Permotettigonia gallica developed a mimicking pattern of forewings very similar to those of the modern leaf-like katydids. Our finding suggests that predation pressure was already high enough during the Permian to favour investment in leaf mimicry. PMID:27996977

Insect mimicry of plants dates back to the Permian.

PubMed

Garrouste, Romain; Hugel, Sylvain; Jacquelin, Lauriane; Rostan, Pierre; Steyer, J-Sébastien; Desutter-Grandcolas, Laure; Nel, André

2016-12-20

In response to predation pressure, some insects have developed spectacular plant mimicry strategies (homomorphy), involving important changes in their morphology. The fossil record of plant mimicry provides clues to the importance of predation pressure in the deep past. Surprisingly, to date, the oldest confirmed records of insect leaf mimicry are Mesozoic. Here we document a crucial step in the story of adaptive responses to predation by describing a leaf-mimicking katydid from the Middle Permian. Our morphometric analysis demonstrates that leaf-mimicking wings of katydids can be morphologically characterized in a non-arbitrary manner and shows that the new genus and species Permotettigonia gallica developed a mimicking pattern of forewings very similar to those of the modern leaf-like katydids. Our finding suggests that predation pressure was already high enough during the Permian to favour investment in leaf mimicry.

Insect mimicry of plants dates back to the Permian

NASA Astrophysics Data System (ADS)

Garrouste, Romain; Hugel, Sylvain; Jacquelin, Lauriane; Rostan, Pierre; Steyer, J.-Sébastien; Desutter-Grandcolas, Laure; Nel, André

2016-12-01

In response to predation pressure, some insects have developed spectacular plant mimicry strategies (homomorphy), involving important changes in their morphology. The fossil record of plant mimicry provides clues to the importance of predation pressure in the deep past. Surprisingly, to date, the oldest confirmed records of insect leaf mimicry are Mesozoic. Here we document a crucial step in the story of adaptive responses to predation by describing a leaf-mimicking katydid from the Middle Permian. Our morphometric analysis demonstrates that leaf-mimicking wings of katydids can be morphologically characterized in a non-arbitrary manner and shows that the new genus and species Permotettigonia gallica developed a mimicking pattern of forewings very similar to those of the modern leaf-like katydids. Our finding suggests that predation pressure was already high enough during the Permian to favour investment in leaf mimicry.

The Permian-Triassic boundary & mass extinction in China

USGS Publications Warehouse

Metcalfe, I.; Nicoll, R.S.; Mundil, R.; Foster, C.; Glen, J.; Lyons, J.; Xiaofeng, W.; Cheng-Yuan, W.; Renne, P.R.; Black, L.; Xun, Q.; Xiaodong, M.

2001-01-01

The first appearance of Hindeodus parvus (Kozur & Pjatakova) at the Permian-Triassic (P-T) GSSP level (base of Bed 27c) at Meishan is here confirmed. Hindeodus changxingensis Wang occurs from Beds 26 to 29 at Meishan and appears to be restricted to the narrow boundary interval immediately above the main mass extinction level in Bed 25. It is suggested that this species is therefore a valuable P-T boundary interval index taxon. Our collections from the Shangsi section confirm that the first occurrence of Hindeodus parvus in that section is about 5 in above the highest level from which a typical Permian fauna is recovered. This may suggest that that some section may be missing at Meishan. The age of the currently defined Permian-Triassic Boundary is estimated by our own studies and a reassessment of previous worker's data at c. 253 Ma, slightly older than our IDTIMS 206Pb/238U age of 252.5 ??0.3 Ma for Bed 28, just 8 cm above the GSSP boundary (Mundil et al., 2001). The age of the main mass extinction, at the base of Bed 25 at Meishan, is estimated at slightly older than 254 Ma based on an age of >254 Ma for the Bed 25 ash. Regardless of the absolute age of the boundary, it is evident that the claimed <165,000 y short duration for the negative carbon isotope excursion at the P-T boundary (Bowring et al., 1998) cannot be confirmed. Purportedly extraterrestrial fullerenes at the boundary (Hecker et al., 2001) have equivocal significance due to their chronostratigraphic non-uniqueness and their occurrence in a volcanic ash.

Shallow lacustrine system of the Permian Pedra de Fogo Formation, Western Gondwana, Parnaíba Basin, Brazil

NASA Astrophysics Data System (ADS)

Araújo, Raphael Neto; Nogueira, Afonso César Rodrigues; Bandeira, José; Angélica, Rômulo Simões

2016-04-01

contact with the Motuca Formation, are considered here as excellent biostratigraphic markers. Fish remains, ostracods, bryozoans and scolecodonts represent other fossils that are present in the succession. Mudflat deposits developed in an arid and hot climate probably in the Early Permian. Semi-arid conditions prevailed in the Middle Permian allowing the proliferation of fauna and flora in adjacent humid regions and onto the lake margin. The climate variation was responsible for the contraction and expansion phases of the lake, fed by sporadic sheet floods carrying plant remains. The reestablishment of the arid climate, at the end of Permian, marks the final sedimentation of the Pedra de Fogo Formation, linked to the consolidation of the Pangaea Supercontinent. This last event was concomitant with the deposition of the Motuca Formation red beds and the development of extensive ergs related to the Triassic Sambaíba Formation in Western Gondwana.

77 FR 65446 - Iowa Pacific Holdings, LLC and Permian Basin Railways-Control Exemption-Cape Rail, Inc. and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-26

... Holdings, LLC and Permian Basin Railways--Control Exemption--Cape Rail, Inc. and Massachusetts Coastal...), and Massachusetts Coastal Railroad, LLC (Mass Coastal) (collectively, applicants) have filed a verified notice of exemption for Iowa Pacific and Permian to acquire indirect control of Mass Coastal, a...

Eopolydiexodina (Middle Permian giant fusulinids) from Afghanistan: Biometry, morphometry, paleobiogeography, and end-Guadalupian events

NASA Astrophysics Data System (ADS)

Colpaert, Clémentine; Monnet, Claude; Vachard, Daniel

2015-04-01

The most spectacular macroevolutionary trend presented by the genera of schwagerinoid fusulinids, during the Pennsylvanian -Permian, is an enormous increase in size, which culminated in the Middle Permian with Eopolydiexodina. However, this potential major biogeographic marker, during the Kubergandian-early Midian time interval, is as yet hampered by its poor taxonomic characterization. Hence, Eopolydiexodina is revised here using biometric and morphometric methods applied to large collections from Afghanistan and selected taxa in the literature. These multivariate analyses consist of classical linear test parameters, as well as new area parameters acquired by computer image analysis. The Afghan species are re-defined, and some other species, occasionally described as Cimmerian, are re-discussed. These methods, combined with classical morphological analyses, also permit to conclude that the largest Eopolydiexodina of Afghanistan are microspheric specimens (probably agamonts) of E. afghanensis and E. bithynica. Two megalospheric groups of individuals (probably gamonts and schizonts) are represented in both species, as well as in E. persica and E. darvasica. Due to this presence of gamonts, agamonts and schizonts in several species, Eopolydiexodina is probably the oldest identified trimorphic genus among the large benthic foraminifers. Biostratigraphically, Eopolydiexodina appears restricted to the late Kubergandian to early Midian. The associated Afghan fusulinids (Dunbarula, Kahlerina, Afghanella, Yangchienia, Sumatrina, and Codonofusiella) allow proposing an accurate biostratigraphy of the Eopolydiexodina species in the Murgabian-Midian boundary interval. Paleobiogeographically, Eopolydiexodina was essentially located in the Laurentian and Perigondwanan borders of the Tethys. The possible presence of Eopolydiexodina in the Cimmerian Continent and in some regions of China has never been irrefutably demonstrated. This paleobiological revision of Eopolydiexodina and

Permian U-Pb (CA-TIMS) zircon ages from Australia and China: Constraining the time scale of environmental and biotic change

NASA Astrophysics Data System (ADS)

Denyszyn, S. W.; Mundil, R.; Metcalfe, I.; He, B.

2010-12-01

In eastern Australia, the interconnected Bowen and Sydney Basins are filled with terrestrial sediments of late Paleozoic to early Mesozoic age. These sedimentary units record significant evolutionary events of eastern Gondwana during the time interval between two major mass extinctions (end Middle Permian and Permian-Triassic), and also provide lithological evidence for the Carboniferous-Permian Late Paleozoic Ice Age of southern Pangea, considered to be divisible into up to seven discrete glaciation events in Australia [e.g., 1]. These glaciations are currently assigned ages that indicate that the last of the glaciations predate the end Middle Permian mass extinction at ca. 260 Ma. However, the estimates for the time and durations are largely based on biostratigraphy and lithostratigraphy that, in the absence of robust and precise radioisotopic ages, are unacceptably fragile for providing an accurate high-resolution framework. Interbedded with the sediments are numerous tuff layers that contain zircon, many of which are associated with extensive coal measures in the Sydney and Bowen Basins. Published SHRIMP U-Pb zircon ages [2, 3] have been shown to be less precise and inaccurate when compared to ages applying the CA-TIMS method to the same horizons. Also within the late Middle Permian, the eruption of the Emeishan flood basalts in SW China has been proposed to have caused the end Middle Permian mass extinction [e.g., 4], though a causal link between these events demands a rigorous test that can only be provided by high-resolution geochronology. We present new U-Pb (CA-TIMS) zircon ages on tuff layers from the Sydney and Bowen Basins, with the purpose of generating a timescale for the Upper Permian of Australia to allow correlation with different parts of the world. Initial results, with permil precision, date a tuff layer within the uppermost Bandanna Fm. to ca. 252 Ma, a tuff within the Moranbah Coal Measures to ca. 256 Ma, and a tuff within the Ingelara Fm. to

Repeated Carbon-Cycle Disturbances at the Permian-Triassic Boundary Separate two Mass Extinctions

NASA Astrophysics Data System (ADS)

Nicol, J. A.; Watson, L.; Claire, M.; Buick, R.; Catling, D. C.

2004-12-01

Non-marine organic matter in Permian-Triassic sediments from the Blue Mountains, eastern Australia shows seven negative δ13C excursions of up to 7%, terminating with a positive excursion of 4%. Fluctuations start at the late Permian Glossopteris floral extinction and continue until just above the palynological Permian-Triassic boundary, correlated with the peak of marine mass extinction. The isotopic fluctuations are not linked to changes in depositional setting, kerogen composition or plant community, so they evidently resulted from global perturbations in atmospheric δ13C and/or CO2. The pattern was not produced by a single catastrophe such as a meteorite impact, and carbon-cycle calculations indicate that gas release during flood-basalt volcanism was insufficient. Methane-hydrate melting can generate a single -7% shift, but cannot produce rapid multiple excursions without repeated reservoir regeneration and release. However, the data are consistent with repeated overturning of a stratified ocean, expelling toxic gases that promoted sequential mass extinctions in the terrestrial and marine realms.

Fluid-rock reactions in an evaporitic melange, Permian Haselgebirge, Austrian Alps

USGS Publications Warehouse

Spotl, C.; Longstaffe, F.J.; Ramseyer, K.; Kunk, Michael J.; Wiesheu, R.

1998-01-01

Tectonically isolated blocks of carbonate rocks present within the anhydritic Haselgebirge melange of the Northern Calcareous Alps record a complex history of deformation and associated deep-burial diagenetic to very low-grade metamorphic reactions. Fluids were hot (up to ~ 250 ??C) and reducing brines charged with carbon dioxide. Individual carbonate outcrops within the melange record different regimes of brine-rock reactions, ranging from pervasive dolomite recrystallization to dedolomitization. Early diagenetic features in these carbonates were almost entirely obliterated. Matrix dolomite alteration was related to thermochemical sulphate reduction (TSR) recognized by the replacement of anhydrite by calcite + pyrite ?? native sulphur. Pyrite associated with TSR is coarsely crystalline and characterized by a small sulphur isotope fractionation relative to the precursor Permian anhydrite. Carbonates associated with TSR show low Fe/Mn ratios reflecting rapid reaction of ferrous iron during sulphide precipitation. As a result, TSR-related dolomite and calcite typically show bright Mn(II)-activated cathodoluminescence in contrast to the dull cathodoluminescence of many (ferroan) carbonate cements in other deep-burial settings. In addition to carbonates and sulphides, silicates formed closely related to TSR, including quartz, K-feldspar, albite and K-mica. 40Ar/39Ar analysis of authigenic K-feldspar yielded mostly disturbed step-heating spectra which suggest variable cooling through the argon retention interval for microcline during the Late Jurassic. This timing coincides with the recently recognized subduction and closure of the Meliata-Hallstatt ocean to the south of the Northern Calcareous Alps and strongly suggests that the observed deep-burial fluid-rock reactions were related to Jurassic deformation and melange formation of these Permian evaporites.

Molecular characterization of Mycobacterium tuberculosis isolated in the State of Parana in southern Brazil.

PubMed

Malaghini, Marcelo; Brockelt, Sonia Regina; Burger, Marion; Kritski, Afrânio; Thomaz-Soccol, Vanete

2009-01-01

Sequence IS6110 has been successfully used throughout the world for characterizing the Mycobacterium tuberculosis lineages. The aim of this study was to obtain data about circulating strains of M. tuberculosis in patients from the State of Parana in southern Brazil. Sixty-two clinical specimens obtained from sputum, bronchial aspirate, biopsy and urine from 62 patients clinically diagnosed with tuberculosis and admitted to the SUS-Brazil - The Brazilian Centralized Health Service System - were genotyped by the mixed-linker PCR DNA fingerprinting technique. The analysis demonstrated that the number of copies of the IS6110 sequence per isolates varied from four to 13 bands, with an average number of 8.5. From this, 93% of the isolates presented multiple copies. Isolates with no copies of the IS6110 element were not observed. The genetic analysis by UPGMA grouped the 62 isolates by similarity into three different groups: the first group contained two strains, the second was composed of 23, and the third, a more heterogeneous group, contained 37 isolates. Only two isolates (3.2%) formed a cluster; in other words, they presented a pattern of polymorphism with similarity above 95%. Such findings suggest that in the State of Parana, illness predominantly develops through reactivation of the latent infection as opposed to exogenous transmission. The methodology used (mixed-linker PCR DNA fingerprinting) allowed for 93.5% differentiation of the isolates tested, and proved to be a powerful tool for differentiation in the molecular genotyping of M. tuberculosis.

Sedimentary conditions of Upper Permian volcano-clastic rocks of Ayan-Yrahskiy anticlinorium (Verhoyansk-Kolyma orogen)

NASA Astrophysics Data System (ADS)

Astakhova, Anna; Khardikov, Aleksandr

2013-04-01

Sedimentation conditions of upper Permian volcano-clastic rocks of Ayan-Yurakhsky anticlinorium are the reason of discussions between researchers. It is important to correctly solve this problem. Investigation allows us to conclude that upper Permian sediments was formed due to high rate deltaic sedimentation on shelf and continental slope of epicontinental sea basin. More than 45 outcrops of upper Permian sediments were described within Ayan-Yurakhsky anticlinorium. Termochemical and X-ray phase, lithological facies, stadial, paleogeographic and others were applied. Investigation allows to classify following types: tuffs, tuffites of andesites, andesi-dacites, sandstone tuffs, siltstone tuffs and claystone tuffs. Two facies were deliniated in the research area: 1) delta channel facies 2) epicontinental sea shelf edge and continental slope. Delta channel facies are located on the south-west part of Aian-Yrahskiy anticlinorium. It is composed of silty packsand and psammitic tuff-siltstone alternation and gravel-psammitic andesi-dacitic tuffute and tuff-breccia bands. Sediments have cross-bedding, through cross-bedding, curvilinear lamination structures. Facies occurred during high rate deltaic sedimentation on the shelf of epicontinental sea. Epicontinental sea shelf edge and continental slope facies are located on the south-west part. Sediments are represented by large thickness tuff-siltstone with tuff-sandstone, tuff-madstone, tuff, tuffite bands and lenses. Large number of submarine landslides sediments provide evidence that there was high angle sea floore environment. 30-50 m diametr eruption centers were described by authors during geological traverses. They are located in Kulu river basin. Their locations are limited by deep-seated pre-ore fault which extended along Ayan-Yurakhsky anticlinorium. U-Pb SHRIMP method showed that the average age of circons, taken from eruption centers, is Permian (256,3±3,7 ma). This fact confirms our emphasis that eruption

Evolving Mantle Sources in Postcollisional Early Permian-Triassic Magmatic Rocks in the Heart of Tianshan Orogen (Western China)

NASA Astrophysics Data System (ADS)

Tang, Gong-Jian; Cawood, Peter A.; Wyman, Derek A.; Wang, Qiang; Zhao, Zhen-Hua

2017-11-01

Magmatism postdating the initiation of continental collision provides insight into the late stage evolution of orogenic belts including the composition of the contemporaneous underlying subcontinental mantle. The Awulale Mountains, in the heart of the Tianshan Orogen, display three types of postcollisional mafic magmatic rocks. (1) A medium to high K calc-alkaline mafic volcanic suite (˜280 Ma), which display low La/Yb ratios (2.2-11.8) and a wide range of ɛNd(t) values from +1.9 to +7.4. This suite of rocks was derived from melting of depleted metasomatized asthenospheric mantle followed by upper crustal contamination. (2) Mafic shoshonitic basalts (˜272 Ma), characterized by high La/Yb ratios (14.4-20.5) and more enriched isotope compositions (ɛNd(t) = +0.2 - +0.8). These rocks are considered to have been generated by melting of lithospheric mantle enriched by melts from the Tarim continental crust that was subducted beneath the Tianshan during final collisional suturing. (3) Mafic dikes (˜240 Ma), with geochemical and isotope compositions similiar to the ˜280 Ma basaltic rocks. This succession of postcollision mafic rock types suggests there were two stages of magma generation involving the sampling of different mantle sources. The first stage, which occurred in the early Permian, involved a shift from depleted asthenospheric sources to enriched lithospheric mantle. It was most likely triggered by the subduction of Tarim continental crust and thickening of the Tianshan lithospheric mantle. During the second stage, in the middle Triassic, there was a reversion to more asthenospheric sources, related to postcollision lithospheric thinning.

End-Permian Mass Extinction in the Oceans: An Ancient Analog for the Twenty-First Century?

NASA Astrophysics Data System (ADS)

Payne, Jonathan L.; Clapham, Matthew E.

2012-05-01

The greatest loss of biodiversity in the history of animal life occurred at the end of the Permian Period (˜252 million years ago). This biotic catastrophe coincided with an interval of widespread ocean anoxia and the eruption of one of Earth's largest continental flood basalt provinces, the Siberian Traps. Volatile release from basaltic magma and sedimentary strata during emplacement of the Siberian Traps can account for most end-Permian paleontological and geochemical observations. Climate change and, perhaps, destruction of the ozone layer can explain extinctions on land, whereas changes in ocean oxygen levels, CO2, pH, and temperature can account for extinction selectivity across marine animals. These emerging insights from geology, geochemistry, and paleobiology suggest that the end-Permian extinction may serve as an important ancient analog for twenty-first century oceans.

Paleomagnetism and Magnetostratigraphy of Upper Permian to Lower Triassic (?) Beaufort Group Strata at Bethulie, Karoo Basin, Free State Province, South Africa

NASA Astrophysics Data System (ADS)

Geissman, J. W.; Gastaldo, R. A.; Neveling, J.; Makubalo, S.

2017-12-01

A multifaceted approach to understand the timing of interpreted environmental changes during the Late Permian to possibly Early Triassic (?) time in the Beaufort Group strata of the Karoo Basin includes work to establish robust magnetic polarity records for sections previously interpreted to encompass end-Permian extinction events. Demonstrating the preservation of an early-acquired remanence (RM) in Karoo strata is required for a robust magnetostratigraphy. Yet, this is challenging due to thermochemical effects related to the Early Jurassic (ca. 183 Ma) Karoo Large Igneous Province (LIP), and the NE to SW increase in burial diagenesis attending Cape Fold Belt tectonism. Documentation of a primary RM in these strata, which appears to be preserved in some areas, requires careful laboratory- and field-based assessment. We report data from 53 sites collected at the well-studied Bethulie section, Free State Province, in which several <2 m wide Karoo LIP dikes crop out. We obtained 7-10+ independent samples per individual horizon to assess ChRM uniformity. Strata well-removed from dikes yield both normal and reverse polarity ChRM. It is always the case that the first-removed RM is a NNW seeking, moderate to steep negative-inclination ChRM (normal polarity); NRM intensities are typically 1 to 5 mA/m. Sites BT15 and BT21, which are located in strata lying some 4 m below the often-cited "event bed" interval inferred to be the terrestrial expression of the Permian/Triassic boundary, is dominated by a well-defined reverse RM with a normal overprint RM unblocked below 400oC, implying elevated temperatures (i.e., 100 to 250oC+) for ca. 1 Ma (+/-). Contact tests are positive but complicated. Host strata collected in distances equal to or less than 1-2 dike widths from the intrusions have been thermally remagnetized and demonstrate high NRM intensities (> 50 mA/m). Collectively, we interpret these data to indicate that any ChRM, with the exception of those from host strata in

High precision time calibration of the Permian-Triassic boundary mass extinction event in a deep marine context

NASA Astrophysics Data System (ADS)

Baresel, Björn; Bucher, Hugo; Brosse, Morgane; Bagherpour, Borhan; Schaltegger, Urs

2015-04-01

To construct a revised and high resolution calibrated time scale for the Permian-Triassic boundary (PTB) we use (1) high-precision U-Pb zircon age determinations of a unique succession of volcanic ash layers interbedded with deep water fossiliferous sediments in the Nanpanjiang Basin (South China) combined with (2) accurate quantitative biochronology based on ammonoids, conodonts, radiolarians, and foraminifera and (3) tracers of marine bioproductivity (carbon isotopes) across the PTB. The unprecedented precision of the single grain chemical abrasion isotope-dilution thermal ionization mass spectrometry (CA-ID-TIMS) dating technique at sub-per mil level (radio-isotopic calibration of the PTB at the <100 ka level) now allows calibrating magmatic and biological timescales at resolution adequate for both groups of processes. Using these alignments allows (1) positioning the PTB in different depositional setting and (2) solving the age contradictions generated by the misleading use of the first occurrence (FO) of the conodont Hindeodus parvus, whose diachronous first occurrences are arbitrarily used for placing the base of the Triassic. This new age framework provides the basis for a combined calibration of chemostratigraphic records with high-resolution biochronozones of the Late Permian and Early Triassic. Here, we present new single grain U-Pb zircon data of volcanic ash layers from two deep marine sections (Dongpan and Penglaitan) revealing stratigraphic consistent dates over several volcanic ash layers bracketing the PTB. These analyses define weighted mean 206Pb/238U ages of 251.956±0.033 Ma (Dongpan) and 252.062±0.043 Ma (Penglaitan) for the last Permian ash bed. By calibration with detailed litho- and biostratigraphy new U-Pb ages of 251.953±0.038 Ma (Dongpan) and 251.907±0.033 Ma (Penglaitan) are established for the onset of the Triassic.

Source and Extent of Volcanic Ashes at the Permian-Triassic Boundary in South China and Its implications

NASA Astrophysics Data System (ADS)

Wang, M.; Zhong, Y. T.; Hou, Y. L.; He, B.

2017-12-01

Highly correlated with the Permian-Triassic Boundary (PTB) Mass Extinction in stratigraphic section, volcanic ashes around the P-T Boundary in South China have been suggested to be a likely cause of the PTB Mass Extinction. So the nature, source and extent of these volcanic ashes have great significance in figuring out the cause of the PTB Mass Extinction. In this study, we attempt to constrain the source and extent of the PTB volcanic ashes in South China by studying pyroclastic sedimentary rocks and the spatial distribution of tuffs and ashes in South China. The detrital zircons of tuffaceous sandstones from Penglaitan section yield an age spectrum peaked at 252Ma, with ɛHf(t) values varying from -20 to -5 ,and have Nb/Hf, Th/Nb and Hf/Th ratios similar to those from arc/orogenic-related settings. Coarse tuffaceous sandstones imply that their source is in limited distance. Those pyroclastic sedimentary rocks in Penglaitan are well correlated with the PTB volcanic ashes in Meishan GSSP section in stratigraphy. In the spatial distribution, pyroclastic sedimentary rocks and tuffs distribute only in southwest of South China, while finer volcanic ashes are mainly in the northern part. This spatial distribution suggests the source of tuffs and ashes was to the south or southwest of South China. Former studies especially that of Permian-Triassic magmatism in Hainan Island have supported the existence of a continental arc related to the subduction and closure of Palaeo-Tethys on the southwestern margin of South China during Permian to early Triassic. It is suggested that the PTB ashes possibly derived from this Paleo-Tethys continental arc. The fact that volcanic ashes haven't been reported or found in PTB stratum in North China or Northwest China implies a limited extent of the volcanism, which thus is too small to cause the PTB mass extinction.

Mid-Permian Phosphoria Sea in Nevada and the Upwelling Model

USGS Publications Warehouse

Ketner, Keith B.

2009-01-01

The Phosphoria Sea extended at least 500 km westward and at least 700 km southwestward from its core area centered in southeastern Idaho. Throughout that extent it displayed many characteristic features of the core: the same fauna, the same unique sedimentary assemblage including phosphate in mostly pelletal form, chert composed mainly of sponge spicules, and an association with dolomite. Phosphoria-age sediments in Nevada display ample evidence of deposition in shallow water. The chief difference between the sediments in Nevada and those of the core area is the greater admixture of sandstone and conglomerate in Nevada. Evidence of the western margin of the Phosphoria Sea where the water deepened and began to lose its essential characteristics is located in the uppermost part of the Upper Devonian to Permian Havallah sequence, which has been displaced tectonically eastward an unknown distance. The relatively deep water in which the mid-Permian part of the Havallah was deposited was a sea of probably restricted east-west width and was floored by a very thick sequence of mainly terrigenous sedimentary rocks. The phosphate content of mid-Permian strata in western exposures tends to be relatively low as a percentage, but the thickness of those strata tends to be high. The core area in and near southeastern Idaho where the concentration of phosphate is highest was separated from any possible site of upwelling oceanic waters by a great expanse of shallow sea.

Lower Permian Dry Mountain trough, eastern Nevada: preliminary basin analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, D.L.; Snyder, W.S.; Spinosa, C.

1987-08-01

The Lower Permian Dry Mountain trough (DMT) is one of several basins that developed during the Late Pennsylvanian to Permian along the western edge of the North American continent. A tectonic mechanism has been suggested for the subsidence of the DMT, possibly due to reactivation of the Antler orogenic belt during the waning stages of Ancestral Rocky Mountain deformation. The DMT records marked subsidence with the appearance during the Artinskian (latest Wolfcampian) of a deeper water facies that consists of thin-bedded silty micrites and micritic mudstones rich in radiolarians and sponge spicules, characterized by a relative abundance of ammonoids, andmore » rarer conodonts and Nereites ichnofacies trace fossils. Taxa recovered from a distinctive concretionary horizon at various locations provide an Artinskian datum on which to palinspastically reconstruct the DMT paleogeography. These taxa include ammonoids: Uraloceras, Medlicottia, Marathonites, Crimites, Metalegoceras, properrinitids; and conodonts: Neogondolella bisselli, Sweetognathus whitei, S. behnkeni, and Diplognathodus stevensi. The western margin facies of the DMT consists of Permian Carbon Ridge/Garden Valley Formations. Here, lowermost black Artinskianage euxinic micrites, considered a potential source rock for petroleum generation, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by a thick, eastwardly prograding conglomerate wedge. Seismic profiles across Diamond Valley indicate a 3.0-4.6-km thick Tertiary sequence above the Paleozoic strata.« less

The Parana paradox: can a model explain the decadal impacts of climate variability and land-cover change?

NASA Astrophysics Data System (ADS)

Lee, E.; Moorcroft, P. R.; Livino, A.; Briscoe, J.

2013-12-01

Since the 1970s, despite a decrease in rainfall, flow in the Parana river has increased. This paradox is explored using the Ecosystem Demography (ED) model. If there were no change in land cover, the modeled runoff decreased from the 1970s to the 2000s by 11.8% (with 1970 land cover) or 18.8% (with 2008 land cover). When the model is run holding climate constant, the decadal average of the modeled runoff increased by 24.4% (with the 1970s climate) or by 33.6% (with 2000s climate). When the model is run allowing both the actual climate and land-cover changes, the model gives an increase in the decadal average of runoff by 8.5%. This agrees well with 10.5% increase in the actual stream flow as measured at Itaipu. There are three main conclusions from this work. First, the ED model is able to explain a major, paradoxical, reality in the Parana basin. Second, it is necessary to take into account both climate and land use changes when exploring past or future changes in river flows. Third, the ED model, now coupled with a regional climate model (i.e., EDBRAMS), is a sound basis for exploring likely changes in river flows in major South American rivers.

Integrated multi-stratigraphic study of the Coll de Terrers late Permian-Early Triassic continental succession from the Catalan Pyrenees (NE Iberian Peninsula): A geologic reference record for equatorial Pangaea

NASA Astrophysics Data System (ADS)

Mujal, Eudald; Fortuny, Josep; Pérez-Cano, Jordi; Dinarès-Turell, Jaume; Ibáñez-Insa, Jordi; Oms, Oriol; Vila, Isabel; Bolet, Arnau; Anadón, Pere

2017-12-01

The most severe biotic crisis on Earth history occurred during the Permian-Triassic (PT) transition around 252 Ma. Whereas in the marine realm such extinction event is well-constrained, in terrestrial settings it is still poorly known, mainly due to the lack of suitable complete sections. This is utterly the case along the Western Tethys region, located at Pangaea's equator, where terrestrial successions are typically build-up of red beds often characterised by a significant erosive gap at the base of the Triassic strata. Henceforth, documenting potentially complete terrestrial successions along the PT transition becomes fundamental. Here, we document the exceptional Coll de Terrers area from the Catalan Pyrenees (NE Iberian Peninsula), for which a multidisciplinary research is conducted along the PT transition. The red-bed succession, located in a long E-W extended narrow rift system known as Pyrenean Basin, resulted from a continuous sedimentary deposition evolving from meandering (lower Upper Red Unit) to playa-lake/ephemeral lacustrine (upper Upper Red Unit) and again to meandering settings (Buntsandstein facies). Sedimentary continuity is suggested by preliminary cyclostratigraphic analysis that warrants further analysis. Our combined sedimentological, mineralogical and geochemical data infer a humid-semiarid-humid climatic trend across the studied succession. The uppermost Permian strata, deposited under an orbitally controlled monsoonal regime, yields a relatively diverse ichnoassemblage mainly composed of tetrapod footprints and arthropod trace fossils. Such fossils indicate appropriate life conditions and water presence in levels that also display desiccation structures. These levels alternate with barren intervals formed under dry conditions, being thus indicative of strong seasonality. All these features are correlated with those reported elsewhere in Gondwana and Laurasia, and suggest that the Permian-Triassic boundary might be recorded somewhere around

Permian-Triassic Tethyan realm reorganization: Implications for the outward Pangea margin

NASA Astrophysics Data System (ADS)

Riel, Nicolas; Jaillard, Etienne; Martelat, Jean-Emmanuel; Guillot, Stéphane; Braun, Jean

2018-01-01

We present a new conceptual model to explain the first order Permian-Triassic evolution of the whole > 30 000 km long Pangea margin facing the Panthalassa ocean. Compilation of available geological, geochemical, geochronogical and paleomagnetic data all along this system allowed us to distinguish three part of the margin: western Laurentia, western Gondwana and eastern Gondwana. These segments record distinct tectonic and magmatic events, which all occur synchronously along the whole margin and correlate well with the main geodynamic events of this period, i.e. subduction of the Paleotethys mid-ocean ridge at 310-280 Ma, opening of the Neotethys at 280-260 Ma, counterclockwise rotation of Pangea at 260-230 Ma and closure of the Paleotethys at 230-220 Ma. Between 260 and 230 Ma, the reorganization of the Tethyan realm triggered the up to 35° rotation of Pangea around an Euler pole located in northernmost South America. This implied both an increase and a decrease of the convergence rate between the margin and the Panthalassa ocean, north and south of the Euler pole, respectively. Thus, the Permian-Triassic Pangean margin was marked: in western Laurentia by marginal sea closure, in western Gondwana by widespread bimodal magmatic and volcanic activity, in eastern Gondwana by transpressive orogenic phase. Therefore, we propose that the Permian-Triassic evolution of the outward margin of Pangea was controlled by the Tethyan realm reorganization.

Prelude of benthic community collapse during the end-Permian mass extinction in siliciclastic offshore sub-basin: Brachiopod evidence from South China

NASA Astrophysics Data System (ADS)

Wu, Huiting; He, Weihong; Weldon, Elizabeth A.

2018-04-01

Analysis of the Permian-Triassic palaeocommunities from basinal facies in South China provides an insight into the environmental deterioration occurring in the prelude to the mass extinction event. Quantitative and multivariate analyses on three brachiopod palaeocommunities from the Changhsingian to the earliest Triassic in basinal facies in South China have been undertaken in this study. Although the end-Permian extinction has been proved to be a one-stepped event, ecological warning signals appeared in the palaeocommunities long before the main pulse of the event. A brachiopod palaeocommunity turnover occurred in the upper part of the Clarkina changxingensis Zone, associated with a significant decrease of palaeocommunity diversity and brachiopod body size. During this turnover the dominant genera changed from Fusichonetes and Crurithyris (or/and Paracrurithyris) to the more competitive genus Crurithyris (or/and Paracrurithyris). The brachiopod palaeocommunity turnover was supposed to be triggered by the decreased marine primary productivity and increased volcanic activity. Moreover, such early warning signals are found not only in the deep-water siliceous facies, but also in the shallow-water clastic facies and carbonate rock facies in South China.

AUthigenic feldspar as an indicator of paleo-rock/water interactions in Permian carbonates of the Northern Calcareous Alps, Austria

USGS Publications Warehouse

Spotl, C.; Kralik, M.; Kunk, Michael J.

1996-01-01

Dolostones interbedded with Upper Permian evaporites at the base of the Northern Calcareous Alps contain abundant authigenic K-feldspar. Two petrographically, structurally, and isotopically distinct generations of K-feldspar can be distinguished: crystals composed of an inclusion-rich core and a clear rim, and optically unzoned, transparent crystals. Both feldspar types have essentially identical K-feldspar end-member compositions with ??? 99.5 mole % Or component. Low oxygen isotope ratios (+16.1??? to +18.1??? SMOW) suggest precipitation from 18O-enriched, saline fluids at temperatures in excess of ??? 140??C. 40Ar/39Ar plateau-age spectra of five samples range from 145 ?? 1 to 144 ?? 1 Ma (Early Berriasian) and suggest that both types of feldspar were formed within an interval that did not exceed ??? 2 m.y. Rb/Sr model ages range from 152 to 140 Ma, assuming that the burial diagenetic regime was buffered with respect to strontium by the associated marine Permian evaporites. Authigenic K-feldspar records two distinct events of hot brine flow, most likely triggered by tectonic movements (detachment) and by an increase in the subsurface temperature in response to thrust loading.

Early Triassic Marine Biotic Recovery: The Predators' Perspective

PubMed Central

Scheyer, Torsten M.; Romano, Carlo; Jenks, Jim; Bucher, Hugo

2014-01-01

Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian) in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles) to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates) for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became apparent. PMID

Early Triassic marine biotic recovery: the predators' perspective.

PubMed

Scheyer, Torsten M; Romano, Carlo; Jenks, Jim; Bucher, Hugo

2014-01-01

Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian) in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles) to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates) for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became apparent.

Carboniferous and Permian evolutionary records for the Paleo-Tethys Ocean constrained by newly discovered Xiangtaohu ophiolites from central Qiangtang, central Tibet

NASA Astrophysics Data System (ADS)

Zhang, Xiu-Zheng; Dong, Yong-Sheng; Wang, Qiang; Dan, Wei; Zhang, Chunfu; Deng, Ming-Rong; Xu, Wang; Xia, Xiao-Ping; Zeng, Ji-Peng; Liang, He

2016-07-01

Reconstructing the evolutionary history of the Paleo-Tethys Ocean remains at the center of debates over the linkage between Gondwana dispersion and Asian accretion. Identifying the remnants of oceanic lithosphere (ophiolites) has very important implications for identifying suture zones, unveiling the evolutionary history of fossil oceans, and reconstructing the amalgamation history between different blocks. Here we report newly documented ophiolite suites from the Longmu Co-Shuanghu Suture zone (LSSZ) in the Xiangtaohu area, central Qiangtang block, Tibet. Detailed geological investigations and zircon U-Pb dating reveal that the Xiangtaohu ophiolites are composed of a suite of Permian (281-275 Ma) ophiolites with a nearly complete Penrose sequence and a suite of Early Carboniferous (circa 350 Ma) ophiolite remnants containing only part of the lower oceanic crust. Geochemical and Sr-Nd-O isotopic data show that the Permian and Carboniferous ophiolites in this study were derived from an N-mid-ocean ridge basalts-like mantle source with varied suprasubduction-zone (SSZ) signatures and were characterized by crystallization sequences from wet magmas, suggesting typical SSZ-affinity ophiolites. Permian and Carboniferous SSZ ophiolites in the central Qiangtang provide robust evidence for the existence and evolution of an ancient ocean basin. Combining with previous studies on high-pressure metamorphic rocks and pelagic radiolarian cherts, and with tectonostratigraphic and paleontological data, we support the LSSZ as representing the main suture of the Paleo-Tethys Ocean which probably existed and evolved from Devonian to Triassic. The opening and demise of the Paleo-Tethys Ocean dominated the formation of the major framework for the East and/or Southeast Asia.

New results of microfaunal and geochemical investigations in the Permian-Triassic boundary interval from the Jadar Block (NW Serbia)

NASA Astrophysics Data System (ADS)

Sudar, Milan N.; Kolar-Jurkovšek, Tea; Nestell, Galina P.; Jovanović, Divna; Jurkovšek, Bogdan; Williams, Jeremy; Brookfield, Michael; Stebbins, Alan

2018-04-01

Detail results of microfaunal, sedimentological and geochemical investigations are documented from a newly discovered section of the Permian-Triassic boundary (PTB) interval in the area of the town of Valjevo (northwestern Serbia). The presence of various and abundant microfossils (conodonts, foraminifers, and ostracodes) found in the Upper Permian "Bituminous limestone" Formation enabled a determination of the Changhsingian Hindeodus praeparvus conodont Zone. This paper is the first report of latest Permian strata from the region, as well as from all of Serbia, where the PTB interval sediments have been part of a complex/integrated study by means of biostratigraphy and geochemistry.

Volatile-organic molecular characterization of shale-oil produced water from the Permian Basin

USGS Publications Warehouse

Khan, Naima A.; Engle, Mark A.; Dungan, Barry; Holguin, F. Omar; Xu, Pei; Carroll, Kenneth C.

2016-01-01

Growth in unconventional oil and gas has spurred concerns on environmental impact and interest in beneficial uses of produced water (PW), especially in arid regions such as the Permian Basin, the largest U.S. tight-oil producer. To evaluate environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of PW. Although hydraulic fracturing has caused a significant increase in shale-oil production, there are no high-resolution organic composition data for the shale-oil PW from the Permian Basin or other shale-oil plays (Eagle Ford, Bakken, etc.). PW was collected from shale-oil wells in the Midland sub-basin of the Permian Basin. Molecular characterization was conducted using high-resolution solid phase micro extraction gas chromatography time-of-flight mass spectrometry. Approximately 1400 compounds were identified, and 327 compounds had a >70% library match. PW contained alkane, cyclohexane, cyclopentane, BTEX (benzene, toluene, ethylbenzene, and xylene), alkyl benzenes, propyl-benzene, and naphthalene. PW also contained heteroatomic compounds containing nitrogen, oxygen, and sulfur. 3D van Krevelen and double bond equivalence versus carbon number analyses were used to evaluate molecular variability. Source composition, as well as solubility, controlled the distribution of volatile compounds found in shale-oil PW. The salinity also increased with depth, ranging from 105 to 162 g/L total dissolved solids. These data fill a gap for shale-oil PW composition, the associated petroleomics plots provide a fingerprinting framework, and the results for the Permian shale-oil PW suggest that partial treatment of suspended solids and organics would support some beneficial uses such as onsite reuse and bio-energy production.

Volatile-organic molecular characterization of shale-oil produced water from the Permian Basin.

PubMed

Khan, Naima A; Engle, Mark; Dungan, Barry; Holguin, F Omar; Xu, Pei; Carroll, Kenneth C

2016-04-01

Growth in unconventional oil and gas has spurred concerns on environmental impact and interest in beneficial uses of produced water (PW), especially in arid regions such as the Permian Basin, the largest U.S. tight-oil producer. To evaluate environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of PW. Although hydraulic fracturing has caused a significant increase in shale-oil production, there are no high-resolution organic composition data for the shale-oil PW from the Permian Basin or other shale-oil plays (Eagle Ford, Bakken, etc.). PW was collected from shale-oil wells in the Midland sub-basin of the Permian Basin. Molecular characterization was conducted using high-resolution solid phase micro extraction gas chromatography time-of-flight mass spectrometry. Approximately 1400 compounds were identified, and 327 compounds had a >70% library match. PW contained alkane, cyclohexane, cyclopentane, BTEX (benzene, toluene, ethylbenzene, and xylene), alkyl benzenes, propyl-benzene, and naphthalene. PW also contained heteroatomic compounds containing nitrogen, oxygen, and sulfur. 3D van Krevelen and double bond equivalence versus carbon number analyses were used to evaluate molecular variability. Source composition, as well as solubility, controlled the distribution of volatile compounds found in shale-oil PW. The salinity also increased with depth, ranging from 105 to 162 g/L total dissolved solids. These data fill a gap for shale-oil PW composition, the associated petroleomics plots provide a fingerprinting framework, and the results for the Permian shale-oil PW suggest that partial treatment of suspended solids and organics would support some beneficial uses such as onsite reuse and bio-energy production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tectonic rotations south of the Bohemian Massif from palaeomagnetic directions of Permian red beds in Hungary

USGS Publications Warehouse

Marton, E.; Elston, D.P.

1987-01-01

Palaeomagnetic studies were carried out in Permian red beds of the Balaton Highlands, the Mecsek Mountains and the Bu??kk Mountains of Hungary. Statistically well defined directions were obtained from six localities in the Balaton Highlands and two localities in the Mecsek Mountains. No meaningful results were obtained from the Bu??kk Mountains. Three magnetic components were identified from red beds of the Balaton Highlands: (1) in haematite with a very high unblocking temperature (700??C), interpreted as a Permian magnetization (Dc= 79??, Ic=-11??, k = 24, ??95 = 13.6 ??), in six samples from three beds in a single locality (2) a secondary but ancient component residing mainly inmaghemite (D = 314??, I = 49??, k = 48, ??95 = 10.0??), in 84 samples from six localities with a within-locality scatter increasing on unfolding; and (3) a direction parallel to the present field (D = 7??, I = 62??, k = 46, ??95 = 7.7 ??), in nine samples from a single locality. For the Balaton Highlands, the component 1 direction agrees with directions obtained from Permian red beds and volcanics in the eastern part of the Southern and Eastern Alps and the Inner West Carpathians. All show large, apparent rotations relative to stable Europe since the Permian. Component 2 is of post-folding (post-Aptian) age. Its direction agrees with known Late Cretaceous directions from the Transdanubian Central Mountains, which also show significant counterclockwise rotation relative to stable Europe. The characteristic magnetization for the Mecsek Mountains resides in haematite and may be primary. The directions indicate only a slight net counterclockwise rotation of the Mecsek Mountains with respect to stable Europe since the Permian. ?? 1987.

Studies of the Permian Phosphoria Formation and related rocks, Great Basin-Rocky Mountain region

USGS Publications Warehouse

Wardlaw, Bruce R.

1979-01-01

PART A: The transgression of the Permian Retort Phosphatic Shale Member of the Phosphoria Formation is dated by the occurrence of diagnostic brachiopods. The complex pattern of this transgression reflects the paleogeography and indicates two initial basins of deposition: one in southwestern Montana and one in southeastern Idaho. PART B: A new formation is proposed for middle Permian rocks of a transitional facies positioned laterally between the Rex Chert Member of the Phosphoria Formation in northeastern Utah and southeastern Idaho and the Plympton Formation in northeastern Nevada and northwestern Utah. PART C: The relationships of the Permian Park City Group to the Phosphoria and Park City Formations are clarified by the stratigraphy of four sections in northwestern Utah, northeastern Nevada, and southern Idaho. PART D: Five biostratigraphic zones based on the distribution of brachiopods and conodonts are proposed for the Park City Group. They are: the Peniculauris ivesi-Neostreptognathodus prayi Zone, the Peniculauris bassi-Neostreptognathodus sulcoplicatus Zone, the Peniculauris bassi-Neostreptognathodus sp. C Zone, the Thamnosia depressa Zone, and the Yakovlevia. multistriata-Neogondolella bitteri Zone. They range in age from Leonardian to Wordian.

A mid-Permian chert event: widespread deposition of biogenic siliceous sediments in coastal, island arc and oceanic basins

USGS Publications Warehouse

Murchey, B.L.; Jones, D.L.

1992-01-01

Radiolarian and conodont of Permian siliceous rocks from twenty-three areas in teh the circum-Pacific and Mediterranean regions reveal a widespread Permian Chert Event during the middle Leonardian to Wordian. Radiolarian- and (or) sponge spicule-rich siliceous sediments accumulated beneath high productivity zones in coastal, island arc and oceanic basins. Most of these deposits now crop out in fault-bounded accreted terranes. Biogenic siliceous sediments did not accumulate in terranes lying beneath infertile waters including the marine sequences in terranes of northern and central Alaska. The Permian Chert Event is coeval with major phosphorite deposition along the western margin of Pangea (Phosphoria Formation and related deposits). A well-known analogue for this event is middle Miocene deposition of biogenic siliceous sediments beneath high productivity zones in many parts of the Pacific and concurrent deposition of phosphatic as well as siliceous sediments in basins along the coast of California. Interrelated factors associated with both the Miocene and Permian depositional events include plate reorientations, small sea-level rises and cool polar waters. ?? 1992.

The end-Permian regression in the western Tethys: sedimentological and geochemical evidence from offshore the Persian Gulf, Iran

NASA Astrophysics Data System (ADS)

Tavakoli, Vahid; Naderi-Khujin, Mehrangiz; Seyedmehdi, Zahra

2018-04-01

Detailed sedimentological and geochemical records across the Permian-Triassic boundary (PTB) in five offshore wells of the central Persian Gulf served to interpret the end-Permian sea-level change in this region. A decrease in sea level at the PTB was established by petrographical and geochemical study of the boundary. Thin sections showed that Upper Permian strata are composed of dolomite with minor anhydrite, changing into limestone in Lower Triassic sediments. Brine dilution toward the boundary supports sea-level fall in the Permian-Triassic transition, reflected by a decrease in anhydrite content and a shallowing-upward trend from lagoonal to peritidal facies. Isotopic changes at the boundary are in favor of sea-level fall. Changes in both carbon (from about 4 to -1‰) and oxygen (from 2 to -5‰) stable isotopes show negative excursions. The shift in carbon isotope values is a global phenomenon and is interpreted as resulting from carbonate sediment interaction with 12C-rich waters at the end-Permian sea-level fall. However, the oxygen isotope shift is attributed to the effect of meteoric waters with negative oxygen isotope values. The increase in strontium isotope ratios is also consistent with the high rate of terrestrial input at the boundary. The effect of meteoric conditions during diagenesis is evident from vuggy and moldic porosities below the PTB. The following transgression at the base of the Triassic is evident from the presence of reworked fossils and intraclasts resulting from deposition from agitated water.

Stratigraphy, depositional environments, and carbonate petrology of the Toroweap and Kaibab Formations (lower Permian), Grand Canyon region, Arizona

NASA Astrophysics Data System (ADS)

Clark, R. A.

Sediments deposited in northwestern Arizona during Late Leonardian and Early Guadalupian (Permian) were controlled chiefly by an arid climate and the tectonic setting. Eastward thrusting of eugeosynclinal rocks onto miogeosynclinal deposits during Middle Devonian to Early Mississippian had a major influence on shelf sedimentation. The Toroweap and Kaibab formations represent two such platform sequences of northwestern Arizona and southern Utah deposited during this phase of sedimentation. The Toroweap Formation is subdivided into three members and represents sediments deposited during initial transgression, maximum extent of the sea, and regression (Seligman, Brady Canyon, and Woods Ranch members respectively). The Fossil Mountain Member of the Kaibab Formation documents the most extensive phase of sedimentation for all members of the Toroweap and Kaibab formations. The Harrisburg Member documents the final phase of sedimentation at the close of the Paleozoic Era.

Permian deposition in the north central Brooks Range, Alaska Constraints for tectonic reconstructions

USGS Publications Warehouse

Adams, K.E.; Mull, C.G.; Crowder, R.K.

1997-01-01

Two opposing tectonic models have been offered to explain the regional structural relations in the north central Brooks Range fold-thrust belt of northern Alaska. The first suggests that rocks of the northern Endicott Mountains were thrust from south to north over the area of the present Mount Doonerak high and are therefore highly allochthonous. The second implies that the rocks of the northern Endicott Mountains were deposited in a basin that lay north of the Mount Doonerak high and later were thrust a short distance southward onto the northern flank of the high and are thus parautochthonous. To provide stratigraphic constraints for these models, this study examines Permian facies of the north central Brooks Range. Permian rocks in the north central Brooks Range comprise a thin (40 to 160 m thick), fining-upward succession of clastic, storm-influenced shelf deposits. When the rocks of the northern Endicott Mountains are restored south of the Mount Doonerak area, a minimum distance of 80 km, the Permian deposits grade systematically from distal facies (Siksikpuk Formation) in the southwest to proximal facies (Echooka Formation) in the northeast. Facies trends in the reconstructed Permian basin include, from southwest to northeast, (1) an increase in carbonate content and corresponding decrease in silica content, (2) a general darkening and thickening of shaley intervals, (3) an increase in proximal features of storm beds, including coarser, thicker, more abundant, and more closely spaced beds, and (4) an increase in abundance and diversity of the faunal assemblage with a corresponding decrease in age. These stratigraphic relations imply that rocks of the northern Endicott Mountains are allochthonous and structurally overlie a proximal stratigraphic succession similar to that exposed in the Mount Doonerak area and northeastern Brooks Range. Copyright 1997 by the American Geophysical Union.

Boron isotopes in brachiopods during the end-Permian mass extinction: constraints on pH evolution and seawater chemistry

NASA Astrophysics Data System (ADS)

Jurikova, Hana; Gutjahr, Marcus; Liebetrau, Volker; Brand, Uwe; Posenato, Renato; Garbelli, Claudio; Angiolini, Lucia; Eisenhauer, Anton

2017-04-01

The global biogeochemical cycling of carbon is fundamental for life on Earth with the ocean playing a key role as the largest and dynamically evolving CO2 reservoir. The boron isotope composition (commonly expressed in δ11B) of marine calcium carbonate is considered to be one of the most reliable paleo-pH proxies, potentially enabling us to reconstruct past ocean pH changes and understand carbon cycle perturbations along Earth's geological record (e.g. Foster et al., 2008; Clarkson et al., 2015). Brachiopods present an advantageous and largely underutilised archive for Phanerozoic carbon cycle reconstructions considering their high abundance in the geological record and its origin dating back to the early Cambrian. Moreover, their shell made of low-magnesium calcite makes these marine calcifiers more resistant to post-depositional diagenetic alteration of primary chemical signals. We have investigated the δ11B using MC-ICP-MS (Neptune Plus) and B/Ca and other elemental ratios (Mg/Ca, Sr/Ca, Al/Ca, Li/Ca, Ba/Ca, Na/Ca and Fe/Ca) using ICP-MS-Quadrupole (Agilent 7500cx) from the same specimens in pristine brachiopod shells from two sections from northern Italy during the Late Permian. These sections cover the δ13C excursion in excess of ˜4 ‰ (Brand et al., 2012) and are associated with major climate and environmental perturbations that lead to the mass extinction event at the Permian-Triassic boundary. Particular emphasis will be placed on the implications of our new paleo-pH estimates on the seawater chemistry during the Late Permian. Brand, U., Posenato, R., Came, R., Affek, H., Angiolini, L., Azmy, K. and Farabegoli, E.: The end-Permian mass extinction: A rapid volcanic CO2 and CH4-climatic catastrophe, Chemical Geology 323, 121-144, doi:10.1016/j.chemgeo.2012.06.015, 2012. Clarkson, M.O., Kasemann, S.A., Wood, R.A., Lenton, T.M., Daines, S.J., Richoz, S., Ohnemueller, F., Meixner, A., Poulton, S.W. and Tipper, E.T.: Ocean acidification and the Permo

Anatomically preserved "strobili" and leaves from the Permian of China (Dorsalistachyaceae, fam. nov.) broaden knowledge of Noeggerathiales and constrain their possible taxonomic affinities.

PubMed

Wang, Shi-Jun; Bateman, Richard M; Spencer, Alan R T; Wang, Jun; Shao, Longyi; Hilton, Jason

2017-01-01

Noeggerathiales are an extinct group of heterosporous shrubs and trees that were widespread and diverse during the Pennsylvanian-Permian Epochs (323-252 Ma) but are of controversial taxonomic affinity. Groups proposed as close relatives include leptosporangiate ferns, sphenopsids, progymnosperms, or the extant eusporangiate fern Tmesipteris. Previously identified noeggerathialeans lacked anatomical preservation, limiting taxonomic comparisons to their external morphology and spore structure. We here document from the upper Permian of China the first anatomically preserved noeggerathialeans, which enhance the perceived distinctiveness of the group and better indicate its systematic affinity. We describe in detail the newly discovered, anatomically preserved heterosporous strobilus Dorsalistachya quadrisegmentorum, gen. et sp. nov., and redescribe its suspected foliar correlate, the pinnate leaf Plagiozamites oblongifolius. Plagiozamites possesses an omega (Ω)-shaped vascular trace and prominent cortical secretory cavities-a distinctive anatomical organization that is echoed in the newly discovered strobili. Dorsalistachya strobili bear highly dissected sporophylls alternately in two vertical rows, suggesting that they are homologs of leaf pinnae. If so, the "strobilus" is strictly a pseudostrobilus and consists of sporangium-bearing units that are one hierarchical level below true sporophylls. The "sporophylls" bear four microsporangia on the lower (abaxial) surface, occasionally interspersed with short longitudinal rows of megasporangia. A single functional megaspore develops within each winged megasporangium, suggesting adaptation for dispersal as a single unit. Dorsalistachya presents a unique combination of reproductive features that amply justifies establishment of a new family, Dorsalistachyaceae. Noeggerathiales represent a distinct taxonomic Order of free-sporing plants that most resembles early-divergent eusporangiate ferns and the more derived among the

A high resolution magnetostratigraphic profile across the Permian-Triassic boundary in the Southern Sydney Basin, eastern Australia

NASA Astrophysics Data System (ADS)

Belica, M. E.; Tohver, E.; Nicoll, R.; Denyszyn, S. W.; Pisarevsky, S.; George, A. D.

2016-12-01

The Permian-Triassic boundary (PTB) is associated with the largest mass extinction in Phanerozoic geologic history. Despite several decades of intense study, there is ongoing debate regarding the exact timing of extinction and the global correlation of marine and terrestrial P-T sections. The terrestrial record is hampered by a lack of index fossils; however, magnetostratigraphy offers an opportunity for correlation because it relies on the global synchronicity of magnetic reversals. A magnetostratigraphic profile across the Permian-Triassic boundary has been obtained from a stratigraphically continuous terrestrial section in the Southern Sydney Basin of eastern Australia. The 60 m section is located within the Narrabeen Group, which consists of fluvial to lacustrine sandstones and mudstones. Paleomagnetic samples were collected at one meter intervals to determine a detailed reversal record. Samples were stepwise thermally demagnetized to isolate a primary remanence, and magnetic susceptibility was measured in the field at 30 cm intervals with values ranging from -0.047-2.50 (10-3 SI units). Three normal and three reverse magnetozones were detected after removal of a low temperature overprint, and the results show good agreement with the Global Magnetic Polarity Timescale as well as marine Permian-Triassic sections where the PTB is well constrained. Furthermore, a reverse polarity subchron has been identified within the normal magnetozone spanning the PTB similar to results published from the Netherlands and China. The magnetic stratigraphy suggests that the Narrabeen Group was deposited during the late Changhsingian to early Induan, and provides a revised placement of the PTB in the lower Wombarra Claystone. Integration of the magnetostratigraphy with existing isotopic datasets suggests that the terrestrial extinction in eastern Australia occurred 7.5 m below the PTB in the Changhsingian Coalcliff Sandstone. A tuff within a coal seam underlying the Coalcliff

Geology of the Pennsylvanian and Permian Culter Group and Permian Kaibab Limestone in the Paradox Basin, southeastern Utah and southwestern Colorado

USGS Publications Warehouse

Condon, Steven M.

1997-01-01

The Cutler Formation is composed of thick, arkosic, alluvial sandstones shed southwestward from the Uncompahgre highlands into the Paradox Basin. Salt tectonism played an important role in deposition of the Cutler in some areas. In the northeast part of the basin, more than 8,000 ft, and as much as 15,000 ft, of arkose was trapped between rising salt anticlines - this arkose is thin to absent over the crests of some anticlines. In the western and southern parts of the basin, the Cutler is recognized as a Group consisting of, in ascending order: the lower Cutler beds, Cedar Mesa Sandstone, Organ Rock Formation, White Rim Sandstone, and De Chelly Sandstone. The aggregate thickness of these formations is less than 2,000 ft. The formations of the Cutler Group were deposited in a complex system of alluvial, eolian, and marine environments characterized by abrupt vertical and lateral lithologic changes. The basal Cutler is Pennsylvanian in age, but the bulk of the Group was deposited during the Permian. The Cutler is conformably underlain by the Pennsylvanian Hermosa Group across most of the basin. It is overlain unconformably by the Permian Kaibab Limestone in the western part of the Paradox Basin. The Cutler or Kaibab are overlain unconformably by the Triassic Moenkopi or Chinle Formations.

High-resolution carbon isotope changes in the Permian-Triassic boundary interval, Chongqing, South China; implications for control and growth of earliest Triassic microbialites

NASA Astrophysics Data System (ADS)

Mu, Xinan; Kershaw, Steve; Li, Yue; Guo, Li; Qi, Yuping; Reynolds, Alan

2009-11-01

High-resolution δ 13C CARB analysis of the Permian-Triassic boundary (PTB) interval at the Laolongdong section, Beibei, near the city of Chongqing, south China, encompasses the latest Permian and earliest Triassic major facies changes in the South China Block (SCB). Microbialites form a distinctive unit in the lowermost 190 cm above the top of the Changhsing Formation (latest Permian) at Laolongdong, comparable to a range of earliest Triassic sites in low latitudes in the Tethyan area. The data show that declining values of δ 13C CARB, well-known globally, began at the base of the microbialite. High positive values (+3 to 4 ppt) of δ 13C CARB in the Late Permian are interpreted to indicate storage of 12C in the deep waters of a stratified ocean, that was released during ocean overturn in the earliest Triassic, contributing to the distinctive fall in isotope values; this interpretation has been stated by other authors and is followed here. The δ 13C CARB curve shows fluctuations within the microbialite unit, which are not reflected in the microbialite structure. Comparisons between microbialite branches and adjacent micritic sediment show little difference in δ 13C CARB, demonstrating that the microbialite grew in equilibrium with surrounding seawater. The Early Triassic microbialites are interpreted to be a response to upwelling of bicarbonate-rich poorly oxygenated water in low latitudes of Tethys Ocean, consistent with current ocean models for the PTB interval. However, the decline of δ 13C CARB may be due to a combination of processes, including productivity collapse resulting from mass extinction, return of deep water to ocean surface, oxidation of methane released from methane hydrate destabilisation, and atmospheric deterioration. Nevertheless, build-up of bicarbonate-rich anoxic deep waters may be expected as a result of the partial isolation of Tethys, due to continental geography; release of bicarbonate-rich deep water, by ocean upwelling, in the

Anoxia, toxic metals and acidification: volcanically-driven causes of the Middle Permian (Capitanian) mass extinction in NW Pangaea?

NASA Astrophysics Data System (ADS)

Bond, David; Grasby, Stephen; Wignall, Paul

2017-04-01

The controversial Capitanian (Middle Permian, 262 Ma) mass extinction, mostly known from equatorial latitudes, has recently been identified in a Boreal setting in Spitsbergen. We now document this extinction in the record of brachiopods from the Sverdrup Basin in NW Pangaea (Ellesmere Island, Canada), confirming Middle Permian losses as a global crisis on par with the "Big Five". Redox proxies (pyrite framboids and trace metals) show that the high latitude crisis coincided with an intensification of oxygen-poor conditions - a potent killer that is not clearly developed in lower latitude sections. Mercury becomes briefly enriched in strata at the level of the Middle Permian extinction level in Spitsbergen and Ellesmere Island, indicating voluminous but short-lived volcanism that is likely to have been the emplacement of the Emeishan large igneous province (LIP) in SW China. A potent cocktail of poisons appears to have impacted across the Boreal Realm, whilst the near-total loss of carbonates near the extinction level is also consistent with reduced pH across the region. Multiple stresses, possibly with origins in low-latitude LIP volcanism, are therefore implicated in the Middle Permian extinction and there was no respite even in the far-distant Boreal Realm.

Permian paleogeography of west-central Pangea: Reconstruction using sabkha-type gypsum-bearing deposits of Parnaíba Basin, Northern Brazil

NASA Astrophysics Data System (ADS)

Abrantes, Francisco R.; Nogueira, Afonso C. R.; Soares, Joelson L.

2016-07-01

Extreme aridity during Late Permian - Early Triassic period was the main factor for resetting the entire paleoclimate of the planet. Permian evaporite basins and lacustrine red beds were widely distributed along the supercontinent of Pangea. Sulphate deposits in Western Pangea, particularly in Northern Brazil, accumulated in an extensive playa lake system. Outcrop-based facies and stratigraphic analysis of up to 20 m thick evaporite-siliciclastic deposits reveal the predominance of laminated reddish mudstone with subordinate limestone, marl and lenses of gypsum. The succession was deposited in shallow lacustrine and inland sabkha environments associated with saline pans and mudflats. Gypsum deposits comprise six lithofacies: 1) bottom-growth gypsum, 2) nodular/micronodular gypsum, 3) mosaic gypsum, 4) fibrous/prismatic gypsum, 5) alabastrine gypsum, and 6) rosettes of gypsum. Gypsum types 1 and 2 are interpreted as primary deposition in saline pans. Bottom-growth gypsum forms grass-like crusts while nodular/micronodular gypsum indicates displacive precipitation of the crust in shallow water and the groundwater capillary zone. Types 3 and 4 are early diagenetic precipitates. Abundant inclusions of tiny lath-like anhydrite crystals suggest a primary origin of anhydrite. Alabastrine gypsum, fibrous gypsum (satinspar) and rosettes of gypsum probably derived from near-surface hydration of anhydrite. The gypsum-bearing deposits in the Parnaíba Basin contribute towards understanding paleogeographic changes in Western Pangea. A progressive uplift of East Pangea, culminated in the forced regression and retreat of epicontinental seas to the West. Restricted seas or large lakes were formed before the definitive onset of desert conditions in Pangea, leading to the development of extensive ergs.

First record of Borrelia burgdorferi B31 strain in Dermacentor nitens ticks in the northern region of Parana (Brazil)

PubMed Central

Gonçalves, Daniela Dib; Carreira, Teresa; Nunes, Mónica; Benitez, Aline; Lopes-Mori, Fabiana Maria Ruiz; Vidotto, Odilon; de Freitas, Julio Cesar; Vieira, Maria Luísa

2013-01-01

The aim of this study was to investigate the presence of DNA of Borrelia burgdorferi sensu lato (s.l.) in ticks that feed on horses used for animal traction in rural Jataizinho, Parana, Brazil. Between February and June 2008, a total of 224 ticks was collected of which 75% were identified as Dermacentor nitens and 25% as Amblyomma cajenense. To amplify B. burgdorferi s.l. DNA, the intergenic space region (ISR) between the 5S (rrf) 23S (rrl) rRNA genes was used as targets for nested-PCR. Two ticks of the D. nitens species were positive for B. burgdorferi s.l. Both species showed a fragment of 184 bp, but the sequencing revealed 99.9% homology with the B. burgdorferi sensu stricto (s.s.) strain B31. These results showed, for the first time, the presence of spirochete DNA infecting ticks that parasitize horses used for animal traction, in the rural municipality mentioned. In conclusion, this study opens up promising prospects for determining the infection rate of B. burgdorferi s.s. genospecies or other species in the equine population, as well as the impact of the infection rate on Lyme disease in the state of Parana. PMID:24516456

The end-Permian mass extinction: A complex, multicausal extinction

NASA Technical Reports Server (NTRS)

Erwin, D. H.

1994-01-01

The end-Permian mass extinction was the most extensive in the history of life and remains one of the most complex. Understanding its causes is particularly important because it anchors the putative 26-m.y. pattern of periodic extinction. However, there is no good evidence for an impact and this extinction appears to be more complex than others, involving at least three phases. The first began with the onset of a marine regression during the Late Permian and resulting elimination of most marine basins, reduction in habitat area, and increased climatic instability; the first pulse of tetrapod extinctions occurred in South Africa at this time. The second phase involved increased regression in many areas (although apparently not in South China) and heightened climatic instability and environmental degradation. Release of gas hydrates, oxidation of marine carbon, and the eruption of the Siberian flood basalts occurred during this phase. The final phase of the extinction episode began with the earliest Triassic marine regression and destruction of nearshore continental habitats. Some evidence suggests oceanic anoxia may have developed during the final phase of the extinction, although it appears to have been insufficient to the sole cause of the extinction.

High sedimentation rates in the Early Triassic after latest Permian mass extinction: Carbonate production is main factor in non-Arctic regions

NASA Astrophysics Data System (ADS)

Horacek, Micha; Brandner, Rainer

2016-04-01

A substantial change in sedimentation rates towards higher values has been documented from the Late Permian to the Lower Triassic. Although it is assumed and also has been shown that the deposition of siliciclastic material increased in the Lower Triassic due to stronger erosion because of loss of land cover and increased chemical and physical weathering with extreme climate warming, the main sediment production occurred by marine carbonate production. Still, carbonate production might have been significantly influenced by weathering and erosion in the hinterland, as the transport of dust by storms into the ocean water probably was a main nutrient source for microbial carbonate producers, because "normal" nutrient supply by ocean circulation, i. e. upwelling was strongly reduced due to the elevated temperatures resulting in water-column stratification . Sediment accumulation was also clearly influenced by the paleo-geographic and latitudinal position, with lower carbonate production and sedimentation rates in moderate latitudes. The existence of a "boundary clay" and microbial carbonate mounds and layers in the immediate aftermath of the latest Permian mass extinction points towards a development from a short-timed acid ocean water - resulting in a carbonate production gap and the deposition of the boundary clay towards the deposition of the microbial mounds and layers due to the microbial production of micro-environments with higher alkalinity allowing the production of carbonate. After the return of the ocean water to normal alkalinity planktic production of carbonate resulted in a very high sedimentation rate, especially taking into account the absence of carbonate producing eukaryotic algae and animals.

Silicification of trace fossils in carbonates; evidence from Permian Kaibab Formation, southwestern Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whidden, K.J.; Bottjer, D.J.

Silicification in carbonates, particularly silicified trace fossils, has received relatively little previous study. Chert comprises a significant percentage of the upper Fossil Mountain Member of the Kaibab Formation, a Permian epicontinental limestone. Distribution and origin of this chert were studied from outcrops in southwestern Utah. The origin of much of this chert is believed to be as silicified Thalassinoides burrows. Field evidence for trace fossil silicification includes (1) silicified cylindrical tubes with Y-shaped branching patterns as well as hollow tubes, and (2) polygonal box-work patterns of tubes. In addition, brachiopods, bryozoans, and abundant specimens of the sponge Actinocelia maendrina Finksmore » are also silicified. Recognition of silicified trace fossils in carbonates provides a different approach to the study of early diagenetic silica precipitation. These silicified trace fossils also represent new information on bioturbation in ancient carbonates, a subject that has, until recently, been relatively unstudied.« less

δ 13C evidence that high primary productivity delayed recovery from end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Meyer, K. M.; Yu, M.; Jost, A. B.; Kelley, B. M.; Payne, J. L.

2011-02-01

Euxinia was widespread during and after the end-Permian mass extinction and is commonly cited as an explanation for delayed biotic recovery during Early Triassic time. This anoxic, sulfidic episode has been ascribed to both low- and high-productivity states in the marine water column, leaving the causes of euxinia and the mechanisms underlying delayed recovery poorly understood. Here we use isotopic analysis to examine the changing chemical structure of the water column through the recovery interval and thereby better constrain paleoproductivity. The δ 13C of limestones from 5 stratigraphic sections in south China displays a negative gradient of approximately 4‰ from shallow-to-deep water facies within the Lower Triassic. This intense gradient declines within Spathian and lowermost Middle Triassic strata, coincident with accelerated biotic recovery and carbon cycle stabilization. Model simulations show that high nutrient levels and a vigorous biological pump are required to sustain such a large gradient in δ 13C, indicating that Early Triassic ocean anoxia and delayed recovery of benthic animal ecosystems resulted from too much productivity rather than too little.

Subsurface Permian reef complexes of southern Tunisia: Shelf carbonate setting and paleogeographic implications

NASA Astrophysics Data System (ADS)

Zaafouri, Adel; Haddad, Sofiene; Mannaî-Tayech, Beya

2017-05-01

2-D seismic reflection sections, borehole data as well as published and unpublished data have been investigated to reconstruct the paleogeography of southern Tunisia during Middle to Late Permian times. Paleogeographical reconstruction based on the integration of petroleum well data and 2-D seismic facies interpretation shows three main depositional areas with very contrasting sedimentary pile. These are 1) a subsiding basin; 2) an outer shelf carbonate, and 3) an inner shelf carbonate. Based on typical electric responses of reef buildups to seismic wave, we shall urge that during Middle Permian times, the outer carbonate shelf was subject of reef barrier development. Lithology evidences from core samples show that reef framework correspond mainly to fossiliferous limestone and dolomite. The WNW-ESE recognized reef barrier led between latitudes 33° 10‧ 00″N and 33° 20‧ 00″N. The Tebaga of Medenine outcrop constitutes the northern-edge of this barrier. Westward it may be extended to Bir Soltane area whereas its extension eastward is still to be determined. Biogenic buildups took place preferentially over faulted Carboniferous and lower Paleozoic paleohighs resulting likely from the Hercynian orogeny. The subsiding basin is located north of Tebaga of Medenine outcrop where Upper Permian sedimentary sequence is made entirely of 4000 m deep marine green silty shale facies. These are ascribed to unorganized and chaotic reflectors. Inner carbonate shelf facies succession corresponds to a typical interbedding of shallow marine carbonate deposits, shale, dolomite, and anhydrite inducing parallel-layered of strong amplitude and good continuity reflectors. Also within the inner carbonate shelf patch reef or reef pinnacles have been identified based on their seismic signature particularly their low vertical development as compared to reef complexes. Southward, towards Sidi Toui area, the Upper Permian depositional sequence thins out and bears witness of land

Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds.

PubMed

Motani, Ryosuke; Chen, Xiao-hong; Jiang, Da-yong; Cheng, Long; Tintori, Andrea; Rieppel, Olivier

2015-03-10

Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic.

Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds

PubMed Central

Motani, Ryosuke; Chen, Xiao-hong; Jiang, Da-yong; Cheng, Long; Tintori, Andrea; Rieppel, Olivier

2015-01-01

Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic. PMID:25754468

High-resolution stratigraphic analyses of Permian-Triassic core material recovered in central Spitsbergen

NASA Astrophysics Data System (ADS)

Sleveland, Arve; Planke, Sverre; Zuchuat, Valentin; Franeck, Franziska; Svensen, Henrik; Midtkandal, Ivar; Hammer, Øyvind; Twitchett, Richard; Deltadalen Study Group

2017-04-01

The Siberian Traps voluminous igneous activity is considered a likely trigger for the Permian-Triassic global extinction event. However, documented evidence of the Siberian Traps environmental effects decreases away from the centre of volcanic activity in north-central Russia. Previous research on the Permian-Triassic boundary (PTB) mostly relies on field observations, and resolution has thus depended on outcrop quality. This study reports on two 90 m cored sedimentary successions intersecting the PTB in Deltadalen, Svalbard, providing high-quality material to a comprehensive documentation of the stratigraphic interval. Sequence stratigraphic concepts are utilised to help constrain the Permian-Triassic basin development models in Svalbard and the high-Arctic region. The cored sections are calibrated with outcrop data from near the drill site. One core has been systematically described and scanned using 500-μm and 200-μm resolution XRF, hyperspectral imagery and microfocus CT (latter only on selected core sections). The base of both cores represents the upper 15 m of the Permian Kapp Starostin Formation, which is dominated by green glauconitic sandstones with spiculitic cherts, and exhibit various degrees of bioturbation. The Kapp Starostin Formation is in turn sharply overlain by 2 m of heavily reworked sand- and mudstones, extensively bioturbated, representing the base of the lower Triassic Vikinghøgda Formation. These bioturbated units are conformably overlain by 9 m of ash-bearing laminated black shale where signs of biological activity both on micro- and macro-scale are limited, and is thus interpreted to have recorded the Permian-Triassic extinction interval. Descriptive sedimentology and sequence stratigraphic concepts reveal the onset of relative sea level rise at the Vikinghøgda Formation base. The disappearance of bioturbation and extensive presence of pyrite in the overlying laminated black shale of the Vikinghøgda Formation suggest near anoxic

Geochronologic evidence of a large magmatic province in northern Patagonia encompassing the Permian-Triassic boundary

NASA Astrophysics Data System (ADS)

Luppo, Tomás; López de Luchi, Mónica G.; Rapalini, Augusto E.; Martínez Dopico, Carmen I.; Fanning, Christopher M.

2018-03-01

The Los Menucos Complex (northern Patagonia) consists of ∼6 km thick succession of acidic and intermediate volcanic and pyroclastic products, which has been traditionally assigned to the Middle/Late Triassic. New U/Pb (SHRIMP) zircon crystallization ages of 257 ± 2 Ma at the base, 252 ± 2 Ma at an intermediate level and 248 ± 2 Ma near the top of the sequence, indicate that this volcanic event took place in about 10 Ma around the Permian-Triassic boundary. This volcanism can now be considered as the effusive terms of the neighboring and coeval La Esperanza Plutono-Volcanic Complex. This indicates that the climax of activity of a large magmatic province in northern Patagonia was coetaneous with the end-Permian mass extinctions. Likely correlation of La Esperanza- Los Menucos magmatic province with similar volcanic and plutonic rocks across other areas of northern Patagonia suggest a much larger extension than previously envisaged for this event. Its age, large volume and explosive nature suggest that the previously ignored potential role that this volcanism might have played in climatic deterioration around the Permian-Triassic boundary should be investigated.

40 CFR 81.242 - Pecos-Permian Basin Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Pecos-Permian Basin Intrastate Air Quality Control Region (New Mexico) consists of the territorial area... Quality Control Region. 81.242 Section 81.242 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of...

40 CFR 81.242 - Pecos-Permian Basin Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Pecos-Permian Basin Intrastate Air Quality Control Region (New Mexico) consists of the territorial area... Quality Control Region. 81.242 Section 81.242 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of...

Redescription of Bellerophon asiaticus Wirth (Early Triassic: Gastropoda) from China, and a survey of Triassic Bellerophontacea.

USGS Publications Warehouse

Yochelson, E.Y.; Yin, Hongfu

1985-01-01

The bilaterally symmetrical gastropod Bellerophon asiaticus Wirth is redescribed from specimens collected in Guizhou Province, PRC. The species is reassigned to Retispira, a common late Paleozoic taxon. Retispira is another example of a Paleozoic gastropod genus that crossed the era boundary. Associated pelecypods that date these Guizhou occurrences as Early Triassic are well known species in PRC and are illustrated. Both Bellerophon and Euphemites probably occur in the Early Triassic, though the quality of illustrations leaves some uncertainty; the existence of Stachella in the Triassic is more problematic. There was no dramatic reduction of the Bellerophontacea from their abundance and diversity in the Permian. It may be a general phenomenon that most late Paleozoic family-level and many generic-level taxa of gastropods were unaffected by the late Permian 'crisis'. from Authors

Dissolution of Permian salt and Mesozoic depositional trends, Powder River basin, Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rasmussen, D.L.; Bean, D.W.

1983-08-01

Salt deposits in the Powder River basin of Wyoming occur in the Late Permian Ervay Member of the Goose Egg Formation which was deposited in a redbed-evaporite trend extending from the Williston basin of North Dakota to the Alliance basin of Nebraska and Wyoming. However, only remnants of the once extensive Ervay salt remain in the Powder River basin, with major salt dissolution events occurring during Late Jurassic and Early Cretaceous. Subsidence and deposition at the surface were contemporaneous with subsurface salt dissolution except in areas where uplift and erosion were occurring. Earliest dissolution of the Ervay salt occurred inmore » the Jurassic, during regional uplift and erosion of the overlying Triassic Chugwater Formation in the present Hartville uplift and southeastern Powder River basin areas. Thickness variations of the Canyon Springs and Stockade Beaver members of the early Late Jurassic Sundance Formation, which unconformably overlie the deeply eroded Chugwater Formation, may be related in part to dissolution of the Ervay salt. Extensive salt dissolution, synsubsidence, and syndeposition occurred throughout most of the Powder River basin during the latest Jurassic and Early Cretaceous. Many producing fields from the Mowry, Muddy, and Dakota formations exhibit either rapid stratigraphic changes syndepositional to salt collapse or fracture-enhanced reservoir quality due to postdepositional salt collapse. Major Muddy accumulations occurring in areas of local Ervay salt collapse include Kitty, Hilight, Fiddler Creek, and Clareton which have produced jointly over 172 million bbl of oil. The relationship of Ervay salt dissolution to Lower Cretaceous deposition can be exploited as an effective exploration tool.« less

Size-frequency distributions along a latitudinal gradient in Middle Permian fusulinoideans.

PubMed

Zhang, Yichun; Payne, Jonathan L

2012-01-01

Geographic gradients in body size within and among living species are commonly used to identify controls on the long-term evolution of organism size. However, the persistence of these gradients over evolutionary time remains largely unknown because ancient biogeographic variation in organism size is poorly documented. Middle Permian fusulinoidean foraminifera are ideal for investigating the temporal persistence of geographic gradients in organism size because they were diverse and abundant along a broad range of paleo-latitudes during this interval (~275-260 million years ago). In this study, we determined the sizes of Middle Permian fusulinoidean fossils from three different paleo-latitudinal zones in order to examine the relationship between the size of foraminifers and regional environment. We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone. Fusulinoidean foraminifers differ from most other marine taxa in exhibiting larger sizes closer to the equator, contrary to Bergmann's rule. Meridional variation in seasonality, water temperature, nutrient availability, and carbonate saturation level are all likely to have favored or enabled larger sizes in equatorial regions. Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to

Size-Frequency Distributions along a Latitudinal Gradient in Middle Permian Fusulinoideans

PubMed Central

Zhang, Yichun; Payne, Jonathan L.

2012-01-01

Geographic gradients in body size within and among living species are commonly used to identify controls on the long-term evolution of organism size. However, the persistence of these gradients over evolutionary time remains largely unknown because ancient biogeographic variation in organism size is poorly documented. Middle Permian fusulinoidean foraminifera are ideal for investigating the temporal persistence of geographic gradients in organism size because they were diverse and abundant along a broad range of paleo-latitudes during this interval (∼275–260 million years ago). In this study, we determined the sizes of Middle Permian fusulinoidean fossils from three different paleo-latitudinal zones in order to examine the relationship between the size of foraminifers and regional environment. We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone. Fusulinoidean foraminifers differ from most other marine taxa in exhibiting larger sizes closer to the equator, contrary to Bergmann's rule. Meridional variation in seasonality, water temperature, nutrient availability, and carbonate saturation level are all likely to have favored or enabled larger sizes in equatorial regions. Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to

Upper Permian magnetic stratigraphy of the lower Beaufort Group, Karoo Basin

NASA Astrophysics Data System (ADS)

Lanci, L.; Tohver, E.; Wilson, A.; Flint, S.

2013-08-01

We carried out a magnetostratigraphic and geochronological study of late Permian sediments in the Karoo Basin of the Western Cape Province, South Africa. A continuous, ~700 m thick section of deltaic sediments of the upper Waterford Formation (uppermost Ecca Group) and the fluvial sediments of the Abrahamskraal Formation (lowermost Beaufort Group) were sampled at the meter scale. U-Pb dating of zircons from interbedded volcanic ash beds by ion microprobe (SHRIMP) provided absolute age constraints on the age of the sedimentary rocks. Paleomagnetic analysis reveals a partial overprint of the Natural Remanent Magnetization (NRM) that is tentatively ascribed to the emplacement of the Karoo Large Igneous Province in the Western Cape region during the middle Jurassic. A stable component of the NRM was found at temperatures higher than 450 °C and was interpreted as a Characteristic Remanent Magnetization (ChRM) acquired during deposition, supported by a positive reversals test for this dual polarity ChRM. The virtual geomagnetic pole position for the Waterford and Abrahamskraal Formations computed from the average ChRM direction is in general agreement with the late Permian directions for stable Gondwana. A significantly different average inclination, and thus paleomagnetic pole position, is obtained by correcting the inclination shallowing error by the Elongation-Inclination method (Tauxe and Kent, 2004). The presence of both normal and reversed polarity zones indicate deposition after the end of the Kiaman Superchron, moreover the polarity sequence is in good agreement with the Illawarra sequence of Steiner (2006). Our results indicate a Capitanian (late Guadalupian) age for the Abrahamskraal Fm., in agreement with the Late Permian age, based on presence of Glossopteris flora and Dicynodont fauna, traditionally assigned to the fluvial-lacustrine sediments of the Beaufort Group. However, the U-Pb zircon ages of ca. 264-268 Ma suggest an age of 269 Ma for the top of the

A Re-Examination of the Bedout High, Offshore Canning Basin, Western Australia - Possible Impact Site for the Permian-Triassic Mass Extinction Event?

NASA Astrophysics Data System (ADS)

Becker, L.; Nicholson, C.; Poreda, R. J.

2002-12-01

The Bedout High, located offshore Canning basin in Western Australia, is an unusual structure and its origin remains problematic. K-Ar dating of volcanic samples encountered at total depth in the Lagrange-1 exploration well indicated an age of about 253+/-5 Ma consistent with the Permian-Triassic boundary event. Gorter (PESA News, pp. 33-34, 1996) speculates that the Bedout High is the uplifted core (30 km) of a circular feature, some 220 km across, formed by the impact of a large bolide (cometary or asteroidal) with the Earth near the end-Permian. Accepting a possible impact origin for the Bedout structure, with the indicated dimensions, would have had profound effects on global climate as well as significant changes in lithotratigraphic, biostratigraphic and chemostratigraphic indicators as seen in several Permian-Triassic boundary locations worldwide. In this work, we re-examine some of the structural data previously presented by Gorter (1996) using some additional seismic lines. We have also evaluated several impact tracers including iridium, shocked quartz, productivity collapse, helium-3, chromium-53 and fullerenes with trapped noble gases from some Permian-Triassic boundary sites in the Tethys and Circum-Pacific regions. Our findings suggest that the Bedout structure is a good candidate for an oceanic impact at the end Permian, triggering the most severe mass extinction in the history of life on Earth.

Paleomagnetic and rock-magnetic studies of the Permian Cutler and Elephant Canyon formations in Utah.

NASA Technical Reports Server (NTRS)

Gose, W. A.; Helsley, C. E.

1972-01-01

Study of the Permian Cutler formation and the upper 15 meters of the Permian Elephant Canyon formation at 0.6-meter stratigraphic intervals southwest of Moab in eastern Utah. The directions of natural remanent magnetization show a pronounced streak distribution, but thermal demagnetization successfully isolates the stable paleomagnetic direction. All directions are reversed, and no significant long-term change in pole position is observed throughout the entire section. The pole calculated from the Elephant Canyon data lies at 43.6 N, 119.6 E; the Cutler pole lies at 44.4 N, 116.2 E. Rock-magnetic analyses suggest that the secondary magnetization results from the iron hydroxides and was acquired after recent surface exposure.

New Early Triassic trace fossil records from South China: implications for biotic recovery following the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Luo, M.; George, A. D.; Chen, Z.; Zhang, Y.

2013-12-01

New Early Triassic trace fossil assemblages are documented from the Susong and Tianshengqiao areas in South China to evaluate the mode and tempo of biotic recovery of epifaunal and infaunal organisms following the end-Permian mass extinction. The Susong succession is exposed in Anhui area of the Lower Yangtze region and comprises mudstone and carbonate facies that record overall shallowing from offshore to supratidal settings. The Tianshengqiao succession crops out in the Luoping area, Yuannan Province of the Upper Yangtze region, and consists of mixed carbonate and siliciclastic facies which were deposited in shallow marine to offshore settings. Bivalve and conodont biostratigraphy helps constrain the chronostratigraphic framework of the Lower Triassic successions in these two sections. Griesbachian to Dieneria ichnological records in both successions are characterized by low ichnodiversity, low ichnofabric indices (ii=1-2) and low bedding plane bioturbation indices (bpbi=1-2). Higher ii (ii= 3 and 4) corresponding to densely populated diminutive Skolithos in the Tianshengqiao succession suggest an opportunistic strategy during earliest Triassic deposition. Ichnological data from the Susong succession show an increase in ichnodiversity during the Smithian. A total of 12 ichnogenera including Arenicolites, Chondrites, Gyrochorte, Laevicyclus, Monocraterion, Palaeophycus, Phycodes, Plaolites, Thalassinoides, Treptichnus, Trichichnus and one problematic trace are identified. Ichnofabric indices (ii) and bpbi increase to moderate to high levels (ii = 4-5, bpbi= 3-5). Although complex traces such as Rhizocorallium are in Spathian strata in this section, the low levels of ichnodiversity, ichnofabric indices and diminutive Planolites suggest a decline in recovery. In the Tianshengqiao succession, ichnofabric indices exhibit a moderate to high value (ii= 3 to 5), however, only six ichnogenera are found and Planolites burrows are consistently small (average diameter at 3

Evaluating Non-potable Water Usage for Oil and Gas Purposes in the Permian Basin

NASA Astrophysics Data System (ADS)

Marsac, K.; Pedrazas, M.; Suydam, S.; Navarre-Sitchler, A.

2016-12-01

Oil and gas company water usage is currently an area of extreme concern in the water stressed Western United States. 87% of the wells in Permian Basin are being drilled in areas of high or extreme water stress. Using recycled produced water or groundwater that does not meet the USDW drinking water standards for oil and gas purposes could assist in relieving both water stress and tension between oil and gas companies and the public. However, non-USDW drinking water (TDS over 10,000 ppm), has the potential to react with formation water causing mineral precipitation, reducing the permeability of the producing formation. To evaluate the potential of non-potable water usage in the Permian Basin, available groundwater chemistry data was compiled into a database. Data was collected from the NETL-run NATCARB database, the USGS Produced Water Database, and the Texas Railroad Commission. The created database went through a system of quality assurance and control for pH, TDS, depth and charge balance. Data was used to make a set of waters representative of Permian Basin groundwater based on TDS, Ca/Mg ratio and Cl/SO 4 ratio. Low, medium and high of these three characteristics; representing the 25 th , 50 th and 75 th percentile respectively; was used to make a matrix of 27 waters. Low TDS is 64,660 ppm, medium TDS is 98,486 ppm, and high TDS is 157,317 ppm. Ca/Mg ratios range from 1.98 to 7.26, and Cl/SO 4 ratios range from 32.96 to 62.34. Geochemical models of the mixing of these 27 waters with an average water were used to evaluate for possible precipitation. Initial results are positive, with the highest total precipitation being 2.371 cm 3 of dolomite and anhydrite in 2000 cm 3 of water with high TDS, high Ca/Mg ratio and low Cl/SO 4 ratio. This indicates a maximum of approximately 0.12% of porosity would be filled with mineral precipitation during the mixing of chosen Permian Basin waters.

Enhanced recycling of organic matter and Os-isotopic evidence for multiple magmatic or meteoritic inputs to the Late Permian Panthalassic Ocean, Opal Creek, Canada

NASA Astrophysics Data System (ADS)

Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.; Henderson, Charles M.; Algeo, Thomas J.

2015-02-01

The geochemical record for the Permian-Triassic boundary in northern latitudes is essential to evaluation of global changes associated with the most profound extinction of life on Earth. We present inorganic and organic geochemical data, and Re-Os isotope systematics in a critical stratigraphic interval of pre- and post-extinction Upper Permian-Lower Triassic sediments from Opal Creek, western Canada (paleolatitude of ∼30°N). We document significant and long-lived changes in Panthalassa seawater chemistry that were initiated during the first of four magmatic or meteoritic inputs to Late Permian seawater, evidenced by notable decreases of Os isotopic ratios upsection. Geochemical signals indicate establishment of anoxic bottom waters shortly after regional transgression reinitiated sedimentation in the Late Permian. Euxinic signals are most prominent in the Upper Permian sediments with low organic carbon and high sulfur contents, and gradually wane in the Lower Triassic. The observed features may have been generated in a strongly euxinic ocean in which high bacterioplankton productivity sustained prolific microbial sulfate reduction in the sediment and/or water column, providing hydrogen sulfide to form pyrite. This scenario requires nearly complete anaerobic decomposition of predominantly labile marine organic matter (OM) without the necessity for a complete collapse of primary marine productivity. Similar geochemical variations could have been achieved by widespread oxidation of methane by sulfate reducers after a methanogenic burst in the Late Permian. Both scenarios could have provided similar kill mechanisms for the latest Permian mass extinction. Despite the moderate thermal maturity of the section, OM in all studied samples is dominantly terrestrial and/or continentally derived, recycled and refractory ancient OM. We argue that, as such, the quantity of the OM in the section mainly reflects changes in terrestrial vegetation and/or weathering, and not in

Sr-Nd-Pb isotope systematics of the Permian volcanic rocks in the northern margin of the Alxa Block (the Shalazhashan Belt) and comparisons with the nearby regions: Implications for a Permian rift setting?

NASA Astrophysics Data System (ADS)

Shi, Guanzhong; Wang, Hua; Liu, Entao; Huang, Chuanyan; Zhao, Jianxin; Song, Guangzeng; Liang, Chao

2018-04-01

The petrogenesis of the Permian magmatic rocks in the Shalazhashan Belt is helpful for us to understand the tectonic evolution of the Central Asian Orogenic Belt (CAOB) in the northern margin of the Alxa Block. The Permian volcanic rocks in the Shalazhashan Belt include basalts, trachyandesites and trachydacites. Our study shows that two basalt samples have negative εNd(t) values (-5.4 to -1.5) and higher radiogenic Pb values, which are relevant to the ancient subcontinental lithospheric mantle. One basalt sample has positive εNd(t) value (+10) representing mafic juvenile crust and is derived from depleted asthenosphere. The trachyandesites are dated at 284 ± 3 Ma with εNd(t) = +2.7 to +8.0; ISr = 0.7052 to 0.7057, and they are generated by different degrees of mixing between mafic magmas and crustal melts. The trachydacites have high εNd(t) values and slightly higher ISr contents, suggesting the derivation from juvenile sources with crustal contamination. The isotopic comparisons of the Permian magmatic rocks of the Shalazhashan Belt, the Nuru-Langshan Belt (representing the northern margin of the Alxa Block), the Solonker Belt (Mandula area) and the northern margin of the North China Craton (Bayan Obo area) indicate that the radiogenic isotopic compositions have an increasingly evolved trend from the south (the northern margins of the Alxa Block and the North China Craton) to the north (the Shalazhashan Belt and the Solonker Belt). Three end-member components are involved to generate the Permian magmatic rocks: the ancient subcontinental lithospheric mantle, the mafic juvenile crust or newly underplated mafic rocks that were originated from depleted asthenosphere, and the ancient crust. The rocks correlative with the mafic juvenile crust or newly underplated mafic rocks are predominantly distributed along the Shalazhashan Belt and the Solonker Belt, and the rocks derived from ancient, enriched subcontinental lithospheric mantle are mainly distributed along

Calcium isotope constraints on the end-Permian mass extinction

PubMed Central

Payne, Jonathan L.; Turchyn, Alexandra V.; Paytan, Adina; DePaolo, Donald J.; Lehrmann, Daniel J.; Yu, Meiyi; Wei, Jiayong

2010-01-01

The end-Permian mass extinction horizon is marked by an abrupt shift in style of carbonate sedimentation and a negative excursion in the carbon isotope (δ13C) composition of carbonate minerals. Several extinction scenarios consistent with these observations have been put forward. Secular variation in the calcium isotope (δ44/40Ca) composition of marine sediments provides a tool for distinguishing among these possibilities and thereby constraining the causes of mass extinction. Here we report δ44/40Ca across the Permian-Triassic boundary from marine limestone in south China. The δ44/40Ca exhibits a transient negative excursion of ∼0.3‰ over a few hundred thousand years or less, which we interpret to reflect a change in the global δ44/40Ca composition of seawater. CO2-driven ocean acidification best explains the coincidence of the δ44/40Ca excursion with negative excursions in the δ13C of carbonates and organic matter and the preferential extinction of heavily calcified marine animals. Calcium isotope constraints on carbon cycle calculations suggest that the average δ13C of CO2 released was heavier than -28‰ and more likely near -15‰; these values indicate a source containing substantial amounts of mantle- or carbonate-derived carbon. Collectively, the results point toward Siberian Trap volcanism as the trigger of mass extinction. PMID:20421502

A new Permian gnetalean cone as fossil evidence for supporting current molecular phylogeny.

PubMed

Wang, Zi-Qiang

2004-08-01

The order Gnetales has been the central focus of controversy in seed plant phylogeny. Traditional treatment of morphology supports the anthophyte hypothesis with Gnetales sister to angiosperms but current molecular data reject this hypothesis. A new fossil gnetalean cone, Palaeognetaleana auspicia gen. et sp. nov., is reported from the Upper Permian in North China, and its phylogenic implications are considered. Samples of cones from the upper part of the Upper Permian redbeds of Baode section, northwestern Shanxi Province, China, were examined. The cone is characterized by its unusual nature of reproduction that combines features of post-Triassic gnetaleans and some of the Palaeozoic conifers. It is made up of a number of imbricate axillary units, each simply formed by an ovule and a subtending bract, which may be comparable with the axillary seed-scale complex of some of the Palaeozoic conifer cones. The cone exhibits at least a partially bisexual character that appears to have pollen sacs with monosulcate ribbed pollen grains and sessile, asymmetric, and radiospermic ovules. The ovule has an integument of three envelopes: an outer one of pointed scales; a middle sclerified one; and an inner cuticle that extends upward into a micropyle with an oblique tip. The new Permian cone has unequivocal affinity with the Gnetales. The fossil has considerably extended the divergence time of the Gnetales from 140 (210?) back to 270 myr ago and, therefore, provides the first significant fossil evidence to support the current conclusion based on molecular data of seed plants, i.e. monophyletic gymnosperms, comprising the Gnetales are closely related to conifers.

Geochemical Identification of Windblown Dust Deposits in the Upper Permian Brushy Canyon Formation, Southern New Mexico

NASA Astrophysics Data System (ADS)

Tice, M. M.; Motanated, K.; Weiss, R.

2009-12-01

Windblown dust is a potentially important but difficult-to-quantify source of siliciclastics for sedimentary basins worldwide. Positively identifying windblown deposits requires distinguishing them from other low density suspension transport deposits. For instance, laminated very fine grained sandstones and siltstones of the Upper Permian Brushy Canyon Formation have been variously interpreted as 1) the deposits of slow-moving, low-density turbidity currents, 2) distal overbank deposits of turbidity currents, 3) the deposits of turbulent suspensions transported across a pycnocline (interflows), and 4) windblown dust. This facies forms the bulk of Brushy Canyon Formation slope deposits, so understanding its origin is critical to understanding the evolution of the basin as a whole. We use a geochemical mapping technique (x-ray fluorescence microscopy) to show that these rocks are up to two times enriched in very fine sand sized zircon and rutile grains relative to Bouma A divisions of interbedded turbidites, suggesting substantial turbulence during transport. However, in contrast with the A divisions, the laminated sandstones and siltstones never show evidence of scour or amalgamation, implying that flow turbulence did not interact with underlying beds. Moreover, proximal loess deposits are often characterized by elevated Zr/Al2O3. These observations are most consistent with windblown interpretations for Brushy Canyon Formation slope sediments, and suggest that evolution of this early deepwater slope system was controlled largely by short-distance aeolian transport of very fine sand and silt from the coast. Heavy mineral incorporation into Brushy Canyon Formation slope deposits as reflected in laminae-scale bulk Zr and Ti abundances may preserve a long-term record of local wind intensity during the Upper Permian.

Modern Pearl River Delta and Permian Huainan coalfield, China: A comparative sedimentary facies study

USGS Publications Warehouse

Suping, P.; Flores, R.M.

1996-01-01

Sedimentary facies types of the Pleistocene deposits of the Modern Pearl River Delta in Guangdong Province, China and Permian Member D deposits in Huainan coalfield in Anhui Province are exemplified by depositional facies of anastomosing fluvial systems. In both study areas, sand/sandstone and mud/mudstone-dominated facies types formed in diverging and converging, coeval fluvial channels laterally juxtaposed with floodplains containing ponds, lakes, and topogenous mires. The mires accumulated thin to thick peat/coal deposits that vary in vertical and lateral distribution between the two study areas. This difference is probably due to attendant sedimentary processes that affected the floodplain environments. The ancestral floodplains of the Modern Pearl River Delta were reworked by combined fluvial and tidal and estuarine processes. In contrast, the floodplains of the Permian Member D were mainly influenced by freshwater fluvial processes. In addition, the thick, laterally extensive coal zones of the Permian Member D may have formed in topogenous mires that developed on abandoned courses of anastomosing fluvial systems. This is typified by Seam 13-1, which is a blanket-like body that thickens to as much as 8 in but also splits into thinner beds. This seam overlies deposits of diverging and converging, coeval fluvial channels of the Sandstone D, and associated overbank-floodplain deposits. The limited areal extent of lenticular Pleistocene peat deposits of the Modern Pearl River Delta is due to their primary accumulation in topogenous mires in the central floodplains that were restricted by contemporaneous anastomosing channels.

A calcium isotope test of end-Permian ocean acidification using biogenic apatite

NASA Astrophysics Data System (ADS)

Hinojosa, J.; Brown, S. T.; DePaolo, D. J.; Paytan, A.; Shen, S.; Chen, J.; Payne, J.

2011-12-01

Submarine erosional truncation of uppermost Permian carbonate strata has been interpreted to reflect ocean acidification coincident with the end-Permian mass extinction. Although this scenario is consistent with carbon isotope and paleontological data, several alternative scenarios, such as ocean overturn or collapse of the biological pump, can also account for the carbon isotope and paleontological evidence. Calcium isotopes provide a geochemical proxy to test between acidification and alternative scenarios. Specifically, a negative shift in the calcium isotope composition (δ44/40Ca) of seawater is predicted under the acidification scenario but not the alternatives. The δ44/40Ca of carbonate rocks from south China exhibits a negative excursion of approximately 0.3%, but this shift could result from either a change in the δ44/40Ca of seawater or a change in carbonate mineralogy because calcite and aragonite exhibit substantially different fractionation factors relative to seawater. To test whether the negative shift in δ44/40Ca reflects seawater δ44/40Ca or carbonate mineralogy, we measured the δ44/40Ca of conodont microfossils (calcium hydroxyapatite) from the global stratotype section for the Permian-Triassic boundary at Meishan, China. The conodont δ44/40Ca record shows a negative excursion similar in stratigraphic position and magnitude to that previously observed in carbonate rocks. Parallel negative excursions in the δ44/40Ca of carbonate rocks and conodont microfossils cannot be accounted for by a change in carbonate mineralogy but are consistent with a negative shift in the δ44/40Ca of seawater. These data add further support for the ocean acidification scenario, pointing toward strong similarities between the greatest catastrophe in the history of animal life and anticipated global change during the 21st century.

Earth's biggest 'whodunnit': unravelling the clues in the case of the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

White, Rosalind V.

2002-12-01

The mass extinction that occurred at the end of the Permian period, 250 million years ago, was the most devastating loss of life that Earth has ever experienced. It is estimated that ca.96% of marine species were wiped out and land plants, reptiles, amphibians and insects also suffered. The causes of this catastrophic event are currently a topic of intense debate. The geological record points to significant environmental disturbances, for example, global warming and stagnation of ocean water. A key issue is whether the Earth's feedback mechanisms can become unstable on their own, or whether some forcing is required to precipitate a catastrophe of this magnitude. A prime suspect for pushing Earth's systems into a critical condition is massive end-Permian Siberian volcanism, which would have pumped large quantities of carbon dioxide and toxic gases into the atmosphere. Recently, it has been postulated that Earth was also the victim of a bolide impact at this time. If further research substantiates this claim, it raises some intriguing questions. The Cretaceous-Tertiary mass extinction, 65 million years ago, was contemporaneous with both an impact and massive volcanism. Are both types of calamity necessary to drive Earth to the brink of faunal cataclysm? We do not presently have enough pieces of the jigsaw to solve the mystery of the end-Permian extinction, but the forensic work continues.

Recovery collapse coincident with ongoing carbon cycle perturbations following the Permian-Triassic mass extinction

NASA Astrophysics Data System (ADS)

Petsios, E.; Bottjer, D. J.

2016-12-01

The Permian-Triassic mass extinction, the largest extinction of the Phanerozoic, is attributed to volcanic outgassing from the Siberian Traps and the resulting climate change. Ongoing volcanism in the Early Triassic is implicated for continued carbon cycle instability following the initial event, reflected in large inorganic carbon isotope excursions throughout the 5 Mya interval. Recent paleoecological studies have shown that timing of recovery from the extinction in the Early Triassic is highly complex, differing between regions, with documented cases of "early" recovery in some environments. The importance of specific environmental factors, such as oxygen levels and sea surface temperatures, in aiding or hindering recovery following the extinction is the topic of ongoing study. Here we present an ecological survey of marine benthic communities from the Lower Triassic Blacktail Creek outcrop of the Dinwoody Formation, correlated bed-for-bed with inorganic carbon isotope values. We observe incipient recovery as communities show increasing richness and evenness throughout the section, followed by a `collapse' with a return of high dominance, low richness fauna coincident with large δ13Ccarb shifts. We observe a statistically significant correlation between the magnitude of δ13Ccarb excursions and benthic community complexity over a stratigraphic section, implying a shared causal mechanism acting at the local scale. The globally correlatable nature of these observed carbon isotope shifts, as well as an absence of lithologic evidence for oxygen limitation, points to thermal stress brought on by pulses of volcanism as the shared cause between recovery collapse and carbon cycle perturbations. We propose that the "early" recovery at Blacktail Creek was truncated by recurrent greenhouse gas induced thermal spikes, highlighting the interplay of local and global environmental conditions in expediting or hindering Early Triassic recovery.

An evaporite-based high-resolution sulfur isotope record of Late Permian and Triassic seawater sulfate

NASA Astrophysics Data System (ADS)

Bernasconi, Stefano M.; Meier, Irene; Wohlwend, Stephan; Brack, Peter; Hochuli, Peter A.; Bläsi, Hansruedi; Wortmann, Ulrich G.; Ramseyer, Karl

2017-05-01

Variations in the sulfur isotope composition of dissolved marine sulfate through time reflect changes in the global sulfur cycle and are intimately related to changes in the carbon and oxygen cycles. A large shift in the sulfur isotope composition of sulfate at the Permian/Triassic boundary has been recognized for long time and a number of studies were carried out to understand the causes and significance of this shift. However, data for the Middle and Late Triassic are very sparse and the stratigraphic evolution of the sulfur isotope composition of seawater is poorly constrained due to the small number of samples analyzed and/or due to the limited stratigraphic intervals studied. Moreover, in the last few years the Triassic timescale has significantly changed due to a wealth of new radiometric and stratigraphic data. In this study we show that for the Late Permian and the Triassic it is possible to obtain a precise reconstruction of the evolution of the sulfur cycle, for parts of it at sub-million year resolution, by analyzing exclusively gypsum and anhydrite deposits. We base our reconstruction on new data from the Middle and Late Triassic evaporites of Northern Switzerland and literature data from evaporites from Germany, Austria, Italy and the Middle East. We propose a revised correlation between the well-dated marine Tethyan sections in northern Italy and the evaporites from Northern Switzerland and from the Germanic Basin calibrated to the newest radiometric absolute age scale. This new correlation allows for a precise dating of the evaporites and constructing a composite sulfur isotope evolution of seawater sulfate from the latest Permian (Lopingian Epoch) to the Norian. We show that a rapid positive shift of approximately 24‰ at the Permian-Triassic boundary can be used to constrain seawater sulfate concentrations in the range of 2-6 mM, thus higher than previous estimates but with less rapid changes. Finally, we discuss two possible evolution scenarios

Blastoid Body Size - Changes from the Carboniferous to the End-Permian

NASA Astrophysics Data System (ADS)

Nguyen, L.; Tolosa, R.; Heim, N. A.; Payne, J.

2013-12-01

Climate, known for affecting biodiversity within genera of animal species, is often addressed as a major variable of geological systems. The Mississippian subperiod of the Carboniferous was noted for its lush, tropical climate that sustained a variety of biological life. In contrast, the Permian era was marked primarily by an ice age that had started earlier during the Pennsylvanian. The blastoids, a class of the Echinodermata phylum, were in existence from the Silurian (443.4 Ma) to the end of the Permian (252.28 Ma). This study focused on whether climate affected blastoid theca size over the span of those one hundred million years between the Mississippian and the Permian or if was simply a negligible factor. We analyzed size data from the Treatise on Invertebrate Paleontology and correlated it to both Cope's Rule, which states that size increases with geologic time, and Bergmann's Rule, which states that latitude and temperature are catalysts for size change. CO2 levels from known records served as a proxy for global temperature. Our results indicated that the blastoids increased in size by 59% over geologic time. The size of the blastoids increased over geologic time, following Cope's Rule. According to our graphs in R, there was an inverse relationship between volume and climate. Size decreased as temperature increased, which follows Bergmann's Rule. However, we also wanted to observe spatial factors regarding Bergmann's Rule such as paleolatitude and paleolongitude. This info was taken from the Paleobiology Database and showed that a majority of the blastoids were found near the equator, which, according to the other part of Bergmann's Rule, suggests that they would therefore increase in size. Further tests implied strong correlations between temperature, volume, and paleolocation. We ultimately believe that although Cope's Rule is in effect, Bergmann's mechanisms for size may not apply to the blastoids due to the environments that the blastoids lived in or

Recovery vs. Restructuring: Establishing Ecologic Patterns in Early and Middle Triassic Paleocommunities (Invited)

NASA Astrophysics Data System (ADS)

Fraiser, M.; Dineen, A.; Sheehan, P.

2013-12-01

Published data has been interpreted as indicating that marine ecological devastation following the end-Permian mass extinction was protracted and may have lasted 5 million years into the Middle Triassic (Anisian). However, a review of previous literature shows that understanding of biotic recovery is typically based on only a few components of the ecosystem, such as on taxonomic diversity, a single genus/phylum, or facies. Typically, paleocommunities are considered fully recovered when dominance and diversity are regained and normal ecosystem functioning has resumed. However, in addition to the biodiversity crash at the end of the Permian, taxonomic and ecologic structure also changed,with the extinction marking the faunal shift from brachiopod-rich Paleozoic Evolutionary Fauna (EF) to the mollusc-rich Modern EF. This suggests that the extreme reorganizational nature of the Triassic does not adhere to the standard definition of recovery, which is a return to previous conditions. Thus, we propose the term 'restructuring' to describe this interval, as Early and Middle Triassic communities might not exhibit the typical characteristics of a 'normal' Permian one. To more fully characterize Triassic ecologic restructuring, paleoecologists should take into account functional diversity and redundancy. We quantified functional richness and regularity in four different paleocommunities from classic Permian and Triassic sections. Functional richness was low in paleocommunities after the end-Permian mass extinction, but increased to high levels by the Middle Triassic. In contrast, functional regularity was low in the Middle Permian, but high in all the Triassic paleocommunities. The change from low to high functional regularity/redundancy at the P/T boundary may be a factor of the highly stressful Triassic environmental conditions (i.e. anoxia, hypercapnia), as high regularity in a community can boost survival in harsh environments. Parameters such as these will more

Changhsingian conodont succession and the end-Permian mass extinction event at the Daijiagou section in Chongqing, Southwest China

NASA Astrophysics Data System (ADS)

Yuan, Dong-xun; Chen, Jun; Zhang, Yi-chun; Zheng, Quan-feng; Shen, Shu-zhong

2015-06-01

Previous studies suggested rapid evolution of conodonts across the Permian-Triassic boundary (PTB), and the end-Permian mass extinction pattern varies in different sections in South China. Here we document a high-resolution conodont succession from a carbonate facies of the Changhsingian Stage and across the PTB at the Daijiagou section, about 35 km north to Chongqing City, Southwest China. Two genera and twelve species are identified. Seven conodont zones are recognized from the uppermost part of the Lungtan Formation to the lowest Feixianguan Formation. They are the Clarkina liangshanensis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, and Hindeodus parvus zones in ascending order. Based on the high-resolution biostratigraphical framework at Daijiagou, the end-Permian mass extinction was rapid and it began in the base of the Clarkina meishanensis Zone. Associated with the extinction, a negative excursion of δ13Ccarb started in the middle part of Clarkina yini Zone with a progressive shift of 1.6‰ to the middle part of the Clarkina meishanensis, followed by a sharp shift of 3.51‰ from the Clarkina meishanensis Zone to the Hindeodus parvus Zone. Our study also suggests that the Triassic index species Hindeodus parvus co-occurred with Hindeodus changxingensis and Clarkina zhejiangensis and directly overlies the Clarkina meishanensis Zone at the Daijiagou section. All these data from the Daijiagou section and some previous studies of other sections in Sichuan, Guizhou provinces and Chongqing City suggest that the first occurrences of Hindeodus parvus are slightly earlier than the sharp negative excursion of δ13Ccarb and the FAD at the Meishan GSSP section. We consider that the slight difference of the end-Permian mass extinction, chemostratigraphy and conodont biostratigraphy at Daijiagou and its adjacent areas is most likely subject to different lithofacies, fossil preservation, and the constraint on the stratigraphic resolution rather

Late Permian vertebrate community of the Pranhita Godavari valley, India

NASA Astrophysics Data System (ADS)

Ray, Sanghamitra; Bandyopadhyay, Saswati

2003-03-01

The Kundaram Formation of the Pranhita-Godavari valley yields the only Late Permian multispecies terrestrial vertebrate assemblage from India. This includes various medium and small dicynodonts such as Endothiodon, Oudenodon, Kingoria, Emydops, Cistecephalus and Pristerodon. At present two species of Endothiodon ( E. mahalanobisi and E. uniseries) are known. Apart from these dicynodonts, the Kundaram vertebrate fauna also contains a medium-sized gorgonopsian and a small captorhinid. The material, from the red mudstone dominated Kundaram Formation, includes numerous isolated, disarticulated skulls and lower jaws. Postcranial elements are relatively rare except for a few broken limb ends and vertebrae. The bones are encrusted by iron rich matrix and most of them had suffered deformation. This skull dominant accumulation is attributed to prolonged aerial exposure prior to burial resulting in disarticulation of the skeletons and subsequent inundation by floodwater. The limb bones and other postcranial elements of the already disarticulated skeletons were winnowed out by shallow competent flow while the relatively heavier skulls and lower jaws resisting transportation were buried near the site of death. The Late Permian scenario of the Pranhita-Godavari valley was characterised by the dominance of herbivores. This abundance of herbivores at the base and the presence of relatively few carnivores and omnivores at the top of the Kundaram food pyramid indicate a trophic structure similar to that of the modern-day terrestrial ecosystem.

Abrupt Changes at the Permian/Triassic Boundary: Tempo of Events from High-Resolution Cyclostratigraphy

NASA Technical Reports Server (NTRS)

Rampino, M. R.; Prokoph, A.; Adler, A. C.

2000-01-01

the nearby Reppwand outcrop section, the same faunal changes occurs over only 0.8 m or about 8,000 years, close to the limit of time-resolution induced by bioturbation and reworking in these sediments. The sharp negative global carbon-isotope shift took place within less than or equal to 40,000 yr, and the isotope excursions persisted for approximately 480,000 yr into the Early Triassic. The results indicate that the severe marine faunal event that marks the P/Tr boundary was very sudden, perhaps less than the resolution window in the GK-1 core, and suggest a catastrophic cause. The wavelet-analysis approach to high-resolution cyclostratigraphy can be applied to other P/Tr boundary sections, and when combined with precise absolute dating and magnetostratigraphic methods promises a significant increase in resolution in determining the correlation and tempo of the end-Permian extinctions and related events worldwide.

Conodont biostratigraphy of the Permian-Triassic boundary sequence at Lung Cam, Vietnam

USGS Publications Warehouse

Wardlaw, Bruce R.; Nestell, Merlynd K.; Nestell, Galina P.; Ellwood, Brooks B.; Lan, Luu Thi Phuong

2015-01-01

The occurrences of a few specimens of Clarkina and many specimens of Hindeodus at the Permian-Triassic boundary section at Lung Cam, Vietnam allow accurate graphic correlation to the P-T boundary stratotype at Meishan, China. One species of Clarkina, ten species and two subspecies of Hindeodus, and the apparatuses of Hindeodus latidentatus and Merrillina ultima are described and illustrated.

Late Permian volcanic dykes in the crystalline basement of the Považský Inovec Mts. (Western Carpathians): U-Th-Pb zircon SHRIMP and monazite chemical dating

NASA Astrophysics Data System (ADS)

Pelech, Ondrej; Vozárová, Anna; Uher, Pavel; Petrík, Igor; Plašienka, Dušan; Šarinová, Katarína; Rodionov, Nikolay

2017-08-01

This paper presents geochronological data for the volcanic dykes located in the northern Považský Inovec Mts. The dykes are up to 5 m thick and tens to hundreds of metres long. They comprise variously inclined and oriented lenses, composed of strongly altered grey-green alkali basalts. Their age was variously interpreted and discussed in the past. Dykes were emplaced into the Tatricum metamorphic rocks, mostly consisting of mica schists and gneisses of the Variscan (early Carboniferous) age. Two different methods, zircon SHRIMP and monazite chemical dating, were applied to determine the age of these dykes. U-Pb SHRIMP dating of magmatic zircons yielded the concordia age of 260.2 ± 1.4 Ma. The Th-U-Pb monazite dating of the same dyke gave the CHIME age of 259 ± 3Ma. Both ages confirm the magmatic crystallization at the boundary of the latest Middle Permian to the Late Permian. Dyke emplacement was coeval with development of the Late Paleozoic sedimentary basin known in the northern Považský Inovec Mts. and could be correlated with other pre-Mesozoic Tethyan regions especially in the Southern Alps.

Dolomitized cells within chert of the Permian Assistência Formation, Paraná Basin, Brazil

NASA Astrophysics Data System (ADS)

Calça, Cléber P.; Fairchild, Thomas R.; Cavalazzi, Barbara; Hachiro, Jorge; Petri, Setembrino; Huila, Manuel Fernando Gonzalez; Toma, Henrique E.; Araki, Koiti

2016-04-01

well-preserved organic-walled cyanobacteria and portions of microbial mat. Clearly, dolomitization began very early in the microbial mats, prior to compaction of the sediment or full obliteration of cellular remains, followed very closely by silicification thereby impeding continued degradation and providing a window onto very well-preserved Permian microbial mats.

Permian-Triassic thermal anomaly of the active margin of South America as a result of plate kinematics reorganization

NASA Astrophysics Data System (ADS)

Riel, Nicolas; Jaillard, Etienne; Guillot, Stéphane; Martelat, Jean-Emmanuel; Braun, Jean

2013-04-01

From Permian to Triassic times, tectonic plate reorganization provoked Pangaea breakup, counterclockwise rotation of Gondwana, closing of the Paleo-Tethys Ocean and opening of the Neo-Tethys oceanic realm. Meanwhile, the switch from arc volcanism to widespread S-type magmatism along the western South American active margin around 275-265 Ma is symptomatic of the onset of a large-scale Permian-Triassic thermal anomaly (PTTA)affecting the whole margin. Here we report metamorphic and U-Pb geochronological results from the El Oro metamorphic complex in the forearc zone of southwestern Ecuador, which recorded the last step, at 230-225 Ma, of the PTTA. The change in the drift direction of Gondwana from north to east at ca. 270 Ma was related to plate reorganization and provoked the verticalization of the subducted Panthalassa slab. As the slab verticalized, strong heat advection produced a high heat flow beneath the active margin inducing the development of a huge thermal anomaly responsible for the PTTA, which lasted 30 Ma. This voluminous magmatic activity culminated at the Permian-Triassic boundary, and may have contributed to the degradation of life conditions on the Earth surface.

A Martian analog in Kansas: Comparing Martian strata with Permian acid saline lake deposits

NASA Astrophysics Data System (ADS)

Benison, Kathleen C.

2006-05-01

An important result of the Mars Exploration Rover's (MER) mission has been the images of sedimentary structures and diagenetic features in the Burns Formation at Meridiani Planum. Bedding, cross-bedding, ripple marks, mud cracks, displacive evaporite crystal molds, and hematite concretions are contained in these Martian strata. Together, these features are evidence of past saline groundwater and ephemeral shallow surface waters on Mars. Geochemical analyses of these Martian outcrops have established the presence of sulfates, iron oxides, and jarosite, which strongly suggests that these waters were also acidic. The same assemblage of sedimentary structures and diagenetic features is found in the salt-bearing terrestrial red sandstones and shales of the middle Permian (ca. 270 Ma) Nippewalla Group of Kansas, which were deposited in and around acid saline ephemeral lakes. These striking sedimentological and mineralogical similarities make these Permian red beds and evaporites the best-known terrestrial analog for the Martian sedimentary rocks at Meridiani Planum.

The large scale structures of the Late Permian Zechstein 3 intra-salt stringer, northern Netherlands

NASA Astrophysics Data System (ADS)

van Gent, H.; Strozyk, F.; Urai, J. L.; de Keijzer, M.; Kukla, P. A.

2012-04-01

The three dimensional study of the internal structure of salt structures on the several different scales is of fundamental importance to understand mechanisms of salt tectonics, for intra-salt storage cavern stability, and for drilling in salt-prone petroleum systems with associated problems like borehole instability and overpressured fluids. While most salt-related studies depict salt as structureless bodies, detailed field-, well- and mining gallery mapping have shown an amazing spectrum of brittle, complexly folded, faulted and boudinaged intra-salt layers ("stringers"), but mostly on a very local scale. First detailed insights into these three-dimensionally heterogeneous and very complex structures of the layered evaporites were provided by observations in modern high-resolution 3D seismic data, such as across the Late Permian Zechstein in the Southern Permian Basin (SPB). In the northern Dutch onshore part of the SPB, the Z2 and Z3 halite interface is characterized by the seismically visible reflections of the 30-150 m thick Z3 anhydrite-carbonate layer that clearly resolves the complex intra-salt structure. This stringer shows a high fragmentation into blocks of several tens of meters to kilometres diameter with complexly folded and faulted structures that correlate to the regionally varying deformation stages of the Zechstein, as it is implied by the shape of Top Salt. After an extensive seismic mapping over the entire northern Netherlands, structures observed include an extensive network of thicker zones, inferred to result from early karstification. Later, this template of relatively strong zones was deformed into large scale folds and boudins as the result of salt tectonics. Non-plane-strain salt flow produced complex fold and boudin geometries that overprint each other. There are some indications of a feedback between the early internal evolution of this salt giant and the position of later salt structures. The stringer has a higher density then the

Flourishing ocean drives the end-Permian marine mass extinction.

PubMed

Schobben, Martin; Stebbins, Alan; Ghaderi, Abbas; Strauss, Harald; Korn, Dieter; Korte, Christoph

2015-08-18

The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian-Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth's history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness.

Calibrating the end-Permian mass extinction.

PubMed

Shen, Shu-zhong; Crowley, James L; Wang, Yue; Bowring, Samuel A; Erwin, Douglas H; Sadler, Peter M; Cao, Chang-qun; Rothman, Daniel H; Henderson, Charles M; Ramezani, Jahandar; Zhang, Hua; Shen, Yanan; Wang, Xiang-dong; Wang, Wei; Mu, Lin; Li, Wen-zhong; Tang, Yue-gang; Liu, Xiao-lei; Liu, Lu-jun; Zeng, Yong; Jiang, Yao-fa; Jin, Yu-gan

2011-12-09

The end-Permian mass extinction was the most severe biodiversity crisis in Earth history. To better constrain the timing, and ultimately the causes of this event, we collected a suite of geochronologic, isotopic, and biostratigraphic data on several well-preserved sedimentary sections in South China. High-precision U-Pb dating reveals that the extinction peak occurred just before 252.28 ± 0.08 million years ago, after a decline of 2 per mil (‰) in δ(13)C over 90,000 years, and coincided with a δ(13)C excursion of -5‰ that is estimated to have lasted ≤20,000 years. The extinction interval was less than 200,000 years and synchronous in marine and terrestrial realms; associated charcoal-rich and soot-bearing layers indicate widespread wildfires on land. A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction.

Elemental and Sr-Nd isotopic geochemistry of the Uradzhongqi magmatic complex in western Inner Mongolia, China: A record of early Permian post-collisional magmatism

NASA Astrophysics Data System (ADS)

Qiao, Xueyuan; Li, Wenbo; Zhong, Richen; Hu, Chuansheng; Zhu, Feng; Li, Zhihua

2017-08-01

The magmatic complex in Uradzhongqi, Inner Mongolia, is located in the western segment of the northern margin of the North China Craton (NCC). The dominant components in the complex include syenogranite, monzogranite, granodiorite, diorite and gabbro. Mafic microgranular enclaves (MMEs) are common in syenogranite and granodiorite. Zircon U-Pb dating shows that the ages of these rocks range from 283 to 270 Ma, suggesting an early Permian emplacement. The syenogranite and monzogranite are peraluminous I-type granites, exhibiting conspicuous negative Eu anomaly, enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE), depletion in high field strength elements (HFSE). The granodiorites, diorites and MMEs are metaluminous in composition, show high Al2O3, MgO and Fe2O3T contents and weak negative Eu anomaly, as well as LREE and LILE enrichment and HFSE depletion. The gabbros show weak positive Eu anomaly and slight REE differentiation. The Sr-Nd isotope compositions show that the source of mafic magma was depleted mantle (DM) with possible involvement of enriched mantle II (EM II), whereas the felsic magma was derived from the Archean lower crust. Petrographic observation and analytical results of mineralogy, geochronology, geochemistry and Sr-Nd isotopes indicate that the main petrogenesis of these magmatic rocks is the mixing of underplating mafic magma and felsic magma. Tectonically, the complex pluton was formed within a post-collisional regime, and the underplating in this area provides another piece of evidence for the vertical growth of the western segment of the northern margin of the NCC.

Aromatized arborane/fernane hydrocarbons as molecular indicators of floral changes in Upper Carboniferous/Lower Permian strata of the Saar-Nahe Basin, southwestern Germany

NASA Astrophysics Data System (ADS)

Vliex, M.; Hagemann, H. W.; Püttmann, W.

1994-11-01

Thirty-seven coal samples of Upper Carboniferous and Lower Permian age from three boreholes in the Saar-Nahe Basin, Germany, have been studied by organic geochemical and coal petrological methods. The investigations were aimed at the recognition of floral changes in the Upper Carboniferous and Lower Permian strata. The results show that compositional changes in the extracts are only partly caused by variations in coalification. Specific aromatic hydrocarbons appear in Upper Westphalian D coal seams and increase in concentration up to the Rotliegendes. The dominant compound has been identified by mass spectrometry and NMR-spectroscopy as 5-methyl-10-(4-methylpentyl)-des- A-25-norarbora(ferna)-5,7,9-triene (MATH) and always occurs associated with 25-norarbora(ferna)-5,7,9-triene. Both compounds are thought to originate from isoarborinol, fernene-3β-ol, or fernenes. The strongly acidic conditions during deposition of the coals might have induced the 4,5-cleavage combined with a methyl-shift in an arborane/fernane-type pentacyclic precursor yielding the MATH. Based on petrological investigations, palynomorphs related to early Gymnospermopsida such as Pteridospermales and Coniferophytes ( Cordaitales and Coniferales) increased in abundance in the strata beginning with the Upper Westphalian D concomitant with the above mentioned biomarkers. The results suggest the arborane/fernane derivatives originate from the plant communities producing these palynomorphs.

Magnetic properties of the remagnetized Middle-Ordovician limestones of the Ponón Trehué Formation (San Rafael Block, central-western Argentina): Insights into the Permian widespread Sanrafaelic overprint

NASA Astrophysics Data System (ADS)

Fazzito, Sabrina Y.; Rapalini, Augusto E.

2016-10-01

The widespread Sanrafaelic remagnetization reset most of the early Cambrian to mid-Ordovician carbonate platform of the Argentine Precordillera and the calcareous units of the San Rafael Block. We conducted a detailed rock-magnetic study on the Middle-Ordovician limestones of the Ponón Trehué Formation at both limbs of a tight anticline exposed in the San Rafael Block (Mendoza province, central-western Argentina) that are carriers of a syntectonic magnetization of Permian age. We found that the magnetic overprint in the Ponón Trehué Formation is carried by both pyrrhotite and magnetite, with goethite and subordinate haematite likely related to weathering. Hysteresis parameters, frequency dependence of magnetic susceptibility, Cisowski and modified Lowrie-Fuller tests suggest the presence of ultrafine particles of chemical origin. Demagnetization of natural remanent magnetization and of three-axis isothermal remanence confirm pyrrhotite and magnetite as important contributors to the remanence. Both minerals carry the same magnetic syntectonic component suggesting a coeval or nearly coeval remanence acquisition and therefore mineral formation. This and the results of the magnetic fabric analyses indicate an authigenic origin of the magnetic minerals during folding associated with the Sanrafaelic tectonic phase (ca. 280 Ma). Although the chemically active (oxidizing?) fluids expelled from the orogen as it developed in the early Permian is a viable explanation for the Sanrafaelic remagnetization, the role of the nearly coeval magmatism in Precordillera and the San Rafael Block remains to be properly evaluated.

Lethally Hot Temperatures During the Early Triassic Greenhouse

NASA Astrophysics Data System (ADS)

Sun, Yadong; Joachimski, Michael M.; Wignall, Paul B.; Yan, Chunbo; Chen, Yanlong; Jiang, Haishui; Wang, Lina; Lai, Xulong

2012-10-01

Global warming is widely regarded to have played a contributing role in numerous past biotic crises. Here, we show that the end-Permian mass extinction coincided with a rapid temperature rise to exceptionally high values in the Early Triassic that were inimical to life in equatorial latitudes and suppressed ecosystem recovery. This was manifested in the loss of calcareous algae, the near-absence of fish in equatorial Tethys, and the dominance of small taxa of invertebrates during the thermal maxima. High temperatures drove most Early Triassic plants and animals out of equatorial terrestrial ecosystems and probably were a major cause of the end-Smithian crisis.

Environmental assessment of the area surrounding Dam Rio Verde - Parana/Brazil. An overview of environmental geomorphology.

PubMed

Garcia, Claudia Moreira; Carrijo, Beatriz Rodrigues; Sessegolo, Gisele; Passos, Everton

2012-04-01

This paper presents a brief essay on the situation in which the environment of the dam of the Rio Verde Basin-Parana, from the vision of environmental geomorphology. The area is located between the cities of Campo Magro and Campo Largo, Paraná plateau in the first part of theAlto Iguaçu basin. This study aims to raise the concepts relating to environmental geomorphology, to identify the anthropogenic impacts caused in the reservoir areas, identify the environmental compartments found around the dam and characterize the geologic and physiographic region. It was found that the area has intense anthropogenic influence, as urban growth is present in areas and wavy and rough terrain, subject to mass movements and floods. Besides these aspects, the use of land for agriculture contributes to fragility of the area.

Unexpected Early Triassic marine ecosystem and the rise of the Modern evolutionary fauna

PubMed Central

Brayard, Arnaud; Krumenacker, L. J.; Botting, Joseph P.; Jenks, James F.; Bylund, Kevin G.; Fara, Emmanuel; Vennin, Emmanuelle; Olivier, Nicolas; Goudemand, Nicolas; Saucède, Thomas; Charbonnier, Sylvain; Romano, Carlo; Doguzhaeva, Larisa; Thuy, Ben; Hautmann, Michael; Stephen, Daniel A.; Thomazo, Christophe; Escarguel, Gilles

2017-01-01

In the wake of the end-Permian mass extinction, the Early Triassic (~251.9 to 247 million years ago) is portrayed as an environmentally unstable interval characterized by several biotic crises and heavily depauperate marine benthic ecosystems. We describe a new fossil assemblage—the Paris Biota—from the earliest Spathian (middle Olenekian, ~250.6 million years ago) of the Bear Lake area, southeastern Idaho, USA. This highly diversified assemblage documents a remarkably complex marine ecosystem including at least seven phyla and 20 distinct metazoan orders, along with algae. Most unexpectedly, it combines early Paleozoic and middle Mesozoic taxa previously unknown from the Triassic strata, among which are primitive Cambrian-Ordovician leptomitid sponges (a 200–million year Lazarus taxon) and gladius-bearing coleoid cephalopods, a poorly documented group before the Jurassic (~50 million years after the Early Triassic). Additionally, the crinoid and ophiuroid specimens show derived anatomical characters that were thought to have evolved much later. Unlike previous works that suggested a sluggish postcrisis recovery and a low diversity for the Early Triassic benthic organisms, the unexpected composition of this exceptional assemblage points toward an early and rapid post-Permian diversification for these clades. Overall, it illustrates a phylogenetically diverse, functionally complex, and trophically multileveled marine ecosystem, from primary producers up to top predators and potential scavengers. Hence, the Paris Biota highlights the key evolutionary position of Early Triassic fossil ecosystems in the transition from the Paleozoic to the Modern marine evolutionary fauna at the dawn of the Mesozoic era. PMID:28246643

Unexpected Early Triassic marine ecosystem and the rise of the Modern evolutionary fauna.

PubMed

Brayard, Arnaud; Krumenacker, L J; Botting, Joseph P; Jenks, James F; Bylund, Kevin G; Fara, Emmanuel; Vennin, Emmanuelle; Olivier, Nicolas; Goudemand, Nicolas; Saucède, Thomas; Charbonnier, Sylvain; Romano, Carlo; Doguzhaeva, Larisa; Thuy, Ben; Hautmann, Michael; Stephen, Daniel A; Thomazo, Christophe; Escarguel, Gilles

2017-02-01

In the wake of the end-Permian mass extinction, the Early Triassic (~251.9 to 247 million years ago) is portrayed as an environmentally unstable interval characterized by several biotic crises and heavily depauperate marine benthic ecosystems. We describe a new fossil assemblage-the Paris Biota-from the earliest Spathian (middle Olenekian, ~250.6 million years ago) of the Bear Lake area, southeastern Idaho, USA. This highly diversified assemblage documents a remarkably complex marine ecosystem including at least seven phyla and 20 distinct metazoan orders, along with algae. Most unexpectedly, it combines early Paleozoic and middle Mesozoic taxa previously unknown from the Triassic strata, among which are primitive Cambrian-Ordovician leptomitid sponges (a 200-million year Lazarus taxon) and gladius-bearing coleoid cephalopods, a poorly documented group before the Jurassic (~50 million years after the Early Triassic). Additionally, the crinoid and ophiuroid specimens show derived anatomical characters that were thought to have evolved much later. Unlike previous works that suggested a sluggish postcrisis recovery and a low diversity for the Early Triassic benthic organisms, the unexpected composition of this exceptional assemblage points toward an early and rapid post-Permian diversification for these clades. Overall, it illustrates a phylogenetically diverse, functionally complex, and trophically multileveled marine ecosystem, from primary producers up to top predators and potential scavengers. Hence, the Paris Biota highlights the key evolutionary position of Early Triassic fossil ecosystems in the transition from the Paleozoic to the Modern marine evolutionary fauna at the dawn of the Mesozoic era.

An alternative plate tectonic model for the Palaeozoic Early Mesozoic Palaeotethyan evolution of Southeast Asia (Northern Thailand Burma)

NASA Astrophysics Data System (ADS)

Ferrari, O. M.; Hochard, C.; Stampfli, G. M.

2008-04-01

An alternative model for the geodynamic evolution of Southeast Asia is proposed and inserted in a modern plate tectonic model. The reconstruction methodology is based on dynamic plate boundaries, constrained by data such as spreading rates and subduction velocities; in this way it differs from classical continental drift models proposed so far. The different interpretations about the location of the Palaeotethys suture in Thailand are revised, the Tertiary Mae Yuam fault is seen as the emplacement of the suture. East of the suture we identify an Indochina derived terrane for which we keep the name Shan-Thai, formerly used to identify the Cimmerian block present in Southeast Asia, now called Sibumasu. This nomenclatural choice was made on the basis of the geographic location of the terrane (Eastern Shan States in Burma and Central Thailand) and in order not to introduce new confusing terminology. The closure of the Eastern Palaeotethys is related to a southward subduction of the ocean, that triggered the Eastern Neotethys to open as a back-arc, due to the presence of Late Carboniferous-Early Permian arc magmatism in Mergui (Burma) and in the Lhasa block (South Tibet), and to the absence of arc magmatism of the same age East of the suture. In order to explain the presence of Carboniferous-Early Permian and Permo-Triassic volcanic arcs in Cambodia, Upper Triassic magmatism in Eastern Vietnam and Lower Permian-Middle Permian arc volcanites in Western Sumatra, we introduce the Orang Laut terranes concept. These terranes were detached from Indochina and South China during back-arc opening of the Poko-Song Ma system, due to the westward subduction of the Palaeopacific. This also explains the location of the Cathaysian West Sumatra block to the West of the Cimmerian Sibumasu block.

PLAY ANALYSIS AND DIGITAL PORTFOLIO OF MAJOR OIL RESERVOIRS IN THE PERMIAN BASIN: APPLICATION AND TRANSFER OF ADVANCED GEOLOGICAL AND ENGINEERING TECHNOLOGIES FOR INCREMENTAL PRODUCTION OPPORTUNITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead

2003-04-01

A play portfolio is being constructed for the Permian Basin in west Texas and southeast New Mexico, the largest petroleum-producing basin in the US. Approximately 1300 reservoirs in the Permian Basin have been identified as having cumulative production greater than 1 MMbbl of oil through 2000. Of these major reservoirs, approximately 1,000 are in Texas and 300 in New Mexico. On a preliminary basis, 32 geologic plays have been defined for Permian Basin oil reservoirs and assignment of each of the 1300 major reservoirs to a play has begun. The reservoirs are being mapped and compiled in a Geographic Informationmore » System (GIS) by play. Detailed studies of three reservoirs are in progress: Kelly-Snyder (SACROC unit) in the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play, Fullerton in the Leonardian Restricted Platform Carbonate play, and Barnhart (Ellenburger) in the Ellenburger Selectively Dolomitized Ramp Carbonate play. For each of these detailed reservoir studies, technologies for further, economically viable exploitation are being investigated.« less

Diet, reproduction and population structure of the introduced Amazonian fish Cichla piquiti (Perciformes: Cichlidae) in the Cachoeira Dourada reservoir (Paranaíba River, central Brazil).

PubMed

Luiz, Tatiane Ferraz; Velludo, Marcela Roquetti; Peret, Alberto Carvalho; Rodrigues Filho, Jorge Luiz; Peret, André Moldenhauer

2011-06-01

The Blue Peacock Bass (Cichla piquiti), native to the Tocantins-Araguaia river basin of the Amazon system, was introduced into the basin of the Paranaíba River, Paraná River system. Cachoeira Dourada reservoir is one of a series of dams on the Paranaíba River in central Brazil, where this fish has become established. A study of its feeding spectrum, combined with information about its reproductive characteristics and population structure, would enable the current state of this species in the reservoir to be assessed and might provide useful data for the management of other species native to this habitat. This study showed that the peacock bass has no predators or natural competitors in the reservoir and that reproduces continuously, with high reproductive rates, and has a smaller median length at first maturity (L50) than other species of Cichla. Its successful establishment in habitats strongly affected by human activity should cause changes in the whole structure of the local fish communities. Nonetheless, in this reservoir, there appears to be some sharing of the functions of this species with native carnivorous fish, a situation that may be sustained by the presence of a wide variety of foraging fish.

Juvenile crustal recycling in an accretionary orogen: Insights from contrasting Early Permian granites from central Inner Mongolia, North China

NASA Astrophysics Data System (ADS)

Yuan, Lingling; Zhang, Xiaohui; Xue, Fuhong; Liu, Fulin

2016-11-01

Coeval high-K calc-alkaline to alkaline granites constitute important components of post-collisional to post-orogenic igneous suites in most orogenic belts of various ages on Earth and their genesis harbors a key to ascertaining critical geodynamic controls on continental crustal formation and differentiation. This zircon U-Pb dating and geochemical study documents three contrasting Early Permian granites from Erenhot of central Inner Mongolia, eastern Central Asian Orogenic Belt (CAOB) and reveals concurrent high-K calc-alkaline to alkaline granite association derived from successive partial melting of distinct protoliths. The ca. 280 Ma Gancihuduge (GCG) pluton shows a calc-alkaline I-type character, with initial 87Sr/86Sr ratios of 0.7035 to 0.7039, εNd(t) of + 1.87 to + 4.70, zircon εHf(t) of + 8.0 to + 13.2 and δ18O from 7.4 to 8.7‰. The ca. 276 Ma Cailiwusu (CLS) pluton is magnesian and peraluminous, with initial 87Sr/86Sr ratios of 0.7036 to 0.7040, εNd(t) of + 1.9 to + 2.4, zircon εHf(t) of + 6.5 to + 12.1 and δ18O from 9.7 to 10.9‰. These features are consistent with partial melts of mixed sources composed of newly underplated meta-basaltic to -andesitic protoliths and variable supracrustal components, with distinctively higher proportion of the latter in the CLS pluton. By contrast, the ca. 279 Ma Kunduleng (KDL) suite exhibits an A-type magmatic affinity, with typical enrichment in alkalis, Ga, Zr, Nb and Y, εNd(t) of + 2.39 to + 3.55, zircon εHf(t) from + 8.3 to + 12.3 and δ18O values from 6.8 to 7.5‰. These features suggest that they stem from high-temperature fusion of dehydrated K-rich mafic to intermediate protoliths. Besides presenting a snapshot into a stratified crustal architecture in δ18O, these contrasting granites could not only serve as a temporal marker for monitoring post-collisional extension in the aftermath of a retreating subduction zone, but also present spatial magmatic proxy for tracing crustal formation and

Early tetrapod evolution and the progressive integration of Permo-Carboniferous terrestrial ecosystems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beerbower, J.R.; Olson, E.C.; Hotton, N. III

1992-01-01

Variation among Permo-Carboniferous tetrapod assemblages demonstrates major transformations in pathways and rates of energy and nutrient transfer, in integration of terrestrial ecosystems and in predominant ecologic modes. Early Carboniferous pathways were through plant detritus to aquatic and terrestrial detritivores and thence to arthropod and vertebrate meso-and macro-predators. Transfer rates (and efficiency) were low as was ecosystem integration; the principal ecologic mode was conservation. Late Carboniferous and Early Permian assemblages demonstrate an expansion in herbivory, primarily in utilization of low-fiber plant tissue by insects. But transfer rates, efficiency and integration were still limited because the larger portion of plant biomass, high-fibermore » tissues, still went into detrital pathways; high-fiber'' herbivores, i.e., tetrapods, were neither abundant or diverse, reflecting limited resources, intense predation and limited capabilities for processing fiber-rich food. The abundance and diversity of tetrapod herbivores in upper Permian assemblages suggests a considerable transfer of energy from high-fiber tissues through these animals to tetrapod predators and thus higher transfer rates and efficiencies. It also brought a shift in ecological mode toward acquisition and regulation and tightened ecosystem integration.« less

Slab break-off and the formation of Permian mafic-ultramafic intrusions in southern margin of Central Asian Orogenic Belt, Xinjiang, NW China

NASA Astrophysics Data System (ADS)

Song, Xie-Yan; Xie, Wei; Deng, Yu-Feng; Crawford, Anthony J.; Zheng, Wen-Qin; Zhou, Guo-Fu; Deng, Gang; Cheng, Song-Lin; Li, Jun

2011-11-01

The Baishiquan and Pobei Early Permian mafic-ultramafic intrusions were emplaced into Proterozoic metamorphic rocks in the Central Tianshan and the Beishan Fold Belt, northern Xinjiang, NW China. The Baishiquan intrusion comprises mainly gabbro, and mela-gabbro sills occurring within and along the margins of the gabbro body. In the Pobei intrusion, two distinct gabbroic packages, a lower gabbro and the main gabbro, are intruded and overlain by small cumulate wehrlite bodies. Both intrusions are characterized by enrichments of large ion lithophile elements and Th and U relative to the high field strength elements, and show strong negative Nb and Ta anomalies and positive K and Pb anomalies, leading to higher Th/Yb and Nb/Yb than in mid-ocean ridge basalt and ocean island basalt. These features are comparable with subduction-related mafic rocks and post-collisional magmas. Geological and geochemical considerations indicate that the parental magmas of the two intrusions were derived from decompression melting of ascending asthenosphere and reacted with overlying subduction-modified lithospheric mantle. We believe that these parental magmas were generated by post-collisional extension along the Chinese Tianshan, perhaps triggered by slab break-off or delamination of thickened lithosphere. Relatively lower (143Nd/144Nd)i and higher (87Sr/86Sr)i than other Permian mafic-ultramafic intrusions in the eastern Chinese Tianshan indicate that the parental magmas of these two intrusions experienced significant contamination by old crustal rocks.

Paleoecological and paleoenvironmental changes during the continental Middle-Late Permian transition at the SE Iberian Ranges, Spain

NASA Astrophysics Data System (ADS)

De la Horra, R.; Galán-Abellán, A. B.; López-Gómez, J.; Sheldon, N. D.; Barrenechea, J. F.; Luque, F. J.; Arche, A.; Benito, M. I.

2012-08-01

The Middle and Late Permian are characterized by a pair of mass-extinction events that are recorded in both marine and continental environments. Here, we present the first continental western peri-Tethyan record of an extinction event located in the Middle-Late interval. In the SE Iberian Ranges, Central Spain, the transition between the Lower and Middle subunits of the Middle Permian Alcotas Formation indicates a significant paleoclimatic change from arid and semiarid conditions towards more humid conditions. Coincident with the onset of humid conditions there were changes in the sedimentology, mineralogy, and geochemistry that indicate significant environmental changes including a shift in weathering intensity and a change of fluvial style from braided to meandering systems. Near the top of the Middle Subunit, a local biotic crisis is recorded by palynomorph assemblages. Following this crisis, there is a total absence of coal beds, plant remains, and microflora that defines a barren zone in the uppermost part of the Alcotas Formation which is recorded throughout the basin. The barren zone is accompanied by a shift back to braided stream systems, but not by a return to carbonate-bearing paleosols indicative of arid or semi-arid conditions. This combination of features is consistent with other Middle-Late continental basins related with mass extinctions, so the barren zone is interpreted as the extinction interval. The regional character of the extinction interval and its proximity with the Middle-Late Permian transition could be related with the global mid-Capitanian biotic turnover described in this period of time in other marine basins. However, the common difficulties of dating with precision non-marine rocks make this relationship difficult to probe in the Iberian Basin and in other Middle-Late Permian basins. Further work, including high resolution carbon-isotope analyses and complete studies of the magnetostratigraphy, should be desirable in order to obtain

Biolaminoid facies in a peritidal sabkha: Permian Platy Dolomite of northern Poland

NASA Astrophysics Data System (ADS)

Brehm, Ulrike; Gasiewicz, Andreij; Gerdes, Giesela; Krumbein, Wolfgang

The Platy Dolomite, a carbonate unit in the Zechstein Formation (Upper Permian) of the Leba Elevation, Poland, was deposited in a semi-closed or completely separated back-barrier sabkha environment. This arid, hypersaline zone is comparable to the recent Gavish Sabkha, Sinai. The processes which formed the modern Gavish Sabkha are similar to those responsible for the biolaminoid formation in the Platy Dolomite series. The deposition of this Platy Dolomite was mainly the result of microbial activity building extensive microbial mats. The Platy Dolomite is characterized by loosely packed microbial biolaminoids (a less significantly laminated build-up of biogenetic sediments) with horizontally or obliquely to vertically orientated filaments. Intermediary coated grains occur. Densely packed, flat laminated stromatolitic rocks, pure oolites, and bioclastic sedimentary strata are rarely intercalated with the biolaminoid beds. Laboratory and field investigations indicate that carbonate formation was induced by the chemoorganotrophic bacterial decay of cyanobacterial mats. Magnesium was bound and absorbed by organic matter and later liberated by anaerobic decay. Early diagenetic processes formed Mg2+- and Ca2+-enriched solutions in which carbonates precipitated biologically and chemically. A system of biogenic carbonate formation of the Platy Dolomite microbiolite series is proposed and supported by the results of microbiological laboratory studies.

Assessment of Permian tight oil and gas resources in the Junggar basin of China, 2016

USGS Publications Warehouse

Potter, Christopher J.; Schenk, Christopher J.; Tennyson, Marilyn E.; Klett, Timothy R.; Gaswirth, Stephanie B.; Leathers-Miller, Heidi M.; Finn, Thomas M.; Brownfield, Michael E.; Pitman, Janet K.; Mercier, Tracey J.; Le, Phuong A.; Drake, Ronald M.

2017-04-05

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 764 million barrels of oil and 3.5 trillion cubic feet of gas in tight reservoirs in the Permian Lucaogou Formation in the Junggar basin of northwestern China.

A geochemical view into continental palaeotemperatures of the end-Permian using oxygen and hydrogen isotope composition of secondary silica in chert rubble breccia: Kaibab Formation, Grand Canyon (USA).

PubMed

Kenny, Ray

2018-01-16

The upper carbonate member of the Kaibab Formation in northern Arizona (USA) was subaerially exposed during the end Permian and contains fractured and zoned chert rubble lag deposits typical of karst topography. The karst chert rubble has secondary (authigenic) silica precipitates suitable for estimating continental weathering temperatures during the end Permian karst event. New oxygen and hydrogen isotope ratios of secondary silica precipitates in the residual rubble breccia: (1) yield continental palaeotemperature estimates between 17 and 22 °C; and, (2) indicate that meteoric water played a role in the crystallization history of the secondary silica. The continental palaeotemperatures presented herein are broadly consistent with a global mean temperature estimate of 18.2 °C for the latest Permian derived from published climate system models. Few data sets are presently available that allow even approximate quantitative estimates of regional continental palaeotemperatures. These data provide a basis for better understanding the end Permian palaeoclimate at a seasonally-tropical latitude along the western shoreline of Pangaea.

Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)

NASA Astrophysics Data System (ADS)

Gómez-Gras, D.; Alonso-Zarza, A. M.

2003-05-01

The Permian and Triassic of Minorca (Balearic Islands) consists of a 670-m-thick, red, alluvial succession that includes in situ calcrete profiles and reworked calcrete material. In the Permian succession, the calcretes vary from laminar forms developed on the Carboniferous basement to weakly developed nodular calcretes in fluvial sediments. The palaeosols in the Triassic are mostly dolomitic, and the profiles reach up to Stage III of soil development (Spec. Pap.-Geol. Surv. Am. 203, (1995) 1). The clasts, formed through reworking of the palaeosol profiles, are about 0.5-10 cm across and include mosaics of calcite/dolomite crystals, brecciated clasts, rhizolith fragments, and aggregates of clay and/or silt. These clasts appear in three different types of deposits. Type 1 corresponds to lenticular bodies that fill small scour surfaces, and consists only of intraformational conglomerates. These deposits are interpreted as ephemeral channels and sheet-floods that represent the interfluvial drainage systems that captured only the precipitation falling on the alluvial plain. Type 2 includes sand dune 3-D bodies with flat bottoms and convex tops. These bodies are about 20 cm high and 2 m wide, and were formed by floodwaters that flowed down the levees of the major streams. Type 3 channel deposits contain reworked calcretes and extrabasinal clasts, which overlie erosive surfaces and are found in layers within cross-bedded sandstones and conglomerates. These are interpreted as channel-floor lag deposits of major channels that entered from distant uplands and drained the alluvial plain. Variations in the aggradation rates of the floodplain resulted in five different infill stages. In the lowstand to early transgressive interval, as in stages I (P1) and IV (B1), the fluvial deposits filled palaeovalleys; calcretes and reworked calcrete deposits were of difficult formation (apart from terraces) and preservation. Accommodation space was at its greatest in the transgressive

Inclination Shallowing in the Permian/Triassic Boundary Sedimentary Sections of the East European Platform: the New Paleomagnetic Pole and its Significance for GAD Hypothesis

NASA Astrophysics Data System (ADS)

Veselovskiy, R. V.; Fetisova, A. M.; Balabanov, Y.

2017-12-01

One of the key challenges which are traditionally encountered in studying the paleomagnetism of terrigenous sedimentary strata is the necessity to allow for the effect of shallowing of paleomagnetic inclinations which takes place under the compaction of the sediment at the early stages of diagenesis and most clearly manifests itself in the case of midlatitude sedimentation. Traditionally, estimating the coefficient of inclination flattening (f) implies routine re-deposition experiments and studying their magnetic anisotropy (Kodama, 2012), which is not possible in every standard paleomagnetic laboratory. The Elongation-Inclination (E/I) statistical method for estimating the coefficient of inclination shallowing, which was recently suggested in (Tauxe and Kent, 2004), does not require the investigation of the rock material in a specially equipped laboratory but toughens the requirements on the paleomagnetic data and, primarily, regarding the volume of the data, which significantly restricts the possibilities of the post factum estimation and correction for inclination shallowing. We present the results of the paleomagnetic reinvestigation of the some key sections of the Upper Permian and Lower Triassic rocks located on the East European Platform. The obtained paleomagnetic data allowed us to estimate the coefficient of inclination shallowing by the E/I method and calculate a new P-Tr paleomagnetic pole for Europe. The absence of a statistically significant difference between the mean Siberian, European and North American Permian-Triassic paleomagnetic poles allow us to conclude that 252 Ma the configuration of the Earth's magnetic field was predominantly dipole. We believe that the assumption of the non-dipolarity of the geomagnetic field at the Permian-Triassic boundary, which has been repeatedly discussed in recent decades (Van der Voo and Torsvik, 2001; Bazhenov and Shatsillo, 2010; Veselovskiy and Pavlov, 2006), arose due to the failure to take into account the

Methanogenic burst in the end-Permian carbon cycle.

PubMed

Rothman, Daniel H; Fournier, Gregory P; French, Katherine L; Alm, Eric J; Boyle, Edward A; Cao, Changqun; Summons, Roger E

2014-04-15

The end-Permian extinction is associated with a mysterious disruption to Earth's carbon cycle. Here we identify causal mechanisms via three observations. First, we show that geochemical signals indicate superexponential growth of the marine inorganic carbon reservoir, coincident with the extinction and consistent with the expansion of a new microbial metabolic pathway. Second, we show that the efficient acetoclastic pathway in Methanosarcina emerged at a time statistically indistinguishable from the extinction. Finally, we show that nickel concentrations in South China sediments increased sharply at the extinction, probably as a consequence of massive Siberian volcanism, enabling a methanogenic expansion by removal of nickel limitation. Collectively, these results are consistent with the instigation of Earth's greatest mass extinction by a specific microbial innovation.

Systemic swings in end-Permian environments from Siberian Traps carbon and sulfur outgassing

NASA Astrophysics Data System (ADS)

Black, B. A.; Neely, R.; Lamarque, J. F.; Elkins-Tanton, L. T.; Kiehl, J. T.; Shields, C. A.; Mills, M. J.; Bardeen, C.

2017-12-01

U-Pb geochronology has revealed that Siberian Traps flood basalt magmatism coincided with the 252 Ma end-Permian mass extinction. Most environmental consequences of magmatism follow directly or indirectly from the release of sulfur and some combination of magmatic and metamorphic carbon to the atmosphere (exceptions include ozone depletion from halogen emissions, release of toxic metals, and enhanced weathering of fresh volcanic rocks). However, the critical combinations of forcing and stress that trigger global mass extinction remain unknown. In particular, the combined and competing effects of sulfur and carbon outgassing on Earth systems remain to be quantified. Here we present results from global climate model simulations of flood basalt outgassing that account for sulfur chemistry and aerosol microphysics. We consider the effects of sulfur and carbon in isolation and in tandem, and find that carbon and sulfur emissions combine to generate swings in climate, ocean circulation, and hydrology. Our simulations provide a self-consistent framework to quantitatively explain observed features of the end-Permian including surface warming, fluctuating ocean oxygenation, intense weathering, and carbon cycle perturbation, unifying observed changes in climate and geochemical cycles with feedbacks initiated by Siberian Traps magmatism.

Parent brine of the castile evaporites (Upper Permian), Texas and New Mexico

USGS Publications Warehouse

Kirkland, Douglas W.; Denison, Rodger E.; Dean, Walter E.

2000-01-01

The Upper Permian (lower Ochoan) Castile Formation is a major evaporite sequence (∼10,000 km3) of calcite, anhydrite, and halite in west Texas and southeastern New Mexico. Traditionally the Castile brine has been considered to have been derived from seawater. This tradition has recently been challenged by two versions of the closed-basin drawdown model. They call for deposition from a mixed brine, in part marine and in large part nonmarine. They propose drawdown of as much as 500 m to form a major sink for ground water issuing from the surrounding Capitan reef complex. A large fraction of the solute in the brine body is inferred to have been recycled from older Permian evaporites on the surrounding shelf. Strontium-isotope analyses show no evidence that meteoric ground water was contributed to the Castile brine. From a stratigraphic, geographic, and lithologic array of 65 samples of anhydrite, gypsum, and calcite, 59 have an 87Sr/86Sr ratio of 0.706923 (Δsw of -225.0), a ratio that is the same as that of strontium in early Ochoan ocean water. If considerable (>15%) influx of meteoric water had occurred, enough continental strontium would have been introduced to have resulted in higher ratios. Low bromide values (20-40 ppm) in Castile halite, which have been used to argue for meteoric influx and for recycled salt, probably resulted from diagenesis. During shallow burial by halite, centimeter-size, bottom-grown crystals of gypsum were altered to nodular anhydrite. The rising water of dehydration caused the halite to recrystallize. During the recrystallization, some bromide was expelled. Despite the large volume of water that evaporated annually from its surface (∼52 km3/yr, assuming an evaporation rate of 2 m/yr), the Castile brine body never completely desiccated. The surrounding shelf was flat, hot, and generally dry. It probably could not have supplied a significant volume of meteoric spring water to the basin over tens of thousands of years. More likely

Microstructure and significance of cordaitean reproductive organs from the lower Permian of Gansu, Northwest China

NASA Astrophysics Data System (ADS)

Wang, Zixi; Sun, Bainian; Sun, Fankai; Xiong, Conghui; Chen, Yingquan; Wang, Xuelian

2018-06-01

The Late Paleozoic strata are well exposed in Yongchang County, Gansu Province, Northwest China. The strata contain numerous plant fossils. Hence, Yongchang County is a good location to study Paleozoic plants and plate movement. Using well-preserved cordaitean cones and seeds from the lower Permian Taiyuan Formation of Yongchang County, two new species of fossil plants are described, one attributed to the new organ genus Hexianthus (H. shenii sp. nov.) and the other to the seed genus Samaropsis (S. shenii sp. nov.). The micro- and macro-scale features of the cones, including the epidermal features of the bracts and scales, are analyzed in the laboratory. Numerous cordaitean cones with helically arranged bracts and scales (H. shenii sp. nov.) present in the Taiyuan Formation of Yongchang County share similar characteristics with the cordaitean cones which are endemic to the Cathaysian flora. This suggests that the study region was characterized by the Cathaysian flora in the Cisuralian, similar to the Hexi Corridor to the south of the study region. Based on the study of fossil cuticles and their associated plants, the study region of Yongchang County probably had a warm and humid climate during the Cisuralian. In addition, according to the associations between different fossil plants from several localities in Gansu Province (from the Cathaysian flora in the lower Permian to the Cathaysian-Angaran mixed flora in the upper Permian), a possible boundary between the Cathaysian and Angaran floras in Gansu Province can be placed along the Hexi Corridor, which provides important information for the study of floral associations in Northwest China during the Late Paleozoic.

When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

PubMed Central

Day, Michael O.; Ramezani, Jahandar; Bowring, Samuel A.; Sadler, Peter M.; Erwin, Douglas H.; Abdala, Fernando; Rubidge, Bruce S.

2015-01-01

A mid-Permian (Guadalupian epoch) extinction event at approximately 260 Ma has been mooted for two decades. This is based primarily on invertebrate biostratigraphy of Guadalupian–Lopingian marine carbonate platforms in southern China, which are temporally constrained by correlation to the associated Emeishan Large Igneous Province (LIP). Despite attempts to identify a similar biodiversity crisis in the terrestrial realm, the low resolution of mid-Permian tetrapod biostratigraphy and a lack of robust geochronological constraints have until now hampered both the correlation and quantification of terrestrial extinctions. Here we present an extensive compilation of tetrapod-stratigraphic data analysed by the constrained optimization (CONOP) algorithm that reveals a significant extinction event among tetrapods within the lower Beaufort Group of the Karoo Basin, South Africa, in the latest Capitanian. Our fossil dataset reveals a 74–80% loss of generic richness between the upper Tapinocephalus Assemblage Zone (AZ) and the mid-Pristerognathus AZ that is temporally constrained by a U–Pb zircon date (CA-TIMS method) of 260.259 ± 0.081 Ma from a tuff near the top of the Tapinocephalus AZ. This strengthens the biochronology of the Permian Beaufort Group and supports the existence of a mid-Permian mass extinction event on land near the end of the Guadalupian. Our results permit a temporal association between the extinction of dinocephalian therapsids and the LIP volcanism at Emeishan, as well as the marine end-Guadalupian extinctions. PMID:26156768

Physiological implications of the abnormal absence of the parietal foramen in a late Permian cynodont (Therapsida)

NASA Astrophysics Data System (ADS)

Benoit, Julien; Abdala, Fernando; Van den Brandt, Marc J.; Manger, Paul R.; Rubidge, Bruce S.

2015-12-01

The third eye (pineal eye), an organ responsible for regulating exposure to sunlight in extant ectotherms, is located in an opening on the dorsal surface of the skull, the parietal foramen. The parietal foramen is absent in extant mammals but often observed in basal therapsids, the stem-group to true mammals. Here, we report the absence of the parietal foramen in a specimen of Cynosaurus suppostus, a Late Permian cynodont from South Africa (SA). Comparison with Procynosuchus delaharpeae, a contemporaneous non-mammalian cynodont from SA, demonstrates that the absence of this foramen is an abnormal condition for such a basal species. Because seasonality was marked during the Late Permian in SA, it is proposed that the third eye was functionally redundant in Cynosaurus, possibly due to the acquisition of better thermoregulation or the evolution of specialized cells in the lateral eyes to compensate for the role of the third eye.

Permian-triassic paleogeography and stratigraphy of the west Netherlands basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speksnijder, A.

1993-09-01

During the Permian, the present West Netherlands basin (WNB) was situated at the southernmost margin of the southern Permian basin (SPB). The thickness of Rotilegende sandstones therefore is very much reduced in the WNB. The relatively thin deposits of the Fringe Zechstein in the WNB, however, also contrast strongly in sedimentary facies with thick evaporite/carbonate alternations in the main SPB to the north, although the classic cyclicity of Zechstein deposition still can be recognized. The Fringe Zechstein sediments are mainly siliciclastic and interfinger with both carbonates and anhydrites toward the evaporite basin. End members are thin clay layers that constitutemore » potential seals to underlying Rotliegende reservoirs and relatively thick sandstones (over 100 m net sand) in the western part of the WNB. Nevertheless, favorable reservoir/seal configurations in the Fringe Zechstein seem to be sparse because only minor hydrocarbon occurrences have been proven in the area to date. The situation is dramatically different for the Triassic in the WNB. The [open quotes]Bunter[close quotes] gas play comprises thick Fringe Buntsandstein sandstones (up to 250 m), vertically sealed by carbonates and anhydritic clays of the Muschelkalk and Keuper formations. The Bunter sandstones are largely of the same age as the classic Volpriehausen, Detfurth, and Hardegsen alluvial sand/shale alternations recognized elsewhere, but the upper onlapping transgressive sands and silts correlate with evaporitic clays of the Roet basin to the north. A total volume of 65 x 10[sup 9]m[sup 3] of gas has so far been found in the Triassic Bunter sandstones of the WNB.« less

Tiarajudens eccentricus and Anomocephalus africanus, two bizarre anomodonts (Synapsida, Therapsida) with dental occlusion from the Permian of Gondwana

PubMed Central

Cisneros, Juan Carlos; Abdala, Fernando; Jashashvili, Tea; de Oliveira Bueno, Ana; Dentzien-Dias, Paula

2015-01-01

Anomodontia was a highly successful tetrapod clade during the Permian and the Triassic. New morphological information regarding two bizarre basal anomodonts is provided and their palaeoecological significance is explored. The osteology of the recently discovered Tiarajudens eccentricus Cisneros et al. 2011, from the Brazilian Permian, is described in detail. The taxon exhibits unusual postcranial features, including the presence of gastralia. Additional preparation and computed tomography scans of the holotype of Anomocephalus africanus Modesto et al. 1999 discovered in the Karoo Basin of South Africa allow a reappraisal of this genus. Anomocephalus is similar to Tiarajudens with regard to several traits, including a battery of large, transversally expanded, palatal teeth. Molariform teeth are present in the mandible of the African taxon, providing additional insight into the function of the earliest tooth-occlusion mechanism known in therapsids. At least two waves of tooth replacement can be recognized in the palate of Anomocephalus. The outsized, blade-like caniniforms of the herbivorous Tiarajudens allow several non-exclusive ecological interpretations, among which we favour intraspecific display or combat. This behaviour was an alternative to the head-butting practised by the contemporary dinocephalians. Combat specializations that are considered typical of Cenozoic herbivores likely evolved during the Middle Permian, at the time the first communities with diverse, abundant tetrapod herbivores were being assembled. PMID:26587266

Community stability and selective extinction during the Permian-Triassic mass extinction

NASA Astrophysics Data System (ADS)

Roopnarine, Peter D.; Angielczyk, Kenneth D.

2015-10-01

The fossil record contains exemplars of extreme biodiversity crises. Here, we examined the stability of terrestrial paleocommunities from South Africa during Earth's most severe mass extinction, the Permian-Triassic. We show that stability depended critically on functional diversity and patterns of guild interaction, regardless of species richness. Paleocommunities exhibited less transient instability—relative to model communities with alternative community organization—and significantly greater probabilities of being locally stable during the mass extinction. Functional patterns that have evolved during an ecosystem's history support significantly more stable communities than hypothetical alternatives.

Ar/Ar geochronology in the western Tianshan (northwestern China): from Carboniferous (ultra)high-pressure metamorphism and thrusting to Permian strike-slip deformation and fluid ingress

NASA Astrophysics Data System (ADS)

de Jong, K.; Wang, B.; Ruffet, G.; Shu, L. S.; Faure, M.

2012-04-01

The Tianshan belt (northwestern China) is a major tectonic element of the southern Central Asian Orogenic Belt that contains a number of ophiolitic mélanges and (ultra)high-pressure metamorphic belts formed after closure of oceanic and back-arc basins that resulted in terrane collisions. Deciphering its tectonic evolution is thus crucial for understanding the amalgamation of Central Asia. We produce robust 40Ar/39Ar laser-probe evidence that the Tianshan is a Late Palaeozoic (ultra)high-pressure metamorphic collision belt, not a Triassic one, as suggested by some SHRIMP zircon ages in recent literature. Instead of trying to date the peak pressure conditions we focused on 40Ar/39Ar analysis of white mica formed during retrograde recrystallisation when the (ultra)high-pressure metamorphic rocks of the Changawuzi-Kekesu complex were exhumed. Exhumation was coeval with their northward thrusting over the southern margin of the Yili terrane, the easternmost element of the Kazakhstan composite super-terrane, which produced main phase tectonic structures. The Yili terrane comprises a Proterozoic basement covered by metasediments, intruded by Early Carboniferous granites when it formed part of a continental margin arc. During the Permian deformation was partitioned in vertical brittle-ductile strike-slip fault zones that reactivated these suture zones and in which bimodal magmatism was concentrated. We also investigate the effects of these events on the isotopic ages of mica. 40Ar/39Ar laser-probe dating of white mica reveals that the strongest retrogressed blueschists immediately above the basal thrust fault of the Changawuzi-Kekesu belt gave the youngest plateau age of 316 ± 2 Ma (1σ). White mica in greenschist-facies metamorphic quartzite from the ductilely deformed metasedimentary cover of the Yili terrane's crystalline basement, taken at about 1 km below the thrust contact with the overlying Changawuzi-Kekesu belt, yielded a plateau age of 323 ± 1 Ma (1�

Inorganic chemistry, petrography and palaeobotany of Permian coals in the Prince Charles Mountains, East Antarctica

USGS Publications Warehouse

Holdgate, G.R.; McLoughlin, S.; Drinnan, A.N.; Finkelman, R.B.; Willett, J.C.; Chiehowsky, L.A.

2005-01-01

Sampled outcrops of Permian coal seams of the Bainmedart Coal Measures in the Lambert Graben, eastern Antarctica, have been analysed for their proximates, ultimates, ash constituents and trace elements. A similar series of samples has been analysed for their principle maceral and microlithotype components and vitrinite reflectance. The coals are sub-bituminous to high volatile bituminous in rank; maturity increases markedly in southern exposures around Radok Lake where the oldest part of the succession is exposed and some strata have been intruded by mafic dykes and ultramafic sills. The coal ash is mostly silica and aluminium oxides, indicating that the mineral ash component is mostly quartz and various clay minerals. The ratio of silica to aluminium oxides appears to increase in an upward stratigraphic direction. The coal macerals include a relatively high liptinite content (mainly sporinite) that is significantly higher than for typical Gondwana coals. Greater degrees of weathering within the floodbasin/peat mire environments associated with climatic drying towards the end of the Permian might account for both preferential sporopollenin preservation and increased silica:aluminium oxide ratios up-section. Correlation of the coal maceral components to adjacent peninsula India coals indicates the closest comparative coals of similar age and rank occur within the Godavari Basin, rather then the Mahanadi Basin, which is traditionally interpreted to have been contiguous with the Lambert Graben before Gondwanan breakup. The petrological characteristics suggest that either previous interpretations of Palaeozoic basin alignments between Antarctica and India are incorrect, or that environmental settings and post-Permian burial histories of these basins were strongly independent of their tectonic juxtaposition. A permineralized peat bed within the succession reveals that the coals predominantly comprise wood- and leaf-rich debris derived from low-diversity forest

New paleomagnetic results from the Permian and Mesozoic rocks in central and northeast Thailand: their implications for the construction of the Indochina block in Pangea

NASA Astrophysics Data System (ADS)

Zhang, D.; Yan, Y.; Huang, B.; Zhao, J.

2015-12-01

Paleomagnetic studies of the Indochina block, aiming to reconstruct the paleogeography, have been undertaken for several decades. Since the Indochina block is lack of reliable paleomagnetic data to constraint its paleo-positions during the Middle Permian to Upper Triassic, the paleogeography reconstruction is still in debate between different models reported. Here we present new paleomagnetic data of Middle Permian to Upper Triassic sediment rocks from the Indochina block in Thailand, and recalculate paleomagnetic data reported by different authors. We collected the Permian samples in 20 sites distributed in the central Thailand, and Triassic samples from the Huai Hin Lat and Nam Phong formations in 13 sites in the northern Thailand.The magnetic directions of the 11 sites of Permian limestones are not significantly clustered after tilt correction which implying a remagnetized result. Remarkably, in geographic coordinate, the 11 sites were distributed along a circle showing a similar inclination which is 22.9° implying the paleolatitude to be about 12°. Totally, 13 sites from the Huai Hin Lat formation are included in the calculation of the formation mean direction Dg/Ig = 21.4°/38.1°, kg = 19.5, α95 = 9.6° before and Ds/Is = 43.0°/48.0°, ks = 47.4, α95 = 6.1°, N = 13 after bedding correction. A pre-folding characteristic magnetization is suggested by the positive fold test result derived from the Huai Hin Lat formation, and thus implies a primary remanence of the Norian Stage Upper Triassic rocks. A new Nam Phong formation mean direction derived from 11 sites is Dg/Ig = 36.5°/31.3°, kg = 14.7, α95 = 12.3°before and Ds/Is = 36.4°/37.8°, ks = 68.5, α95 = 5.6°, N = 11 after bedding correction. The two formation mean directions correspond to the magnetic pole positions , Plat./Plon=48.7°N/165.9°E, A95=7.2° and Plat./Plon=55.2°N/178.0°E, A95=5.9°, respectively. A remarkable tectonic movement (~8° southward) of the Indochina block from the age of

The Cordon del Portillo Permian magmatism, Mendoza, Argentina, plutonic and volcanic sequences at the western margin of Gondwana

NASA Astrophysics Data System (ADS)

Gregori, Daniel; Benedini, Leonardo

2013-03-01

The Cerro Punta Blanca, Cerro Bayo and Cerro Punta Negra stocks, parts of the Cordillera Frontal Composite Batholith, cropping out in the Cordón del Portillo, records the Gondwana magmatic development of the Cordillera Frontal of Mendoza, in western Argentina. In this area, the San Rafael Orogenic phase, that represents the closure of the Late Carboniferous-Early Permian marine basins, begins at 284 Ma, and ceased before 276 Ma. The Cerro Punta Blanca, Cerro Bayo and Cerro Punta Negra stocks represent a post-orogenic magmatism and are equivalents to the Choiyoi Group. The Gondwana magmatic activity in the Cordón del Portillo area can be divided into two stages. The Cerro Punta Blanca stock (c.a. 276 Ma) represents an early post-orogenic, subduction-related magmatism similar to the basic-intermediate section of the Choiyoi Group (c.a. 277 Ma). The late post-orogenic second event was recorded by the Cerro Bayo (262 Ma) and Cerro Punta Negra stocks which represent a transition between subduction-related and intra-plate magmatism. This event represents the intrusive counterpart of the acidic facies of the upper section of the Choiyoi Group (c.a. 273 Ma). This extensional condition continued during the Triassic when the Cacheuta basin developed.

78 FR 16569 - Iowa Pacific Holdings, LLC, Permian Basin Railways, and San Luis & Rio Grande Railroad-Corporate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... Exemption-- Massachusetts Coastal Railroad, LLC Iowa Pacific Holdings, LLC (IPH), its wholly owned subsidiaries Permian Basin Railways (PBR) and San Luis & Rio Grande Railroad (SLRG), and Massachusetts Coastal Railroad, LLC (Mass Coastal) (collectively, applicants), have jointly filed a verified notice of exemption...

Depositional paleoenvironments of the Lower Permian (upper Cisuralian) carbonate succession of Paso Hondo Formation in Chiapas State, southeastern Mexico

NASA Astrophysics Data System (ADS)

Torres-Martínez, Miguel A.; Barragán, Ricardo; Sour-Tovar, Francisco; González-Mora, Sergio

2017-11-01

The Paso Hondo Formation outcrops around of the Chicomuselo region, Chiapas State, Mexico. It is a Permian lithostratigraphic unit mainly composed of massive limestone which has been dated for the Artinskian-Kungurian (late Cisuralian). A microfacies analysis carried out on the carbonate rocks of a stratigraphic section, allowed for the first time the recognition of the depositional conditions that prevailed in the Chicomuselo region at the end of the Cisuralian. The facies associations studied allowed identifying different marine paleoenvironments related with a homoclinal carbonate ramp. The presence of anhydrite nodules, a mud-dominated carbonate production in euphotic zone (precursor of mudstones and packstones) and the presence of a diverse fauna mainly composed of photic-independent biota (mollusks, bryozoans, brachiopods and crinoids), indicate that the studied section was deposited in a relatively uniform low angle ramp. Thus, facies of different environments of inner ramp were detected, including those of a lagoon close to a peritidal area, with periodical restricted or open circulation, and open waters deposits influenced by the storm zone. In addition, mid-ramp facies were also observed. Facies associations of the basal levels on the studied section were mainly correlated with lagoonal shallow marine environments, being ostracods, calcispheres and peloids the dominant allochems. In contrast, there is a shift upwards to facies of open waters and mid-ramp environments, characterized by abundant skeletal grains of bryozoans, brachiopods and crinoids. The paleoenvironments recorded through the stratigraphic section were related with specific bathymetries, having a general tend towards the sea level rise. This record coincides with the global transgression event occurred during the Early Permian which have also been described for coeval localities of Texas and New Mexico in the United States and western Venezuela.

The age of the Tunas formation in the Sauce Grande basin-Ventana foldbelt (Argentina): Implications for the Permian evolution of the southwestern margin of Gondwana

NASA Astrophysics Data System (ADS)

López-Gamundí, Oscar; Fildani, Andrea; Weislogel, Amy; Rossello, Eduardo

2013-08-01

New SHRIMP radiogenic isotope dating on zircons in tuffs (280.8 ± 1.9 Ma) confirms the Early Permian (Artinskian) age of the uppermost section of the Tunas Formation. Tuff-rich levels in the Tunas Formation are exposed in the Ventana foldbelt of central Argentina; they are part of a deltaic to fluvial section corresponding to the late overfilled stage of the Late Paleozoic Sauce Grande foreland basin. Recent SHRIMP dating of zircons from the basal Choiyoi volcanics exposed in western Argentina yielded an age of 281.4 ± 2.5 Ma (Rocha-Campos et al., 2011). The new data for the Tunas tuffs suggest that the volcanism present in the Sauce Grande basin can be considered as the distal equivalent of the earliest episodes of the Choiyoi volcanism of western Argentina. From the palaeoclimatic viewpoint the new Tunas SHRIMP age confirms that by early Artinskian glacial conditions ceased in the Sauce Grande basin and, probably, in adajacent basins in western Gondwana.

Physicochemical analysis of Permian coprolites from Brazil

NASA Astrophysics Data System (ADS)

Rodrigues, M. I. C.; da Silva, J. H.; Santos, F. Eroni P.; Dentzien-Dias, P.; Cisneros, J. C.; de Menezes, A. S.; Freire, P. T. C.; Viana, B. C.

2018-01-01

In this paper we performed the study of two coprolites (fossilized feces) collected from the exposed levels of the Pedra de Fogo Formation, Parnaiba Sedimentary Basin, and Rio do Rasto Formation, Paraná Sedimentary Basin, both of the Palaeozoic era (Permian age). They were characterized using X-ray diffractometry, infrared, Raman and energy dispersive spectroscopy techniques in order to aid our understanding of the processes of fossilization and to discuss issues related to the feeding habits of the animals which generated those coprolites, probably cartilaginous fishes. The results obtained using a multitechnique approach showed that although these coprolites are from different geological formations, 3000 km away from each other, they show the same major crystalline phases and elemental composition. The main phases found were hydroxyapatite, silica, calcite and hematite, which lead to infer that those coprolites were formed under similar conditions and produced by a similar group of carnivore or omnivore fishes.

Taeniopterid lamina on Phasmatocycas megasporophylls (Cycadales) from the Lower Permian of Kansas, U.S.A.

USGS Publications Warehouse

Gillespie, W.H.; Pfefferkorn, H.W.

1986-01-01

New specimens of Phasmatocycas and Taeniopteris from the original Lower Permian locality in Kansas demonstrate organic attachment of the two and corroborate Mamay's hypothesis that Phasmatocycas and Taeniopteris were parts of the same plant. These forms also suggest that cycads evolved from taxa with entire leaves; i.e. Taeniopteris, rather than from pteridosperms with compound leaves. ?? 1986.

Assessment of potential unconventional Carboniferous-Permian gas resources of the Liaohe Basin eastern uplift, Liaoning Province, China, 2011

USGS Publications Warehouse

Pollastro, Richard M.; Potter, Christopher J.; Schenk, Christopher J.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.; Kirschbaum, Mark A.

2012-01-01

The U.S. Geological Survey estimated a mean of 448 billion cubic feet of potential technically recoverable unconventional natural gas in Carboniferous and Permian coal-bearing strata in the eastern uplift of the Liaohe Basin, Liaoning Province, China.

Using AMS to Help Interpret Glaciogenic Deposits of the Late Paleozoic Ice Age in the Parana Basin, Brazil

NASA Astrophysics Data System (ADS)

Amato, James Anthony

The term 'diamictite' is used as a lithologic descriptive term without assigning a particular origin to a rock unit as either glacial deposits (till), proglacial, glacially influenced deposits (resulting from meltwater plumes and ice rafted debris), or mass transport deposits (glacial or non-glacial related). While in some cases, it is possible to delineate between the origins of diamictites, in other instances, weathering and lack of exposures make it difficult to determine. In general, the occurrence of diamictites within the Gondwana succession has been traditionally used to indicate the occurrence of subglacial deposition despite the potential occurrence of other depositional modes. Thus, the extent of glaciation during the Late Paleozoic Ice Age is interpreted to be much greater than it actually was. . One area of interest in Gondwana where interpretation of these deposits is problematic, and hence has resulted in problems determining ice extent, is the Parana Basin in Brazil. The ability to better differentiate subglacial processes from proglacial, subaqueous mass transport, glaciomarine/glaciolacustrine rainout, and/or ice rafting, in addition to determining glacier flow or mass transport directions, will allow researchers studying these deposits to more accurately reconstruct the environments timing and extent of glaciation during the LPIA. In sedimentary fabrics, anisotropy of magnetic susceptibility (AMS) is a geophysical method, which depicts the preferred orientation of magnetic particles during the final stages of transport and/or synsedimentary deformation. The technique is used to determine the preferred orientation of the constituent grains, therefore a useful indicator to help determine the mode of deposition, direction of sediment transport, and the nature of stress and strain during deformation. In August of 2016, samples were collected from deposits assigned to the Itarare Group, which outcrop along the southern and eastern margins of the Parana

A feasibility study for an emergency medical services system to serve the Permian basin in the state of Texas

NASA Technical Reports Server (NTRS)

1975-01-01

The development of an Emergency Medical Services System grant application for the Permian Basin Region of West Texas is described along with the application of NASA-developed technology. Conclusions and recommendations are included.

Ductile and Brittle Neogene Deformation of Late Permian Orthogneiss in the Northern Ailao Shan-Red River Shear Zone: View from the Xuelong Shan Block

NASA Astrophysics Data System (ADS)

Wintsch, R. P.; Yi, D.; Yi, K.; Wang, Q. F.; Wang, G. H.

2014-12-01

The orthogneisses in the core of the Xuelong Shan block are surrounded by ductile and then brittle fault rocks. This lens-shape block is in fault contact with Triassic marbles on the eastern margin and Jurassic-Cretaceous mudstones on the western margin. The rocks in the core of the Xuelong Shan block contain multiply foliated feldspathic orthogneisses with local amphibolites, largely overprinted by protomylonitic deformation. Foliation strengthens to the east to become mylonites and ultramylonites, with a 30 m wide zone of loosely cemented fault breccia adjacent to brittlely faulted Triassic marbles. In contrast, the rocks to the west are dominated by brittle deformation, with mylonites becoming cataclasites and then breccias facing the mudstones to the east. Well-foliated phyllonites are locally present within the cataclasites. Early S1 gneissosity striking ENE are recognized only in the interior protomylonite. In the east, the dominate mylonitic S2 foliation strikes 340° with a moderate dip to the east, and an L2 mineral stretching lineation plunges gently north. However, in the west S2 cleavage is transposed into a NNW trending schistosity that dips steeply to the ENE, with down-dip mineral stretching lineations. Whole rock chemistry indicates a granitic to granodioritic protolith for all the rocks including the ultramylonites, but also suggests the progressive loss of alkalis with increasing deformation. Trace element compositions show these rocks lie in the volcanic arc/syn-collisional granite field. U-Pb SHRIMP ages show an Early Triassic age for these granite, with possible Middle Permian inheritance in some cores. These ages are consistent with the period of the closure of the northern Paleo-Tethys ocean. Metamorphic rim ages of ~ 30 Ma record a small amount of zircon dissolution/precipitation probably associated with the Oligocene ductile deformation that produced the upper greenschist facies mylonites. These results support the geologic history of the

Isotopic evidence for an anomalously low oceanic sulfate concentration following end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Luo, Genming; Kump, Lee R.; Wang, Yongbiao; Tong, Jinnan; Arthur, Michael A.; Yang, Hao; Huang, Junhua; Yin, Hongfu; Xie, Shucheng

2010-11-01

The cataclysmic end-Permian mass extinction was immediately followed by a global expansion of microbial ecosystems, as demonstrated by widespread microbialite sequences (disaster facies) in shallow water settings. Here we present high-resolution carbonate carbon ( δ13C carb) and carbonate-associated sulfate-sulfur isotope ( δ34S CAS) records from the microbialite in the Cili Permian-Triassic (P-Tr) section in South China. A stepwise decline in δ13C carb begins in the underlying skeletal limestone, predating the main oceanic mass extinction and the first appearance of microbialite, and reaches its nadir in the upper part of the microbialite layer. The corresponding δ34S CAS, in the range of 17.4‰ to 27.4‰, is relatively stable in the underlying skeletal limestone, and increases gradually from 2 m below the microbialite rising to a peak at the base of the microbialite. Two episodes of positive and negative shifts occurred within the microbialite layer, and exhibit a remarkable co-variance of sulfur and carbon isotope composition. The large amplitude of the variation in δ34S CAS, as high as 7‰ per 100 kiloyears, suggests a small oceanic sulfate reservoir size at this time. Furthermore, the δ13C carb and δ34S CAS records co-vary without phase lag throughout the microbialite interval, implying a marine-driven C cycle in an anoxic ocean with anomalously low oceanic sulfate concentrations. On the basis of a non-steady-state box model, we argue that the oceanic sulfate concentration may have fallen to less than 15%, perhaps as low as 3%, of that in the modern oceans. Low oceanic sulfate concentration likely was the consequence of evaporite deposition and widespread anoxic/sulfidic conditions prior to the main mass extinction. By promoting methanogenesis and a build-up of atmospheric CH 4 and CO 2, low oceanic sulfate may have intensified global warming, exacerbating the inimical environmental conditions of the latest Permian.

Hydrous parental magmas of Early to Middle Permian gabbroic intrusions in western Inner Mongolia, North China: New constraints on deep-Earth fluid cycling in the Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

Pang, Chong-Jin; Wang, Xuan-Ce; Xu, Bei; Luo, Zhi-Wen; Liu, Yi-Zhi

2017-08-01

The role of fluids in the formation of the Permian-aged Xigedan and Mandula gabbroic intrusions in western Inner Mongolia was significant to the evolution of the Xing'an Mongolia Orogenic Belt (XMOB), and the active northern margin of the North China Craton (NCC). Secondary Ion Mass Spectroscopy (SIMS) U-Pb zircon geochronology establishes that the Xigedan gabbroic intrusion in the northern NCC was emplaced at 266 Ma, and is therefore slightly younger than the ca 280 Ma Mandula gabbroic intrusion in the XMOB. Along with their felsic counterparts, the mafic igneous intrusions record extensive bimodal magmatism along the northern NCC and in the XMOB during the Early to Middle Permian. The Mandula gabbroic rocks have low initial 87Sr/86Sr ratios (0.7040-0.7043) and positive εNd(t) (+6.2 to +7.3) and εHf(t) values (+13.4 to +14.5), resembling to those of contemporaneous Mandula basalts. These features, together with the presence of amphibole and the enrichment of large ion lithophile elements (LILE, e.g., Rb, Ba, U and Sr) and depletion of Nb-Ta suggest that the parental magmas of the Mandula mafic igneous rocks were derived from a depleted mantle source metasomatized by water-rich fluids. In contrast, the Xigedan gabbroic rocks are characterised by high 87Sr/86Sr ratios (0.7078-0.7080) and zircon δ18O values (5.84-6.61‰), but low εNd(t) (-9.3 to -10.2) and εHf(t) values (-8.76 to -8.54), indicative of a long-term enriched subcontinental lithosphere mantle source that was metasomatized by recycled, high δ18O crustal materials prior to partial melting. The high water contents (4.6-6.9 wt%) and arc-like geochemical signature (enrichment of fluid-mobile elements and depletion of Nb-Ta) of the parental magmas of the Xigedan gabbroic rocks further establish the existence of a mantle hydration event caused by fluid/melts released from hydrated recycled oceanic crust. Incompatible element modelling shows that 5-10% partial melting of an enriched mantle source by

Genesis of the Permian karstic Pingguo bauxite deposit, western Guangxi, China

NASA Astrophysics Data System (ADS)

Liu, Xuefei; Wang, Qingfei; Zhang, Qizuan; Yang, Shujuan; Liang, Yayun; Zhang, Ying; Li, Yan; Guan, Tao

2017-10-01

More than 0.5 billion tons of late Permian bauxite overlies the karstic topography of the Maokou Formation of western Guangxi in China. Here, we provide new mineralogical, geochemical, Sr-Nd-Pb isotopic, and pyrite S isotope and trace element compositional data for the Pingguo bauxite deposit, aiming to further our understanding of the genesis of Permian bauxite. The Pingguo bauxite contains three distinct layers: a lower layer dominated by ferric clay or weathered iron ore, a middle layer of cryptocrystalline and oolitic bauxite ore, and an upper layer dominated by argillaceous bauxite. The bauxite ore is mainly diaspore, pyrite, chamosite, and anatase, whereas the argillaceous bauxite contains diaspore, kaolinite, pyrophyllite, pyrite, and anatase. Two types of pyrite have been identified within the bauxite: fine-grained and framboidal pyrite (Py1) occurring in aggregates and coarse-grained and euhedral pyrite (Py2). Py1 is enriched in trace elements and is thought to have a diagenetic origin, whereas Py2 is deficient in trace elements and is considered to have formed by later recrystallization. The S isotopic composition of pyrite (-34.11 to -18.91‰) and visible ovoid microorganisms within the bauxite provide evidences of microbial activity during bauxite formation. The Sr-Nd-Pb isotopic composition of the bauxite indicates that these ores were generated by the weathering of basalts belonging to the Emeishan Large Igneous Province (LIP) and limestones of the Maokou Formation. Microorganisms were likely to have enhanced the dissolution and weathering of the parent rock and facilitated the precipitation of diaspore under near-surface conditions.

Play Analysis and Digital Portfolio of Major Oil Reservoirs in the Permian Basin: Application and Transfer of Advanced Geological and Engineering Technologies for Incremental Production Opportunities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead

2004-01-13

A play portfolio is being constructed for the Permian Basin in west Texas and southeast New Mexico, the largest onshore petroleum-producing basin in the United States. Approximately 1,300 reservoirs in the Permian Basin have been identified as having cumulative production greater than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of oil through 2000. Of these significant-sized reservoirs, approximately 1,000 are in Texas and 300 in New Mexico. There are 32 geologic plays that have been defined for Permian Basin oil reservoirs, and each of the 1,300 major reservoirs was assigned to a play. The reservoirs were mapped and compiledmore » in a Geographic Information System (GIS) by play. The final reservoir shapefile for each play contains the geographic location of each reservoir. Associated reservoir information within the linked data tables includes RRC reservoir number and district (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are smaller than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. Oil production from the reservoirs in the Permian Basin having cumulative production of >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl [5.25 x 10{sup 8} m{sup 3}]), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San Andres Platform Carbonate play (2.15 Bbbl [3.42 x 10{sup 8} m{sup 3}]). Detailed studies of three

Lipid Biomarker Records Across the Permian-Triassic Boundary from Kap Stosch, Greenland

NASA Astrophysics Data System (ADS)

Hays, L. E.; Love, G. D.; Foster, C. B.; Grice, K.; Summons, R. E.

2006-12-01

The end-Permian extinction was the most severe in the past 500 million years of the Earth's history and evidence that an oceanic anoxic event (OAE) occurred contemporaneously has been presented previously [1,2]. OAEs have, therefore, been proposed as responsible for the mass mortality, and if the anoxic ocean was also euxinic, the release of hydrogen sulfide during upwelling and/or transgression provides an extinction agent in the ocean as well as on land. Chlorobiaceae, as indicators of photic zone euxinia (PZE), utilize hydrogen sulfide as an electron donor for anoxygenic photosynthesis. The detection of isorenieratane and a series of short-chain monoaromatic aryl isoprenoids, biomarkers for Chlorobiaceae, in sediments indicates the presence of hydrogen sulfide in the photic zone of the water column during sediment deposition. The Kap Stosch area in Eastern Greenland was identified as a Permian-Triassic boundary (PTB) outcrop of homogeneous shale, silty shale, and siltstone facies [3]. Another late Permian section in Eastern Greenland, the Ravnefjeld Formation, has framboidal pyrites indicative of sulfidic deep water [4]. A sample suite from the Kap Stosch region was studied using standard organic geochemistry methods including stable isotopic analyses of organic carbon, Rock-Eval pyrolysis, and biomarker hydrocarbon analysis. Aryl isoprenoids, including isorenieratane, were present in all samples studied and the concentrations were observed to fluctuate in tandem with TOC, similar to other Mesozoic OAEs. The molecular ratios of pristane/phytane and hopanes/steranes as well as the 2-methyl-hopane index (2-MHI) fluctuated dramatically through this section as they do at the type section at Meishan and in the Perth Basin [5]. The 2-MHI shows an inverse pattern to the total aryl isoprenoids, perhaps indicative of instability in the form of primary productivity in the water column during euxinic episodes. This can result in nitrogen limitation and a competitive

The roles of ecological first principles and evolutionary contingency in unraveling ecosystem response and reconstruction during the Permian-Triassic transition.

NASA Astrophysics Data System (ADS)

Roopnarine, P. D.; Weik, A.; Dineen, A.; Angielczyk, K.

2016-12-01

The Permian-Triassic mass extinction (PTME) is the most severe mass extinction recorded in Earth's history. Effects on the biosphere were complicated and often contradictory, e.g. selective species extinctions and exceptional species survival; prolonged miniaturization of some Early Triassic clades but rapid increases of size in others; and both simplified and complex trophic structures in various E. Triassic ecosystems. Here we present the results of a new generalized model of paleocommunity global stability (number of species capable of persistent coexistence in the absence of external perturbation), suggesting that community dynamics in response to species extinction, and the addition of new species in the aftermath of the PTME, is best understood as a complex outcome of predictable community dynamics and contingent, unpredictable evolutionary pathways. We applied the model to the best known PTME transitional terrestrial ecosystem, the Karoo Basin of South Africa. The model verifies previous claims that global stability scales negatively with increasing species richness and the strength of interspecific interactions. We also show that global stability scales negatively with intrinsic population growth rates. Taxon-rich Permian communities could therefore have persisted only under a restricted range of those parameters. Communities during three phases of the PTME, however, exhibited greater global stability than would be predicted from the pre-PTME communities. Those communities could therefore have maintained relative stabilities under a broader range of parameters, implying that species could have adapted by modifying life history and ecological traits with lesser negative consequences to community stability. The earliest post-PTME community with increased species richness, however, was less stable than would be predicted from pre-PTME communities. In both the extinction and aftermath communities, nonlinear deviations from the general scaling of stability

Carbon isotopic shift and its cause at the Wuchiapingian-Changhsingian boundary in the Upper Permian at the Zhaojiaba section, South China: Evidences from multiple geochemical proxies

NASA Astrophysics Data System (ADS)

Wei, Hengye; Yu, Hao; Wang, Jianguo; Qiu, Zhen; Xiang, Lei; Shi, Guo

2015-06-01

The Late Permian environmental change, connecting the Guadalupian-Lopingian (G-L) (Middle-Upper Permian) boundary mass extinction and the Permain-Triassic (P-Tr) boundary mass extinction, has attracted more and more attentions. A significant negative shift for carbon isotope had been found at the Wuchiapingian-Changhsingian (W-C) boundary in the Upper Permian recently. However, the cause(s) of this negative excursion is still unknown. To resolve this problem, we analyzed the bulk organic carbon isotope, total organic carbon (TOC) content, pyritic sulfur (Spy) content, major element concentrations, and molecular organic biomarkers in the Wujiaping and Dalong formations in the Upper Permian from the Zhaojiaba section in western Hubei province, South China. Our results show that (1) there was a significant negative excursion in organic carbon isotopes at the W-C boundary and again a negative excursion at the top of Changhsingian stage; (2) the significant negative excursion at the W-C boundary was probably a global signal and mainly caused by the low primary productivity; and (3) the negative carbon isotope excursion at the top of Changhsingian was probably caused by the Siberian Traps eruptions. A decline in oceanic primary productivity at the W-C boundary probably represents a disturbance of the marine food web, leading to a vulnerable ecosystem prior to the P-Tr boundary mass extinction.

Palynomorphs of Permian Gondwana coal from borehole GDH-38, Barapukuria Coal Basin, Bangladesh

USGS Publications Warehouse

Akhtar, A.; Kosanke, R.M.

2000-01-01

Thirty-two core samples of Permian Gondwana coal from three coal beds of borehole GDH-38, Barapukuria Coal Basin, Dinajpur, the north-northwestern part of Bangladesh, have been collected for palynological analysis. All samples except one yielded palynomorphs and some samples contain well-preserved and abundant palynomorphs of the gymnospermal and cryptogamic groups that are considered to be useful for future correlation studies. The lower coal bed (331.6-372.5 m) can easily be differentiated from the upper two coal beds by the presence of Alisporites, Cordaitina, Corisaccites, Hamiapollenites, Leuckisporites, Nuskoisporites, Tumoripollenites, Vestgisporites and Vittatina. It is difficult to palynologically differentiate the middle (198.1-208 m) and upper (162.3-172.9 m) coal beds as they contain a very limited number of specimens by which they can be identified. The middle bed is distinguished by the presence of Microbaculispora and Weylandites and the upper bed by the presence of a single taxon Acanthotriletes. Some of the vesiculate or saccate taxa extracted from these coal beds are typical of those occurring in Permian strata of Gondwana in India, South Africa, South America, Russia, Australia and Antarctica. They are thought to be derived from Glossopteris flora, which is characterised by an abundance of Pteridospermic plants of the gymnosperm group. ?? 2000 Elsevier Science Limited. All rights reserved.

Paleomagnetic and magnetostratigraphic investigations of the whitehorse group/quartermaster (Dewey Lake) formation (upper permian-lowermost triassic) in the Palo Duro basin, northwest Texas, USA

NASA Astrophysics Data System (ADS)

Collins, Dylan R.

In northwest Texas, upper Permian to lowermost Triassic hematite-cemented detrital sedimentary rocks, which include a small number of regionally extensive ash beds, were deposited during the time interval of the greatest mass extinction event sequences in Earth history. The magnetic polarity stratigraphy, as well as key rock magnetic properties, of the upper Whitehorse Group (WH) and Quartermaster formations (QM) at selected sections in the Palo Duro Basin, have been determined using thermal, and chemical demagnetization approaches and anisotropy of magnetic susceptibility, acquisition of isothermal remanent magnetization (IRM) and backfield demagnetization, and thermal demagnetization of three component IRM methods. Demagnetization results show that the WH/QM contains a primary/near-primary characteristic remanent magnetization at each level sampled and thus the magnetic polarity stratigraphy for each section can be compared with existing polarity time scales across the Permian-Triassic boundary. Estimated site mean directions yield a paleomagnetic pole for the latest Permian for North America of 57.8°N, 130.6°E from 38 sampled sites.

Paleobiology of a unique vertebrate coprolites concentration from Rio do Rasto Formation (Middle/Upper Permian), Paraná Basin, Brazil

NASA Astrophysics Data System (ADS)

Dentzien-Dias, Paula C.; de Figueiredo, Ana Emilia Q.; Horn, Bruno; Cisneros, Juan Carlos; Schultz, Cesar L.

2012-12-01

A large number of coprolites were collected in one outcrop in the lacustrine facies of Rio do Rasto Formation (Middle/Upper Permian) in Southern Brazil. The material ranges from 0.6 cm to 11 cm in length. Their mineralogy, inclusions and morphology were studied to infer their biological source and taphonomy. All of them contain fragments of bones and fish scales, as well as crystalline apatite, and therefore are assigned to carnivores. A wide variety of morphotypes is described, including the knots and the well-known spiral coprolites (heteropolar and amphipolar), as well as a new kind of heteropolar coprolite we called as "edge", that has the whorls grouped in the very end of one pole. These data allow us to instead that a wide variety of vertebrates lived in the lakes of the Middle/Upper Permian in southern Brazil.

Two-phase southward subduction of the Mongol-Okhotsk oceanic plate constrained by Permian-Jurassic granitoids in the Erguna and Xing'an massifs (NE China)

NASA Astrophysics Data System (ADS)

Liu, Huichuan; Li, Yinglei; He, Hongyun; Huangfu, Pengpeng; Liu, Yongzheng

2018-04-01

Geodynamics of the Mongol-Okhotsk oceanic plate southward subduction are still pending problems. This paper presents new zircon LA-ICP-MS U-Pb age and whole-rock geochemical data for the middle Permian to Middle Jurassic granitoids in the western Erguna and central Xing'an massifs. 267-264 Ma, 241 Ma and 173 Ma I-type granites, and 216 Ma A-type granites were identified in the Erguna and Xing'an massifs (NE China). The I-type granites were produced by partial melting of the lower mafic crust. The 216 Ma A-type granites were derived from partial melting of crustal materials with tonalitic to granodioritic compositions. The 267-264 Ma and 241 Ma I-type granites were generated in an Andean-type arc setting, wheras the 216 Ma A-type and 173 Ma granites were formed in supra subduction extensional setting. We summarized previous age data of the middle Permian to Middle Jurassic magmtaic rocks in the Erguna and Xing'an Massifs and identified two isolated phases of magmatic activity including the ca. 267-225 Ma and ca. 215-165 Ma periods, with a significant magmatic gap at ca. 225-215 Ma. These middle Permian to Middle Jurassic magmatic rocks are closely related to the southward subduction of the Mongol-Okhotsk ocean. A two-stage tectonic evolutionary model was proposed to account for these geological observations in the Erguna and Xing'an massifs, involving Permian to Middle Triassic continuous southward subduction of the Mongol-Okhotsk oceanic plate and Late Triassic to Jurassic slab-rollback and supra subduction extension.

New high precision U-Pb calibration of the late Early-Triassic (Smithian-Spathian Boundary, South China)

NASA Astrophysics Data System (ADS)

Widmann, Philipp; Leu, Marc; Goudemand, Nicolas; Schaltegger, Urs; Bucher, Hugo

2017-04-01

Following the Permian-Triassic mass extinction (PTME), the Early Triassic is characterized by large short-lived perturbations of the global carbon cycle associated with radiation and extinction pulses of the biota. More stable conditions resumed in the Middle Triassic (Anisian). The exact ages and duration of these short-lived but intense radiation-extinction events as well as carbon cycle perturbations are poorly constrained and a robust intercalibration of U-Pb dates, biochronozones and carbon isotope fluctuations is still lacking. An accurate and precise time frame is essential in order to quantify the dynamics of the underlying mechanistic processes and to assess the validity of the various explanatory scenarios. The most drastic Early Triassic extinction occurred at the Smithian-Spathian boundary (SSB) and is associated with a globally recognized sharp positive excursion of the marine d13C signal. Based on the most recently published ages for the Permian-Triassic boundary (251.938 ± 0.029 Ma, Baresel et al., 2016) and for the Early-Middle Triassic boundary (247.05 ± 0.16 Ma, Ovtcharova et al., 2015), we know the Early Triassic lasted 4.9 myr. However, neither the position of the SSB nor the durations of the major biotic and abiotic events around the SSB are constrained by radiometric dates. Here, we will present new high precision, chemical abrasion, isotope dilution, thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb ages from single zircon crystals, sampled from closely spaced volcanic ash layers that bracket the SSB in the Nanpanjiang Basin (Guizhou province, South China). These ash layers are found in a mixed carbonate-siliciclastic, conodont-rich sedimentary succession (Luolou Formation) that is well calibrated biochronologically. We obtained best estimates of the ages of the SSB and associated events by applying Bayesian age modelling. References: Baresel, B., Bucher, H., Brosse, M., Cordey, F., Guodun, K., and Schaltegger, U., 2016. Precise age

Permian to recent volcanism in northern sumatra, indonesia: a preliminary study of its distribution, chemistry, and peculiarities

NASA Astrophysics Data System (ADS)

Rock, N. M. S.; Syah, H. H.; Davis, A. E.; Hutchison, D.; Styles, M. T.; Lena, Rahayu

1982-06-01

Sumatra has been a ‘volcanic arc’, above an NE-dipping subduction zone, since at least the Late Permian. The principal volcanic episodes in Sumatra N of the Equator have been in the Late Permian, Late Mesozoic, Palaeogene, Miocene and Quaternary. Late Permian volcanic rocks, of limited extent, are altered porphyritic basic lavas interstratified with limestones and phyllites. Late Mesozoic volcanic rocks, widely distributed along and W of the major transcurrent. Sumatra Fault System (SFS), which axially bisects Sumatra, include ophiolite-related spilites, andesites and basalts. Possible Palaeogene volcanic rocks include an altered basalt pile with associated dyke-swarm in the extreme NW, intruded by an Early Miocene (19 my) dioritic stock; and variable pyroxene rich basic lavas and agglomerates ranging from alkali basaltic to absarokitic in the extreme SW. Miocene volcanic rocks, widely distributed (especially W of the SFS), and cropping out extensively along the W coast, include calc-alkaline to high-K calc-alkaline basalts, andesites and dacites. Quaternary volcanoes (3 active, 14 dormant or extinct) are irregularly distributed both along and across the arc; thus they lie fore-arc of the SFS near the Equator but well back-arc farther north. The largest concentration of centres, around Lake Toba, includes the >2000 km3 Pleistocene rhyolitic Toba Tuffs. Quaternary volcanics are mainly calc-alkaline andesites, dacites and rhyolites with few basalts; they seem less variable, but on the whole more acid, than the Tertiary. The Quaternary volcanism is anomalous in relation to both southern Sumatra and adjacent Java/Bali: in southern Sumatra, volcanoes are regularly spaced along and successively less active away from the SFS, but neither rule holds in northern Sumatra. Depths to the subduction zone below major calc-alkaline volcanoes in Java/Bali are 160-210 km, but little over 100 km in northern Sumatra, which also lacks the regular K2O-depth correlations seen in

Bauxite to eclogite: Evidence for late Permian supracontinental subduction at the Red River shear zone, northern Vietnam

NASA Astrophysics Data System (ADS)

Nakano, Nobuhiko; Osanai, Yasuhito; Nam, Nguyen Van; Tri, Tran Van

2018-03-01

We have investigated the geological processes recorded in aluminous granulites from the Red River shear zone in northern Vietnam using mineral and whole-rock chemistries, fluid inclusions, metamorphic pressure-temperature paths, and geochronology. The granulites are extremely rich in Al2O3 (36.3-50.9 wt%), TiO2, and total Fe2O3, and poor in SiO2 (7.9-24.1 wt%), MgO, CaO, Na2O, and K2O. The granulites are enriched in high-field-strength elements and rare earth elements, and severely depleted in large-ion lithophile elements. These features strongly suggest the protolith was lateritic bauxite. Moreover, the other elemental concentrations and the Zr/Ti ratios point to basaltic rock as the precursor of the bauxite. Some of the aluminous granulites contain high-pressure mineral inclusions of kyanite, staurolite, siderite, and rutile, none of which are observed in the matrix. Abundant primary carbonic fluid inclusions are observed in garnet, corundum, and staurolite, but are rare in quartz and zircon. The average densities of fluid inclusions in garnet, corundum, staurolite, quartz, and zircon are 1.00 ± 0.06, 1.07 ± 0.04, 1.09 ± 0.03, 0.29 ± 0.07, and 1.15 ± 0.05 g/cm3, respectively. The mineral features not only in the matrix and but also in garnet from all rock types, isochemical phase diagrams obtained for each bulk rock composition, and Zr-in-rutile thermometry indicate an early eclogite-facies metamorphism ( 2.5 GPa at 650 °C) and a subsequent nearly isothermal decompression. Zircons yield a wide range of U-Pb ages from 265 to 36 Ma, whereas the dark luminescent cores of the zircons, which contain high-density CO2 inclusions, yield a concordia age of 257 ± 8 Ma. These observations suggest that the dark luminescent zircon cores were formed at the same time as the garnet, corundum, and staurolite that contain high-density CO2 fluid inclusions. Based on the carbonic fluid inclusion isochore and the densities as well as calculated phase diagram, the concordia

Time-calibrated Milankovitch cycles for the late Permian.

PubMed

Wu, Huaichun; Zhang, Shihong; Hinnov, Linda A; Jiang, Ganqing; Feng, Qinglai; Li, Haiyan; Yang, Tianshui

2013-01-01

An important innovation in the geosciences is the astronomical time scale. The astronomical time scale is based on the Milankovitch-forced stratigraphy that has been calibrated to astronomical models of paleoclimate forcing; it is defined for much of Cenozoic-Mesozoic. For the Palaeozoic era, however, astronomical forcing has not been widely explored because of lack of high-precision geochronology or astronomical modelling. Here we report Milankovitch cycles from late Permian (Lopingian) strata at Meishan and Shangsi, South China, time calibrated by recent high-precision U-Pb dating. The evidence extends empirical knowledge of Earth's astronomical parameters before 250 million years ago. Observed obliquity and precession terms support a 22-h length-of-day. The reconstructed astronomical time scale indicates a 7.793-million year duration for the Lopingian epoch, when strong 405-kyr cycles constrain astronomical modelling. This is the first significant advance in defining the Palaeozoic astronomical time scale, anchored to absolute time, bridging the Palaeozoic-Mesozoic transition.

Bringing Dicynodonts Back to Life: Paleobiology and Anatomy of a New Emydopoid Genus from the Upper Permian of Mozambique

PubMed Central

Júnior, Luís C.; Angielczyk, Kenneth D.; Martins, Gabriel G.; Martins, Rui M. S.; Chaouiya, Claudine; Beckmann, Felix; Wilde, Fabian

2013-01-01

Dicynodontia represent the most diverse tetrapod group during the Late Permian. They survived the Permo-Triassic extinction and are central to understanding Permo-Triassic terrestrial ecosystems. Although extensively studied, several aspects of dicynodont paleobiology such as, neuroanatomy, inner ear morphology and internal cranial anatomy remain obscure. Here we describe a new dicynodont (Therapsida, Anomodontia) from northern Mozambique: Niassodon mfumukasi gen. et sp. nov. The holotype ML1620 was collected from the Late Permian K5 formation, Metangula Graben, Niassa Province northern Mozambique, an almost completely unexplored basin and country for vertebrate paleontology. Synchrotron radiation based micro-computed tomography (SRµCT), combined with a phylogenetic analysis, demonstrates a set of characters shared with Emydopoidea. All individual bones were digitally segmented allowing a 3D visualization of each element. In addition, we reconstructed the osseous labyrinth, endocast, cranial nerves and vasculature. The brain is narrow and the cerebellum is broader than the forebrain, resembling the conservative, “reptilian-grade” morphology of other non-mammalian therapsids, but the enlarged paraflocculi occupy the same relative volume as in birds. The orientation of the horizontal semicircular canals indicates a slightly more dorsally tilted head posture than previously assumed in other dicynodonts. In addition, synchrotron data shows a secondary center of ossification in the femur. Thus ML1620 represents, to our knowledge, the oldest fossil evidence of a secondary center of ossification, pushing back the evolutionary origins of this feature. The fact that the specimen represents a new species indicates that the Late Permian tetrapod fauna of east Africa is still incompletely known. PMID:24324653

Bringing dicynodonts back to life: paleobiology and anatomy of a new emydopoid genus from the Upper Permian of Mozambique.

PubMed

Castanhinha, Rui; Araújo, Ricardo; Júnior, Luís C; Angielczyk, Kenneth D; Martins, Gabriel G; Martins, Rui M S; Chaouiya, Claudine; Beckmann, Felix; Wilde, Fabian

2013-01-01

Dicynodontia represent the most diverse tetrapod group during the Late Permian. They survived the Permo-Triassic extinction and are central to understanding Permo-Triassic terrestrial ecosystems. Although extensively studied, several aspects of dicynodont paleobiology such as, neuroanatomy, inner ear morphology and internal cranial anatomy remain obscure. Here we describe a new dicynodont (Therapsida, Anomodontia) from northern Mozambique: Niassodon mfumukasi gen. et sp. nov. The holotype ML1620 was collected from the Late Permian K5 formation, Metangula Graben, Niassa Province northern Mozambique, an almost completely unexplored basin and country for vertebrate paleontology. Synchrotron radiation based micro-computed tomography (SRµCT), combined with a phylogenetic analysis, demonstrates a set of characters shared with Emydopoidea. All individual bones were digitally segmented allowing a 3D visualization of each element. In addition, we reconstructed the osseous labyrinth, endocast, cranial nerves and vasculature. The brain is narrow and the cerebellum is broader than the forebrain, resembling the conservative, "reptilian-grade" morphology of other non-mammalian therapsids, but the enlarged paraflocculi occupy the same relative volume as in birds. The orientation of the horizontal semicircular canals indicates a slightly more dorsally tilted head posture than previously assumed in other dicynodonts. In addition, synchrotron data shows a secondary center of ossification in the femur. Thus ML1620 represents, to our knowledge, the oldest fossil evidence of a secondary center of ossification, pushing back the evolutionary origins of this feature. The fact that the specimen represents a new species indicates that the Late Permian tetrapod fauna of east Africa is still incompletely known.

Evaluating Non-potable Water Usage for Oil and Gas Purposes in the Permian Basin Using Reactive Transport Modeling

NASA Astrophysics Data System (ADS)

Marsac, K.; Navarre-Sitchler, A.

2017-12-01

Oil and gas company water usage is currently an area of concern in the water stressed western United States. 87% of recent wells in the Permian Basin are located in areas of high or extreme water stress. Using recycled produced water or groundwater that does not meet the USDW drinking water standards for oil and gas purposes could assist in relieving both water stress and tension between oil and gas companies and the public. However, non-USDW drinking water (TDS over 10,000 ppm) has the potential to react with formation water causing mineral precipitation, reducing the permeability of the producing formation. To evaluate the potential of non-potable water usage in the Permian Basin, available groundwater chemistry data was compiled into a database. Data was collected from the NETL-run NATCARB database, the USGS Produced Water and NWIS Databases, and the Texas Water Development Board. The created database went through a system of quality assurance and control for pH, TDS, depth and charge balance. Data was used to generate a set of waters representative of Permian Basin groundwater based on TDS, Ca/Mg ratio and Cl/SO4 ratio. Low, medium and high values of these three characteristics; representing the 25th, 50th and 75th percentile respectively; were used to create a matrix of 27 waters. Low TDS is 64,660 ppm, medium TDS is 98,486 ppm, and high TDS is 157,317 ppm. Ca/Mg ratios range from 1.98 to 7.26, and Cl/SO4 ratios range from 32.96 to 62.34. Results from mixing and titration models between these 27 waters and average Permian Basin water using Geochemist's Workbench show a maximum total precipitation of 1.815 cm3 in 1 L of water. In term of porosity, this represents a maximum porosity decrease due to mineral precipitation of 0.18%. This maximum precipitation scenario resulted from mixing average water with high TDS, high Ca/Mg ratio and low Cl/SO4 ratio water. We further investigate the impact of mineral precipitation on porosity and permeability using reactive

Configuration of the magnetic field and reconstruction of Pangaea in the Permian period.

PubMed

Westphal, M

1977-05-12

The virtual geomagnetic poles of Laurasia and Gondwanaland in the Carboniferous and Permian periods diverge significantly when these continents are reassembled according to the fit calculated by Bullard et al. Two interpretations have been offered: Briden et al. explain these divergences by a magnetic field configuration very different from that of a geocentric axial dipole; Irving (and private communication), Van der Voo and French(4) suggest a different reconstruction and it is shown here that these two interpretations are not incompatible and that the first may help the second.

Range of movement in ray I of manus and pes and the prehensility of the autopodia in the Early Permian to Late Cretaceous non-anomodont Synapsida.

PubMed

Kümmell, Susanna B; Frey, Eberhard

2014-01-01

The mobility of ray I was analysed in seventy-eight Early Permian to Late Cretaceous specimens of non-mammalian Synapsida and one extant mammal. In all non-mammaliamorph Synapsida investigated, ray I formed a digital arcade. The first phalanx was maximally extendable to the zero position in the metapodiophalangeal joint I. Metapodiale I was the functional equivalent to a basal phalanx of digits II-V. In contrast, there was no digital arcade in ray I in Mesozoic Mammaliamorpha. Phalanx 1 I was dorsally extendable and metapodiale I was functionally part of the metapodium. During the propulsion phase, autopodial rotation occurred in the majority of Synapsida with abducted limb posture. Regarding ray I, the reduction of autopodial rotation can be estimated, e.g., from the decrease of lateral rotation and medial abduction of the first phalanx in the metapodiophalangeal joint I. Autopodial rotation was high in Titanophoneus and reduced in derived Cynodontia. In Mammaliamorpha the mobility of the first ray suggests autopodial rolling in an approximately anterior direction. Most non-mammaliamorph Therapsida and probably some Mesozoic Mammaliamorpha had prehensile autopodia with an opposable ray I. In forms with a pronounced relief of the respective joints, ray I could be opposed to 90° against ray III. A strong transverse arch in the row of distalia supported the opposition movement of ray I and resulted in a convergence of the claws of digits II-V just by flexing those digits. A tight articular coherence in the digital joints of digits II-V during strong flexion supported a firm grip capacity. Usually the grip capacity was more pronounced in the manus than in the pes. Prehensile autopodia of carnivorous Therapsida may have been utilized to hold prey while biting, thus helping to avoid fractures of the laterally compressed fangs.

Range of Movement in Ray I of Manus and Pes and the Prehensility of the Autopodia in the Early Permian to Late Cretaceous Non-Anomodont Synapsida

PubMed Central

Kümmell, Susanna B.; Frey, Eberhard

2014-01-01

The mobility of ray I was analysed in seventy-eight Early Permian to Late Cretaceous specimens of non-mammalian Synapsida and one extant mammal. In all non-mammaliamorph Synapsida investigated, ray I formed a digital arcade. The first phalanx was maximally extendable to the zero position in the metapodiophalangeal joint I. Metapodiale I was the functional equivalent to a basal phalanx of digits II–V. In contrast, there was no digital arcade in ray I in Mesozoic Mammaliamorpha. Phalanx 1 I was dorsally extendable and metapodiale I was functionally part of the metapodium. During the propulsion phase, autopodial rotation occurred in the majority of Synapsida with abducted limb posture. Regarding ray I, the reduction of autopodial rotation can be estimated, e.g., from the decrease of lateral rotation and medial abduction of the first phalanx in the metapodiophalangeal joint I. Autopodial rotation was high in Titanophoneus and reduced in derived Cynodontia. In Mammaliamorpha the mobility of the first ray suggests autopodial rolling in an approximately anterior direction. Most non-mammaliamorph Therapsida and probably some Mesozoic Mammaliamorpha had prehensile autopodia with an opposable ray I. In forms with a pronounced relief of the respective joints, ray I could be opposed to 90° against ray III. A strong transverse arch in the row of distalia supported the opposition movement of ray I and resulted in a convergence of the claws of digits II–V just by flexing those digits. A tight articular coherence in the digital joints of digits II–V during strong flexion supported a firm grip capacity. Usually the grip capacity was more pronounced in the manus than in the pes. Prehensile autopodia of carnivorous Therapsida may have been utilized to hold prey while biting, thus helping to avoid fractures of the laterally compressed fangs. PMID:25517726

Assessment of undiscovered oil and gas resources in the Spraberry Formation of the Midland Basin, Permian Basin Province, Texas, 2017

USGS Publications Warehouse

Marra, Kristen R.; Gaswirth, Stephanie B.; Schenk, Christopher J.; Leathers-Miller, Heidi M.; Klett, Timothy R.; Mercier, Tracey J.; Le, Phuong A.; Tennyson, Marilyn E.; Finn, Thomas M.; Hawkins, Sarah J.; Brownfield, Michael E.

2017-05-15

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean resources of 4.2 billion barrels of oil and 3.1 trillion cubic feet of gas in the Spraberry Formation of the Midland Basin, Permian Basin Province, Texas.

Assessment of undiscovered continuous oil resources in the Wolfcamp shale of the Midland Basin, Permian Basin Province, Texas, 2016

USGS Publications Warehouse

Gaswirth, Stephanie B.; Marra, Kristen R.; Lillis, Paul G.; Mercier, Tracey J.; Leathers-Miller, Heidi M.; Schenk, Christopher J.; Klett, Timothy R.; Le, Phuong A.; Tennyson, Marilyn E.; Hawkins, Sarah J.; Brownfield, Michael E.; Pitman, Janet K.; Finn, Thomas M.

2016-11-15

Using a geology-based assessment methodology, the U.S. Geological Survey assessed technically recoverable mean resources of 20 billion barrels of oil and 16 trillion cubic feet of gas in the Wolfcamp shale in the Midland Basin part of the Permian Basin Province, Texas.

A low diversity, seasonal tropical landscape dominated by conifers and peltasperms: Early Permian Abo Formation, New Mexico

USGS Publications Warehouse

DiMichele, W.A.; Chaney, D.S.; Nelson, W.J.; Lucas, S.G.; Looy, C.V.; Quick, K.; Jun, W.

2007-01-01

Walchian conifers (Walchia piniformis Sternberg, 1825) and peltasperms similar to Supaia thinnfeldioides White and cf. Supaia anomala White dominate floodplain deposits of a narrow stratigraphic interval of the middle Abo Formation, Lower Permian of central New Mexico. The plant fossils occur in thinly bedded units up to two meters thick, consisting of coarse siltstone to very fine sandstone with clay partings. Bedding is primarily tabular, thin, and bears rare ripple marks and trough cross beds. Bedding surfaces display mud cracks, raindrop imprints, horizontal and vertical burrows of invertebrates, and footprints of terrestrial vertebrates. These features indicate intermittent and generally unchannelized stream flow, with repeated exposure to air. Channels appear to have cannibalized one another on a slowly subsiding coastal plain. Conifers are dominant at three collecting sites and at three others Supaia dominates. Although each of these genera occurs in assemblages dominated by the other, there are no truly co-dominant assemblages. This pattern suggests alternative explanations. Landscapes could have consisted of a small-scale vegetational patchwork dominated almost monospecifically in any one patch, meaning that these plants could have coexisted across the landscape. On the other hand, conifer and supaioid dominance could have been temporally distinct, occurring during different episodes of sedimentation; although in the field there are no noticeable sedimentological differences between conifer-dominated and Supaia-dominated channel deposits, they may represent slightly different climatic regimes. The considerable morphological differences between conifers and Supaia suggest that the floristic patterns are not a taphonomic effect of the loss of a significant part of the original biodiversity. In general, the climate under which this vegetation developed appears to have been relatively warm and arid, based on the geology (pervasive red color [oxidation

Geochemistry of formation waters from the Wolfcamp and “Cline” shales: Insights into brine origin, reservoir connectivity, and fluid flow in the Permian Basin, USA

USGS Publications Warehouse

Engle, Mark A.; Reyes, Francisco R.; Varonka, Matthew S.; Orem, William H.; Lin, Ma; Ianno, Adam J.; Westphal, Tiffani M.; Xu, Pei; Carroll, Kenneth C.

2016-01-01

Despite being one of the most important oil producing provinces in the United States, information on basinal hydrogeology and fluid flow in the Permian Basin of Texas and New Mexico is lacking. The source and geochemistry of brines from the basin were investigated (Ordovician- to Guadalupian-age reservoirs) by combining previously published data from conventional reservoirs with geochemical results for 39 new produced water samples, with a focus on those from shales. Salinity of the Ca–Cl-type brines in the basin generally increases with depth reaching a maximum in Devonian (median = 154 g/L) reservoirs, followed by decreases in salinity in the Silurian (median = 77 g/L) and Ordovician (median = 70 g/L) reservoirs. Isotopic data for B, O, H, and Sr and ion chemistry indicate three major types of water. Lower salinity fluids (<70 g/L) of meteoric origin in the middle and upper Permian hydrocarbon reservoirs (1.2–2.5 km depth; Guadalupian and Leonardian age) likely represent meteoric waters that infiltrated through and dissolved halite and anhydrite in the overlying evaporite layer. Saline (>100 g/L), isotopically heavy (O and H) water in Leonardian [Permian] to Pennsylvanian reservoirs (2–3.2 km depth) is evaporated, Late Permian seawater. Water from the Permian Wolfcamp and Pennsylvanian “Cline” shales, which are isotopically similar but lower in salinity and enriched in alkalis, appear to have developed their composition due to post-illitization diffusion into the shales. Samples from the “Cline” shale are further enriched with NH4, Br, I and isotopically light B, sourced from the breakdown of marine kerogen in the unit. Lower salinity waters (<100 g/L) in Devonian and deeper reservoirs (>3 km depth), which plot near the modern local meteoric water line, are distinct from the water in overlying reservoirs. We propose that these deep meteoric waters are part of a newly identified hydrogeologic unit: the Deep Basin Meteoric Aquifer System

Water Issues Associated with Increasing Unconventional Oil Production in the Permian Basin

NASA Astrophysics Data System (ADS)

Reedy, R. C.; Scanlon, B. R.; Male, F.; Walsh, M.

2017-12-01

The Permian Basin is being transformed from a major conventional oil play to the world's largest unconventional play; however, managing water for this transition is critical in this semiarid region. The study included quantifying produced water volumes with oil and gas production along with water demands for hydraulic fracturing using a detailed well-by-well analysis. Our results show that oil wells in conventional reservoirs generate large volumes of produced water relative to oil production with produced water to oil ratios of 13 (i.e. 13 barrels [bbl] of water relative to a bbl of oil). However, produced water from conventional reservoirs has been mostly injected back into the pressure-depleted oil-producing reservoirs for enhanced oil recovery using water flooding. Unconventional horizontal wells use large volumes of water for hydraulic fracturing that has been markedly increasing by factors of 10 - 16 per well and by factors of 7-10 after dividing by lateral well length (2008-2015). Although unconventional wells generate less produced water relative to oil ( 3 bbl of water relative to oil) than conventional wells, the main difference is that this produced water cannot be reinjected into the low permeability shale reservoirs. Instead, the produced water is disposed into non-producing geologic zones that could result in overpressuring and induced seismicity. There is a high potential for reusing produced water from unconventional wells in the Permian Basin because the produced water volumes can support the hydraulic fracturing water demand based on 2014 data. Reusing produced water with minimal water treatment (clean brine) could partially mitigate produced water injection concerns while reducing water demand for hydraulic fracturing.

Early Triassic fluctuations of the global carbon cycle: New evidence from paired carbon isotopes in the western USA basin

NASA Astrophysics Data System (ADS)

Caravaca, Gwénaël; Thomazo, Christophe; Vennin, Emmanuelle; Olivier, Nicolas; Cocquerez, Théophile; Escarguel, Gilles; Fara, Emmanuel; Jenks, James F.; Bylund, Kevin G.; Stephen, Daniel A.; Brayard, Arnaud

2017-07-01

In the aftermath of the catastrophic end-Permian mass extinction, the Early Triassic records recurrent perturbations in the carbon isotope signal, most notably during the Smithian and through the Smithian/Spathian Boundary (SSB; 1.5 myr after the Permian/Triassic boundary), which show some of the largest excursions of the Phanerozoic. The late Smithian also corresponds to major biotic turnovers and environmental changes, such as temperature fluctuations, that deeply impacted the recovery after the end-Permian mass extinction. Here we document the paired carbon isotope signal along with an analysis of the trace and major elements at the long-known Hot Springs section (southeastern Idaho, USA). This section records Early Triassic sediments from the Griesbachian-Dienerian up to the lower Spathian. We show that the organic and carbonate δ13C variations mirror the signals identified at a global scale. Particularly, the middle Smithian-SSB event represented by a negative-positive isotopic couplet is well identified and is not of diagenetic origin. We also document a positive excursion potentially corresponding to the Dienerian/Smithian Boundary. Observed Smithian-Spathian excursions are recorded similarly in both the organic and carbonate reservoirs, but the organic matter signal systematically shows unexpectedly dampened variations compared to its carbonate counterpart. Additionally, we show that variations in the net isotopic effect (i.e., Δ13C) probably resulted from a complex set of forcing parameters including either a mixing between terrestrial and marine organic matter depending on the evolution of the depositional setting, or variations in the biological fractionation. We establish that the Δ13C signal cannot be directly related to CO2-driven temperature variations at Hot Springs. Even though the carbon isotope signal mirrors the Early Triassic variations known at the global scale, the Hot Springs signal probably also reflects local influences on the carbon

HLA-A, B and DRB1 allele and haplotype frequencies in volunteer bone marrow donors from the north of Parana State.

PubMed

Bardi, Marlene Silva; Jarduli, Luciana Ribeiro; Jorge, Adylson Justino; Camargo, Rossana Batista Oliveira Godoy; Carneiro, Fernando Pagotto; Gelinski, Jair Roberto; Silva, Roseclei Assunção Feliciano; Lavado, Edson Lopes

2012-01-01

Knowledge of allele and haplotype frequencies of the human leukocyte antigen (HLA) system is important in the search for unrelated bone marrow donors. The Brazilian population is very heterogeneous and the HLA system is highly informative of populations because of the high level of polymorphisms. The aim of this study was to characterize the immunogenetic profile of ethnic groups (Caucasians, Afro-Brazilians and Asians) in the north of Parana State. A study was carried out of 3978 voluntary bone marrow donors registered in the Brazilian National Bone Marrow Donor Registry and typed for the HLA-A, B and DRB1 (low resolution) loci. The alleles were characterized by the polymerase chain reaction sequence-specific oligonucleotides method using the LabType SSO kit (One Lambda, CA, USA). The ARLEQUIN v.3.11 computer program was used to calculate allele and haplotype frequencies The most common alleles found in Caucasians were HLA-A*02, 24, 01; HLA-B*35, 44, 51; DRB1*11, 13, 07; for Afro-Brazilians they were HLA-A*02, 03, 30; HLA-B*35, 15, 44; DRB1*13, 11, 03; and for Asians they were: HLA-A*24, 02, 26; HLA-B*40, 51, 52; DRB1*04, 15, 09. The most common haplotype combinations were: HLA-A*01, B*08, DRB1*03 and HLA-A*29, B*44, DRB1*07 for Caucasians; HLA-A*29, B*44, DRB1*07 and HLA-A*01, B*08 and DRB1*03 for Afro-Brazilians; and HLA-A*24, B*52, DRB1*15 and HLA-A*24, B*40 and DRB1*09 for Asians. There is a need to target and expand bone marrow donor campaigns in the north of Parana State. The data of this study may be used as a reference by the Instituto Nacional de Cancer/Brazilian National Bone Marrow Donor Registry to evaluate the immunogenetic profile of populations in specific regions and in the selection of bone marrow donors.

HLA-A, B and DRB1 allele and haplotype frequencies in volunteer bone marrow donors from the north of Parana State

PubMed Central

Bardi, Marlene Silva; Jarduli, Luciana Ribeiro; Jorge, Adylson Justino; Camargo, Rossana Batista Oliveira Godoy; Carneiro, Fernando Pagotto; Gelinski, Jair Roberto; Silva, Roseclei Assunção Feliciano; Lavado, Edson Lopes

2012-01-01

Background Knowledge of allele and haplotype frequencies of the human leukocyte antigen (HLA) system is important in the search for unrelated bone marrow donors. The Brazilian population is very heterogeneous and the HLA system is highly informative of populations because of the high level of polymorphisms. Aim The aim of this study was to characterize the immunogenetic profile of ethnic groups (Caucasians, Afro-Brazilians and Asians) in the north of Parana State. Methods A study was carried out of 3978 voluntary bone marrow donors registered in the Brazilian National Bone Marrow Donor Registry and typed for the HLA-A, B and DRB1 (low resolution) loci. The alleles were characterized by the polymerase chain reaction sequence-specific oligonucleotides method using the LabType SSO kit (One Lambda, CA, USA). The ARLEQUIN v.3.11 computer program was used to calculate allele and haplotype frequencies Results The most common alleles found in Caucasians were HLA-A*02, 24, 01; HLA-B*35, 44, 51; DRB1*11, 13, 07; for Afro-Brazilians they were HLA-A*02, 03, 30; HLA-B*35, 15, 44; DRB1*13, 11, 03; and for Asians they were: HLA-A*24, 02, 26; HLA-B*40, 51, 52; DRB1*04, 15, 09. The most common haplotype combinations were: HLA-A*01, B*08, DRB1*03 and HLA-A*29, B*44, DRB1*07 for Caucasians; HLA-A*29, B*44, DRB1*07 and HLA-A*01, B*08 and DRB1*03 for Afro-Brazilians; and HLA-A*24, B*52, DRB1*15 and HLA-A*24, B*40 and DRB1*09 for Asians. Conclusion There is a need to target and expand bone marrow donor campaigns in the north of Parana State. The data of this study may be used as a reference by the Instituto Nacional de Cancer/Brazilian National Bone Marrow Donor Registry to evaluate the immunogenetic profile of populations in specific regions and in the selection of bone marrow donors PMID:23049380

Geochemistry, geochronology, and Sr-Nd isotopic compositions of Permian volcanic rocks in the northern margin of the North China Block: implications for the tectonic setting of the southeastern Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

Ji, Zejia; Zhang, Zhicheng; Chen, Yan; Li, Ke; Yang, Jinfu; Qian, Xiaoyan

2018-02-01

The southeastern part of the Central Asian Orogenic Belt (CAOB), which records the collision of the North China Block (NCB) with the South Mongolian microcontinent, is a key area for reconstructing the tectonic history of the CAOB. Controversy persists regarding the timing of the final structural amalgamation of the region; therefore, it remains unclear whether the Late Paleozoic thick volcanic successions were generated in a subduction or post-orogenic environment. Redefining the age of the formation and analyzing the geochemical compositions of these volcanic rocks can provide clues regarding the regional tectonic evolution during the Late Paleozoic and place constraints on the closure time of the Paleo-Asian Ocean. In this study, we present geochemical, geochronologic, and Sr-Nd isotopic data for 29 volcanic rock samples from the Elitu Formation in Xianghuangqi, central Inner Mongolia. The Elitu volcanic rocks have latest early-to-middle Permian ages between 272 and 268 Ma. Most of the mafic-intermediate and felsic rocks show K-normal and high-K calc-alkaline characteristics. Melting is considered to be due to large scale upwelling of the metasomatic lithospheric mantle and different degrees of melting of the thickened lower crust. The northern margin of the NCB, which represents the southeastern boundary of the CAOB, records transtensional and, subsequently, extensional tectonics associated with late Carboniferous to middle Permian volcanic activity.

Research on genesis of pyrite near the Permian-Triassic boundary in meishan, Zhejiang, China

USGS Publications Warehouse

Jiang, Y.-F.; Tang, Y.-G.; Chou, C.-L.

2006-01-01

The content and crystal forms of pyrite and sulfur isotope composition of pyrite sulfur as well as its vertical distribution near the Permian-Triassic (P/T) boundary in the Meishan section, Changxing county, Zhejiang province, China were studied using geological, petrological, mineralogical and geochemical methods (techniques). The result showed that the genesis of abundant pyrites in bed 24e2 at the uppermost part of the Changxing Formation in the Meishan section may be related to volcanic activity. In bed 24e2 of the Meishan section, pyrite has its highest content of 1.84% and the sulfur isotope composition has the highest ??34S value at + 2.2??? which is very similar to that of the average value of volcanic gas. There are some volcanic products such as ??-quartz, siliceous cylinders and siliceous spherules which coexisted with pyrites in beds 24e2 and 24f. It can be concluded that a large quantity of volcanic ash fell into the South China Sea and was incorporated into marine sediments during the formation of limestone at the uppermost part of the Changxing Formation. The volcanic eruption with massive amounts of H2S and S02 gas at the end of the Permian period resulted in the enrichment of H2S in the South China Sea areas. The reaction of H2S with reactive iron minerals formed the mass of abundant pyrites.

An unusual Middle Permian flora from the Blaine Formation (Pease River Group: Leonardian-Guadalupian Series) of King County, West Texas

USGS Publications Warehouse

DiMichele, W.A.; Hook, R.W.; Nelson, W.J.; Chaney, D.S.

2004-01-01

A new Middle Permian plant assemblage from South Ash Pasture in King County, Texas, may be the youngest and is certainly the most unusual flora known from the Permian of either West Texas or adjoining north-central Texas. Found serendipitously in the evaporite-rich upper Blaine Formation (Pease River Group, Guadalupian Series), the flora is of very low diversity despite intensive collecting efforts, and the affinities of nearly all taxa are enigmatic. The most common elements are parallel-veined leaves that resemble cordaites but that could be isolated pinnules of a pinnate leaf. Gigantopterid foliage is present but not assignable to any known taxon. A single foliar conifer specimen is too incomplete for assignment. Numerous reproductive organs, however, and an abundance of axes may represent conifers. Conchostracans, palaeoniscoid fish scales, and small heteropolar coprolites also occur in the deposit, which originated as a small, claystone-dominated channel fill in a coastal plain setting.

Geochronology and geochemistry of late Paleozoic-early Mesozoic igneous rocks of the Erguna Massif, NE China: Implications for the early evolution of the Mongol-Okhotsk tectonic regime

NASA Astrophysics Data System (ADS)

Li, Yu; Xu, Wen-Liang; Wang, Feng; Tang, Jie; Zhao, Shuo; Guo, Peng

2017-08-01

We undertook geochemical and geochronological studies on late Paleozoic-early Mesozoic igneous rocks from the Erguna Massif with the aim of constraining the early evolution of the Mongol-Okhotsk tectonic regime. Zircon crystals from nine representative samples are euhedral-subhedral, display oscillatory growth zoning, and have Th/U values of 0.14-6.48, indicating a magmatic origin. U-Pb dating of zircon using SIMS and LA-ICP-MS indicates that these igneous rocks formed during the Late Devonian (∼365 Ma), late Carboniferous (∼303 Ma), late Permian (∼256 Ma), and Early-Middle Triassic (246-238 Ma). The Late Devonian rhyolites, together with coeval A-type granites, formed in an extensional environment related to the northwestwards subduction of the Heihe-Nenjiang oceanic plate. Their positive εHf(t) values (+8.4 to +14.4) and Hf two-stage model ages (TDM2 = 444-827 Ma) indicate they were derived from a newly accreted continental crustal source. The late Carboniferous granodiorites are geochemically similar to adakites, and their εHf(t) values (+10.4 to +12.3) and Hf two-stage model ages (TDM2 = 500-607 Ma) suggest they were sourced from thickened juvenile lower crustal material, this thickening may be related to the amalgamation of the Erguna-Xing'an and Songnen-Zhangguangcai Range massifs. Rocks of the late Permian to Middle Triassic suite comprise high-K calc-alkaline monzonites, quartz monzonites, granodiorites, and monzogranites. These rocks are relatively enriched in light rare earth elements and large ion lithophile elements, and depleted in heavy rare earth elements and high field strength elements. They were emplaced, together with coeval porphyry-type ore deposits, along an active continental margin where the Mongol-Okhotsk oceanic plate was subducting beneath the Erguna Massif.

High-Resolution Zircon U-Pb CA-TIMS Dating of the Carboniferous—Permian Successions, Paraná Basin, Brazil

NASA Astrophysics Data System (ADS)

Griffis, N. P.; Mundil, R.; Montanez, I. P.; Isbell, J.; Fedorchuk, N.; Lopes, R.; Vesely, F.; Iannuzzi, R.

2015-12-01

The late Paleozoic Ice Age (LPIA) is Earth's only record of a CO2-forced climatic transition from an icehouse to greenhouse state in a vegetated world. Despite a refined framework of Gondwanan ice distribution, questions remain about the timing, volume, and synchronicity of high-latitude continental ice and the subsequent deglaciation. These questions ultimately preclude our understanding of linkages between ice volume, sea level, and high- and low-latitude climate. Poor constraints on the timing and synchronicity of glacial and interglacial transitions reflect a lack of high-resolution radioisotopic dates from high-latitude, ice-proximal Carboniferous-Permian successions. The Rio Bonito Fm in Rio Grande do Sul State of southern Brazil hosts the oldest non-glaciogenic Carboniferous- Permian deposits of the Paraná Basin, thus recording the icehouse-to-greenhouse transition. Despite a widespread effort over the last two decades to constrain these deposits in time by means of U-Pb zircon geochronology, published data sets of the Candiota and Faxinal coals of the Rio Bonito Fm host discrepancies that may reflect post- eruptive open system behavior of zircon and analytical artifacts. These discrepancies have hindered the correlation of the Candiota and Faxinal sediments within the larger Gondwanan framework. Here we present the first U-Pb ages on closed system single zircons using CA-TIMS techniques on Permo-Carboniferous ash deposits of the Paraná Basin. Preliminary results indicate two major and distinct coal-forming periods that are separated by ca 10 Ma. Our results and conclusions are not in agreement with multi- crystal U-Pb TIMS and SIMS ages that suggest coeval deposition of the Candiota and Faxinal coals. CA-TIMS analyses applied to zircons from additional ash deposits are aimed at constructing a robust chronostratigraphic framework for the Carboniferous- Permian succession of the Paraná Basin, which will facilitate a better understanding of the timing and

Paleomagnetic and 40Ar/39Ar results from the Grant intrusive breccia and coparison to the Permian Downeys Bluff Sill; evidence for Permian igneous activity at Hicks Dome, southern Illinois Basin

USGS Publications Warehouse

Reynolds, Richard L.; Goldhaber, Martin B.; Snee, Lawrence W.

1997-01-01

Igneous processes at Hicks dome, a structural upwarp at lat 37.5 degrees N., long 88.4 degrees W. in the southern part of the Illinois Basin, may have thermally affected regional basinal fluid flow and may have provided fluorine for the formation of the Illinois-Kentucky Fluorspar district. The timing of both igneous activity and mineralization is poorly known. For this reason, we have dated an intrusive breccia at Hicks dome, the Grant intrusion, using 40Ar/39Ar geochronometric and paleomagnetic methods. Concordant plateau dates, giving Permian ages, were obtained from amphibole (272.1+or-0.7 [1 sigma] Ma) and phlogopite (272.7+or-0.7 [1 sigma] Ma). After alternating-field (AF) demagnetization, specimens that contain titanomagnetite-bearing igneous rock fragments give a mean remanent direction of declination (D)=168.4 degrees; inclination (I)=-8 degrees; alpha 95=8.6 degrees; number of specimens (N)=10; this direction yields a virtual geomagnetic pole (VGP) at lat 54.8 degrees N., long 119.0 degrees E., delta p=4.4 degrees, delta m=8.7 degrees, near the late Paleozoic part of the North American apparent pole wander path. A nearly identical magnetization was found for the nearby Downeys Bluff sill (previously dated at about 275+or-24 Ma by the Rb-Sr method), in southern Illinois. Both AF and thermal demagnetization isolated shallow, southeasterly remanent directions carried by magnetite in the sill and from pyrrhotite in the baked contact of the Upper Mississippian Downeys Bluff Limestone: D=158.6 degrees; I=-11.8 degrees; alpha 95=3.8 degrees; N=15, yielding a VGP at lat 53.0 degrees N., long 128.7 degrees E., delta p=2.0 degrees, delta m=3.9 degrees. The paleomagnetic results, isotopic dates, and petrographic evidence thus favor the acquisition of thermal remanent magnetization by the Grant breccia and the Downeys Bluff sill during the Permian. The isotopic dates record rapid cooling from temperatures greater than 550 degrees C to less than 300 degrees C (the

Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhu, Deyu; Luo, Qun; Liu, Luofu; Liu, Dongdong; Yan, Lin; Zhang, Yunzhao

2017-09-01

Natural fractures in seven wells from the Middle Permian Lucaogou Formation in the Junggar Basin were evaluated in light of regional structural evolution, tight reservoir geochemistry (including TOC and mineral composition), carbon and oxygen isotopes of calcite-filled fractures, and acoustic emission (AE). Factors controlling the development of natural fractures were analyzed using qualitative and/or semi-quantitative techniques, with results showing that tectonic factors are the primary control on fracture development in the Middle Permian Lucaogou Formation of the Junggar Basin. Analyses of calcite, dolomite, and TOC show positive correlations with the number of fractures, while deltaic lithofacies appear to be the most favorable for fracture development. Mineral content was found to be a major control on tectonic fracture development, while TOC content and sedimentary facies mainly control bedding fractures. Carbon and oxygen isotopes vary greatly in calcite-filled fractures (δ13C ranges from 0.87‰ to 7.98‰, while δ18O ranges from -12.63‰ to -5.65‰), indicating that fracture development increases with intensified tectonic activity or enhanced diagenetic alteration. By analyzing the cross-cutting relationships of fractures in core, as well as four Kaiser Effect points in the acoustic emission curve, we observed four stages of tectonic fracture development. First-stage fractures are extensional, and were generated in the late Triassic, with calcite fracture fills formed between 36.51 °C and 56.89 °C. Second-stage fractures are shear fractures caused by extrusion stress from the southwest to the northeast, generated by the rapid uplift of the Tianshan in the Middle and Late Jurassic; calcite fracture fills formed between 62.91 °C and 69.88 °C. Third-stage fractures are NNW-trending shear fractures that resulted from north-south extrusion and thrusting in a foreland depression along the front of the Early Cretaceous Bogda Mountains. Calcite fracture

Paleosol sequences within Lower Permian cyclothems of Kansas: Evidence of climatic cyclicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, K.B.; McCahon, T.J.

The Lower Permian (Wolfcampian) cycles of Kansas are broadly similar to the better known Upper Pennsylvanian (Missourian) cyclothems of the midcontinent. The morphological features of paleosols within five successive variegated mudstone units of the Council Grove and Chase Groups have been described in detail. A consistent pattern has emerged with aridic paleosols near the bases of the mudstones intervals and vertic paleosols toward the tops. The lower paleosol profiles are typically calcareous with well-developed carbonate accumulation (Bk) horizons. These may contain carbonate nodules, rhizocretions, or less commonly calcretes (K-horizons). Drab haloed root races are a common feature of these grayishmore » reddish brown B horizons. The reddish color records oxidation under fairly well drained conditions, the underlying greenish gray horizons probably indicating the average position of the water table. Thin greenish gray to gray elluvial (E) horizons are preserved at the tops of many profiles. The upper paleosols within each variegated interval are characterized by well-developed vertic structures. Pedogenic slickensides, pseudoanticlines, and occasional gilgai result from the expansion and contraction of the soil such as occurs in a seasonal wet/dry environment. These paleosols are greenish gray to olive gray and often have abundant concertina root traces. The absence of a red oxidized horizon suggests more poorly drained conditions. The upward trend from drier, better drained soils to vertic, poorly drained soils could have been generated by short-term climate change toward increasing, though still seasonal, precipitation. If so, this observation suggests that cyclic climatic change may have been an important factor in generating Lower Permian cyclothems. Such a conclusion is consistent with other evidence that the limestone and shale facies of these cyclothems were deposited in consistently shallow depositional environments.« less

Relationships between carbon isotope evolution and variation of microbes during the Permian-Triassic transition at Meishan Section, South China

NASA Astrophysics Data System (ADS)

Luo, Genming; Huang, Junhuang; Xie, Shucheng; Wignall, Paul B.; Tang, Xinyan; Huang, Xianyu; Yin, Hongfu

2010-06-01

This paper investigates kerogen carbon isotopes, the difference between carbonate and kerogen carbon isotopes (Δ13Ccarb-kero = δ 13Ccarb - δ 13Ckero) and the difference between carbonate and n-C19 alkane compound-specific carbon isotopes (Δ13Ccarb- n-C19 = δ 13Ccarb - δ 13C n-C19) during the Permian-Triassic transition at Meishan, South China. The results show that kerogen carbon isotopes underwent both gradual and sharp shifts in beds 23-25 and 26-29, respectively. The differences between carbonate and organic carbon isotopes, both the Δ13Ccarb-kero and Δ13Ccarb- n-C19, which are mainly affected by CO2-fixing enzyme and pCO2, oscillated frequently during the Permian-Triassic transition. Both the variations of Δ13Ccarb- n-C19 and Δ13Ccarb-kero coupled with the alternation between cyanobacteria and green sulfur bacteria indicated by biomarkers. The episodic low values of Δ13Ccarb- n-C19 corresponded to episodic blooms of green sulfur bacteria, while the episodic high values of Δ13Ccarb- n-C19 corresponded to episodic blooms of cyanobacteria. The relationships between the variation of carbon isotopes and biota show that the microbes which flourished after the extinction of macroorganism affected the carbon isotope fractionation greatly. Combining the carbon isotope compositions and the pattern of size variation of the conodont Neogondolella, this paper supposes that anoxia of the photic zone at bed 24 was episodic and it would be caused by the degradation of terrigenous organic matters by sulfate reducing bacteria in the upper water column. Considered together with results from previous research, the high resolution variation of the biogeochemistry presents the sequence of the important geo-events during the Permian-Triassic crisis.

Abnormal high surface heat flow caused by the Emeishan mantle plume

NASA Astrophysics Data System (ADS)

Jiang, Qiang; Qiu, Nansheng; Zhu, Chuanqing

2016-04-01

It is commonly believed that increase of heat flow caused by a mantle plume is small and transient. Seafloor heat flow data near the Hawaiian hotspot and the Iceland are comparable to that for oceanic lithosphere elsewhere. Numerical modeling of the thermal effect of the Parana large igneous province shows that the added heat flow at the surface caused by the magmatic underplating is less than 5mW/m2. However, the thermal effect of Emeishan mantle plume (EMP) may cause the surface hear-flow abnormally high. The Middle-Late Emeishan mantle plume is located in the western Yangtze Craton. The Sichuan basin, to the northeast of the EMP, is a superimposed basin composed of Paleozoic marine carbonate rocks and Mesozoic-Cenozoic terrestrial clastic rocks. The vitrinite reflectance (Ro) data as a paleogeothermal indicator records an apparent change of thermal regime of the Sichuan basin. The Ro profiles from boreholes and outcrops which are close to the center of the basalt province exhibit a 'dog-leg' style at the unconformity between the Middle and Upper Permian, and they show significantly higher gradients in the lower subsection (pre-Middle Permian) than the Upper subsection (Upper Permian to Mesozoic). Thermal history inversion based on these Ro data shows that the lower subsection experienced a heat flow peak much higher than that of the upper subsection. The abnormal heat flow in the Sichuan basin is consistent with the EMP in temporal and spatial distribution. The high-temperature magmas from deep mantle brought heat to the base of the lithosphere, and then large amount of heat was conducted upwards, resulting in the abnormal high surface heat flow.

Evolution of bone microanatomy of the tetrapod tibia and its use in palaeobiological inference.

PubMed

Kriloff, A; Germain, D; Canoville, A; Vincent, P; Sache, M; Laurin, M

2008-05-01

Bone microanatomy appears to track changes in various physiological or ecological properties of the individual or the taxon. Analyses of sections of the tibia of 99 taxa show a highly significant (P Early Permian), the basal synapsid Dimetrodon (Early Permian), the dicynodont therapsid Dicynodon (Late Permian), an unindentified gorgonopsian (Late Permian); the parareptile Pareiasaurus (Middle or Late Permian) is modelled as being aquatic, but was more likely amphibious.

The role of land-marine teleconnections in the tropical proximal Permian-Triassic Marine Zone, Levant Basin, Israel: Insights from stable isotope pairing

NASA Astrophysics Data System (ADS)

Korngreen, D.; Zilberman, T.

2017-07-01

Three Late Permian - early Middle Triassic successions (Avdat 1, Pleshet 1 and David 1 boreholes, Levant Basin, Israel), located in relatively proximal and distal order from land within a broad tropical mixed carbonate/siliciclastic open marine zone, were studied using carbonate and organic matter contents (organic and inorganic carbon) in order to demonstrate the degree of effect of the land-marine teleconnection on the isotopic signatures at the depositional environment. The δ13Ccarb profiles exhibit sequential negative/positive fluctuations, which are correlatable with the reported worldwide sequential negative-shift events, enabled further stratigraphic division of the successions to stages and sub-stages. The successions changed their relative siliciclastic content relative to the degree of influence of each terrestrial influx source (eastern or southern), an outcome of humid up to extreme aridization hinterland exchanges, actually recording the expansion or contraction of the paleo-ITCZ. The δ18O profiles exhibited a range of values (- 5‰ to - 7.5‰ on average) typical to the western NeoTethys and similar to the reported worldwide climate trends with three major warming periods: (I) Late Permian to the PTB; (II) Late Dienerian - most of the Smithian; (III) early-mid Anisian, and two relatively cool periods: Griesbachian-Dienerian and Late Smithian - Spathian, but each of the three periods exhibiting short respites with the opposite trend. The δ13Ccarb, δ18Ocarb and the δ13Corg profiles of the proximal position consistently differ in magnitude from the distal ones, assuming a high contribution and involvement of meteoric water rich in terrestrial OM derived from the nearby supercontinent and affecting also the original water δ18Oseawater value (calculated to about - 3‰),which seemingly should be applied on the entire western Tethys seaway. During times of associations with maximum ITCZ contraction, the δ13Corg values of - 31‰ to - 33‰ in the

The History of Water Discharge in the Margaritifer Sinus Region of Mars

NASA Technical Reports Server (NTRS)

Grant, J. A.; Parker, T.

2001-01-01

Uzboi-Holden-Ladon-Margaritifer Valles and Samara and Parana-Loire Valles discharge into Margaritifer Basin during late-Noachian/early-Hesperian caused ponding, infiltration, and storage. Early-to-mid Hesperian release formed Margaritifer Chaos and Ares Valles. Additional information is contained in the original extended abstract.

Ca and Sr isotope records support ocean acidification during end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Wang, J.; Jacobson, A. D.; Zhang, H.; Ramezani, J.; Sageman, B. B.; Hurtgen, M.; Bowring, S. A.; Shen, S.

2017-12-01

The end-Permian mass extinction represents the most devastating loss of biodiversity during the Phanerozoic. A negative carbon isotope (δ13C) excursion that accompanies the event suggests a significant perturbation to the global carbon cycle, likely induced by CO2 emissions during eruption of the Siberian Traps large igneous province. The carbon cycle is linked with the Ca and Sr cycles through chemical weathering and carbonate precipitation. Therefore, analyses of Ca (δ44/40Ca), radiogenic Sr (87Sr/86Sr), and stable Sr (δ88/86Sr) isotope abundance variations in marine carbonate rocks spanning the Permian-Triassic Boundary (PTB) can reveal key information about biogeochemical changes that occurred during this time. We report δ44/40Ca, 87Sr/86Sr, and δ88/86Sr records analyzed by TIMS for the Meishan and Dajiang sections in China. δ44/40Ca values exhibit similar patterns in both sections. The values remain unchanged across the extinction event layer (EXT) and then decrease by 0.20‰ before increasing by 0.20‰ to 0.40‰ around the PTB. In the Meishan section, 87Sr/86Sr ratios increase after the EXT and return to pre-excursion levels by the PTB. Simultaneously, δ88/86Sr values decrease by 0.12‰ across the EXT and increase by 0.08‰ by the PTB. The patterns of our data support the hypothesis that elevated atmospheric CO2 levels enhanced chemical weathering inputs and might have caused transient ocean acidification, with an "alkalinity overshoot" and increased carbonate deposition occurring after the extinction. Additional measurements and model calculations are underway to help refine and improve these preliminary interpretations.

Synchronism of the Siberian Traps and the Permian-Triassic boundary

USGS Publications Warehouse

Campbell, I.H.; Czamanske, G.K.; Fedorenko, V.A.; Hill, R.I.; Stepanov, V.

1992-01-01

Uranium-lead ages from an ion probe were taken for zircons from the ore-bearing Noril'sk I intrusion that is comagmatic with, and intrusive to, the Siberian Traps. These values match, within an experimental error of ??4 million years, the dates for zircons extracted from a tuff at the Permian-Triassic (P-Tr) boundary. The results are consistent with the hypothesis that the P-Tr extinction was caused by the Siberian basaltic flood volcanism. It is likely that the eruption of these magmas was accompanied by the injection of large amounts of sulfur dioxide into the upper atmosphere, which may have led to global cooling and to expansion of the polar ice cap. The P-Tr extinction event may have been caused by a combination of acid rain and global cooling as well as rapid and extreme changes in sea level resulting from expansion of the polar ice cap.

Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

USGS Publications Warehouse

Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

2011-01-01

To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

A Major Unconformity Between Permian and Triassic Strata at Cape Kekurnoi, Alaska Peninsula: Old and New Observations on Stratigraphy and Hydrocarbon Potential

USGS Publications Warehouse

Blodgett, Robert B.; Sralla, Bryan

2008-01-01

A major angular unconformity separates carbonates and shales of the Upper Triassic Kamishak Formation from an underlying unnamed sequence of Permian agglomerate, volcaniclastic rocks (sandstone), and limestone near Puale Bay on the Alaska Peninsula. For the first time, we photographically document the angular unconformity in outcrop, as clearly exposed in a seacliff ~1.3 mi (2.1 km) west of Cape Kekurnoi in the Karluk C?4 and C?5 1:63,360-scale quadrangles. This unconformity is also documented by examination of core chips, ditch cuttings, and (or) open-hole electrical logs in two deep oil-and-gas-exploration wells (Humble Oil & Refining Co.?s Bear Creek No. 1 and Standard Oil Co. of California?s Grammer No. 1) drilled along the Alaska Peninsula southwest of Puale Bay. A third well (Richfield Oil Corp.?s Wide Bay Unit No. 1), south of and structurally on trend with the other two wells, probed deeply into the Paleozoic basement, but Triassic strata are absent, owing to either a major unconformity or a large fault. Here we briefly review current and newly acquired data on Permian and Triassic rocks of the Puale Bay-Becharof Lake-Wide Bay area on the basis of an examination of surface and subsurface materials. The resulting reinterpretation of the Permian and Triassic stratigraphy has important economic ramifications for oil and gas exploration on the Alaska Peninsula and in the Cook Inlet basin. We also present a history of petroleum exploration targeting Upper Triassic reservoirs in the region.

PLAY ANALYSIS AND DIGITAL PORTFOLIO OF MAJOR OIL RESERVOIRS IN THE PERMIAN BASIN: APPLICATION AND TRANSFER OF ADVANCED GEOLOGICAL AND ENGINEERING TECHNOLOGIES FOR INCREMENTAL PRODUCTION OPPORTUNITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead

2004-05-01

The Permian Basin of west Texas and southeast New Mexico has produced >30 Bbbl (4.77 x 10{sup 9} m{sup 3}) of oil through 2000, most of it from 1,339 reservoirs having individual cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}). These significant-sized reservoirs are the focus of this report. Thirty-two Permian Basin oil plays were defined, and each of the 1,339 significant-sized reservoirs was assigned to a play. The reservoirs were mapped and compiled in a Geographic Information System (GIS) by play. Associated reservoir information within linked data tables includes Railroad Commission of Texas reservoir number and districtmore » (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are <1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. This report contains a summary description of each play, including key reservoir characteristics and successful reservoir-management practices that have been used in the play. The CD accompanying the report contains a pdf version of the report, the GIS project, pdf maps of all plays, and digital data files. Oil production from the reservoirs in the Permian Basin having cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 from these significant-sized reservoirs was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl 5.25 x 10{sup 8} m{sup 3}), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San

Permian charnockites in the Pobeda area: Implications for Tarim mantle plume activity and HT metamorphism in the South Tien Shan range

NASA Astrophysics Data System (ADS)

Loury, Chloé; Rolland, Yann; Lanari, Pierre; Guillot, Stéphane; Bosch, Delphine; Ganino, Clément; Jourdon, Anthony; Petit, Carole; Gallet, Sylvain; Monié, Patrick; Riel, Nicolas

2018-04-01

The Permian history of the Central Asian Orogenic belt is marked by large-scale strike-slip faults that reactivate former Paleozoic structures, delineated by widespread alkaline magmatism. The genetic link between the syn-kinematic granitoids emplaced in the Tien Shan range and magmas emplaced within the Tarim Large Igneous Province, and the interaction between this plume and transcurrent tectonics, are still unsolved issues. We investigated the Pobeda massif, in the eastern Kyrgyz Tien Shan, located at the boundary between the Tien Shan range and the Tarim Craton, which exhibits a high-temperature unit. In this unit, Permian magmatism resulted in the emplacement of alkaline charnockites at mid-crustal levels. The primary mineralogical assemblage is nominally anhydrous and made of ortho- and clino-pyroxenes, fayalite, K-feldspar, plagioclase and quartz. These charnockites are associated with partially-molten paragneisses and marbles. Thermobarometry on these rocks indicates that the charnockites emplaced following the intrusion of a melt at a temperature > 1000 °C and pressure of around 6 kbar, corresponding to depth of 20 km. The resulting thermal anomaly triggered the partial melting of paragneisses. Bulk geochemistry including Sr, Nd, Pb and Hf isotopes suggests that charnockites fit into the Tarim Large Igneous Province magmatic series, with minor crustal assimilation. U-Pb ages on zircons of charnockites and surrounding paragneisses indicate that charnockites intruded and triggered partial melting of the gneisses at c. 287, 275 and 265 Ma. 40Ar/39Ar dating on amphibole gives a similar age as the U-Pb age at 276.2 ± 2.0 Ma. 40Ar/39Ar dating on biotite from the Charnockite unit marbles gives ages at ca. 256-265 Ma, which shows that exhumation onset directly follows the HT history, and is tentatively correlated to top-to-the-North thrusting of the Charnockite unit in a transpressive context. Additional 40Ar/39Ar dating on syn-kinematic white micas from an

Palaeoecological aspects of some invertebrate trace fossils from the mid- to Upper Permian Middleton Formation (Adelaide Subgroup, Beaufort Group, Karoo Supergroup), Eastern Cape, South Africa

NASA Astrophysics Data System (ADS)

Bordy, Emese M.; Linkermann, Sean; Prevec, Rose

2011-10-01

Ichnological and sedimentological analyses in the Eastern Cape allowed the first description of a Cochlichnus-dominated ichnofossil site from the mid- to Upper Permian Middleton Formation (Karoo Supergroup) in South Africa. The locality is within the uppermost Pristerognathus Assemblage Zone, a biostratigraphic interval characterized by a low vertebrate biodiversity at the turn of the mid- to Late Permian. Our field data indicates that the surficial bioturbation of very fine to fine-grained sand layers resulted from life activities of shallow infaunal and epifaunal invertebrates (possibly annelids, aquatic oligochaetes, nematodes, insect larvae) and fish. The morphology of the trails, their relationship to the substrate and the behaviour inferred from them indicate that the tracemakers developed a strategy that facilitated the optimization of low food resources in a permanently submerged freshwater setting. Combined ichnological and sedimentological evidence suggests a low-energy, freshwater lacustrine depositional environment, where occasional higher energy currents brought nutrients. Data also imply that colonization of these erratic event beds by opportunistic sediment-feeders was short-lived and followed by longer intervals of lower energy deposition under possibly poorly oxygenated conditions. We propose that these event beds as well as the sporadic red mudstones of the Middleton Formation may have formed during short-term, higher storm-frequency and dryer periods, signalling changes in the otherwise humid climate in this part of the main Karoo Basin during the mid- to Late Permian.

Stratigraphy and conodont biostratigraphy of the uppermost Carboniferous and Lower Permian from the North American Midcontinent

USGS Publications Warehouse

Boardman, Darwin R.; Wardlaw, Bruce R.; Nestell, Merlynd K.

2009-01-01

Part A The uppermost Wabaunsee, Admire, Council Grove, and lower Chase Groups of Kansas, Oklahoma, and Nebraska are placed into three third-order depositional sequences: a Gzhelian late-highstand sequence set, a Council Grove transgressive and highstand sequence set, and a Chase transgressive sequence set. Sequences are defined by bounding maximum-exposure surfaces and are placed within the zone of exposure surfaces (typically, stacked paleosols). Conodonts are abundant in open-marine deposits and most marine units have a differing and characteristic faunal make-up. Eleven species are described as new: Streptognathodus binodosus, S. denticulatus, S. elongianus, S. florensis, S. lineatus, S. nevaensis, S. postconstrictus, S. postelongatus, S. robustus, S. translinearis, and S. trimilus. Part B Maximum-marine flooding levels and marine-condensed sections from uppermost Carboniferous and Lower Permian fourth-order (0.1-1 m.y.) depositional sequences of the North American midcontinent reveal a rich stratigraphic succession of species of Streptognathodus and Sweetognathus conodonts that permits high-precision correlation of the Carboniferous-Permian boundary as well as the Asselian-Sakmarian and Sakmarian-Artinskian boundaries. Eleven new species of Streptognathodus are described: Streptognathodus binodosus, S. denticulatus, S. elongianus, S. florensis, S. lineatus, S. nevaensis, S. postconstrictus, S. postelongatus, S. robustus, S. translinearis, and S. trimilus. Seventeen species are redescribed and clarified and include Streptognathodus alius, S. barskovi, S. bellus, S. brownvillensis, S. conjunctus, S. constrictus, S. elongatus, S. farmeri, S. flexuosus, S. fuchengensis, S. fusus, S. invaginatus, S. isolatus, S. longissimus, S. minacutus, S. nodulinearis, and S. wabaunsensis. The correlated level of the Carboniferous-Permian boundary is recognized in the lower part of the Red Eagle Depositional Sequence based on the introduction of Streptognathodus isolatus Chernykh

Cadmium-isotopic evidence for increasing primary productivity during the Late Permian anoxic event

NASA Astrophysics Data System (ADS)

Georgiev, Svetoslav V.; Horner, Tristan J.; Stein, Holly J.; Hannah, Judith L.; Bingen, Bernard; Rehkämper, Mark

2015-01-01

Earth's most extreme extinction event near the end of the Late Permian decimated more than 90% of all extant marine species. Widespread and intensive oceanic anoxia almost certainly contributed to the catastrophe, though the driving mechanisms that sustained such conditions are still debated. Of particular interest is whether water column anoxia was a consequence of a 'stagnant ocean', or if it was controlled by increases in nutrient supply, primary productivity, and subsequent heterotrophic respiration. Testing these competing hypotheses requires deconvolving sedimentary/bottom water redox conditions from changes in surface water productivity in marine sediments. We address this issue by studying marine shales from East Greenland and the mid-Norwegian shelf and combining sedimentary redox proxies with cadmium-isotopic analyses. Sedimentary nitrogen-isotopic data, pyrite framboid analyses, and organic and inorganic shale geochemistry reveal sulfidic conditions with vigorous upwelling, and increasingly anoxic conditions with a strengthening upwelling in the Greenland and Norwegian sections, respectively. Detailed analysis of sedimentary metal budgets illustrates that Cd is primarily associated with organic carbon and records primary geochemical signatures, thus enabling reconstruction of surface water nutrient utilization. Cadmium-isotopic analyses of the authigenic shale fraction released by inverse aqua regia digestion yield an average δ114Cd110 of + 0.15 ± 0.01 ‰ (2 SE, n = 12; rel. NIST SRM 3108), indicative of incomplete surface water nutrient utilization up-section. The constant degree of nutrient utilization combined with strong upwelling requires increasing primary productivity - and not oceanic stagnation - to balance the larger nutrient fluxes to both study sites during the development of the Late Permian water column anoxia. Overall, our data illustrate that if bottom water redox and upwelling can be adequately constrained, Cd-isotopic analyses of

Ca, Sr, Mo and U isotopes evidence ocean acidification and deoxygenation during the Late Permian mass extinction

NASA Astrophysics Data System (ADS)

Silva-Tamayo, Juan Carlos; Payne, Jon; Wignall, Paul; Newton, Rob; Eisenhauer, Anton; Weyer, Stenfan; Neubert, Nadja; Lau, Kim; Maher, Kate; Paytan, Adina; Lehrmann, Dan; Altiner, Demir; Yu, Meiyi

2014-05-01

The most catastrophic extinction event in the history of animal life occurred at the end of the Permian Period, ca. 252 Mya. Ocean acidification and global oceanic euxinia have each been proposed as causes of this biotic crisis, but the magnitude and timing of change in global ocean chemistry remains poorly constrained. Here we use multiple isotope systems - Ca, Sr, Mo and U - measured from well dated Upper Permian- Lower Triassic sedimentary sections to better constrain the magnitude and timing of change in ocean chemistry and the effects of ocean acidification and de-oxygenation through this interval. All the investigated carbonate successions (Turkey, Italy and China) exhibit decreasing δ44/40Ca compositions, from ~-1.4‰ to -2.0‰ in the interval preceding the main extinction. These values remain low during most of the Griesbachian, to finally return to -1.4‰ in the middle Dienerian. The limestone succession from southern Turkey also displays a major decrease in the δ88/86Sr values from 0.45‰ to 0.3‰ before the extinction. These values remain low during the Griesbachian and finally increase to 0.55‰ by the middle Dienerian. The paired negative anomalies on the carbonate δ44/40Ca and δ88/86Sr suggest a decrease in the carbonate precipitation and thus an episode of ocean acidification coincident with the major biotic crisis. The Mo and U isotope records also exhibit significant rapid negative anomalies at the onset of the main extinction interval, suggesting rapid expansion of anoxic and euxinic marine bottom waters during the extinction interval. The rapidity of the isotope excursions in Mo and U suggests substantially reduced residence times of these elements in seawater relative to the modern, consistent with expectations for a time of widespread anoxia. The large C-isotope variability within Lower Triassic rocks, which is similar to that of the Lower-Middle Cambrian, may reflect biologically controlled perturbations of the oceanic carbon cycle

Origin and distribution of tonsteins in late permian coal seams of Southwestern China

USGS Publications Warehouse

Zhou, Yinzhu; Ren, Y.-L.; Bohor, B.F.

1982-01-01

We have surveyed the areal and stratigraphic distribution of tonsteins in Late Permian coalfields of southwestern China over an area of several hundred thousand square kilometers. We studied the relationship between tonstein distribution and sedimentary environment. Based on mineralogical and petrographic data, we have concluded that these tonsteins originated as air-fall volcanic ashes. Following accumulation in the peat swamps, in situ alteration of the vitric and lithic components took place under acidic conditions, leading to the formation of kaolinite. Based on petrologic, mineralogic, and chemical analytical data, we have determined that the application of mineralogic and geochemical criteria for tonsteins may be useful in correlating coal beds, predicting coal qualities and reconstructing related sedimentary paleoenvironmental conditions. ?? 1982.

A middle Permian ophiolite fragment in Late Triassic greenschist- to blueschist-facies rocks in NW Turkey: An earlier pulse of suprasubduction-zone ophiolite formation in the Tethyan belt

NASA Astrophysics Data System (ADS)

Topuz, Gültekin; Okay, Aral I.; Schwarz, Winfried H.; Sunal, Gürsel; Altherr, Rainer; Kylander-Clark, Andrew R. C.

2018-02-01

The Eastern Mediterranean region within the Tethyan belt is characterised by two main pulses of suprasubduction-zone ophiolite formation during the Early-Middle Jurassic and Late Cretaceous. Despite vast exposures of the Permo-Triassic accretionary complexes, related suprasubduction-zone ophiolites and the timing of subduction initiation leading to the formation of Permo-Triassic accretionary complexes are unknown so far. Here we report on a 40 km long and 0.3 to 1.8 km wide metaophiolite fragment within transitional greenschist- to blueschist-facies oceanic rocks from NW Turkey. The metaophiolite fragment is made up mainly of serpentinite and minor dykes or stocks of strongly sheared metagabbro with mineral assemblages involving actinolite/winchite, chlorite, epidote, albite, titanite and phengite. The metagabbro displays (i) variable CaO and MgO contents, (ii) anomalously high Mg# (= 100 ∗ molar MgO/(MgO + FeOtot)) of 75-88, and (iii) positive Eu anomalies, together with low contents of incompatible elements such as Ti, P and Zr, suggesting derivation from former plagioclase cumulates. The serpentinites comprise serpentine, ± chlorite, ± talc, ± calcite and relict Cr-Al spinel surrounded by ferrichromite to magnetite. Relict Cr-Al spinels are characterised by (i) Cr/(Cr + Al) ratios of 0.45-0.56 and Mg/(Mg + Fe2 +) ratio of 0.76-0.22, (ii) variable contents of ZnO and MnO, and (iii) extremely low TiO2 contents. Zn and Mn contents are probably introduced into Cr-Al spinels during greenschist- to blueschist metamorphism. Compositional features of the serpentinite such as (i) Ca- and Al-depleted bulk compositions, (ii) concave U-shaped, chondrite-normalised rare earth element patterns (REE) with enrichment of light and heavy REEs, imply that serpentinites were probably derived from depleted peridotites which were refertilised by light rare earth element enriched melts in a suprasubduction-zone mantle wedge. U-Pb dating on igneous zircons from three metagabbro

New Evidence for opening of the Black Sea; U-Pb analysis of detrital zircons and paleocurrent measurements of the Early Cretaceous turbidites

NASA Astrophysics Data System (ADS)

Akdoğan, Remziye; Okay, Aral I.; Sunal, Gürsel; Tari, Gabor; Kylander-Clark, Andrew R. C.

2015-04-01

Shelf to submarine turbidite fan deposits of the Early Cretaceous crop out over a large area along the southern coast of the Black Sea. Early Cretaceous turbidites have a thickness of over 2000 meters in the Central Pontides. The shelf of this turbidite basin, represented by shallow marine clastics and carbonates, crops out along the Black Sea coast between Zonguldak and Amasra. Paleocurrent directions in the Lower Cretaceous turbidites were measured in 90 localities using mostly flute and groove casts and to a lesser extend cross-beds. At the eastern part of the basin, the paleocurrents were from north to south. It is scattered in the west of the basin, however, the main paleocurrent directions were from the north. Detrital zircons were analyzed using LA-ICP-MS in eleven samples from the turbiditic sandstones and two samples from the shelf sandstones. Four samples are from the western part (two samples from shelf sediments), four samples from the central part and five samples from the eastern part of the Lower Cretaceous basin. 1085 of 1348 zircon analyses are concordant with rates of 95-105% and the zircon ages range between 141 ± 4 Ma (Berriasian) and 3469 ± 8 Ma (Paleoarchean). 22% of the detrital zircon ages are Paleoproterozoic, 20% Archean, 16% Carboniferous, 13% Neoproterozoic, 8% Permian, 6% Triassic, 5% Mesoproterozoic and 11% other ages. In the western part of the basin the Carboniferous zircons constitute the main population with a less dominant peak at Ordovician, Cambrian and Late Neoproterozoic. The zircons from the center of the basin show scattered distribution with dominant populations in the Triassic, Permian, Carboniferous, Silurian, Paleoproterozoic, Early Neoproterozoic-Late Mesoproterozoic, and minor peak at Late Neoarchean. On the other hand, zircons from the eastern most part of the basin, show dominant peaks in the Paleoproterozoic, Mesoarchean and Permian with minor peaks in Triassic, Carboniferous and Silurian. Anatolia and the Balkans

Astronomical forcing of a Middle Permian chert sequence in Chaohu, South China

NASA Astrophysics Data System (ADS)

Yao, Xu; Zhou, Yaoqi; Hinnov, Linda A.

2015-07-01

Astronomical forcing has been shown to be a fundamental driver of climate change through geological time. Pelagic, bedded cherts deposited in Mesozoic ocean basins with chert-mudstone cycles have been shown to contain the imprint of Milankovitch astronomical climate forcing. In the Chaohu region, South China, we studied a Middle Permian radiolarian chert sequence (Gufeng Formation) with chert-mudstone couplets reminiscent of the Mesozoic cherts, but deposited on a continental shelf. Spectral analysis of lithologic bed thickness data from two sections of this chert sequence reveals that 13 cm to 20 cm chert-mudstone cycles in the stratigraphic domain match theoretical 32-kyr Middle Permian obliquity cycling, together with a hierarchy of other cycles with 12 cm, 9 cm, 7 cm, 6.6 cm and 5.4 cm wavelengths. Tuning the 13 cm to 20 cm stratigraphic cycles to Earth's obliquity cycle periodicity indicates that the cm-scale cycles are precession-scale variations with a strong ∼400 kyr amplitude modulation. Tuning to theoretical precession terms provides further support for the astronomical forcing of the chert sequence. We propose that monsoon-controlled upwelling contributed to the development of the chert-mudstone cycles. A seasonal monsoon controlled by astronomical forcing (i.e., insolation) influenced the intensity of upwelling. Stronger upwelling increased radiolarian productivity in the surface ocean, increasing silica deposition. Glacio-eustatic oscillations from ice sheet dynamics in southern Gondwana modulated terrigenous mud flux to the basin. The two processes jointly contributed to the astronomical rhythms of these tropical chert-mudstone sequences, which are characterized by comparably strong obliquity and precession responses. Subsequent diagenesis distorted the chert and mudstone layering, but not enough to destroy the original stratigraphic patterns. The resulting astronomical time scale (ATS) assumes a Roadian/Wordian boundary age of 268.8 Ma for the

The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction.

PubMed

Fröbisch, Jörg; Angielczyk, Kenneth D; Sidor, Christian A

2010-02-01

Fossils from the central Transantarctic Mountains in Antarctica are referred to a new species of the Triassic genus Kombuisia, one of four dicynodont lineages known to survive the end-Permian mass extinction. The specimens show a unique combination of characters only present in this genus, but the new species can be distinguished from the type species of the genus, Kombuisia frerensis, by the presence of a reduced but slit-like pineal foramen and the lack of contact between the postorbitals. Although incomplete, the Antarctic specimens are significant because Kombuisia was previously known only from the South African Karoo Basin and the new specimens extend the taxon's biogeographic range to a wider portion of southern Pangaea. In addition, the new finds extend the known stratigraphic range of Kombuisia from the Middle Triassic subzone B of the Cynognathus Assemblage Zone into rocks that are equivalent in age to the Lower Triassic Lystrosaurus Assemblage Zone, shortening the proposed ghost lineage of this taxon. Most importantly, the occurrence of Kombuisia and Lystrosaurus mccaigi in the Lower Triassic of Antarctica suggests that this area served as a refuge from some of the effects of the end-Permian extinction. The composition of the lower Fremouw Formation fauna implies a community structure similar to that of the ecologically anomalous Lystrosaurus Assemblage Zone of South Africa, providing additional evidence for widespread ecological disturbance in the extinction's aftermath.

Suboxic conditions at the Permian-Triassic boundary in the NE Panthalassic Ocean suggest a different extinction mechanism compared to Paleotethys anoxia

NASA Astrophysics Data System (ADS)

Foriel, J.; Shen, Y.; Algeo, T. J.; Henderson, C. M.; Ward, P. D.

2008-12-01

The Permian-Triassic boundary marks the most important mass extinction event recorded in Earth history. Based on numerous studies of Permian-Triassic sites, most of them located around the Paleotethys, an anoxic event has been assumed to be the most likely killing mechanism. Here we present a high-resolution study of a Permian-Triassic section on the north- eastern shore of the Panthalassic Ocean. The Opal Creek shale section in SW Alberta was sampled over 40 m with a 50 cm resolution and at a 10 cm-scale around the extinction event; paleontological and geochemical data were collected. The extinction event is correlated by conodont biostratigraphy and a ~5‰ carbon isotope negative trend. The onset of suboxic/euxinic conditions is suggested by trace elements (V, Mo, U) and organic carbon data and a negative trend of non-acid volatile sulfur isotope data to a minimum of -31.2‰ just above the extinction horizon. However, this episode appears to be very short-lived as all geochemical tracers return to background values over a ~50 cm interval. Our results from the Opal Creek section seem to argue against the model of a prolonged euxinic ocean as seen in Paleotethys sections. Such discrepancy may be explained by contrasting geography and climate. The semi-closed, equatorial Paleotethys would have been much more prone to reaching euxinic conditions because of high continental nutrient delivery. On the open shore of the Panthalassic global ocean, with a much lower terrigenous input, lower temperatures and hence presumably lower bioproductivity, sustaining euxinia would have been difficult. In spite of the lack of evidence for strong prolonged anoxia, extinction does occur at Opal Creek, albeit at a lesser scale than in the Paleotethys, which may imply a different mechanism for the prolonged delay in biotic recovery.

Ocean anoxia did not cause the Latest Permian Extinction

NASA Astrophysics Data System (ADS)

Proemse, Bernadette C.; Grasby, Stephen E.; Wieser, Michael E.; Mayer, Bernhard; Beauchamp, Benoit

2014-05-01

The Latest Permian Extinction (LPE, ~252 million years ago) was a turning point in the history of life on Earth with a loss of ~96% of all marine species and ~70% of all terrestrial species. While, the event undoubtedly shaped the evolution of life its cause remains enigmatic. A leading hypothesis is that the global oceans became depleted in oxygen (anoxia). In order to test this hypothesis we investigated a proxy for marine oxygen levels (molybdenum isotopic composition) in shale across the LPE horizon located on the subtropical northwest margin of Pangea at that time. We studied two sedimentary records in the Sverdrup basin, Canadian High Arctic: Buchanan Lake (eastern Axel Heiberg Island; 79° 26.1'N, 87° 12.6'W), representing a distal deep-water slope environment, and West Blind Fiord (southwest Ellesmere Island; 78° 23.9'N, 85° 57.2'W), representing a deep outer shelf environment (below storm wave base). The molybdenum isotopic composition (δ98/95Mo) of sediments has recently become a powerful tool as a paleo-oceanographic proxy of marine oxygen levels. Sample preparation was carried out in a metal-free clean room facility in the isotope laboratory of the Department of Physics and Astronomy, University of Calgary, Canada, that is supplied by HEPA-filtered air. Molybdenum isotope ratios were determined on a Thermo Scientific multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) with an uncertainty better than ±0.10o for δ98/95Mo values. Results from the Buchanan Lake section show a large shift in δ98/95Mo values from 2.02o to +2.23o at the extinction horizon, consistent with onset of euxinic conditions. In contrast, West Blind Fiord shales, representing the sub-storm wave base shelf environment, show little change in the molybdenum isotopic composition (1.34o to +0.05), indicating ongoing oxic conditions across the LPE (Proemse et al., 2013). Our results suggest that areas of the Pangea continental shelf (North West Pangea) experienced

The petrogenesis of the Early Permian Variscan granites of the Cornubian Batholith: Lower plate post-collisional peraluminous magmatism in the Rhenohercynian Zone of SW England

NASA Astrophysics Data System (ADS)

Simons, B.; Shail, Robin K.; Andersen, Jens C. Ø.

2016-09-01

The Early Permian Cornubian Batholith was generated during an extensional regime following Variscan convergence within the Rhenohercynian Zone of SW England. Its component granites can be classified, using mineralogical, textural and geochemical criteria, into five main types, all of which are peraluminous (A/CNK > 1.1): G1 (two-mica), G2 (muscovite), G3 (biotite), G4 (tourmaline) and G5 (topaz). G1 granites formed through up to 20% muscovite and minor biotite dehydration melting of a metagreywacke source at moderate temperatures and pressures (731-806 °C, > 5 kbar). Younger G3 granites formed through higher temperature, lower pressure (768-847 °C, < 4 kbar) biotite-dominated melting of a similar source. Partial melting was strongly influenced by the progressive lower-mid crustal emplacement of mafic igneous rocks during post-Variscan extension and a minor (< 5%-10%) mantle-derived component in the granites is possible. Two distinct fractionation series, G1-G2 and G3-G4, are defined using whole-rock geochemical and mineral chemical data. Variations in the major elements, Ba, Sr and Rb indicate that G1 and G3 granites underwent 15%-30% fractionation of an assemblage dominated by plagioclase, alkali feldspar and biotite to form more evolved G2 and G4 granites, respectively. Decreasing whole-rock abundances of Zr, Th and REE support the fractionation of zircon, monazite, apatite and allanite. Subsolidus alteration in G2 and G4 granites is indicated by non-primary muscovite and tourmaline and modification of major and trace element trends for G3-G4 granites, particularly for P2O5 and Rb. Topaz (G5) granites show low Zr, REE and extreme enrichment in Rb (up to 1530 ppm) and Nb (79 ppm) that cannot be related in a straightforward manner to continued differentiation of the G1-G2 or G3-G4 series. Instead, they are considered to represent partial melting, mediated by granulite facies fluids, of a biotite-rich restite following extraction of G1 and/or G3 magmas; they do

Geochemistry of Permian rocks from the margins of the Phosphoria Basin

USGS Publications Warehouse

Perkins, Robert B.; McIntyre, Brandie; Hein, James R.; Piper, David Z.

2003-01-01

The Permian Phosphoria Formation and interbedded units of the Park City Formation and Shedhorn Sandstone in western Wyoming represent deposition along a carbonate ramp at the eastern margin of the Phosphoria Basin, with portions of the Phosphoria units reflecting periods of upwelling and widespread phosphogenesis. Thickness-weighted slab-samples of these units were collected at a maximum interval of 3 m along an 80+ m-length of unweathered core and analyzed for major-, minor-, and trace-element contents. Interpretations of geochemistry were made within the confines of a previously recognized sequence stratigraphy framework. Major shifts in element ratios characteristic of terrigenous debris that occur at sequence boundaries at the base of the Meade Peak and Retort Members of the Phosphoria Formation are attributed to changing sediment sources. Inter-element relationships in the marine fraction indicate that bottom waters of the Phosphoria Basin were predominantly denitrifying during deposition of the Ervay, Grandeur, and Phosphoria sediments, although sulfate-reducing conditions may have existed during deposition of the lower Meade Peak sediments. Oxic conditions were prevalent during deposition of a large part of the Franson Member, which represents sedimentation in a shallow, inner- to back-ramp setting. Variations in sediment facies and organic matter and trace element contents largely reflect changes in Permian sea level. Changes in sea level in basin-margin areas, such as represented by the study section, may have affected the oxidation of settling organic matter, the foci of intersection of upwelling bottom waters with the photic zone, the rate of terrigenous sedimentation, and, ultimately, the overall environment of deposition. Our study suggests that phosphogenesis can occur under lowstand, transgressive, and highstand conditions in marginal areas, assuming water depths sufficient for upwelling to occur. Formation of phosphorite layers under upwelling

Paleomagnetic and AMS study of Permian and Triassic rocks from the Hronic Nappe and Paleogene rocks from the Central Carpathian Paleogene Basin, Western Carpathians

NASA Astrophysics Data System (ADS)

Márton, Emö; Madzin, Jozef; Bučová, Jana; Grabowski, Jacek; Plašienka, Dušan; Aubrecht, Roman

2017-04-01

The Hronic (Choč) units form the highest cover nappe system of the Central Western Carpathians which was emplaced over the Fatric (Krížna) nappe system during the Late Cretaceous. The Permian (red beds and lava flows) and Triassic (sediments) rocks, the main targets of our study, were affected only by diagenetic or very low-grade, burial-related recrystallization and were tilted and transported together. The pre-late Cretaceous sequence is overlapped by Paleogene mainly flysch sequences. Three laboratories (Bratislava, Budapest and Warsaw) were involved in standard paleomagnetic processing and AMS measurements of the samples, while Curie-points were determined in Budapest. The site/locality mean paleomagnetic directions obtained were significantly different from the local direction of the present Earth magnetic field, indicating the long term stability of the paleomagnetic signal. The magnetic fabrics varied from un-oriented to dominantly schistose with well-defined lineations. The latter were normally subhorizontal, although subvertical maxima also occurred among the Triassic sediments. Shallow inclinations, after tilt corrections, suggest near-equatorial position for most of the Permian and Lower Triassic, while around 20°N for the Middle-Upper Triassic localities. The paleomagnetic declinations are interpreted in terms of CW tectonic rotations, which are normally larger for the Permian than for the Triassic samples, although there are some differences within the same age groups. This may be attributed to differential movements during nappe emplacement or subsequent tectonic disturbances. For two localities from the Paleogene cover sequence of the Hronic units, close to the main sampling area (Low Tatra Mts) of the present study documented fairly large CCW rotations, thus obtained additional evidence for the general CCW rotation of the Central Western Carpathians during the Cenozoic. Thus, we conclude that the Cenozoic CCW rotation was pre-dated by large CW

The volcano-sedimentary succession of Upper Permian in Wuli area, central Qinghai-Tibetan Plateau: Sedimentology, geochemistry and paleogeography

NASA Astrophysics Data System (ADS)

Liu, Shengqian; Jiang, Zaixing; Gao, Yi

2017-04-01

Detailed observations on cores and thin sections well documented a volcano-sedimentary succession from Well TK2, which is located in Wuli area, central Qinghai-Tibetan Plateau. The TK2 volcano-sedimentary succession reflects an active sedimentary-tectonic setting in the north margin of North Qiangtang-Chamdo terrane in the late Permian epoch. Based on the observation and recognition on lithology and mineralogy, the components of TK2 succession are mainly volcanic and volcaniclastic rocks and four main lithofacies are recognized, including massive volcanic lithofacies (LF1), pyroclastic tuff lithofacies (LF2), tuffaceous sandstone lithofacies (LF3) and mudstone lithofacies (LF4). LF1 is characterized by felsic components, massive structure and porphyrotopic structure with local flow structure, which indicates submarine intrusive domes or extrusion-fed lavas that formed by magma ascents via faults or dykes. Meanwhile, its eruption style may reflect a relative high pressure compensation level (PCL) that mainly determined by water depth, which implies a deep-water environment. LF2 is composed of volcanic lapilli or ash and featured with massive structure, parallel bedding and various deformed laminations including convolve structure, slide deformation, ball-and-pillow structure, etc.. LF2 indicates the sedimentation of initial or reworked explosive products not far away from volcano centers, reflecting the proximal accumulation of volcano eruption-fed clasts or their resedimentation as debris flows. In addition, the submarine volcano eruptions may induced earthquakes that facilitate the resedimentation of unconsolidated sediments. LF3 contains abundant pyroclastic components and is commonly massive with rip-up mudstone clasts or usually interbedded with LF4. In addition, typical flute casts, scour structures and graded beddings in thin-interbedded layers of sandstone and mudstone are commonly observed, which also represents the sedimentation of debris flows or

Permian A-type rhyolites of the Muráň Nappe, Inner Western Carpathians, Slovakia: in-situ zircon U-Pb SIMS ages and tectonic setting

NASA Astrophysics Data System (ADS)

Ondrejka, Martin; Li, Xian-Hua; Vojtko, Rastislav; Putis, Marian; Uher, Pavel; Sobocký, Tomas

2018-04-01

Three representative A-type rhyolitic rock samples from the Muráň Nappe of the inferred Silicic Unit of the Inner Western Carpathians (Slovakia) were dated using the high-precision SIMS U-Pb isotope technique on zircons. The geochronological data presented in this paper is the first in-situ isotopic dating of these volcanic rocks. Oscillatory zoned zircon crystals mostly revealed concordant Permian (Guadalupian) ages: 266.6 ± 2.4 Ma in Tisovec-Rejkovo (TIS-1), 263.3 ± 1.9 Ma in Telgárt-Gregová Hill (TEL-1) and 269.5 ± 1.8 Ma in Veľká Stožka-Dudlavka (SD-2) rhyolites. The results indicate that the formation of A-type rhyolites and their plutonic equivalents are connected to magmatic activity during the Permian extensional tectonics and most likely related to the Pangea supercontinent break-up.

Constraints on Early Triassic carbon cycle dynamics from paired organic and inorganic carbon isotope records

NASA Astrophysics Data System (ADS)

Meyer, K. M.; Yu, M.; Lehrmann, D.; van de Schootbrugge, B.; Payne, J. L.

2013-01-01

Large δ13C excursions, anomalous carbonate precipitates, low diversity assemblages of small fossils, and evidence for marine euxinia in uppermost Permian and Lower Triassic strata bear more similarity to Neoproterozoic carbonates than to the remainders of the Permian and Triassic systems. Middle Triassic diversification of marine ecosystems coincided with the waning of anoxia and stabilization of the global carbon cycle, suggesting that environment-ecosystem linkages were important to biological recovery. However, the Earth system behavior responsible for these large δ13C excursions remains poorly constrained. Here we present a continuous Early Triassic δ13Corg record from south China and use it to test the extent to which Early Triassic excursions in δ13Ccarb record changes in the δ13C of marine dissolved inorganic carbon (DIC). Regression analysis demonstrates a significant positive correlation between δ13Corg and δ13Ccarb across multiple sections that span a paleoenvironmental gradient. Such a correlation is incompatible with diagenetic alteration because no likely mechanism will alter both δ13Corg and δ13Ccarb records in parallel and therefore strongly indicates a primary depositional origin. A simple explanation for this correlation is that a substantial portion of the preserved Corg was derived from the contemporaneous DIC pool, implying that the observed excursions reflect variation in the δ13C of the exogenic carbon reservoir (ocean, atmosphere, biomass). These findings support existing evidence that large δ13C excursions are primary and therefore strengthen the case that large-scale changes to the carbon cycle were mechanistically linked to the low diversity and small size of Early Triassic fossils. Associated sedimentary and biogeochemical phenomena further suggest that similar associations in Neoproterozoic and Cambrian strata may reflect the same underlying controls.

États de contraintes et mécanismes d'ouverture et de fermeture des bassins permiens du Maroc hercynien. L'exemple des bassins des Jebilet et des RéhamnaStates of stresses and opening/closing mechanisms of the Permian basins in Hercynian Morocco. The example of the Jebilet and Réhamna Basins

NASA Astrophysics Data System (ADS)

Saidi, Amal; Tahiri, Abdelfatah; Ait Brahim, Lahcen; Saidi, Maraim

The fracturing analysis in the Permian basins of Jebilet and Rehamna (Hercynian Morocco) and the underlying terranes allowed us to suggest a model for their opening. Three tectonic episodes are distinguished: a transtensional episode NNE-SSW-trending (Permian I), occurring during the opening along sinistral wrench faults N70-110-trending, associated with synsedimentary normal faults; a transpressive episode ESE-WNW-trending (Permian II), initiating the closure, the normal faults playing back reverse faults and the N70 trending faults dextral wrench faults; a compressional episode NNW-SSE (post-Permian, ante-Triassic), accentuating the closure and the deformation and putting an end to the Tardi-Hercynian compressive movements. To cite this article: A. Saidi et al., C. R. Geoscience 334 (2002) 221-226.

Midland's Economy: Past, Present and Future; The Midland/Odessa Economy: Foundation and Future; and Report on Labor Demand in the Permian Basin.

ERIC Educational Resources Information Center

Williams, James L.; McCarty, Nolan M.

As part of an effort to identify ways in which Midland College (Texas) and local businesses can respond to the economic needs of the community, these three papers by the Midland's Business and Economic Development Center offer various perspectives on the economic climate and labor market of the Permian Basis. The first report, "Midland's…

The Case for Pangea B: Paleomagnetic Contributions from Adria

NASA Astrophysics Data System (ADS)

Muttoni, G.

2004-12-01

The pre-drift Wegenerian model of Pangea is almost universally accepted, but debate exists on its pre-Jurassic configuration since Ted Irving introduced Pangea B. We review Permian and recently acquired Jurassic-Cretaceous paleomagnetic data from para-autochthonous regions of Adria such as the Southern Alps, which we show to be broadly consistent with "African" APWPs. Paleomagnetic data from para-autochthonous Adria can therefore be used to bolster the Gondwana APWP in the poorly known Late Permian-Triassic time interval. Adria paleopoles are integrated with the Gondwana and Laurasia APWPs and used to generate a tectonic model for the evolution of Pangea. The Early Permian paleopole of Adria from radiometrically dated igneous rocks, in conjunction with the coeval Gondwana and Laurasia paleopoles again from igneous rocks, support Pangea B. The use of paleomagnetic data strictly from igneous rocks excludes artifacts from sedimentary inclination error as a contributing explanation for Pangea B. The ultimate option to reject Pangea B is to introduce a significant zonal octupole component in the Late Paleozoic time-averaged geomagnetic field. Our dataset consisting entirely of paleomagnetic directions with low inclinations from sampling sites confined to one hemisphere show that the effects of a zonal octupole field contribution cannot explain away the paleomagnetic evidence for Pangea B. We therefore regard the paleomagnetic evidence for an Early Permian Pangea B as robust. Because the Late Permian/Early Triassic and the Middle/early Late Triassic paleopoles from Adria and Laurussia support Pangea A, the phase of transcurrent motion between Laurasia and Gondwana that caused the Pangea B to A transition occurred essentially in the Permian. It took place after the cooling of the Variscan mega-suture and lasted ~20 m.y., with an average relative plate velocity of approximately 15 cm/yr. Finally, we review geological and paleomagnetic evidence in support of an intra

An Exceptionally Preserved Transitional Lungfish from the Lower Permian of Nebraska, USA, and the Origin of Modern Lungfishes

PubMed Central

Pardo, Jason D.; Huttenlocker, Adam K.; Small, Bryan J.

2014-01-01

Complete, exceptionally-preserved skulls of the Permian lungfish Persephonichthys chthonica gen. et sp. nov. are described. Persephonichthys chthonica is unique among post-Devonian lungfishes in preserving portions of the neurocranium, permitting description of the braincase of a stem-ceratodontiform for the first time. The completeness of P. chthonica permits robust phylogenetic analysis of the relationships of the extant lungfish lineage within the Devonian lungfish diversification for the first time. New analyses of the relationships of this new species within two published matrices using both maximum parsimony and Bayesian inference robustly place P. chthonica and modern lungfishes within dipterid-grade dipnoans rather than within a clade containing Late Devonian ‘phaneropleurids’ and common Late Paleozoic lungfishes such as Sagenodus. Monophyly of post-Devonian lungfishes is not supported and the Carboniferous-Permian taxon Sagenodus is found to be incidental to the origins of modern lungfishes, suggesting widespread convergence in Late Paleozoic lungfishes. Morphology of the skull, hyoid arch, and pectoral girdle suggests a deviation in feeding mechanics from that of Devonian lungfishes towards the more dynamic gape cycle and more effective buccal pumping seen in modern lungfishes. Similar anatomy observed previously in ‘Rhinodipterus’ kimberyensis likely represents an intermediate state between the strict durophagy observed in most Devonian lungfishes and the more dynamic buccal pump seen in Persephonichthys and modern lungfishes, rather than adaptation to air-breathing exclusively. PMID:25265394

Carboniferous-Permian tectonic transition envisaged in two magmatic episodes at the Kuruer Cu-Au deposit, Western Tianshan (NW China)

NASA Astrophysics Data System (ADS)

Yu, Jie; Li, Nuo; Qi, Nan; Guo, Jian-Ping; Chen, Yan-Jing

2018-03-01

The Western Tianshan in NW China is one of the most important gold provinces in the Central Asian Orogenic Belt (CAOB). The recently discovered Kuruer Cu-Au deposit has been interpreted to represent a transition from high-sulfidation epithermal to porphyry mineralization system. In this study, we present new LA-ICP-MS zircon U-Pb ages for the many magmatic rock types at Kuruer, including the Dahalajunshan Formation andesitic tuff (333.2 ± 1.6 Ma), diorite porphyry (269.7 ± 2.0 Ma), slightly-altered (264.4 ± 2.6 Ma) and intensively-altered (270.5 ± 2.5 Ma) albite porphyry. These ages reveal two distinct magmatic episodes: The Early Carboniferous Dahalajunshan Formation (wall rocks) andesitic tuff samples contain narrow ranges of SiO2 (60.29-61.28 wt.%), TiO2 (0.96-0.98 wt.%), Al2O3 (16.55-16.57 wt.%) and Fe2O3T (5.36-5.57 wt.%). The tuff is characterized by LREE enrichment and HFSE depletion, as well as LREE/HREE enrichment ((La/Yb)N = 8.31-8.76) and negative Eu anomalies (δEu = 0.64-0.76). Zircon εHf (t) values are 5.4-8.2, and two-stage Hf model ages (TDM2) are 821-1016 Ma, indicating partial melting of a moderately depleted mantle wedge with Precambrian continental crustal input. The ore-forming Middle Permian diorite porphyry and (quartz) albite porphyry have variable major oxide compositions (e.g., SiO2 = 53.09-53.12 wt.% for the diorite porphyry, 70.84-78.03 wt.% for the albite porphyry, and 74.07-75.03 wt.% for the quartz albite porphyry) but similar chondrite-normalized REE and primitive mantle-normalized multi-element patterns. These porphyries display LREE enrichment and HFSE depletion, as well as elevated LREE/HREE enrichment and negative Eu anomalies. The positive zircon εHf(t) values (11.7-15.9 for the diorite porphyry, 8.9-14.9 for the albite porphyry) and young two-stage Hf model ages (TDM2) (282-542 Ma for the diorite porphyry, 337-717 Ma for the albite porphyry) indicate a major juvenile continental crustal involvement. We propose that the

Extremely acid Permian lakes and ground waters in North America

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.; Wopenka, B.; Burruss, R.C.; Pasteris, J.D.

1998-01-01

Evaporites hosted by red beds (red shales and sandstones), some 275-265 million years old, extend over a large area of the North American mid- continent. They were deposited in non-marine saline lakes, pans and mud- flats, settings that are typically assumed to have been alkaline. Here we use laser Raman microprobe analyses of fluid inclusions trapped in halites from these Permian deposits to argue for the existence of highly acidic (pH < 1) lakes and ground waters. These extremely acidic systems may have extended over an area of 200,000 km2. Modern analogues of such systems may be natural acid lake and groundwater systems (pH ~2-4) in southern Australia. Both the ancient and modern acid systems are characterized by closed drainage, arid climate, low acid-neutralizing capacity, and the oxidation of minerals such as pyrite to generate acidity. The discovery of widespread ancient acid lake and groundwater systems demands a re-evaluation of reconstructions of surface conditions of the past, and further investigations of the geochemistry and ecology of acid systems in general.

Leaiid conchostracans from the uppermost Permian strata of the Paraná Basin, Brazil: Chronostratigraphic and paleobiogeographic implications

NASA Astrophysics Data System (ADS)

Ferreira-Oliveira, Luis Gustavo; Rohn, Rosemarie

2010-03-01

Conchostracan fossils are abundant and relatively diversified in the Rio do Rasto Formation (Passa Dois Group, Paraná Basin, southern Brazil), but leaiids (' Leaia pruvosti' [Reed, F.R.C., 1929. Novos Phyllopodos Fósseis do Brasil. Boletim do Serviço Geológico e Mineralógico do Brasil 34, 2-16]) were previously found at only one locality of the formation in the northern Santa Catarina State. New specimens of the Family Leaiidae, collected from two outcrops in central Paraná State near the top of the formation, stimulated a revision of related taxa. Both the new and the previously known leaiids are herein assigned to Hemicycloleaia mitchelli [Etheridge Jr., R., 1892. On Leaia mitchelli Etheridge. Proceedings of the Linnean Society of New South Wales 7, 307-310] based on the presence of three carinae and subovate shape. This species was originally recorded in the upper Tatarian (Wuchiapingian, Late Permian) of Sydney Basin, eastern Australia and therefore corroborates the interpretation that the leaiid bearing strata of the Rio do Rasto Formation cannot be younger than Permian. H. mitchelli possibly was one of the most widespread, eurytopic and conservative Late Paleozoic conchostracans of Gondwana (although records from Africa, India and Antarctica must still be confirmed) and it was also found in the Tatarian of Russia. The sudden disappearance of leaiids after their apparent success is consistent with the hypothesis about the biotic crisis around the Permo-Triassic boundary.

The beginning of the Buntsandstein cycle (Early-Middle Triassic) in the Catalan Ranges, NE Spain: Sedimentary and palaeogeographic implications

NASA Astrophysics Data System (ADS)

Galán-Abellán, Belén; López-Gómez, José; Barrenechea, José F.; Marzo, Mariano; De la Horra, Raúl; Arche, Alfredo

2013-10-01

The Early-Middle Triassic siliciclastic deposits of the Catalan Ranges, NE Spain, are dominated by aeolian sediments indicating a predominance of arid climate during this time span, in sharp contrast with the coeval fluvial sediments found in the Castilian Branch of the Iberian Ranges, 300 km to the SW. The NE-SW-oriented Catalan Basin evolved during the Middle-Late Permian as the result of widespread extension in the Iberian plate. This rift basin was bounded by the Pyrenees, Ebro and Montalbán-Oropesa highs. The Permian-Early Triassic-age sediments of the Catalan Basin were deposited in three isolated subbasins (Montseny, Garraf, Prades), separated by intrabasinal highs, but linked by transversal NW-SE oriented faults. The three subbasins show evidence of diachronic evolution with different subsidence rates and differences in their sedimentary records. The Buntsandstein sedimentary cycle started in the late Early Triassic (Smithian-Spathian) in the central and southern domains (Garraf and Prades), with conglomerates of alluvial fan origin followed by fluvial and aeolian sandstones. Source area of the fluvial sediments was nearby Paleozoic highs to the north and west, in contrast with the far-away source areas of the fluvial sediments in the Iberian Ranges, to the SW. These fluvial systems were interacting with migrating aeolian dune fields located towards the S, which developed in the shadow areas behind the barriers formed by the Paleozoic highs. These highs were separating the subbasins under arid and semi-arid climate conditions. The dominating winds came from the east where the westernmost coast of the Tethys Sea was located, and periods of water run-off and fields of aeolian dunes development alternated. Some of the fluvial systems were probably evaporating as they were mixed into the interdune areas, never reaching the sea. From the end of the Smithian to the Spathian, the Catalan Basin and neighbour peri-Tethys basins of the present-day southern France

Integrated Synthesis of the Permian Basin: Data and Models for Recovering Existing and Undiscovered Oil Resources from the Largest Oil-Bearing Basin in the U.S.

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Jackson; Katherine Jackson

2008-09-30

Large volumes of oil and gas remain in the mature basins of North America. This is nowhere more true than in the Permian Basin of Texas and New Mexico. A critical barrier to recovery of this vast remaining resource, however, is information. Access to accurate geological data and analyses of the controls of hydrocarbon distribution is the key to the knowledge base as well as the incentives needed by oil and gas companies. The goals of this project were to collect, analyze, synthesize, and deliver to industry and the public fundamental information and data on the geology of oil andmore » gas systems in the Permian Basin. This was accomplished in two ways. First we gathered all available data, organized it, and placed it on the web for ready access. Data include core analysis data, lists of pertinent published reports, lists of available cores, type logs, and selected PowerPoint presentations. We also created interpretive data such as type logs, geological cross sections, and geological maps and placed them in a geospatially-registered framework in ARC/GIS. Second, we created new written syntheses of selected reservoir plays in the Permian basin. Although only 8 plays were targeted for detailed analysis in the project proposal to DOE, 14 were completed. These include Ellenburger, Simpson, Montoya, Fusselman, Wristen, Thirtyone, Mississippian, Morrow, Atoka, Strawn, Canyon/Cisco, Wolfcamp, Artesia Group, and Delaware Mountain Group. These fully illustrated reports include critical summaries of published literature integrated with new unpublished research conducted during the project. As such these reports provide the most up-to-date analysis of the geological controls on reservoir development available. All reports are available for download on the project website and are also included in this final report. As stated in our proposal, technology transfer is perhaps the most important component of the project. In addition to providing direct access to data and reports

Magnetostratigraphy susceptibility for the Guadalupian Series GSSPs (Middle Permian) in Guadalupe Mountains National Park and adjacent areas in West Texas

USGS Publications Warehouse

Wardlaw, Bruce R.; Ellwood, Brooks B.; Lambert, Lance L.; Tomkin, Jonathan H.; Bell, Gordon L.; Nestell, Galina P.

2012-01-01

Here we establish a magnetostratigraphy susceptibility zonation for the three Middle Permian Global boundary Stratotype Sections and Points (GSSPs) that have recently been defined, located in Guadalupe Mountains National Park, West Texas, USA. These GSSPs, all within the Middle Permian Guadalupian Series, define (1) the base of the Roadian Stage (base of the Guadalupian Series), (2) the base of the Wordian Stage and (3) the base of the Capitanian Stage. Data from two additional stratigraphic successions in the region, equivalent in age to the Kungurian–Roadian and Wordian–Capitanian boundary intervals, are also reported. Based on low-field, mass specific magnetic susceptibility (χ) measurements of 706 closely spaced samples from these stratigraphic sections and time-series analysis of one of these sections, we (1) define the magnetostratigraphy susceptibility zonation for the three Guadalupian Series Global boundary Stratotype Sections and Points; (2) demonstrate that χ datasets provide a proxy for climate cyclicity; (3) give quantitative estimates of the time it took for some of these sediments to accumulate; (4) give the rates at which sediments were accumulated; (5) allow more precise correlation to equivalent sections in the region; (6) identify anomalous stratigraphic horizons; and (7) give estimates for timing and duration of geological events within sections.

High-resolution earthquake relocation in the Fort Worth and Permian Basins using regional seismic stations

NASA Astrophysics Data System (ADS)

Ogwari, P.; DeShon, H. R.; Hornbach, M.

2017-12-01

Post-2008 earthquake rate increases in the Central United States have been associated with large-scale subsurface disposal of waste-fluids from oil and gas operations. The beginning of various earthquake sequences in Fort Worth and Permian basins have occurred in the absence of seismic stations at local distances to record and accurately locate hypocenters. Most typically, the initial earthquakes have been located using regional seismic network stations (>100km epicentral distance) and using global 1D velocity models, which usually results in large location uncertainty, especially in depth, does not resolve magnitude <2.5 events, and does not constrain the geometry of the activated fault(s). Here, we present a method to better resolve earthquake occurrence and location using matched filters and regional relative location when local data becomes available. We use the local distance data for high-resolution earthquake location, identifying earthquake templates and accurate source-station raypath velocities for the Pg and Lg phases at regional stations. A matched-filter analysis is then applied to seismograms recorded at US network stations and at adopted TA stations that record the earthquakes before and during the local network deployment period. Positive detections are declared based on manual review of associated with P and S arrivals on local stations. We apply hierarchical clustering to distinguish earthquakes that are both spatially clustered and spatially separated. Finally, we conduct relative earthquake and earthquake cluster location using regional station differential times. Initial analysis applied to the 2008-2009 DFW airport sequence in north Texas results in time continuous imaging of epicenters extending into 2014. Seventeen earthquakes in the USGS earthquake catalog scattered across a 10km2 area near DFW airport are relocated onto a single fault using these approaches. These techniques will also be applied toward imaging recent earthquakes in the

Rock mechanics evaluation of potential repository sites in the Paradox, Permian, and Gulf Coast Basins: Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-09-01

Thermal and thermomechanical analyses of a conceptual radioactive waste repository containing commercial and defense high-level wastes and spent fuel have been performing using finite element models. The thermal and thermomechanical responses of the waste package, disposal room, and repository regions were evaluated. four bedded salt formations, in Davis and Lavender Canyons in the Paradox Basin of southeastern Utah and in Deaf Smith and Swisher counties in the Permian Basin of northwestern Texas, and three salt domes, Vacherie Dome in northwestern Louisiana and Richton and Cypress Creek Domes in southeastern Mississippi, located in the Gulf Coast Basin, were examined. In themore » Paradox Basin, the pressure exerted on the waste package overpack was much greater than the initial in situ stress. The disposal room closure was less than 10 percent after 5 years. Surface uplift was nominal, and no significant thermomechanical perturbation of the aquitards was observed. In the Permian Basin, the pressure exerted on the waste package overpack was greater than the initial in situ stress. The disposal room closures were greater than 10 percent in less than 5 years. Surface uplift was nominal, and no significant thermomechanical perturbation of the aquitards was observed. In the Gulf Coast Basin, the pressure exerted on the waste package overpack was greater than the initial in situ stress. The disposal room closures were greater than 10 percent in less than 5 years. No significant thermomechanical perturbation of the overlying geology was observed. 40 refs., 153 figs., 32 tabs.« less

Subsequent biotic crises delayed marine recovery following the late Permian mass extinction event in northern Italy

PubMed Central

Danise, Silvia; Price, Gregory D.; Twitchett, Richard J.

2017-01-01

The late Permian mass extinction event was the largest biotic crisis of the Phanerozoic and has the longest recovery interval of any extinction event. It has been hypothesised that subsequent carbon isotope perturbations during the Early Triassic are associated with biotic crises that impeded benthic recovery. We test this hypothesis by undertaking the highest-resolution study yet made of the rock and fossil records of the entire Werfen Formation, Italy. Here, we show that elevated extinction rates were recorded not only in the Dienerian, as previously recognised, but also around the Smithian/Spathian boundary. Functional richness increases across the Smithian/Spathian boundary associated with elevated origination rates in the lower Spathian. The taxonomic and functional composition of benthic faunas only recorded two significant changes: (1) reduced heterogeneity in the Dienerian, and (2) and a faunal turnover across the Smithian/Spathian boundary. The elevated extinctions and compositional shifts in the Dienerian and across the Smithian/Spathian boundary are associated with a negative and positive isotope excursion, respectively, which supports the hypothesis that subsequent biotic crises are associated with carbon isotope shifts. The Spathian fauna represents a more advanced ecological state, not recognised in the previous members of the Werfen Formation, with increased habitat differentiation, a shift in the dominant modes of life, appearance of stenohaline taxa and the occupation of the erect and infaunal tiers. In addition to subsequent biotic crises delaying the recovery, therefore, persistent environmental stress limited the ecological complexity of benthic recovery prior to the Spathian. PMID:28296886

Paleozoic–early Mesozoic gold deposits of the Xinjiang Autonomous Region, northwestern China

USGS Publications Warehouse

Rui, Zongyao; Goldfarb, Richard J.; Qiu, Yumin; Zhou, T.; Chen, R.; Pirajno, Franco; Yun, Grace

2002-01-01

The late Paleozoic–early Mesozoic tectonic evolution of Xinjiang Autonomous Region, northwestern China provided a favorable geological setting for the formation of lode gold deposits along the sutures between a number of the major Eastern Asia cratonic blocks. These sutures are now represented by the Altay Shan, Tian Shan, and Kunlun Shan ranges, with the former two separated by the Junggar basin and the latter two by the immense Tarim basin. In northernmost Xinjiang, final growth of the Altaid orogen, southward from the Angara craton, is now recorded in the remote mid- to late Paleozoic Altay Shan. Accreted Early to Middle Devonian oceanic rock sequences contain typically small, precious-metal bearing Fe–Cu–Zn VMS deposits (e.g. Ashele). Orogenic gold deposits are widespread along the major Irtysh (e.g. Duyolanasayi, Saidi, Taerde, Kabenbulake, Akexike, Shaerbulake) and Tuergen–Hongshanzui (e.g. Hongshanzui) fault systems, as well as in structurally displaced terrane slivers of the western Junggar (e.g. Hatu) and eastern Junggar areas. Geological and geochronological constraints indicate a generally Late Carboniferous to Early Permian episode of gold deposition, which was coeval with the final stages of Altaid magmatism and large-scale, right-lateral translation along older terrane-bounding faults. The Tian Shan, an exceptionally gold-rich mountain range to the west in the Central Asian republics, is only beginning to be recognized for its gold potential in Xinjiang. In this easternmost part to the range, northerly- and southerly-directed subduction/accretion of early to mid-Paleozoic and mid- to late Paleozoic oceanic terranes, respectively, to the Precambrian Yili block (central Tian Shan) was associated with 400 to 250 Ma arc magmatism and Carboniferous through Early Permian gold-forming hydrothermal events. The more significant resulting deposits in the terranes of the southern Tian Shan include the Sawayaerdun orogenic deposit along the Kyrgyzstan

Permo-Triassic radiolaria from the Semanggol Formation, northwest Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Jasin, Basir

1997-02-01

A total of 32 species of radiolaria were identified from 20 chert samples at eight localities of the Semanggol Formation in north and south Kedah. Three assemblages of Radiolaria were recognised representing the Early Permian Pseudoalbaillella scalprata m. rhombothoracata. Late Permian Albaillella levis, and Middle Triassic Triassocampe deweveri Assemblage-Zone. The Pseudoalbaillella scalprata m. rhombothoracata Assemblage-Zone is discovered from Bukit Kampung Yoi and Bukit Larek, north Kedah. The Albaillella levis Assemblage-Zone is recorded from Bukit Tok Bertanduk, north Kedah and Merbau Palas, south Kedah. The Triassocampe deweveri Assemblage-Zone is found from the Lanjut Malau area, north Kedah. The radiolarian assemblages indicate that the age of the chert sequence in the Semanggol Formation ranges from Early permian to Middle Triassic.

Sedimentology and petroleum occurrence, Schoolhouse Member, Maroon Formation (Lower Permian), northwestern Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, S.Y.; Schenk, C.J.; Anders, D.L.

The Lower Permian Schoolhouse Member of the Maroon Formation (formerly considered the Schoolhouse Tongue of the Weber Sandstone) forms a partly exhumed petroleum reservoir in the Eagle basin of northwestern Colorado. The Schoolhouse consists mainly of yellowish gray to gray, low-angle to parallel bedded, very fine to fine-grained sandstone of eolian sand-sheet origin; interbedded fluvial deposits are present in most sections. The sand-sheet deposits of the Schoolhouse Member are sedimentologically and petrologically similar to those in the underlying red beds of the main body of the Maroon Formation, and the Schoolhouse is considered the uppermost sand sheet in the Maroonmore » depositional sequence. The bleached and oil-stained Schoolhouse member is distinguished from the underlying Maroon red beds on the basis of its diagenetic history, which is related to regional hydrocarbon migration and development of secondary porosity. Geological and geochemical data suggest that Schoolhouse Member oils have upper Paleozoic sources, including the intrabasinal Belden Formation. 13 figs., 1 tab.« less

Permian single crystal U-Pb zircon age of the Rožňava Formation volcanites (Southern Gemeric Unit, Western Carpathians, Slovakia)

NASA Astrophysics Data System (ADS)

Vozárová, Anna; Šmelko, Miloš; Paderin, Ilya

2009-12-01

Zircon populations from the Rožňava Formation volcanic rock complex have been analysed. Euhedral zircons from the 1st volcanogenic horizon with fine oscillatory growth zoning, typical of magmatic origin, gave the average concordia age of 273.3 ± 2.8 Ma, with Th/U ratios in the range of 0.44-0.73. The Permian ages ranging from 266 to 284 Ma were identified in the wider, zoned or unzoned, central zircon parts, as well as in their fine-zoned oscillatory rims. The average concordia age of 275.3 ± 2.9 was obtained from the euhedral zircon population of the 2nd volcanogenic horizon of the Rožňava Formation. The analyses were performed on zoned magmatic zircons in the age interval from 267 to 287 Ma, with Th/U ratios in the range of 0.39-0.75. In the later zircon population two inherited zircon grains were dated giving the age of 842 ± 12 Ma (Neoproterozoic) and 456 ± 7 Ma (Late Ordovician). The magmatic zircon ages document the Kungurian age of Permian volcanic activity and contemporaneous establishment of the south-Gemeric basin. The time span of volcanic activity corresponds to the collapse of the Western Carpathian Variscan foreland which expanded southward.

Evaluating the temporal link between Siberian Traps magmatism and the end-Permian mass extinction (Invited)

NASA Astrophysics Data System (ADS)

Burgess, S. D.; Bowring, S. A.

2013-12-01

Interest in Large Igneous Provinces as agents for massive climatic and biological change is steadily increasing, though the temporal constraints on both are seldom precise enough to allow detailed testing of a causal relationship. The end-Permian mass extinction is one of the most biologically important and intensely studied events in Earth history and has been linked to many possible trigger mechanisms, from voluminous volcanism to bolide impact. Proposed kill mechanisms range from acidic and/or anoxic oceans to a cocktail of toxic gases, although the link between trigger and kill mechanisms is unconstrained due to the lack of a high-precision timeline. Critical to assessing the plausibility of different trigger and kill mechanisms is an accurate age model for the biotic crisis and the perturbations to the global carbon cycle and ocean chemistry. Recent work using the EARTHTIME U/Pb tracer solution has refined the timing of the onset and duration of the marine mass extinction event and the earliest Triassic recovery at the GSSP for the Permian-Triassic boundary in Meishan, China. This work constrains the mass extinction duration to less than 100 kyr and provides an accurate and precise time point for the onset of extinction, against which the timing of potential trigger mechanisms may be compared. For more than two decades, eruption and emplacement of the Siberian traps has been implicated as a potential trigger of the end-Permian extinction. In this scenario, magmatism drives the biotic crisis through mobilization of volatiles from the sedimentary rock with which intruding and erupting magmas interact. Massive volatile release is believed to trigger major changes in atmospheric chemistry and temperature, both of which have been proposed as kill mechanisms. Current temporal constrains on the timing and duration of the Siberian magmatism are an order of magnitude less precise than those for the mass extinction event and associated environmental perturbations

The late early Miocene Sabine River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manning, E.

Work on a new late early Miocene vertebrate fossil site, in a paleochannel deposit of the upper Carnahan Bayou Member of the lower Fleming Formation, has revealed unexpected data on the course and nature of the Sabine River of that time. Screen washing for smaller vertebrate remains at the site, just west of the Sabine River in Newton County, central eastern Texas, has resulted in the recovery of early Permian, Early Cretaceous, Late Cretaceous (Maestrichtian), Paleocene/Eocene, late Eocene, and Oligocene/Miocene fossils, in addition to the main early Miocene fauna. The reworked fossils, as well as distinctive mineral grains, show thatmore » the late early Miocene Sabine River was connected to the Texas/Oklahoma/Arkansas boundary section of the Red River, as well as to rivers draining the southern Ouachita Mountains. These rivers must have joined the Texas/Louisiana boundary section of the Sabine River somewhere in northwest Louisiana at that time. This suggests that the Louisiana section of the present Red River pirated the Texas/Oklahoma/Arkansas boundary section of the river some time after the early Miocene. The preservation of recognizable fossils transported hundreds of miles in a large river itself requires explanation. It is speculated here that the late early Miocene Sabine River incorporated a large amount of the then recently deposited volcanic ash from the Trans-Pecos Volcanic Field. Montmorillonite clay from the altered volcanic ash would have made the river very turbid, which could have allowed coarse sand-sized particles to be carried in the suspended load of the river, rather than in its bed load (where they would have been destroyed by the rolling chert gravel). Additional evidence for such long-distance fossil transport in the late early Miocene rivers of the western Gulf Coastal Plain comes from the abundant Cretaceous fossils of the upper Oakville Formation of southeast Texas and the Siphonina davisi zone of the southeast Texas subsurface.« less

Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay

PubMed Central

Velozo, Pablo; Meneghel, Melitta; Piñeiro, Graciela

2015-01-01

The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe cranial and postcranial bones from the Permo-Triassic Buena Vista Formation of northeastern Uruguay that contribute to increase the meagre early archosauromorph record from South America. A basioccipital fused to both partial exoccipitals and three cervical vertebrae are assigned to Archosauromorpha based on apomorphies or a unique combination of characters. The archosauromorph remains of the Buena Vista Formation probably represent a multi-taxonomic assemblage composed of non-archosauriform archosauromorphs and a ‘proterosuchid-grade’ animal. This assemblage does not contribute in the discussion of a Late Permian or Early Triassic age for the Buena Vista Formation, but reinforces the broad palaeobiogeographic distribution of ‘proterosuchid grade’ diapsids in Permo-Triassic beds worldwide. PMID:25737816

Occurrence and origin of minerals in a chamosite-bearing coal of Late Permian age, Zhaotong, Yunnan, China

USGS Publications Warehouse

Dai, S.; Chou, C.-L.

2007-01-01

The minerals found in the no.5 coal (Late Permian) from the Zhaotong Coalfield, Yunnan Province, southwestern China, have been examined and found to consist mainly of kaolinite, pyrite, chamosite, quartz, and calcite, with trace amounts of illite and mixed-layer illite-smectite. The proportion of chamosite in clay minerals ranges from 32 to 56 wt%, with an average of 46 wt%. Chamosite is distributed not only in collodetrinite, but also occurs as cell fillings in fusinite, semifusinite, and telinite. The high content and mode of occurrence of chamosite in this mine indicate its formation by interaction of kaolinite with Fe-Mg-rich fluids during early diagenesis. Except for a minor amount of terfigenous quartz, most quartz is of authigenic origin and formed from kaolinite desilication. The calcite content of the no. 5 coal is 1.4-6.3% (with an average of 3%) and is distributed in collodetrinite and as cell fillings of coal-forming plants. Calcite originated from seawater invasion during peat accumulation. Pyrite occurs in several ways: as massive, framboidal, isolated enhedral/ anhedral, and euhedral forms. In addition, the presence of a large amount of pyritized red algae provides strong evidence of seawater invasion during peat accumulation. The red algae may have played an important role in the enrichment of sulfur in the coal. The characteristic assemblage of minerals in this mine resulted from a unique basinal environment in which the mineral matter was derived from a basaltic source region, volcanic activity, and seawater transgression during coal formation.

Late Paleozoic tectonics of the Solonker Zone in the Wuliji area, Inner Mongolia, China: Insights from stratigraphic sequence, chronology, and sandstone geochemistry

NASA Astrophysics Data System (ADS)

Shi, Guanzhong; Song, Guangzeng; Wang, Hua; Huang, Chuanyan; Zhang, Lidong; Tang, Jianrong

2016-09-01

The geology in the Wuliji area (including the Enger Us and Quagan Qulu areas) is important for understanding the Late Paleozoic tectonics of the Solonker Zone. Ultramafic/mafic rocks in the Enger Us area, previously interpreted as an ophiolitic suture, are actually lava flows and sills in a Permian turbiditic sequence and a small body of fault breccia containing serpentinite. Subduction zone features, such as accretionary complexes, magmatic arc volcanics or LP/HP metamorphism are absent. Early Permian N-MORB mafic rocks and Late Permian radiolarian cherts accompanied by turbidites and tuffeous rocks indicate a deep water setting. In the Quagan Qulu area, outcrops of the Late Carboniferous to Permian Amushan Formation are composed of volcano-sedimenary rocks and guyot-like reef limestone along with a Late Permian volcano-sedimentary unit. A dacite lava in the Late Permian volcano-sedimentary unit yields a zircon U-Pb age of 254 Ma. The gabbros in the Quagan Qulu area are intruded into the Amushan Formation and caused contact metamorphism of country rocks. Sandstones in the Upper Member of the Amushan Formation contain detrital clasts of volcanic fragments and mineral clasts of crystalline basement rocks (i.e. biotite, muscovite and garnet). Geochemical analysis of volcaniclastic sandstones shows a magmatic affinity to both continental island arc (CIA) and active continental margin (ACM) tectonic settings. A Late Permian incipient rift setting is suggested by analyzing the lithostratigraphic sequence and related magmatism in the Wuliji area. The volcano-sedimentary rocks in the Wuliji area experienced a nearly N-S shortening that was probably related to the Early Mesozoic nearly N-S compression well developed in other areas close to the Wuliji area.

Magnetic history of Early and Middle Ordovician sedimentary sequence, northern Estonia

NASA Astrophysics Data System (ADS)

Plado, J.; Preeden, U.; Pesonen, L. J.; Mertanen, S.; Puura, V.

2010-01-01

Alternating field and thermal demagnetization of lime- and dolostones from the Lower and Middle Ordovician (Floian to Darriwilian stages) subhorizontally bedded sequences in NW and NE Estonia reveal two characteristic magnetization components (named P and S). The intermediate-coercivity (demagnetized at 30-60 mT, up to 300-350°C) reversed polarity component P (mean of Floian Stage: Dref = 147.8 +/- 10.8°, Iref = 65.8 +/- 5.4° combined mean of Dapingian and Darriwilian stages: Dref = 166.0 +/- 8.4°, Iref = 56.1 +/- 6.5°) is regarded as the primary remanence of early diagenetic (chemical) origin. On the Baltica's apparent polar wander path (APWP), the palaeopoles (Floian: Plat = 25.0°N, Plon = 50.8°E, K = 52.7, A95 = 7.2° Dapingian and Darriwilian: Plat = 11.4°N, Plon = 39.1°E, K = 33.8, A95 = 6.7°) are placed on the Lower and Middle Ordovician segment. The poles indicate that Estonia was located at southerly latitudes, decreasing with time (Floian: ~48°S Dapingian and Darriwilian: ~37°S), when the remanence was acquired. A high-coercivity and high-unblocking-temperature component S (mean of samples: Dref = 33.7 +/- 6.3°, Iref = 51.9 +/- 5.7°) that is regarded as a secondary remanence has both normal and reversed polarities. On the European APWP, its palaeopole (Plat = 52.5°N, Plon = 157.9°E, K = 38.9, A95 = 5.3°) gives middle to late Permian age. According to mineralogical (SEM and optical microscopy) and rock magnetic (three-component induced remnant magnetization) studies, component P is carried by magnetite (coexisting with glauconite) and component S by haematite. Magnetite is of chemical origin, formed in the course of early diagenesis and/or dolomitization. During the Permian continental period haematite, the carrier of component S, was likely precipitated from oxidizing meteoric fluids in the already existing or simultaneously formed pore space between the dolomite crystals.

Tetrapod distribution and temperature rise during the Permian-Triassic mass extinction.

PubMed

Bernardi, Massimo; Petti, Fabio Massimo; Benton, Michael J

2018-01-10

The Permian-Triassic mass extinction (PTME) had an enormous impact on life in three ways: by substantially reducing diversity, by reshuffling the composition of ecosystems and by expelling life from the tropics following episodes of intense global warming. But was there really an 'equatorial tetrapod gap', and how long did it last? Here, we consider both skeletal and footprint data, and find a more complex pattern: (i) tetrapods were distributed both at high and low latitudes during this time; (ii) there was a clear geographic disjunction through the PTME, with tetrapod distribution shifting 10-15° poleward; and (iii) there was a rapid expansion phase across the whole of Pangea following the PTME. These changes are consistent with a model of generalized migration of tetrapods to higher latitudinal, cooler regions, to escape from the superhot equatorial climate in the earliest Triassic, but the effect was shorter in time scale, and not as pronounced as had been proposed. In the recovery phase following the PTME, this episode of forced range expansion also appears to have promoted the emergence and radiation of entirely new groups, such as the archosaurs, including the dinosaurs. © 2018 The Authors.

The Haselgebirge evaporitic mélange in central Northern Calcareous Alps (Austria): Part of the Permian to Lower Triassic rift of the Meliata ocean?

PubMed

Schorn, Anja; Neubauer, Franz; Genser, Johann; Bernroider, Manfred

2013-01-11

For the reconstruction of Alpine tectonics of the Eastern Alps, the evaporitic Permian to Lower Triassic Haselgebirge Formation plays a key role in (1) the origin of Haselgebirge bearing nappes, (2) the inclusion of magmatic and metamorphic rocks revealing tectonic processes not preserved in other units, and (3) the debated mode of emplacement of the nappes, namely gravity-driven or tectonic. Within the Moosegg quarry of the central Northern Calcareous Alps gypsum/anhydrite bodies are tectonically mixed with lenses of sedimentary rocks and decimeter- to meter-sized tectonic clasts of plutonic and subvolcanic rocks and rare metamorphics. We examined various types of (1) widespread biotite-diorite, meta-syenite, (2) meta-dolerite and rare ultramafic rocks (serpentinite, pyroxenite) as well as (3) rare metamorphic banded meta-psammitic schists and meta-doleritic blueschists. The apparent 40 Ar/ 39 Ar biotite ages from three biotite-diorite, meta-dolerite and meta-doleritic blueschist samples with variable composition and fabrics range from 248 to 270 Ma (e.g., 251.2 ± 1.1 Ma) indicating a Permian age of cooling after magma crystallisation or metamorphism. The chemical composition of biotite-diorite and meta-syenite indicates an alkaline trend interpreted to represent a rift-related magmatic suite. These, as well as Permian to Jurassic sedimentary rocks, were incorporated during Cretaceous nappe emplacement forming the sulphatic Haselgebirge mélange. The scattered 40 Ar/ 39 Ar white mica ages of a meta-doleritic blueschist (of N-MORB origin) and banded meta-psammitic schist are ca. 349 and 378 Ma, respectively, proving the Variscan age of pressure-dominated metamorphism. These ages are similar to detrital white mica ages reported from the underlying Rossfeld Formations, indicating a close source-sink relationship. According to our new data, the Haselgebirge bearing nappe was transported over the Lower Cretaceous Rossfeld Formations, which include many clasts

A short review of paleoenvironments for Lower Beaufort (Upper Permian) Karoo sequences from southern to central Africa: A major Gondwana Lacustrine episode

NASA Astrophysics Data System (ADS)

Yemane, K.; Kelts, K.

This paper compares Karoo deposits within the Lower Beaufort (Late Permian) time interval from southern to central Africa. Facies aspects are summarized for selected sequences and depositional environments assessed in connection with the palaeogeography. The comparison shows that thickness of Lower Beaufort sequences varies greatly; sequences are over a kilometre thick at the southern tip, but decrease drastically to the north, northwest and northeast, and is commonly absent from the western part of the subcontinent. Depositional environments are continental except for small estuarine intervals from a sequence in Tanzania. The commonest lithologies comprise mudstones, siltstones, arkoses and carbonates. In spite of the dominance of fluvial facies, the records preserved by intervals of lacustrine sequences suggest that large lakes were major features of the palaeogeography, and that lacustrine environments may have been dominant deposition environments. The Lower Beaufort landscape is generally interpreted as an expansive cratonic lowland with meandering rivers and streams crossing vast floodplains, which were indented by concomitant shallow lakes of various sizes. The lakes from the Karoo tectono-sedimentary terrain were often ephemeral and closely linked with fluvial processes, but large, anoxic lakers are also documented. On the other hand, giant, freshwater lakes, covered large areas of the Zambezian tectono-sedimentary terrain and may have been locally connected. Evidence from abundant freshwater fossil assemblages, particularly from the Zambezian tectono-sedimentary terrain suggest that in spite of the generally semi-arid global climate of the Upper Permian, seasonal precipitation (monsoonal?) supplied enough moisture to sustain large perennial lakes. Because of the unique nature of the Permian cotinental configuration and palaeogeography, however, modern analogues of large systems are lacking. The general lithological and palaeontological correlability of

Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic.

PubMed

Brusatte, Stephen L; Niedźwiedzki, Grzegorz; Butler, Richard J

2011-04-07

The ascent of dinosaurs in the Triassic is an exemplary evolutionary radiation, but the earliest phase of dinosaur history remains poorly understood. Body fossils of close dinosaur relatives are rare, but indicate that the dinosaur stem lineage (Dinosauromorpha) originated by the latest Anisian (ca 242-244 Ma). Here, we report footprints from the Early-Middle Triassic of Poland, stratigraphically well constrained and identified using a conservative synapomorphy-based approach, which shifts the origin of the dinosaur stem lineage back to the Early Olenekian (ca 249-251 Ma), approximately 5-9 Myr earlier than indicated by body fossils, earlier than demonstrated by previous footprint records, and just a few million years after the Permian/Triassic mass extinction (252.3 Ma). Dinosauromorph tracks are rare in all Polish assemblages, suggesting that these animals were minor faunal components. The oldest tracks are quadrupedal, a morphology uncommon among the earliest dinosauromorph body fossils, but bipedality and moderately large body size had arisen by the Early Anisian (ca 246 Ma). Integrating trace fossils and body fossils demonstrates that the rise of dinosaurs was a drawn-out affair, perhaps initiated during recovery from the Permo-Triassic extinction.

An appraisal of the Permian palaeobiodiversity and geology of the Ib-River Basin, eastern coastal area, India

NASA Astrophysics Data System (ADS)

Goswami, Shreerup; Saxena, Anju; Singh, Kamal Jeet; Chandra, Shaila; Cleal, Christopher J.

2018-05-01

The Ib-River Basin situated in the east coastal area of India, in Odisha State is a south-eastern part of the Mahanadi Master Basin. A large number of plant macrofossils belonging to the Glossopteris flora were described and documented between 2006 and 2010 from various localities of the Barakar and Lower Kamthi formations of this basin. The floral components representing leaves, roots and fructifications in these assemblages belong to the Lycopodiales, Equisetales, Sphenophyllales, Filicales, Cordaitales, Cycadales, Ginkgoales, Coniferales and Glossopteridales. In the present study, all the available data pertaining to the biological remains, petrological analyses as well as the geology of this basin are reviewed and analyzed to deduce and reconstruct the biostratigraphy, palaeoclimate, palaeoenvironment and the landscape of this basin during Permian time in general and during the deposition of Barakar (Artinskian - Kungurian) and Lower Kamthi (Lopingian) formations in particular. The floral composition suggests the prevalence of a temperate climate with a slight change from warm moist to warm dry conditions during the deposition of the Barakar Formation and warm and humid during the deposition of Lower Kamthi sediments. Distribution of various plant groups in the Barakar and Lower Kamthi formations have been shown to depict the biodiversity trends. Vegetational reconstructions during the deposition of the Barakar and Lower Kamthi formations around the Ib-River Basin have also been attempted based on all the fossil records from this area. The status of unclassified Barakar and Kamthi formations has been redefined. Apart from megafloristics, the palynology of the basin is also discussed. Possible marine incursions and marine marginal environment in the Ib-Basin during Permian are overtly summarized on the basis of records of acritarchs, typical marine ichnofossils and evidences of wave activity in Lower Gondwana sediments of this Basin.

Late Paleozoic transpression in Buenos Aires and northeast Patagonia ranges, Argentina

NASA Astrophysics Data System (ADS)

Rossello, E. A.; Massabie, A. C.; López-Gamundí, O. R.; Cobbold, P. R.; Gapais, D.

1997-12-01

Paleozoic sediments are present in three regions in eastern central Argentina: (1) the Sierras Australes of Buenos Aires, (2) Sierras Septentrionales of Buenos Aires and (3) Northeast Patagonia. All of these deposits share a common deformational imprint imparted by late Paleozoic Gondwanan deformation. Exposures of these rocks are scattered, variably deformed, and isolated by younger sediments deposited in basins related to the Mesozoic through Tertiary opening of the South Atlantic such as the offshore Colorado Basin. The Sierras Australes of Buenos Aires outcrops are the best preserved. They are mostly located along the Sierras Australes foldbelt, with minor outliers distributed in the adjacent Claromec-basin. The Tunas Formation (early-early late? Permian) is the uppermost unit of the Pillahuincó Group (late Carboniferous-Permian) and is crucial to the understanding of the tectono-sedimentary evolution of the region during the late Paleozoic. The underlying units of the Pillahuincó Group (Sauce Grande, Piedra Azul and Bonete Formations) exhibit a depositional and compositional history characterized by glaciomarine sedimentation and postglacial transgression. They are also characterized by rather uniform quartz-rich compositions indicative of a cratonic provenance from the La Plata craton to the NE. In contrast, the sandstone-rich Tunas Formation has low quartz contents, and abundant volcanic and metasedimentary fragments; paleocurrents are consistently from the SW. Glassrich tuffs are interbedded with sandstone in the upper half of the Tunas Formation. The age of the deformation in the Sierras Australes is Permian and early-middle Triassic. This is based on metamorphic events indicated by formation of illite at 282 ± 3 Ma, 273 ± 8 Ma, 265 ± 3 Ma, and 260 ± 3 Ma ( {K}/{Ar} illite) in the Silurian Curamalal Group. Evidence of syntectonic magmatism is provided by a radiometric date of 245 ± 12 Ma ( {K}/{Ar} hornblende) for the López Lecube Granite

Source, evolution and emplacement of Permian Tarim Basalts: Evidence from U-Pb dating, Sr-Nd-Pb-Hf isotope systematics and whole rock geochemistry of basalts from the Keping area, Xinjiang Uygur Autonomous region, northwest China

NASA Astrophysics Data System (ADS)

Zhang, Dayu; Zhou, Taofa; Yuan, Feng; Jowitt, Simon M.; Fan, Yu; Liu, Shuai

2012-04-01

Permian basalts distribute at least 250,000 km2, and underlie the southwest Tarim Basin in Xinjiang Uygur Autonomous region, northwest China. This vast accumulation of basalt is the main part of the Tarim Large Igneous Province (LIP). The basaltic units in the Lower Permian Kupukuziman and Kaipaizileike Formations in the Keping area, Tarim Basin; were the best exposure of the Permian basalt sequence in the basin. LA-ICP-MS U-Pb dating of zircon from the basal basaltic unit in the section gives an age of 291.9 ± 2.2 Ma (MSWD = 0.30, n = 17); this age, combined with previously published geochronological data, indicates that the basalts in the Tarim Basin were emplaced between 292 Ma and 272 Ma, with about 90% of the basalts being emplaced between 292 and 287 Ma. Basalts from the Keping area have high FeOT (10.8-18.6 wt.%), low Mg#s (0.26-0.60), and exhibit primitive mantle normalized patterns with positive Pb, P and Ti but negative Zr, Y and Ta anomalies. The basalts from both formations have similar 206Pb/204Pb (18.192-18.934), 207Pb/204Pb (15.555-15.598) and 208Pb/204Pb (38.643-38.793) ratios. The basalts also have high ɛSr(t) (45.7-62.1), low ɛNd(t) (-3.6 to -2.2) and low zircon ɛHf(t) (-4.84 to -0.65) values. These characteristics are typical of alkali basalts and suggest that the basalts within the Tarim Basin were derived from an OIB-type mantle source and interacted with enriched mantle (EMI-type) before emplacement. Rare earth element systematics indicate that the parental melts for the basalts were high-degree partial melts derived from garnet lherzolite mantle at the base of the lithosphere. Prior to emplacement, the Tarim Permian Basalts (TPB) underwent fractional crystallization and assimilated crustal material; the basalts were finally emplaced during crustal extension in an intra-plate setting. The wide distribution, deep source and high degree partial melting of the TPB was consistent with a mantle plume origin. The TPB and other coeval igneous

Complete tylosis formation in a latest Permian conifer stem

PubMed Central

Feng, Zhuo; Wang, Jun; Rößler, Ronny; Kerp, Hans; Wei, Hai-Bo

2013-01-01

Background and Aims Our knowledge of tylosis formation is mainly based on observations of extant plants; however, its developmental and functional significance are less well understood in fossil plants. This study, for the first time, describes a complete tylosis formation in a fossil woody conifer and discusses its ecophysiological implications. Methods The permineralized stem of Shenoxylon mirabile was collected from the upper Permian (Changhsingian) Sunjiagou Formation of Shitanjing coalfield, northern China. Samples from different portions of the stem were prepared by using the standard thin-sectioning technique and studied in transmitted light. Key Results The outgrowth of ray parenchyma cells protruded into adjacent tracheids through pits initially forming small pyriform or balloon-shaped structures, which became globular or slightly elongated when they reached their maximum size. The tracheid luminae were gradually occluded by densely spaced tyloses. The host tracheids are arranged in distinct concentric zones representing different growth phases of tylosis formation within a single growth ring. Conclusions The extensive development of tyloses from the innermost heartwood (metaxylem) tracheids to the outermost sapwood tracheids suggests that the plant was highly vulnerable and reacted strongly to environmental stress. Based on the evidence available, the tyloses were probably not produced in response to wound reaction or pathogenic infection, since evidence of wood traumatic events or fungal invasion are not recognizable. Rather, they may represent an ecophysiological response to the constant environmental stimuli. PMID:23532049

Fullerenes and interplanetary dust at the Permian-Triassic boundary.

PubMed

Poreda, Robert J; Becker, Luann

2003-01-01

We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich magnetic carrier phase in three fractions from the Graphite Peak section. The noble gases in this magnetic fraction were similar to zero-age deep-sea interplanetary dust particles (IDPs) and some magnetic grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated magnetic fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene).

Mesogondolella and Jinogondolella (Conodonta): Multielement definition of the taxa that bracket the basal Guadalupian (Middle Permian Series) GSSP

USGS Publications Warehouse

Lambert, L.L.; Wardlaw, B.R.; Henderson, C.M.

2007-01-01

Multielement definitions are presented here for Mesogondolella and Jinogondolella based on species that bracket the basal Guadalupian (Middle Permian Series) GSSP. Distinctive apparatus characters that appear with the first Jinogondolella include several details of P2 element dimorphism and process bifurcation in S3 elements. The sequential expression of these multielement characters is traced through M. idahoensis, M. lamberti, and J. nankingensis. The resulting multielement definition of Jinogondolella serves to distinguish it from all other closely related genera. Mesogondolella lamberti is recognized as a distinct species, and J. serrata is formally designated a junior synonym of J. nankingensis. ?? 2007 Nanjing Institute of Geology and Palaeontology, CAS.

Dynamique sédimentaire comparative dans les bassins stéphano-permiens des Ida Ou Zal et Ida Ou Ziki, haut Atlas Occidental, MarocDynamic sedimentology of two Upper Stephano-Lower Permian basins: Ida Ou Zal and Ida Ou Ziki, western High Atlas, Morocco

NASA Astrophysics Data System (ADS)

Saber, H.; El-Wartiti, M.; Broutin, J.

2001-05-01

The intra-mountainous Ida Ou Zal Basin developed as a graben during the Stephanian (Carboniferous) and Lower Permian. Along its borders from east to west are the remnants of basal conglomerates. Passing laterally towards the centre of the basin are fine-grained fluvial-lacustrine sediments or flood-plain deposits. The important accumulation (1800 m) of sediments, associated with climatic and tectonic changes, caused substantial subsidence in a late orogenic setting. The remnants of sporadic volcanic products (shards) found in the Ida Ou Zal and the Ida Ou Zika Basins suggest nearby simultaneous magmatic activity. A comparison between the basins of Ida Ou Zal and Ida Ou Ziki suggest that the two basins formed a single unit, called the Souss Basin, ultimately terminated between the Lower Permian and Upper Permian times by a sinistral movement of the N70-80° Agadir Ou Anzizen Fault (west branch of the Tizi N'Test Fault) at the very end of the Hercynian Orogeny in Morocco.

Salinity changes and anoxia resulting from enhanced run-off during the late Permian global warming and mass extinction event

NASA Astrophysics Data System (ADS)

van Soelen, Elsbeth E.; Twitchett, Richard J.; Kürschner, Wolfram M.

2018-04-01

The late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focuses on one of the stratigraphically most expanded Permian-Triassic records known, from Jameson Land, East Greenland. High-resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The start of the extinction event, here defined by a peak in spore : pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 and 8 kyr, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced run-off and increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more nearshore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be

Populational fluctuation and spatial distribution of Alphitobius diaperinus (Panzer) (Coleoptera; Tenebrionidae) in a poultry house, Cascavel, Parana state, Brazil.

PubMed

Chernaki-Leffer, A M; Almeida, L M; Sosa-Gómez, D R; Anjos, A; Vogado, K M

2007-05-01

Knowledge of the population fluctuation and spatial distribution of pests is fundamental for establishing an appropriate control method. The population fluctuation and spatial distribution of the Alphitobius diaperinus in a poultry house in Cascavel, in the state of Parana, Brazil, was studied between October, 2001 and October 2002. Larvae and adults of the lesser mealworm were sampled weekly using Arends tube traps (n = 22) for six consecutive flock grow-outs. The temperature of the litter and of the poultry house was measured at the same locations of the tube traps. Beetle numbers increased continuously throughout all the sampling dates (average 5,137 in the first week and 18,494 insects on the sixth week). Significantly greater numbers of larvae were collected than adults (1 to 20 times in 95% of the sampling points). There was no correlation between temperature and the number of larvae and adults collected, therefore no fluctuation was observed during the sampling period. The population growth was correlated to litter re-use. The highest temperatures were observed in deep litter. The spatial distribution of larvae and adults in the poultry house was heterogeneous during the whole period of evaluation. Results suggest that monitoring in poultry houses is necessary prior to adopting and evaluating control measures due to the great variability of the insect distribution in the poultry house.

The Jurassic-early Cretaceous Ilo batholith of southern coastal Peru: geology, geochronology and geochemistry

NASA Astrophysics Data System (ADS)

Boekhout, Flora; Sempere, Thierry; Spikings, Richard; Schaltegger, Urs

2010-05-01

The Ilo batholith (17°00 - 18°30 S) crops out in an area of about 20 by 100 km, along the coast of southern Peru. This batholith is emplaced into the ‘Chocolate‘ Formation of late Permian to middle Jurassic age, which consists of more than 1000 m of basaltic and andesitic lavas, with interbedded volcanic agglomerates and breccias. The Ilo Batholith is considered to be a rarely exposed fragment of the Jurassic arc in Peru. Our aim is to reconstruct the magmatic evolution of this batholith, and place it within the context of long-lasting magma genesis along the active Andean margin since the Paleozoic. Sampling for dating and geochemical analyses was carried out along several cross sections through the batholith that were exposed by post-intrusion eastward tilting of 20-30°. Sparse previous work postulates early to middle Jurassic and partially early Cretaceous emplacement, on the basis of conventional K/Ar and 40Ar/39Ar dating methods in the Ilo area. Twenty new U-Pb zircon ages (LA-ICP-MS and CA-ID-TIMS) accompanied by geochemical data suggests the Ilo batholith formed via the amalgamation of middle Jurassic and early Cretaceous, subduction-related plutons. Preliminary Hf isotope studies reveal a primitive mantle source for middle Jurassic intrusions. Additional Sr, Nd and Hf isotope analyses are planned to further resolve the source regions of different pulses of plutonic activity. We strongly suggest that batholith emplacement was at least partly coeval with the emplacement of the late Permian to middle Jurassic Chocolate Formation, which was deposited in an extensional tectonic regime. Our age results and geochemical signature fit into the scheme of episodic emplacement of huge amounts of subduction related magmatism that is observed throughout the whole Andean event, particularly during the middle Jurassic onset of the first Andean cycle (southern Peru, northern Chile and southern Argentina). Although the exact geodynamic setting remains to be precisely

Magnetostratigraphic correlations of Permian-Triassic marine-to-terrestrial sections from China

USGS Publications Warehouse

Glen, J.M.G.; Nomade, S.; Lyons, J.J.; Metcalfe, I.; Mundil, R.; Renne, P.R.

2009-01-01

We have studied three Permian–Triassic (PT) localities from China as part of a combined magnetostratigraphic, 40Ar/39Ar and U–Pb radioisotopic, and biostratigraphic study aimed at resolving the temporal relations between terrestrial and marine records across the Permo-Triassic boundary, as well as the rate of the biotic recovery in the Early Triassic. The studied sections from Shangsi (Sichuan Province), Langdai (Guihzou Province), and the Junggar basin (Xinjiang Province), span marine, paralic, and terrestrial PT environments, respectively. Each of these sections was logged in detail in order to place geochronologic, paleomagnetic, geochemical, conodont and palynologic samples within a common stratigraphic context. Here we present rock-magnetic, paleomagnetic and magnetostratigraphic results from the three localities.At Shangsi, northern Sichuan Province, we sampled three sections spanning Permo-Triassic marine carbonates. Magnetostratigraphic results from the three sections indicate that the composite section contains at least eight polarity chrons and that the PT boundary occurs within a normal polarity chron a short distance above the mass extinction level and a reversed-to-normal (R-N) polarity reversal. Furthermore, the onset of the Illawarra mixed interval lies below the sampled section indicating that the uppermost Permian Changhsingian and at least part of the Wuchiapingian stages postdate the end of the Kiaman Permo-Carboniferous Reversed Superchron.At Langdai, Guizhou Province, we studied magnetostratigraphy of PT paralic mudstone and carbonate sediments in two sections. The composite section spans an R-N polarity sequence. Section-mean directions pass a fold test at the 95% confidence level, and the section-mean poles are close to the mean PT pole for the South China block. Based on biostratigraphic constraints, the R-N transition recorded at Langdai is consistent with that at Shangsi and demonstrates that the PT boundary occurred within a normal

Facies mosaic in a fiord: Carboniferous-Permian Talchir Formation, India

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bose, P.K.; Mukhopadhyay, G.; Bhattacharya, H.N.

1988-01-01

Facies analysis of the basal 37m of the Carboniferous-Permian Talchir Formation is a glacier-fed bedrock trough in Dudhi nala, Bihar, India, provides insight into the pattern of sedimentation of course gravels in a fiord. Rapid transitions between 11 recognized facies, together with their complex organization, random variability in bed thickness, and differences in clast, shape, size, and composition indicate coalescence of fans developed from numerous point sources bordering the elongated trough. Converging slide masses and lodgment tillites on the slopes flanking the trough give way to sediment gravity flow deposits composed of an array of conglomerates (matrix and clast supportedmore » with normal, inverse of absence of grading), attendant turbidite sands, and prodelta mud. The rheology of the in-trough flows ranged from plastic laminar to fluidal turbulent in response to flow from slope to floor of the trough. Rapid calving of icebergs during the onset of deglaciation established a wave regime at the mouth of the trough and deposited cross-stratified sandstone replete with dripstones. The impact of large dripstones landing triggered turbidity currents. Continued rise in water level led to eventual preservation of the fan complex under onlapping wave-built shoal facies that grade into a sequence of upward-thinning hummocky cross-stratified sandstone beds virtually devoid of dripstones.« less

The Timan-Pechora Basin province of northwest Arctic Russia; Domanik, Paleozoic total petroleum system

USGS Publications Warehouse

Lindquist, Sandra J.

1999-01-01

The Domanik-Paleozoic oil-prone total petroleum system covers most of the Timan-Pechora Basin Province of northwestern Arctic Russia. It contains nearly 20 BBOE ultimate recoverable reserves (66% oil). West of the province is the early Precambrian Eastern European craton margin. The province itself was the site of periodic Paleozoic tectonic events, culminating with the Hercynian Uralian orogeny along its eastern border. The stratigraphic record is dominated by Paleozoic platform and shelf-edge carbonates succeeded by Upper Permian to Triassic molasse siliciclastics that are locally present in depressions. Upper Devonian (Frasnian), deep marine shale and limestone source rocks ? with typically 5 wt % total organic carbon ? by middle Mesozoic time had generated hydrocarbons that migrated into reservoirs ranging in age from Ordovician to Triassic but most focused in Devonian and Permian rocks. Carboniferous structural inversions of old aulacogen borders, and Hercynian (Permian) to Early Cimmerian (Late Triassic to Early Jurassic) orogenic compression not only impacted depositional patterns, but also created and subsequently modified numerous structural traps within the province.

Environmental risk assessment in five rivers of Parana River basin, Southern Brazil, through biomarkers in Astyanax spp.

PubMed

Barros, Ivaldete Tijolin; Ceccon, Juliana Parolin; Glinski, Andressa; Liebel, Samuel; Grötzner, Sonia Regina; Randi, Marco Antonio Ferreira; Benedito, Evanilde; Ortolani-Machado, Claudia Feijó; Filipak Neto, Francisco; de Oliveira Ribeiro, Ciro Alberto

2017-07-01

In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set of biomarkers in fish Astyanax spp. Population growth and inadequate use of land are challenges to the preservation of biodiversity and resources such as water. Some physicochemical parameters as well as somatic indexes, gills and liver histopathology, genotoxicity, and biochemical biomarkers were evaluated. The highest gonadosomatic index (GSI) and antioxidant parameters (catalase and glutathione S-transferase activities, non-protein thiols), as well as the lowest damage to biomolecules (lipid peroxidation, protein carbonylation, DNA damage) were observed in site 0 (Piava River), which is located at an environmental protected area. Site 1, located in the same river, but downstream site 0 and outside the protection area, presents some level of impact. Fish from site 2 (Antas River), which lack of riparian forest and suffer from silting, presented the highest micronucleus incidence and no melanomacrophages. Differently, individuals from site 3 (Xambrê River) and site 4 (Pinhalzinho River) which receive surface runoff from Umuarama city, urban and industrial sewage, have the highest incidences of liver and gill histopathological alterations, including neoplasia, which indicated the worst health conditions of all sites. In particular, site 4 had high levels of total nitrogen and ammonia, high turbidity, and very low oxygen levels, which indicate important chemical impact. Comparison of the biomarkers in fish allowed classification of the five sites in terms of environmental impact and revealed that sites 3 and 4 had particular poor water quality.

Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis

USGS Publications Warehouse

Lewan, M.D.; Kotarba, M.J.; Wieclaw, D.; Piestrzynski, A.

2008-01-01

Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977–984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations. Although experiments have been conducted to test the metal-catalysis hypothesis, their approach and results remain equivocal in evaluating natural assemblages of transition metals and organic matter in shale. The Permian Kupferschiefer of Poland offers an excellent opportunity to test the hypothesis with immature to marginally mature shale rich in both transition metals and organic matter. Twelve subsurface samples containing similar Type-II kerogen with different amounts and types of transition metals were subjected to hydrous pyrolysis at 330° and 355 °C for 72 h. The gases generated in these experiments were quantitatively collected and analyzed for molecular composition and stable isotopes. Expelled immiscible oils, reacted waters, and spent rock were also quantitatively collected. The results show that transition metals have no effect on methane yields or enrichment. δ13C values of generated methane, ethane, propane and butanes show no systematic changes with increasing transition metals. The potential for transition metals to enhance gas generation and oil cracking was examined by looking at the ratio of the generated hydrocarbon gases to generated expelled immiscible oil (i.e., GOR), which showed no systematic change with increasing transition metals. Assuming maximum yields at 355 °C for 72 h and first-order reaction rates, pseudo-rate constants for methane generation at 330 °C were calculated. These rate constants showed no increase with increasing transition metals. The lack of a significant catalytic effect of transition metals on the extent, composition, and timing of

Depositional evolution of permo-triassic karoo basins in Tanzania with reference to their economic potential

NASA Astrophysics Data System (ADS)

Kreuser, T.; Wopfner, H.; Kaaya, C. Z.; Markwort, S.; Semkiwa, P. M.; Aslandis, P.

The Karoo basins of Tanzania contain in excess of 3000 m of sediments which were preserved in several NNE-NE striking half grabens or other structural basin conditions. They are all intracratonic basins, most of which filled with terrestrial sediments. In some basins situated nearer the coastal region short marine incursions occurred in the Late Permian. The Ruhuhu Rasin in SW Tanzania provides a typical depositional sequence of a Karoo basin in eastern Africa. Sedimentation commenced with glacigene deposits. These are of Late Carboniferous to Early Permian age and may be equated with other glacial successions in Africa and elsewhere in Gondwana. The glacigene beds are overlain by fluvial-deltaic coal-bearing deposits succeeded by arkoses and continental red beds. A transitionary formation of carbonaceous shales with impure coals gradually develops into thick lacustrine series which are topped by Late Permian bone bearing beds. The Triassic is characterized by a very thick fluvio-deltaic succession of siliciclastics resting with regional unconformity on the Permian. This Early Triassic sequence exhibits well-developed repetitive depositional cycles. Current azimuth measurements indicate fluctuating flow regimes in the Early Permian but relative stable source areas to the west of the basin later on. The depositional evolution of the Ruhuhu Basin is controlled by both tectonic and climatic factors. During basin evolution important energy resources were deposited such as considerable reserves of coal and source rocks of moderate potential for hydrocarbon generation. Uranium enrichment is observed in the Triassic arenaceous series where diagenetic alterations and subsequent cementation processes led to the formation of laumontite. Post Karoo dykes and plugs had only local effect on thermal evolution of potential source rocks. Enrichments of elements, i.e., Nb, Zr, Rb, Cr, and V present additional exploration targets. A comparison with the Karoo basins of the coastal

Floral responses to the Late Paleozoic deglaciation

NASA Astrophysics Data System (ADS)

Looy, C. V.; DiMichele, W. A.

2011-12-01

The current human-induced thawing of ice house Earth prompts the careful examination of similar earlier events and their biotic consequences. The most recent full transition from a cool earth to a warm world took place in the Early to Middle Permian. Against a background of global warming, plant communities were affected globally resulting in migrations, extinctions and changed evolutionary patterns as a response to the environmental changes. The collapse of the southern hemisphere ice-sheets resulted in significant changes, not just at higher latitudes, but also in the tropics where the rainfall regime changed from seasonally dry to seasonally wet. In the Early Permian tropics - in areas where net sedimentation facilitates fossilization, to be more specific - vegetation rich in walchian conifers began to replace the spore plants and seed ferns that previously dominated the Late Pennsylvanian wetlands. The replacing drier floras probably lived in the basinal lowlands as well, but episodically at the drier times of climate cycles. New finds within the tropics of latest Early to Middle Permian-age, in particular from north-central Texas, indicate the existence of floras which were adapted to even more extended periods of drought. These were populated by the more derived voltzian conifers and other seed plants, such as cycads. Surprisingly, the clades in these floras were until recently only known from the tens-of-millions-of-years younger Late Permian and Early Mesozoic, where they were the dominant forms. These occurrences demonstrate that even more derived groups were already in existence and well differentiated by the Early Permian, outside the window of preservation. This pattern of change in conifers and their communities from north-central Texas is unique in that it represents the best documented record in the Phanerozoic of terrestrial ecosystem response to a change from a global cool-mode to warm-mode Earth. Conifers serve as "marker plants" for the

New absolute paleointensity determinations for the Permian-Triassic boundary from the Kuznetsk Trap Basalts.

NASA Astrophysics Data System (ADS)

Kulakov, E.; Metelkin, D. V.; Kazansky, A.

2015-12-01

We report the results of a pilot absolute paleointensity study of the ~250 Ma basalts of Kuznetsk traps (Kuznetsk Basin, Altai-Sayan folded area). Studied samples are characterized by a reversed polarity of natural remanent magnetization that corresponds to the lower part of Siberian Trap basalts sequence. Geochemical similarity of Kuznets basalts with those from Norilsk region supports this interpretation. Primary origin of thermal remanence in our sample is confirmed by a positive backed contact test. Rock magnetic analyses indicate that the ChRM is carried by single-domain titanomagnetite. The Coe-version of the Thellier-Therllier double-heating method was utilized for the paleointensity determinations. In contrast to the previous studies of the Permian-Triassic Siberian trap basalts, our data indicate that by the P-T boundary the paleofield intensity was relatively high and comparable with geomagnetic field strength for the last 10 millions of years. New results question the duration of the "Mesozoic dipole-low".

Section of Permian deposits and fusulinids in the Halvan Mountains, Yazd province, Central Iran

NASA Astrophysics Data System (ADS)

Leven, E. Ya.; Gorgij, M. N.

2009-04-01

The Permian section situated northwest of Tabas in the Halvan Mountains is studied and fusulinids occurring in the section are described. The Chili, Sartakht, and Hermez formations distinguished in the section are separated by horizons of bauxitic laterite and belong to the Khan Group formerly ranked as a synonymous formation. Fusulinids occur at two levels in the section. The lower one confined to the Chili Formation yields the so-called Kalaktash fusulinid assemblage of the late Sakmarian age. The second late Asselian assemblage has been discovered in pebbles from conglomerate-breccia in the basal laterite of the Sartakht Formation. A brief characterization of fusulinids is presented and three new species are described. The new Benshiella genus is discriminated from the Rugosofusulinidae family. As Skinner and Wilde (1965, 1966) changed the original diagnosis of the Pseudofusulina genus, we suggest, regarding all species, which have been attributed to this genus but do not satisfy the new diagnosis, as representing the new Nonpseudofusulina genus.

Flourishing ocean drives the end-Permian marine mass extinction

PubMed Central

Schobben, Martin; Stebbins, Alan; Ghaderi, Abbas; Strauss, Harald; Korn, Dieter; Korte, Christoph

2015-01-01

The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian−Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth’s history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness. PMID:26240323

Origin of the Permian-Triassic komatiites, northwestern Vietnam

NASA Astrophysics Data System (ADS)

Hanski, Eero; Walker, Richard J.; Huhma, Hannu; Polyakov, Gleb V.; Balykin, Pavel A.; Tran Trong Hoa; Ngo Thi Phuong

Rare examples of Phanerozoic komatiites are found in the Song Da zone, NW Vietnam. These komatiites were erupted through continental crust and may belong to the SE extension of the Permo-Triassic Emeishan volcanic province located in SW China. They provide a good opportunity to study the source characteristics of starting plume magmas in a continental flood basalt province. Erupted on late-Permian carbonate rocks, the komatiitic rocks are interbedded with low-Ti olivine basalts. Basaltic komatiites display pyroxene spinifex textures, while more magnesian rocks (MgO up to 32 wt.%) are porphyritic, containing a single, cognate population of euhedral to elongated olivine phenocrysts with Fo up to 93.0%. This suggests a highly magnesian parental magma with 22-23 wt.% MgO. In terms of major and minor elements, the komatiites are similar to the ca. 89 Ma old Gorgona Island komatiites of Colombia. The Song Da komatiites are also strongly light-rare-earth-element- (LREE) depleted (CeN/YbN 0.30-0.62) and have unfractionated heavy rare earth element (HREE) patterns. The komatiites have high Os concentrations (up to 7.0 ppb), low but variable Re/Os ratios, and define an isochron with an age of 270+/-21 Ma, and an initial 188Os/187Os ratio of 0.12506+/- 0.00041 (γOs=+0.02+/-0.40). The Os isotopic systematics of the komatiites show no effects of crustal contamination. In contrast, their initial ɛNd values range from +3 to +8, reflecting varying but generally small degrees of contamination with Proterozoic sialic basement material. Associated low-Ti basalts have low initial ɛNd values (-0.8 to -7.5), high initial γOs values (>=15), flat or LREE-enriched REE patterns, and Nb-Ta depletion. These characteristics are also attributed to variable extents of crustal contamination.

Geochemical Variability and the Potential for Beneficial Use of Waste Water Coproduced with Oil from Permian Basin of the Southwest USA

NASA Astrophysics Data System (ADS)

Khan, N. A.; Holguin, F. O.; Xu, P.; Engle, M.; Dungan, B.; Hunter, B.; Carroll, K. C.

2014-12-01

The U.S. generates 21 billion barrels/year of coproduced water from oil and gas exploration, which is generally considered waste water. Growth in unconventional oil and gas production has spurred interest in beneficial uses of produced water, especially in arid regions such as the Permian Basin of Texas and New Mexico, the largest U.S. tight oil producer. Produced waters have variable chemistries, but generally contain high levels of organics and salts. In order to evaluate the environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of produced water. In the present study, produced water samples were collected from 12 wells across the Permian Basin. Compositional analyses including coupled gas chromatography-time of flight-mass spectrometry and inductively coupled plasma-optical emission spectroscopy were conducted. The samples show elevated benzene, ethylbenzene, toluene, xylene, alkyl benzenes, propyl-benzene, and naphthalene compared to other heteroaromatics; they also contain complex hydrocarbon compounds containing oxygen, nitrogen, and sulfur. Van Krevelen diagrams show an increase in the concentration of heteroaromatic hydrocarbons with increasing well depth. The salinity, dominated by sodium-chloride, also increases with depth, ranging from 37-150 g/L TDS. Depth of wells (or producing formation) is a primary control on predicting water quality for treatment and beneficial use. Our results suggest that partial treatment by removing suspended solids and organic contaminants would support some beneficial uses such as onsite reuse, bioenergy production, and other industrial uses. Due to the high salinity, conventional desalination processes are not applicable or very costly, making beneficial uses requiring low salinity not feasible.

Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

USGS Publications Warehouse

Piper, D.Z.; Perkins, R.B.; Rowe, H.D.

2007-01-01

The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000 km2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al2O3 suggest two sources-seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea as O2-depleted, denitrifying (suboxic) most of the time, and seldom sulfate-reducing (anoxic). This interpretation is supported by earlier research that showed progressively greater ratios in the marine sediment fraction of Cr:Ni>V:Ni???Mo:Ni, relative to their ratios in seawater; for which marine Cr, V, and Mo can have a dominantly O2-depleted bottom-water source and Ni a photic-zone, largely algal, source. The water chemistry was maintained by a balance between bacterial oxidation of organic matter settling through the water column, determined largely by primary productivity in the photic zone, and the flux of oxidants into the bottom water via advection of seawater from the open ocean. Samples strongly enriched in carbonate fluorapatite, the dominant REE host mineral, have variable Er/Sm, Tm/Sm, and Yb/Sm ratios. Their distribution may represent greater advection of seawater between the Phosphoria Sea and open ocean during deposition of two ore zones than a center waste and greater upwelling of nutrient-enriched water into the photic zone. However, the mean rate of deposition of marine Ni, a trace nutrient of algae, and PO43-, a limiting nutrient, indicate that primary productivity was probably high throughout the depositional history. An alternative interpretation of the variable enrichments of Er, Tm, and Yb, relative to Sm, is that they may reflect temporally variable carbonate alkalinity of open-ocean seawater in Permian time. A more strongly negative Ce anomaly for all phosphatic units than the Ce anomaly of modern pelletal phosphate is

Rare-earth elements in the Permian Phosphoria Formation: Paleo proxies of ocean geochemistry

NASA Astrophysics Data System (ADS)

Piper, D. Z.; Perkins, R. B.; Rowe, H. D.

2007-06-01

The geochemistry of deposition of the Meade Peak Member of the Phosphoria Formation (MPM) in southeast Idaho, USA, a world-class sedimentary phosphate deposit of Permian age that extends over 300,000 km 2, is ascertained from its rare earth element (REE) composition. Ratios of REE:Al 2O 3 suggest two sources—seawater and terrigenous debris. The seawater-derived marine fraction identifies bottom water in the Phosphoria Sea as O 2-depleted, denitrifying (suboxic) most of the time, and seldom sulfate-reducing (anoxic). This interpretation is supported by earlier research that showed progressively greater ratios in the marine sediment fraction of Cr:Ni>V:Ni≫Mo:Ni, relative to their ratios in seawater; for which marine Cr, V, and Mo can have a dominantly O 2-depleted bottom-water source and Ni a photic-zone, largely algal, source. The water chemistry was maintained by a balance between bacterial oxidation of organic matter settling through the water column, determined largely by primary productivity in the photic zone, and the flux of oxidants into the bottom water via advection of seawater from the open ocean. Samples strongly enriched in carbonate fluorapatite, the dominant REE host mineral, have variable Er/Sm, Tm/Sm, and Yb/Sm ratios. Their distribution may represent greater advection of seawater between the Phosphoria Sea and open ocean during deposition of two ore zones than a center waste and greater upwelling of nutrient-enriched water into the photic zone. However, the mean rate of deposition of marine Ni, a trace nutrient of algae, and PO 43-, a limiting nutrient, indicate that primary productivity was probably high throughout the depositional history. An alternative interpretation of the variable enrichments of Er, Tm, and Yb, relative to Sm, is that they may reflect temporally variable carbonate alkalinity of open-ocean seawater in Permian time. A more strongly negative Ce anomaly for all phosphatic units than the Ce anomaly of modern pelletal phosphate

Biostratigraphic reappraisal of the Lower Triassic Sanga do Cabral Supersequence from South America, with a description of new material attributable to the parareptile genus Procolophon

NASA Astrophysics Data System (ADS)

Dias-da-Silva, Sérgio; Pinheiro, Felipe L.; Stock Da-Rosa, Átila Augusto; Martinelli, Agustín G.; Schultz, Cesar L.; Silva-Neves, Eduardo; Modesto, Sean P.

2017-11-01

The Sanga do Cabral Supersequence (SCS), comprises the Brazilian Sanga do Cabral Formation (SCF) and the Uruguayan Buena Vista Formation (BVF). So far, the SCS has yielded temnospondyls, parareptiles, archosauromorphs, putative synapsids, and a number of indeterminate specimens. In the absence of absolute dates for these rocks, a biostratigraphic approach is necessary to establish the ages of the SCF and the BVF. It is well established that the SCF is Early Triassic mainly due to the presence of the widespread Gondwanan reptile Procolophon trigoniceps. Conversely, the age of the BVF is subject of great controversy, being regarded alternatively as Permian, Permo-Triassic, and Early Triassic. The BVF has yielded the definite procolophonid Pintosaurus magnidentis. Procolophonoidea is one of the most diverse and conspicuous terrestrial tetrapod groups of the Lower Triassic Lystrosaurus Assemblage Zone in the Karoo Basin of South Africa, which preserves tetrapods from the aftermath of the end-Permian extinction event. Based on a previous interpretation that the fauna of the BVF is Permian, and in the reinterpretation of disarticulated vertebrae from SCF with 'swollen' neural arches as belonging to either seymouriamorphs or diadectomorphs, it was recently suggested that at least part of the SCF is Permian in age, which prompted this comprehensive reevaluation of both SCS's faunal content and geology. Moreoever, new, strikingly large procolophonid specimens (skull, vertebra, and a mandibular fragment) from the SCF are described and referred to the genus Procolophon. The large procolophonid vertebra described here contradicts the recent hypothesis that similar specimens from the SCF belong to seymouriamorphs or diadectomorphs, because its morphology is consistent with that found in Procolophon. There is not a single diagnostic specimen that supports the inference of Permian levels in the SCS. Accordingly, because all diagnostic and biostratigraphically informative fossils

Origin of Permian OIB-like basalts in NW Thailand and implication on the Paleotethyan Ocean

NASA Astrophysics Data System (ADS)

Wang, Yuejun; He, Huiying; Zhang, Yuzhi; Srithai, Boontarika; Feng, Qinglai; Cawood, Peter A.; Fan, Weiming

2017-03-01

The basaltic rocks in NW Thailand belong to part of giant Southeast Asian igneous zone that delineates the extension of the Paleotethyan Ocean from SW China into NW Thailand. The Chiang Mai basaltic samples from the Chiang Dao, Fang, Lamphun and Ban Sahakorn sections are divisible into two groups of high-iron basalt. Group 1 has SiO2 of 38.30-49.18 wt.%, FeOt of 13.09-25.37 wt.%, MgO of 8.38-1.60 wt.%, TiO2 of 3.92-6.30 wt.%, which is rarely observed in nature. Group 2 shows SiO2 = 44.71-49.21 wt.%, FeOt = 10.88-14.34 wt.%, MgO = 5.24-16.11 wt.%, TiO2 = 2.22-3.07 wt.% and mg# = 44-70. Olivine and pyroxene are responsible for the fractionation of the Group 2 magma whereas low oxygen fugacity during the late-stage differentiation of the Group 1 magma prolonged fractionation of ilmenite and magnetite. The onset of ilmenite and magnetite fractionations controls the distinct differentiation commencing at MgO = 7 wt.%. Both groups show similar REE and primitive mantle-normalized patterns with insignificant Eu, Nb-Ta and Zr-Hf anomalies. They have similar Nd isotopic compositions with εNd (t) values ranging from + 2.8 to + 3.7 and similar Nb/La, Nb/U, Th/La, Zr/Nb, Th/Ta, La/Yb, Nb/Th, Nb/Y and Zr/Y, resembling those of OIB-like rocks. The representative basaltic sample yields the argon plateau age of 282.3 ± 1.4 Ma, suggestive of Early Permian origin. Our data argue for Group 1 and Group 2 are coeval in the intra-oceanic seamount setting within the Paleotethyan Ocean, which at least continued till 283 Ma. These data, along with other observations, suggest that the Inthanon zone defines the main Paleotethyan suture zone, which northerly links with the Changning-Menglian suture zone in SW China.

A cathodoluminescence study on zircons with a complex thermal history traces back Permian crustal events in the Ivrea Zone (South Alpine, Northern Italy)

NASA Astrophysics Data System (ADS)

Peressini, G.; Poller, U.

2003-04-01

In the context of a U-Pb SHRIMP data-set, a cathodoluminescence (CL) study has been performed on zircons from the Ivrea-Verbano Zone; this is a tectonically bounded section of intermediate to deep crust, tilted and obducted in Alpine time, in which a large deep-crustal intrusion of mantle origin, the Mafic Complex (MC), was emplaced in the Early Permian. Zircons from 16 samples from the different units of the MC have been studied using CL. Three samples collected from the Paragneiss Bearing Belt (PBB) yield some partially reset spot-ages, reflecting the field observation that country rock slabs are frequent in that area. On the other side, unlike in zircons from granites, the cores are invisible under CL-imaging, and this makes the U-Pb spot-age results unpredictable, with a continuous range of ages in the same sample, spanning for an interval of over 35 Ma, followed by some much older peaks, up to 600 Ma. A fourth sample, collected 2 km far, but still within the PBB, defines instead a unique, well-defined age at 287±3 Ma, with no older peaks, its zircons showing a CL pattern typical for metamorphic grains. A different case is displayed by a sample collected from the deeper Amphibole Gabbro unit: each single grain records a complex story of magmatic growth with variable diffusivity conditions. All of them show a second major overprint, that lead to both (re)crystallization and resorption, always corresponding to much lower U and Th contents, with no sensible modification of the Th-U ratio. The age of the second event, though, is not distinguishable from that of first crystallization of the grains, and has not been at such a temperature as to obliterate the fine zoning pattern of the primary grain. The CL patterns of each single grain, composed of different domains, allow considerations on the environmental conditions of growth and (re)crystallization. CL is a very powerful tool itself, revealing crystal-chemical processes. The integration of the CL-study with the

Jelly Bean conglomerate (lower Permian): record of a forebulge in southeastern Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armin, R.

The most incongruous stratigraphic unit the Earp Formation (Pennsylvanian-Permian) is the Jelly Bean conglomerate (JBC), a unit rarely more than 5 m thick, but occurring over 15,000 km/sup 2/. The JBC consists mostly of clast-supported chert-pebble and limestone-clast conglomerate, litharenite, and pebbly sandstone, whereas most of the Earp Formation is marine limestone, siltstone, and shale. The JCB lies on eroded siltstone or limestone, and is capped conformably by siltstone. The JBC is probably a braided-stream deposit as indicated by presence of fluvial dunes and ripples, amalgamated bar and channel conglomerates, imbricated clasts, channeled underbeds, and lack of point bars. Paleocurrentsmore » were generally southward. The thinness and widespread occurrence of the JBC suggest a uniform, gentle paleoslope down which the streams flowed. Deposition of the JBC occurred at about the climax of the Marathon phase of the Ouachita orogeny in west Texas and northern Mexico. The age and location of the JBC, which fringes cratonic North America, indicate that it was related to the late Paleozoic convergence of North and South America, and may have resulted from flexural forebulging caused by thrusting in the Marathon orogene and associated sedimentation in a foredeep.« less

Studying the Permian Cross-section (Volga Region) Using Chemical and Isotopic Investigations

NASA Astrophysics Data System (ADS)

Gareev, B. I.; Batalin, G. A.; Nurgalieva, N. G.; Nourgaliev, D. K.

2016-12-01

This paper presents a study of international important site: the cross-section of Permian system's Urzhumian Stagein the ravine "Pechischy". Outcrop is located on the right bank of the Volga River (about 10 km West of Kazan). Ithas local, regional and planetary correlation features and also footprints of different geographical scale events.The main objective in the research is the deep study of sediments using chemical and isotopic investigations. XRFspectrometer was used for chemical investigations of samples. Chemistry of carbonates and clastic rocks includesthe analysis of chemical elements, compounds, petrochemical (lithogeochemical) modules for the interpretationof the genesis of lithotypes. For the review of the geochemistry of stable isotopes of carbon (oxygen) we usedIRMS. The main objective is the nature of the isotope fractionation issues, to addressing the issues of stratigraphyand paleogeography.The measurements have shown the variability of chemical parameters in cross-section. It gives us opportunity tosee small changes in sedimentation and recognize the factors that influence to the process.The work was carried out according to the Russian Government's Program of Competitive Growth of KazanFederal University, supported by the grant provided to the Kazan State University for performing the state programin the field of scientific research.

Explosive eruption of coal and basalt and the end-Permian mass extinction

PubMed Central

Ogden, Darcy E.; Sleep, Norman H.

2012-01-01

The end-Permian extinction decimated up to 95% of carbonate shell-bearing marine species and 80% of land animals. Isotopic excursions, dissolution of shallow marine carbonates, and the demise of carbonate shell-bearing organisms suggest global warming and ocean acidification. The temporal association of the extinction with the Siberia flood basalts at approximately 250 Ma is well known, and recent evidence suggests these flood basalts may have mobilized carbon in thick deposits of organic-rich sediments. Large isotopic excursions recorded in this period are potentially explained by rapid venting of coal-derived methane, which has primarily been attributed to metamorphism of coal by basaltic intrusion. However, recently discovered contemporaneous deposits of fly ash in northern Canada suggest large-scale combustion of coal as an additional mechanism for rapid release of carbon. This massive coal combustion may have resulted from explosive interaction with basalt sills of the Siberian Traps. Here we present physical analysis of explosive eruption of coal and basalt, demonstrating that it is a viable mechanism for global extinction. We describe and constrain the physics of this process including necessary magnitudes of basaltic intrusion, mixing and mobilization of coal and basalt, ascent to the surface, explosive combustion, and the atmospheric rise necessary for global distribution. PMID:22184229

Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran

NASA Astrophysics Data System (ADS)

Shadan, Mahdi; Hosseini-Barzi, Mahboubeh

2010-05-01

Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran M. Shadan & M. Hosseini-Barzi Geology Department, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran shadangeo@gmail.com Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian) have been studied in two sections (Chahroof with 197 m thick in north and Cheshmeh Bakhshi with 204 m thick in south) along basement Kalmard fault in Posht-e-Badam block, Central Iran. Siliciclastic units are characterized by well sorted, fine to medium grain quartzarenites with laterite interbeds, deposited in shoreline zone (foreshore, upper and lower shoreface) influencing wave and longshore currents. Longshore sands which have been transported along the coast made the sand bars in the shoreface. Further along the coast, returning of these currents as rip currents produced erosive channel inlets and caused to carry fine grain into the deeper regions of the basin. Based on this sedimentary model we introduced longshore currents as a probable agent for mixing, by transporting some volumes of sands into the adjacent carbonate environments. Vertically, clastic units of Khan Formation underlined by carbonate units of a tidal flat and high-energy inner ramp system. Repeating of this pattern produced 3 cycles in each section. Cyclic evolution, in studied sections, is accompanied with discrepancy in erosion and sedimentation. These factors caused to disperse local sub-aerial exposures in successions which are recognizable by laterite and conglomerate interbeds. These horizons of sub-aerial exposures are more often in Chahroof section than in Cheshmeh Bakhshi section and indicate more fluctuations of relative sea level probably due to more local tectonic activity in the northern part of the Kalmard fault than in the southern part of it. Also, thicker siliciclastic units in Chahroof section show higher rate of sediment supply and/or more accommodation space

Significance of detrital zircons in upper Devonian ocean-basin strata of the Sonora allochthon and Lower Permian synorogenic strata of the Mina Mexico foredeep, central Sonora, Mexico

USGS Publications Warehouse

Poole, F.G.; Gehrels, G.E.; Stewart, John H.

2008-01-01

U-Pb isotopic dating of detrital zircons from a conglomeratic barite sandstone in the Sonora allochthon and a calciclastic sandstone in the Mina Mexico foredeep of the Minas de Barita area reveals two main age groups in the Upper Devonian part of the Los Pozos Formation, 1.73-1.65 Ga and 1.44-1.42 Ga; and three main age groups in the Lower Permian part of the Mina Mexico Formation, 1.93-1.91 Ga, 1.45-1.42 Ga, and 1.1-1.0 Ga. Small numbers of zircons with ages of 2.72-2.65 Ga, 1.30-1.24 Ga, ca. 2.46 Ga, ca. 1.83 Ga, and ca. 0.53 Ga are also present in the Los Pozos sandstone. Detrital zircons ranging in age from 1.73 to 1.65 Ga are considered to have been derived from the Yavapai, Mojave, and Mazatzal Provinces and their transition zones of the southwestern United States and northwestern Mexico. The 1.45-1.30 Ga detrital zircons were probably derived from scattered granite bodies within the Mojave and Mazatzal basement rocks in the southwestern United States and northwestern Mexico, and possibly from the Southern and Eastern Granite-Rhyolite Provinces of the southern United States. The 1.24-1.0 Ga detrital zircons are believed to have been derived from the Grenville (Llano) Province to the east and northeast or from Grenvilleage intrusions or anatectites to the north. Several detrital zircon ages ranging from 2.72 to 1.91 Ga were probably derived originally from the Archean Wyoming Province and Early Paleoproterozoic rocks of the Lake Superior region. These older detrital zircons most likely have been recycled one or more times into the Paleozoic sandstones of central Sonora. The 0.53 Ga zircon is believed to have been derived from a Lower Cambrian granitoid or meta-morphic rock northeast of central Sonora, possibly in New Mexico and Colorado, or Oklahoma. Detrital zircon geochronology suggests that most of the detritus in both samples was derived from Laurentia to the north, whereas some detritus in the Permian synorogenic foredeep sequence was derived from the

Timing of the final closure of the Paleo-Asian Ocean in the Alxa Terrane: Constraints from geochronology and geochemistry of Late Carboniferous to Permian gabbros and diorites

NASA Astrophysics Data System (ADS)

Liu, Qian; Zhao, Guochun

2017-04-01

The Alxa Terrane is a crucial place situated between the North China Craton to the east and the Tarim Craton to the west. The Late Paleozoic magmatic record in the Alxa Terrane places important constraints on the timing of the final closure of the middle segment of the Paleo-Asian Ocean (PAO). In this study, new LA-ICPMS zircon U-Pb dating results reveal ca. 300-268 Ma gabbros and diorites in the Bayan Nuru area in the eastern part of the Alxa Terrane. The 300 Ma gabbros show plagioclase accumulations with anorthite compositions (An92-95), arc-like geochemical affinities with relative enrichment in large ionic lithophile elements and depletion in high field strength elements (e.g., Ti, Nb and Ta), as well as negative Hf(t) (-6.01 to -1.75) and Nd(t) (-9.5 to -7.1) values and high initial 87Sr/86Sr ratios (0.707157-0.707220). These features indicate a magma source of an enriched lithospheric mantle metasomatized by high fluid activities. In comparison, the 280-268 Ma gabbros and diorites also have arc-like geochemical affinities but show increasingly evolved isotope compositions, implying more sediment inputs. Compiled zircon ɛHf(t) and whole-rock ɛNd(t) values of the magmatic rocks in the Alxa Terrane decrease from the Late Carboniferous to the Early Permian, and increase from the Middle Permian to the Triassic. The considerably large spread in ɛHf(t) and ɛNd(t) values at ca. 280-265 Ma likely reflects a tectonic switch from a subduction setting to a post-collisional setting, corresponding to the timing of the final closure of the PAO in the Alxa Terrane. Thus, the PAO progressively closed from west to east along the northern margin of the Tarim Craton, the Alxa Terrane, and then the northern margin of the North China Craton during Late Carboniferous to Middle Triassic time. This work was financially supported by a NSFC Project (41190075) entitled "Final Closure of the Paleo-Asian ocean and Reconstruction of East Asian Blocks in Pangea", the fifth

Early crocodylomorph increases top tier predator diversity during rise of dinosaurs.

PubMed

Zanno, Lindsay E; Drymala, Susan; Nesbitt, Sterling J; Schneider, Vincent P

2015-03-19

Triassic predatory guild evolution reflects a period of ecological flux spurred by the catastrophic end-Permian mass extinction and terminating with the global ecological dominance of dinosaurs in the early Jurassic. In responding to this dynamic ecospace, terrestrial predator diversity attained new levels, prompting unique trophic webs with a seeming overabundance of carnivorous taxa and the evolution of entirely new predatory clades. Key among these was Crocodylomorpha, the largest living reptiles and only one of two archosaurian lineages that survive to the present day. In contrast to their existing role as top, semi-aquatic predators, the earliest crocodylomorphs were generally small-bodied, terrestrial faunivores, occupying subsidiary (meso) predator roles. Here we describe Carnufex carolinensis a new, unexpectedly large-bodied taxon with a slender and ornamented skull from the Carnian Pekin Formation (~231 Ma), representing one of the oldest and earliest diverging crocodylomorphs described to date. Carnufex bridges a problematic gap in the early evolution of pseudosuchians by spanning key transitions in bauplan evolution and body mass near the origin of Crocodylomorpha. With a skull length of >50 cm, the new taxon documents a rare instance of crocodylomorphs ascending to top-tier predator guilds in the equatorial regions of Pangea prior to the dominance of dinosaurs.

Early Cretaceous Umkomasia from Mongolia: implications for homology of corystosperm cupules.

PubMed

Shi, Gongle; Leslie, Andrew B; Herendeen, Patrick S; Herrera, Fabiany; Ichinnorov, Niiden; Takahashi, Masamichi; Knopf, Patrick; Crane, Peter R

2016-06-01

Corystosperms, a key extinct group of Late Permian to Early Cretaceous plants, are important for understanding seed plant phylogeny, including the evolution of the angiosperm carpel and anatropous bitegmic ovule. Here, we describe a new species of corystosperm seed-bearing organ, Umkomasia mongolica sp. nov., based on hundreds of three-dimensionally preserved mesofossils from the Early Cretaceous of Mongolia. Individual seed-bearing units of U. mongolica consist of a bract subtending an axis that bifurcates, with each fork (cupule stalk) bearing a cupule near the tip. Each cupule is formed by the strongly reflexed cupule stalk and two lateral flaps that partially enclose an erect seed. The seed is borne at, or close to, the tip of the reflexed cupule stalk, with the micropyle oriented towards the stalk base. The corystosperm cupule is generally interpreted as a modified leaf that bears a seed on its abaxial surface. However, U. mongolica suggests that an earlier interpretation, in which the seed is borne directly on an axis (shoot), is equally likely. The 'axial' interpretation suggests a possible relationship of corystosperms to Ginkgo. It also suggests that the cupules of corystosperms may be less distinct from those of Caytonia than has previously been supposed. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Early crocodylomorph increases top tier predator diversity during rise of dinosaurs

PubMed Central

Zanno, Lindsay E.; Drymala, Susan; Nesbitt, Sterling J.; Schneider, Vincent P.

2015-01-01

Triassic predatory guild evolution reflects a period of ecological flux spurred by the catastrophic end-Permian mass extinction and terminating with the global ecological dominance of dinosaurs in the early Jurassic. In responding to this dynamic ecospace, terrestrial predator diversity attained new levels, prompting unique trophic webs with a seeming overabundance of carnivorous taxa and the evolution of entirely new predatory clades. Key among these was Crocodylomorpha, the largest living reptiles and only one of two archosaurian lineages that survive to the present day. In contrast to their existing role as top, semi-aquatic predators, the earliest crocodylomorphs were generally small-bodied, terrestrial faunivores, occupying subsidiary (meso) predator roles. Here we describe Carnufex carolinensis a new, unexpectedly large-bodied taxon with a slender and ornamented skull from the Carnian Pekin Formation (~231 Ma), representing one of the oldest and earliest diverging crocodylomorphs described to date. Carnufex bridges a problematic gap in the early evolution of pseudosuchians by spanning key transitions in bauplan evolution and body mass near the origin of Crocodylomorpha. With a skull length of >50 cm, the new taxon documents a rare instance of crocodylomorphs ascending to top-tier predator guilds in the equatorial regions of Pangea prior to the dominance of dinosaurs. PMID:25787306

The sail-backed reptile Ctenosauriscus from the latest Early Triassic of Germany and the timing and biogeography of the early archosaur radiation.

PubMed

Butler, Richard J; Brusatte, Stephen L; Reich, Mike; Nesbitt, Sterling J; Schoch, Rainer R; Hornung, Jahn J

2011-01-01

Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3-247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the 'sail' of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian-Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs.

Exceptionally well-preserved Permocalculus cf. tenellus (Pia) (Gymnocodiaceae) from Upper Permian Khuff Formation limestones, Saudi Arabia

NASA Astrophysics Data System (ADS)

Hughes, G. W.

2017-04-01

An exceptionally well-preserved specimen of the articulated rhodophyte Permocalculus, compared with P. tenellus sensu Elliott, 1955, is described from fine-grained Upper Permian limestones of the Khuff Formation of Saudi Arabia. Longitudinal medullary and sheaf-like cortical filaments extend through the uniserial series of elongate-globular, concave- and convex-terminating, interlocking segments for which they are interpreted to have functioned in articulation. The filaments tend to splay and branch laterally into the cortex where they terminate at the pores. At the terminal aperture, the filaments extend as bifurcating and possibly trifurcating branches and may serve as the origin of a new segment. Numerous elongate-globular chambers, up to five in each row and intimately involved with the filaments, are developed in the outer medulla and are considered to represent reproductive sporangia. The specimen is considered to have occupied predominantly low-energy, normal to slightly elevated salinity, shallow conditions within the subtidal regime of a lagoon.

Geomicrobiological perspective on the pattern and causes of the 5-million-year Permo/Triassic biotic crisis

NASA Astrophysics Data System (ADS)

Xie, Shucheng; Wang, Yongbiao

2011-03-01

The pattern and causes of Permo/Triassic biotic crisis were mainly documented by faunal and terrestrial plant records. We reviewed herein the geomicrobiological perspective on this issue based on the reported cyanobacterial record. Two episodic cyanobacterial blooms were observed to couple with carbon isotope excursions and faunal mass extinction at Meishan section, suggestive of the presence of at least two episodic biotic crises across the Permian-Triassic boundary (PTB). The two episodes of cyanobacterial blooms, carbon isotope excursions and faunal mass extinction were, respectively, identified in several sections of the world, inferring the presence of two global changes across the PTB. Close associations among the three records (cyanobacterial bloom, shift in carbon isotope composition, and faunal extinction) were subsequently observed in three intervals in the Early Triassic, the protracted recovery period as previously thought, inferring the occurrence of more episodes of global changes. Spatiotemporal association of cyanobacterial blooms with volcanic materials in South China, and probably in South-east Asia, infers their causal relationship. Volcanism is believed to trigger the biotic crisis in several ways and to cause the close association among microbial blooms, the carbon isotope excursions and faunal mass extinctions in four intervals from the latest Permian to the Early Triassic. The major episodes of the well-known Siberian flood eruption are proposed to be responsible for the extinctions in the Early Triassic, but their synchronicity with the end-Permian extinction awaits more precise dating data to confirm. Geomicrobial records are thus suggestive of a long-term episodic biotic crisis (at least four episodes) lasting from the latest Permian to the end of the Early Triassic, induced by the global volcanic eruptions and sea level changes during Pangea formation.

Middle Permian paleomagnetism of the Sydney Basin, Eastern Gondwana: Testing Pangea models and the timing of the end of the Kiaman Reverse Superchron

NASA Astrophysics Data System (ADS)

Belica, M. E.; Tohver, E.; Pisarevsky, S. A.; Jourdan, F.; Denyszyn, S.; George, A. D.

2017-03-01

Paleomagnetic and geochronologic data from the eastern margin of Gondwana have been obtained from the Gerringong Volcanics in the southern Sydney Basin, Australia. The corresponding paleomagnetic pole at 56.9°S, 154.8°E (N = 131; A95 = 9.1°) has a 40Ar/39Ar plagioclase plateau age of 265.05 ± 0.35 [0.46] Ma from the Bumbo Latite, and overlaps with recent radio-isotopic and paleomagnetic results published from Western Gondwana. The long-documented inconsistency between Middle Permian Eastern and Western Gondwanan paleomagnetic datasets is most likely an artefact of a lack of reliable paleomagnetic data from Eastern Gondwana for this period. A number of well-dated and recently published ca. 265 Ma paleomagnetic results from Gondwana and Laurussia are shown to be consistent with the Wegenerian Pangea A configuration, with a loose N-S fit of the continents for the Middle Permian. The lack of crustal overlap negates the need for a Pangea B configuration, which if valid must have been assembled to Pangea A by ca. 265 Ma. The reverse polarity Bumbo Latite was sampled from the Kiaman type-section located in the southern Sydney Basin. Three cases of normal polarity were detected in the overlying Saddleback, Dapto, and Berkeley Latites, previously assigned to the Kiaman Reverse Superchron (KRS). We review KRS-aged magnetostratigraphic data and propose that an age assignment of 265 Ma most likely represents the termination of the non-reversing field, with longer stable intervals of normal polarity recorded and able to be correlated globally.

The depositional environment and petrology of the White Rim Sandstone Member of the Permian Cutler Formation, Canyonlands National Park, Utah

USGS Publications Warehouse

Steele-Mallory, B. A.

1982-01-01

The White Rim Sandstone Member of the Cutler Formation of Permian age in Canyonlands National Park, Utah, was deposited in coastal eolian and associated interdune environments. This conclusion is based on stratigraphic relationships primary sedimentary structures, and petrologic features. The White Rim consists of two major genetic units. The first represents a coastal dune field and the second represents related interdune ponds. Distinctive sedimentary structures of the coastal dune unit include large- to medium-scale, unidirectional, tabular-planar cross-bedding; high-index ripples oriented parallel to dip direction of the foresets; coarse-grained lag layers; avalanche or slump marks; and raindrop impressions. Cross-bedding measurements suggest the dunes were deposited as transverse ridges by a dominantly northwest to southeast wind. Distinctive sedimentary structures of the interdune pond unit include wavy, horizontally laminated bedding, adhesion ripples, and desiccation polygons. These features may have been produced by alternate wetting and drying of sediment during water-table fluctuations. Evidence of bioturbation is also present in this unit. Petrologic characteristics of the White Rim helped to define the depositional environment as coastal. A crinoid fragment was identified at one location; both units are enriched in heavy minerals, and small amounts of well rounded, reworked glauconite were found in the White Rim throughout the study area. Earlier work indicates that the White Rim sandstone is late Wolfcampian to early Leonardian in age. During this time, the Canyonlands area was located in a depositional area alternately dominated by marine and nonmarine environments. Results of this study suggest the White Rim represents a coastal dune field that was deposited by predominantly on-shore winds during a period of marine transgression.

Astronomical timescale calibration for the Permian-Triassic boundary transition interval from global correlation of cyclic marine sequences

NASA Astrophysics Data System (ADS)

Huang, C.; Hinnov, L. A.; Tong, J.; Chen, Z.

2011-12-01

The mass extinctions near the Permian-Triassic boundary (PTB) resulted in the greatest dying of life on Earth. The cause of this catastrophe remains enigmatic. High-resolution chronology is crucial to understanding the recorded pattern of biotic evolution and possible causes for the extinctions. Magnetic susceptibility (MS) data from Shangsi, South China shows evidence for astronomical forcing through the PTB interval, with strong 405-kyr cycling. This allows development of an astrochronology for the PTB interval based on the 405-kyr orbital eccentricity metronome that has been proposed for the Mesozoic timescale. Radioisotope dating combined with the 405-kyr tuned MS series from Shangsi shows that the 405-kyr-cycle predominates throughout the PTB interval. In the Permian segment, ~100-kyr cyclicity dominates, and the 100-kyr-scale MS maxima correlate with high-amplitude precession-scale MS variations. Minima in the ~1.5-Myr, 405-kyr and ~100-kyr cycles converge at 252.6 Ma, approximately 200 kyr before the onset of the main mass extinction near the PTB. In the Triassic aftermath, the recorded astronomical signal is different, with predominant 405-kyr cycles and loss of 100 kyr cyclicity, and appearance of ~33 kyr (obliquity scale) cyclicity; 100-kyr cyclicity strengthens again 2 Myr later. This pattern indicates a change in the response of the depositional environment (or magnetic susceptibility) to astronomical forcing before and after the mass extinction interval. The astrochronology interpolates the timescale between the radioisotopically determined absolute dates; this facilitates estimation of ages for specific events in the PTB crisis, including magnetic reversals, biozone boundaries, and the mass extinctions. An estimated ~700 kyr duration for the Mass Extinction Interval (MEI) at Shangsi based on the 405-kyr tuning is supported by eccentricity-tuned estimates of three other sections in China (Meishan, Huangzhishan, and Heping), and two Alpine sections

Mineralogical characterization of strata of the Meade Peak phosphatic shale member of the Permian Phosphoria Formation: channel and individual rock samples of measured section J and their relationship to measured sections A and B, central part of Rasmussen Ridge, Caribou County, Idaho

USGS Publications Warehouse

Knudsen, A.C.; Gunter, M.E.; Herring, J.R.; Grauch, R.I.

2002-01-01

The Permian Phosphoria Formation of southeastern Idaho hosts one of the largest phosphate deposits in the world. Despite the economic significance of this Formation, the fine-grained nature of the phosphorite has discouraged detailed mineralogical characterization and quantification studies. Recently, selenium and other potentially toxic trace elements in mine wastes have drawn increased attention to this formation, and motivated additional study. This study uses powder X-ray diffraction (XRD), with Rietveld quantification software, to quantify and characterize the mineralogy of composite channel samples and individual samples collected from the stratigraphic sections measured by the U.S. Geological Survey in the Meade Peak Member of the Permian Phosphoria Formation at the Enoch Valley mine on Rasmussen Ridge, approximately 15 miles northeast of Soda Springs, Idaho.

Terrestrial origin of viviparity in mesozoic marine reptiles indicated by early triassic embryonic fossils.

PubMed

Motani, Ryosuke; Jiang, Da-yong; Tintori, Andrea; Rieppel, Olivier; Chen, Guan-bao

2014-01-01

Viviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia), which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic). This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction.

Chondrites isp. Indicating Late Paleozoic Atmospheric Anoxia in Eastern Peninsular India

PubMed Central

Bhattacharya, Biplab; Banerjee, Sudipto

2014-01-01

Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting. Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian. Monospecific Chondrites ichnoassemblage in different sedimentary horizons in geographically wide apart (~400 km) areas demarcates multiple short-spanned phases of anoxia in eastern India. Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations. PMID:24616628

Borehole seismic monitoring of seismic stimulation at OccidentalPermian Ltd's -- South Wason Clear Fork Unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daley, Tom; Majer, Ernie

2007-04-30

Seismic stimulation is a proposed enhanced oil recovery(EOR) technique which uses seismic energy to increase oil production. Aspart of an integrated research effort (theory, lab and field studies),LBNL has been measuring the seismic amplitude of various stimulationsources in various oil fields (Majer, et al., 2006, Roberts,et al.,2001, Daley et al., 1999). The amplitude of the seismic waves generatedby a stimulation source is an important parameter for increased oilmobility in both theoretical models and laboratory core studies. Theseismic amplitude, typically in units of seismic strain, can be measuredin-situ by use of a borehole seismometer (geophone). Measuring thedistribution of amplitudes within amore » reservoir could allow improved designof stimulation source deployment. In March, 2007, we provided in-fieldmonitoring of two stimulation sources operating in Occidental (Oxy)Permian Ltd's South Wasson Clear Fork (SWCU) unit, located near DenverCity, Tx. The stimulation source is a downhole fluid pulsation devicedeveloped by Applied Seismic Research Corp. (ASR). Our monitoring used aborehole wall-locking 3-component geophone operating in two nearbywells.« less

Sedimentology of the Pennsylvanian and Permian Strathearn Formation, Northern Carlin Trend, Nevada; with a section on microfossil controls on the age of the Strathearn Formation

USGS Publications Warehouse

Berger, Vladimir I.; Singer, Donald A.; Theodore, Ted G.; Harris, Anita G.; Stevens, Calvin H.

2001-01-01

Two framework-supported, poorly bedded conglomerate units of the middle Upper Pennsylvanian and middle Lower Permian Strathearn Formation belonging to the overlap assemblage of the Antler orogen are prominent in the northern Carlin trend. These horizons stratigraphically and temporally bracket thrust emplacement of a major allochthonous thrust plate of mainly quartzarenite of the Ordovician Vinini Formation. Lithologic and shape-ratio data from approximately 4,200 pebbles and cobbles at 17 sites as well as biostratigraphic data in the Strathearn, and their geologic implications, are included in this report. Conodont biofacies throughout the Strathearn Formation are normal marine and suggest middle shelf or deeper depositional environments. The conglomerate units roughly are similar in that they contain only chert and quartzarenite pebbles, but they differ in compositional proportions of the two lithologies. The relative proportion of quartzarenite pebbles increases sixfold in the middle Lower Permian upper conglomerate unit versus its content in the middle Upper Pennsylvanian lower unit, whereas chert pebbles predominate in both units. Various roundness categories of chert pebbles in both conglomerate units of the Strathearn show that the equant pebble class (B/A) = 1 clearly is represented strongly even in the subangular category, the lowest roundness categories for the pebbles. Thus, development of equant pebbles cannot be ascribed totally to a rounding process during predeposition transport. The equant character of many pebbles might, in part, be an original feature inherited from pre-erosion rock fractures and (or) bedding that control overall form of the fragments prior to their release to the transport environment. The allochthon of the Coyote thrust has been thrust above the lower conglomerate unit of the Strathearn during a regionally extensive contractional event in the late Paleozoic. The middle Lower Permian upper conglomerate unit, highest unit

The drift history of the Indochina Block from Gondwana to Eurasia, constraints from paleomagnetism

NASA Astrophysics Data System (ADS)

Yan, Yonggang; Huang, Baochun; Zhang, Donghai; Charusiri, Punya

2017-04-01

The Late Paleozoic to Mesozoic paleopositions of Indochina Block has long been debated, which is regarded as one of the biggest problems unresolved in the reconstruction of Eastern Asian blocks in the Gondwana or Pangea Supercontinent. We reported new high quality Early-Middle Permian and Late Triassic paleomagnetic results from Thailand, the central of Indochina, in the aiming to constraint the drift history of Indochina from Gondwana to Eurasia. Following detailed rock magnetic and paleomagnetic analyses, new datasets with positive fold tests and reversal tests are obtained, and an Early-Middle Permian (ca. 280Ma) paleomagnetic pole is suggested to be located at 34.1°N/331.7°E (A95 = 5.7°), corresponds to a paleolatitude of 21°S at the center of study area (15°N, 101°E); and the Norian of Late Triassic (ca.220 Ma) pole is 48.7°N/165.9°E (A95=7.2°), indicating the Indochina block was located at 26°N. The two key poles indicate the Indochina drift for 5000 km from the Gondwana region to the south margin of the Eurasia during Early-Middle Permian to Late Traissic. And its averaged movement rate relative to Gondwana is calculated to be 4.5cm/yr.

A new captorhinid reptile from the Lower Permian of Oklahoma showing remarkable dental and mandibular convergence with microsaurian tetrapods

NASA Astrophysics Data System (ADS)

Reisz, R. R.; LeBlanc, Aaron R. H.; Sidor, Christian A.; Scott, Diane; May, William

2015-10-01

The Lower Permian fossiliferous infills of the Dolese Brothers Limestone Quarry, near Richards Spur, Oklahoma, have preserved the most diverse assemblage of Paleozoic terrestrial vertebrates, including small-bodied reptiles and lepospondyl anamniotes. Many of these taxa were previously known only from fragmentary remains, predominantly dentigerous jaw elements and numerous isolated skeletal elements. The recent discovery of articulated skulls and skeletons of small reptiles permits the recognition that dentigerous elements, previously assigned at this locality to the anamniote lepospondyl Euryodus primus, belong to a new captorhinid eureptile, Opisthodontosaurus carrolli gen. et sp. nov. This mistaken identity points to a dramatic level of convergence in mandibular and dental anatomy in two distantly related and disparate clades of terrestrial tetrapods and sheds light on the earliest instance of durophagy in eureptiles.

A new captorhinid reptile from the Lower Permian of Oklahoma showing remarkable dental and mandibular convergence with microsaurian tetrapods.

PubMed

Reisz, R R; LeBlanc, Aaron R H; Sidor, Christian A; Scott, Diane; May, William

2015-10-01

The Lower Permian fossiliferous infills of the Dolese Brothers Limestone Quarry, near Richards Spur, Oklahoma, have preserved the most diverse assemblage of Paleozoic terrestrial vertebrates, including small-bodied reptiles and lepospondyl anamniotes. Many of these taxa were previously known only from fragmentary remains, predominantly dentigerous jaw elements and numerous isolated skeletal elements. The recent discovery of articulated skulls and skeletons of small reptiles permits the recognition that dentigerous elements, previously assigned at this locality to the anamniote lepospondyl Euryodus primus, belong to a new captorhinid eureptile, Opisthodontosaurus carrolli gen. et sp. nov. This mistaken identity points to a dramatic level of convergence in mandibular and dental anatomy in two distantly related and disparate clades of terrestrial tetrapods and sheds light on the earliest instance of durophagy in eureptiles.

Basin fill evolution and paleotectonic patterns along the Samfrau geosyncline: the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) revisited

NASA Astrophysics Data System (ADS)

López-Gamundí, O. R.; Rossello, E. A.

As integral parts of du Toit's (1927) ``Samfrau Geosyncline'', the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) share similar paleoclimatic, paleogeographic, and paleotectonic aspects related to the Late Paleozoic tectono-magmatic activity along the Panthalassan continental margin of Gondwanaland. Late Carboniferou-earliest Permian glacial deposits were deposited in the Sauce Grande (Sauce Grande Formation) and Karoo (Dwyka Formation) basins and Falkland-Malvinas Islands (Lafonia Formation) during an initial (sag) phase of extension. The pre-breakup position of the Falkland (Malvinas) Islands on the easternmost part of the Karoo basin (immediately east of the coast of South Africa) is supported by recent paleomagnetic data, lithofacies associations, paleoice flow directions and age similarities between the Dwyka and the Lafonia glacial sequences. The desintegration of the Gondwanan Ice Sheet (GIS) triggered widespread transgressions, reflected in the stratigraphic record by the presence of inter-basinally correlatable, open marine, fine-grained deposits (Piedra Azul Formation in the Sauce Grande basin, Prince Albert Formation in the Karoo basin and Port Sussex Formation in the Falkland Islands) capping glacial marine sediments. These early postglacial transgressive deposits, characterised by fossils of the Eurydesma fauna and Glossopteris flora, represent the maximum flooding of the basins. Cratonward foreland subsidence was triggered by the San Rafael orogeny (ca. 270 Ma) in Argentina and propogated along the Gondwanan margin. This subsidence phase generated sufficient space to accommodate thick synorogenic sequences derived from the orogenic flanks of the Sauce Grande and Karoo basins. Compositionally, the initial extensional phase of these basins was characterized by quartz-rich, craton-derived detritus and was followed by a compressional (foreland) phase characterized by a paleocurrent reversal and dominance of

Timing of the Late Paleozoic Ice Age: A Review of the Status Quo and New U-Pb Zircon Ages From Southern Gondwana

NASA Astrophysics Data System (ADS)

Mundil, R.; Griffis, N. P.; Keller, C. B.; Fedorchuk, N.; Montanez, I. P.; Isbell, J.; Vesely, F.; Iannuzzi, R.

2017-12-01

Throughout the Carboniferous and Permian Late Paleozoic Ice Age (LPIA), glaciations in southern Gondwana exerted a profound influence on global climate and environment, ocean chemistry, and the nature of sedimentary processes. The LPIA is widely regarded as an analogue for Pleistocene glaciations. Our understanding of the latter, as well as the validity of predictions for the future global climate and environment, depends therefore on our ability to reconstruct the LPIA. A robust chronostratigraphic framework built on high precision/high accuracy geochronology is crucial for the reconstruction of events and processes that occurred during the LPIA, particularly in the absence of high-resolution terrestrial biostratigraphic constraints that apply to both near- and far-field proxy records. The occurrence of volcaniclastic layers containing primary volcanic zircon at many levels throughout southern Gondwana makes such a reconstruction feasible, but complications inevitably arise due to the mixing of older age components with primary volcanic crystals, as well as the potential of unrecognized open system behavior to produce spurious younger ages. These pitfalls cause age dispersion that may be difficult to interpret, or is unrecognized if low precision geochronological techniques are used, resulting in inaccurate radioisotopic ages. Our current efforts in the Parana Basin (Southern Brazil) and the Karoo Basin (South Africa/Namibia) concentrate on building a robust and exportable chronostratigraphic framework based on U-Pb zircon CA-TIMS ages with sub-permil level precision combined with Bayesian approaches for resolving the eruption age of dispersed age spectra to facilitate the reconstruction of glaciogenic processes through the Carboniferous-Permian transition, as well as their implications for global sea level, atmospheric pCO2 and ocean chemistry. We will also review currently available geochronological data from contemporaneous Australian successions and their

Milankovitch and sub-Milankovitch cycles of the Early Triassic Daye Formation, South China and their geochronological and paleoclimatic implications

NASA Astrophysics Data System (ADS)

Wu, H.; Zhang, S.; Feng, Q.; Jiang, G.; Li, H.; Yang, T.

2011-12-01

The most profound mass extinction in the Phanerozoic occurred at the end of the Permian, with global loss of nearly 90% of marine invertebrate species and 70% of terrestrial vertebrate genera. Recent studies suggested that volcanisms represented by the Siberian Trap were most likely cause of the end-Permian extinction. The post-extinction periods in the Early Triassic was characterized by low biodiversity, reduced abundance and size of invertebrates, hiatus in coal deposition, anomalously high sediment fluxes, and large perturbations of the carbon cycle, which have been interpreted as the consequence of persistently unfavorable environmental conditions. However, the time framework for the Early Triassic geological, biological and geochemical events is traditionally established by conodont biostratigraphy, but the absolute duration of condont biozones are not well constrained. In this study, a rock magnetic cyclostratigraphy, based on high-resolution analysis (2440 samples) of magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) intensity variations, was developed for the 55.1-m-thick, Early Triassic Daye Formation at the Daxiakou section, Hubei province in South China. The Daye Formation shows exceptionally well-preserved lithological cycles with alternations of thin-bedded mudstone, marl and limestone, which are closely tracked by the MS and ARM variations. Power spectral, wavelet and amplitude modulation (AM) analysis of the ARM and MS series reveal strong evidence for the presence of Milankovitch to sub-Milankovitch frequencies dominated by precession index signal and 4-5 ka cycles. Cycles expressed by variations in MS and ARM were likely controlled by the input of fine-grained detrital magnetite, which in turn may be driven by astronomically induced changes in monsoon intensity in the equatorial eastern Tethys during the Early Triassic greenhouse period. On the basis of the 100-ka tuning results, the astronomically constrained duration of

Petrography of Permian "Gondwana" coals from boreholes in northwestern Bangladesh, based on semiautomated reflectance scanning

USGS Publications Warehouse

Bostick, N.H.; Betterton, W.J.; Gluskoter, H.J.; Nazrul, Islam M.

1991-01-01

Drilling through Quaternary alluvium and Tertiary cover at low-gravity anomalies in northwestern Bangladesh showed the presence of Permian sedimentary rocks in depressions that may be as much as a thousand meters deep in the crystalline basement. These Permian strata include low-sulfur, high-volatile bituminous coals in beds as thick as 15 m. The maceral group composition of these coals was determined by semiautomated reflectance scanning with a motorized microscope stage, rather than by point counting. This method was chosen to give objectively recorded raw analytical data and to provide a graphical picture of each sample. The coals are mostly "Gondwana" type (poorly layered "plum pudding" with abundant minerals and inertinite in a vitrinite groundmass) that would be classed as semi-dull (inerto-gelitite) coals. However, six samples have more than 70% vitrinite. None of the samples would be classed as sapropelic (liptinitic). The upper, middle, and lower main seams in borehole GDH-45 were sampled in 10 benches (0.1-3 m thick) each. Inertinite ranges from 7 to 100 vol% (mineral free basis) in individual benches, but composite seam averages are 41, 54 and 67%. Inertinite increases toward the top of two main seams so the bottom would yield the most valuable first mine slices. Some benches with extremely high inertinite content, such as the top 7 m of the lower thick seam, might be mined specially for blending with foreign low-inert coals to increase coke strength. The free swelling index reaches 7.5 in several vitrinite-rich benches, which can indicate good coking coal. Much of the vitrinite is fluorescent, which indicates secondary bituminization characteristic of vitrinite in good coking coals. Ash yields range from 8 to 52%, with composite seam averages of 15, 14 and 24%. Rare visible pyrite is in veinlets or small nodules; framboids and dispersed pyrite are absent. In borehole GDH-40 near Barapukuria (200-500 m depth), the mean random reflectance of vitrinite "A

Permian-Triassic boundary microbialites at Zuodeng Section, Guangxi Province, South China: Geobiology and palaeoceanographic implications

NASA Astrophysics Data System (ADS)

Fang, Yuheng; Chen, Zhong-Qiang; Kershaw, Stephen; Yang, Hao; Luo, Mao

2017-05-01

A previously unknown microbialite bed in the Permian-Triassic (P-Tr) boundary beds of Zuodeng section, Tiandong County, Guangxi, South China comprises a thin (5 cm maximum thickness) stromatolite in the lower part and the remaining 6 m is thrombolite. The Zuodeng microbialite has a pronounced irregular contact between the latest Permian bioclastic limestone and microbialite, as in other sites in the region. The stromatolite comprises low-relief columnar and broad domal geometries, containing faint laminations. The thrombolite displays an irregular mixture of sparitic dark coloured altered microbial fabric and light coloured interstitial sediment in polished blocks. Abundant microproblematic calcimicrobe structures identified here as Gakhumella are preserved in dark coloured laminated areas of the stromatolite and sparitic areas in thrombolites (i.e. the calcimicrobial part, not the interstitial sediment) and are orientated perpendicular to stromatolitic laminae. Each Gakhumella individual has densely arranged segments, which form a column- to fan-shaped structure. Single segments are arch-shaped and form a thin chamber between segments. Gakhumella individuals in the stromatolite and thrombolite are slightly different from each other, but are readily distinguished from the Gakhumella- and Renalcis-like fossils reported from other P-Tr boundary microbialites in having a smaller size, unbranching columns and densely arranged, arch-shaped segments. Renalcids usually possess a larger body size and branching, lobate outlines. Filament sheath aggregates are also observed in the stromatolite and they are all orientated in one direction. Both Gakhumella and filament sheath aggregates may be photosynthetic algae, which may have played an important role in constructing the Zuodeng microbialites. Other calcimicrobes in the Zuodeng microbialite are spheroids, of which a total of five morphological types are recognized from both stromatolite and thrombolite: (1) sparry calcite

The Permian-Triassic granitoids in Bayan Obo, North China Craton: A geochemical and geochronological study

NASA Astrophysics Data System (ADS)

Ling, Ming-Xing; Zhang, Hong; Li, He; Liu, Yu-Long; Liu, Jian; Li, Lin-Qing; Li, Cong-Ying; Yang, Xiao-Yong; Sun, Weidong

2014-03-01

Granitoids near the Bayan Obo giant rare earth element (REE) deposit at the north margin of the North China Craton (NCC), the world's largest light REE (LREE) deposit, have been taken by some authors as the key factors that controlled the mineralization. In contrast, others proposed that the REE deposit has been partially destructed by these granitoids. Here we report systematic studies on geochronology and geochemical characteristics of granitoids of different distances from the orebodies, to investigate the genesis and their relationship to the giant Bayan Obo deposit. Granitoids studied here, including granites and quartz monzonites, are peraluminous with A/CNK = 0.99-1.11, LREE enriched and heavy REE (HREE) depleted, with variable REE concentrations (total REE = 54-330 ppm) and large negative Eu anomaly (δEu = 0.19-0.70). The REE patterns are distinct from those of ore-bearing dolomites. Some samples have slightly higher LREE concentrations, which may have been contaminated by the orebodies during intrusion. Trace elements of the granitoids are characterized by positive Pb anomaly, strong negative Ti anomaly and Nb, Ta and Sr anomalies. The granites exhibit negative Ba anomaly. The granitoids plot within the post-collision granite field in the Pearce diagram, which is consistent with the tectonic regime. The quartz monzonites and one granite have A-type granite characteristics and belong to the A2 subgroup. Zircons in these granitoids have high Th/U values, which are typical for magmatic zircons. High precision U-Pb dating for these zircons by secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) yields Permian-Triassic 206Pb/238U ages ranging from 243.2 to 293.8 Ma. The formation of the granitoids is > 55 Ma later than the latest ore forming age. The zircons have low La concentrations (0.02-12 ppm), high (Sm/La)N (0.8-685) and Ce/Ce* (1.4-80). The Ti-in-zircon temperature of the granitoids ranges

The Permian palynological Lueckisporites-Weylandites Biozone in the San Rafael Block and its correlation in Western Gondwana

NASA Astrophysics Data System (ADS)

Vázquez, María Soledad; Césari, Silvia N.

2017-07-01

A palynological study of the Yacimiento Los Reyunos Formation (San Rafael Block) Argentina was carried out in order to correlate the palynological data with other Permian assemblages and biozones from South America. The unit is included in the Cochicó Group deposited under the volcanic influence of the Choiyoi event. The palynological assemblages recovered from subsurface samples show a dominance of taeniate bisaccates like Corisaccites, Lueckisporites, Lunatisporites, Protohaploxypinus, Vittatina and Weylandites. A Lueckisporites complex, which would have biostratigraphical value, is established to include species of Lueckisporites, Corisaccites and Staurosaccites showing a wide morphological variation. The composition of the assemblages allows their inclusion in the Lueckisporites/Weylandites Biozone of Argentina, which is closely related to other biozones from southern South America. Analysis of the distribution of the species using cluster analysis confirms its similarity with the biozones from Bolivia and Brazil. Radiometric datings suggest an age not older than Kungurian for the occurrence of these assemblages in the Southern Hemisphere.

Late Permian marine ecosystem collapse began in deeper waters: evidence from brachiopod diversity and body size changes.

PubMed

He, W-H; Shi, G R; Twitchett, R J; Zhang, Y; Zhang, K-X; Song, H-J; Yue, M-L; Wu, S-B; Wu, H-T; Yang, T-L; Xiao, Y-F

2015-03-01

Analysis of Permian-Triassic brachiopod diversity and body size changes from different water depths spanning the continental shelf to basinal facies in South China provides insights into the process of environmental deterioration. Comparison of the temporal changes of brachiopod diversity between deepwater and shallow-water facies demonstrates that deepwater brachiopods disappeared earlier than shallow-water brachiopods. This indicates that high environmental stress commenced first in deepwater settings and later extended to shallow waters. This environmental stress is attributed to major volcanic eruptions, which first led to formation of a stratified ocean and a chemocline in the outer shelf and deeper water environments, causing the disappearance of deep marine benthos including brachiopods. The chemocline then rapidly migrated upward and extended to shallow waters, causing widespread mass extinction of shallow marine benthos. We predict that the spatial and temporal patterns of earlier onset of disappearance/extinction and ecological crisis in deeper water ecosystems will be recorded during other episodes of rapid global warming. © 2014 John Wiley & Sons Ltd.

Long-term paradoxical aftermath of the Early Permian climatic warming in the Northern Hemisphere: biotic and abiotic aspects

NASA Astrophysics Data System (ADS)

Kossovaya, Olga

2014-05-01

Far distant influence of the climatic changes is rather variable and sometimes paradoxical. One of the examples is the flourish of the Photozoan association in the Northern Hemisphere during time of Southern Hemisphere glaciation (P2) and it following collapse in the interglacial phase. Modelling of the possible extrinsic factors using isotope data from the Urals has demonstrated the complex succession of abiotic changes including circulation changes and penetration of cold water from Northern Panthalassa. The invasion of cold water into the Uralian Basin led to disarray of the coastal circulation and rising of cold water via upwelling. It was resulted by change of biota and wide distribution of the heterozoan biota. The replacement took place both in carbonate ramp and reef facies. The depletion of δ18O during the early Artinskian was demonstrated by analyses of the biogenic carbonates from Belaya Gora (Most) section. This coincides with the previously known trend for d18O shown for low latitudes from the Sakmarian to early Artinskian with a minimum during the middle Artinskian and is in accordance with recent data from the South Urals. The heterochrony of the impact in the far-distant and discrete photozoan assemblages depends on their bathymetric and paleo-latitudinal position.

Permian ultrafelsic A-type granite from Besar Islands group, Johor, peninsular Malaysia

NASA Astrophysics Data System (ADS)

Ghani, Azman A.; Hazad, Fatin Izzani; Jamil, Azmiah; Xiang, Quek Long; Atiqah Wan Ismail, Wan Nur; Chung, Sun-Lin; Lai, Yu-Ming; Roselee, Muhammad Hatta; Islami, Nur; Nyein, Kyaw Kyaw; Amir Hassan, Meor Hakif; Abu Bakar, Mohd Farid; Umor, Mohd Rozi

2014-12-01

The granitic rocks of the peninsula have traditionally been divided into two provinces, i.e., Western and Eastern provinces, corresponding to S- and I-type granite respectively. The Western Province granite is characterised by megacrystic and coarse-grained biotite, tin-mineralised, continental collision granite, whereas, the Eastern Province granite is bimodal I-type dominated by granodiorite and associated gabbroic of arc type granite. This paper reports the occurrence of an A-type granite from peninsular Malaysia. The rocks occur in the Besar, Tengah, and Hujung islands located in the southeastern part of the peninsula. The granite is highly felsic with SiO2 ranging from 75.70% to 77.90% (differentiation index = 94.2-97.04). It is weakly peraluminous (average ACNK =1.02), has normative hypersthene (0.09-2.19%) and high alkali content (8.32-8.60%). The granites have many A-type characteristics, among them are shallow level of emplacement, high Ga, FeT/MgO and low P, Sr, Ti, CaO and Nb. Calculated zircon saturation temperatures for the Besar magma ranging from 793 ∘ to 806 ∘C is consistent with high temperature partial melting of a felsic infracrustal source which is taken as one of the mechanisms to produce A-type magma. The occurrence of the A-type granite can be related to the extensional back arc basin in the Indo-China terrane during the earliest Permian.

Boreal earliest Triassic biotas elucidate globally depauperate hard substrate communities after the end-Permian mass extinction.

PubMed

Zatoń, Michał; Niedźwiedzki, Grzegorz; Blom, Henning; Kear, Benjamin P

2016-11-08

The end-Permian mass extinction constituted the most devastating biotic crisis of the Phanerozoic. Its aftermath was characterized by harsh marine conditions incorporating volcanically induced oceanic warming, widespread anoxia and acidification. Bio-productivity accordingly experienced marked fluctuations. In particular, low palaeolatitude hard substrate communities from shallow seas fringing Western Pangaea and the Tethyan Realm were extremely impoverished, being dominated by monogeneric colonies of filter-feeding microconchid tubeworms. Here we present the first equivalent field data for Boreal hard substrate assemblages from the earliest Triassic (Induan) of East Greenland. This region bordered a discrete bio-realm situated at mid-high palaeolatitude (>30°N). Nevertheless, hard substrate biotas were compositionally identical to those from elsewhere, with microconchids encrusting Claraia bivalves and algal buildups on the sea floor. Biostratigraphical correlation further shows that Boreal microconchids underwent progressive tube modification and unique taxic diversification concordant with changing habitats over time. We interpret this as a post-extinction recovery and adaptive radiation sequence that mirrored coeval subequatorial faunas, and thus confirms hard substrate ecosystem depletion as a hallmark of the earliest Triassic interval globally.

Boreal earliest Triassic biotas elucidate globally depauperate hard substrate communities after the end-Permian mass extinction

NASA Astrophysics Data System (ADS)

Zatoń, Michał; Niedźwiedzki, Grzegorz; Blom, Henning; Kear, Benjamin P.

2016-11-01

The end-Permian mass extinction constituted the most devastating biotic crisis of the Phanerozoic. Its aftermath was characterized by harsh marine conditions incorporating volcanically induced oceanic warming, widespread anoxia and acidification. Bio-productivity accordingly experienced marked fluctuations. In particular, low palaeolatitude hard substrate communities from shallow seas fringing Western Pangaea and the Tethyan Realm were extremely impoverished, being dominated by monogeneric colonies of filter-feeding microconchid tubeworms. Here we present the first equivalent field data for Boreal hard substrate assemblages from the earliest Triassic (Induan) of East Greenland. This region bordered a discrete bio-realm situated at mid-high palaeolatitude (>30°N). Nevertheless, hard substrate biotas were compositionally identical to those from elsewhere, with microconchids encrusting Claraia bivalves and algal buildups on the sea floor. Biostratigraphical correlation further shows that Boreal microconchids underwent progressive tube modification and unique taxic diversification concordant with changing habitats over time. We interpret this as a post-extinction recovery and adaptive radiation sequence that mirrored coeval subequatorial faunas, and thus confirms hard substrate ecosystem depletion as a hallmark of the earliest Triassic interval globally.

Late Carboniferous to Early Permian magmatic pulses in the Uliastai continental margin linked to slab rollback: Implications for evolution of the Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

Chai, Hui; Wang, Qingfei; Tao, Jixiong; Santosh, M.; Ma, Tengfei; Zhao, Rui

2018-05-01

The Paleo Asian Ocean underwent a protracted closure history during Late Paleozoic. Here we investigate the magmatic evolution during this process based on a detailed study in the Baiyinwula region along the Uliastai continental margin. The major rock types in this area are Late Carboniferous-Early Permian volcanic sequences and coeval intrusions. We identified four stages of magmatic evolution based on the diverse assemblages and their precise isotopic ages. The first stage is represented by andesites with a zircon 206Pb/238U age of ca. 326 ± 12 Ma. These rocks are metaluminous to weakly peraluminous, high-K calc-alkaline, and possess high Na2O/K2O ratios in the range of 1.23 to 2.45. They also display enrichment of large ion lithophile elements (LILE) and depletion of high field strength elements (HFSE), with markedly positive zircon εHf (t) varying from 8.1 to 15.6.The geochemical features of these andesites are similar to those of typical arc volcanic rocks. The second stage includes granodiorites emplaced at 318.6 + 1.8 Ma. The rocks are high-K calc-alkaline with A/CNK values ranging from 0.95 to 1.06, and show enrichment in LILE and depletion in HFSE. They show geochemical affinities to adakites, with high Sr and low Y and Yb contents, indicating magma derivation from thickened lower crust. Zircon grains from these rocks display positive initial εHf (t) values ranging from 11.1 to 14.6 with corresponding two-stage Hf model ages (TDM2) of 394-622 Ma. The third stage consists of syenogranite together with a volcanic suite ranging in composition from rhyolite todacite, which formed during 303.4 ± 1.2 to 285.1 ± 2.2 Ma. They possess elevated silica and alkali contents, high FeOt/MgO and Ga/Al ratios, low Al2O3, MgO and CaO contents, and high Rb, Y, Nb, Ce, Zr, Y, and Ga contents, strong negative Ba, Sr and Eu anomalies, showing I- to A-type granitic affinities. Zircons in these rocks show elevated Hf isotopic compositions (εHf (t) = 9.9 to 14.6) with TDM2

Geochronological and sedimentological evidences of Panyangshan foreland basin for tectonic control on the Late Paleozoic plate marginal orogenic belt along the northern margin of the North China Craton

NASA Astrophysics Data System (ADS)

Li, Jialiang; Zhou, Zhiguang; He, Yingfu; Wang, Guosheng; Wu, Chen; Liu, Changfeng; Yao, Guang; Xu, Wentao; Zhao, Xiaoqi; Dai, Pengfei

2017-08-01

There is a wide support that the Inner Mongolia Palaeo-uplift on the northern margin of the North China Craton has undergone an uplifting history. However, when and how did the uplift occurred keeps controversial. Extensive field-based structural, metamorphic, geochemical, geochronological and geophysical investigations on the Inner Mongolia Palaeo-uplift, which suggested that the Inner Mongolia Palaeo-uplift was an uplifted region since the Early Precambrian or range from Late Carboniferous-Early Jurassic. The geochemical characteristics of the Late Paleozoic to Early Mesozoic intrusive rocks indicated that the Inner Mongolia Palaeo-uplift was an Andean-type continental margin that is the extensional tectonic setting. To address the spatial and temporal development of the Inner Mongolia Palaeo-uplift, we have carried out provenance analysis of Permian sedimentary rocks which collected from the Panyangshan basin along the northern margin of the North China Craton. The QFL diagram revealed a dissected arc-recycled orogenic tectonic setting. Moreover, the framework grains are abundant with feldspar (36-50%), indicating the short transport distance and unstable tectonic setting. Detrital zircon U-Pb analysis ascertained possible provenance information: the Precambrian basement ( 2490 and 1840 Ma) and continental arc magmatic action ( 279 and 295 Ma) along the northern margin of the North China Craton. The projection in rose diagrams of the mean palaeocurrent direction, revealing the SSW and SSE palaeoflow direction, also shows the provenance of the Panyangshan basin sources mainly from the Inner Mongolia Palaeo-uplift. The andesite overlying the Naobaogou Formation has yielded U-Pb age of 277.3 ± 1.4 Ma. The additional dioritic porphyry dike intruded the Naobaogou and Laowopu Formations, which has an emplacement age of 236 ± 1 Ma. The above data identify that the basin formed ranges from Early Permian to Middle Triassic (277-236 Ma). Accordingly, the Inner Mongolia

Geochronological and sedimentological evidences of Panyangshan foreland basin for tectonic control on the Late Paleozoic plate marginal orogenic belt along the northern margin of the North China Craton

NASA Astrophysics Data System (ADS)

Li, Jialiang; Zhou, Zhiguang; He, Yingfu; Wang, Guosheng; Wu, Chen; Liu, Changfeng; Yao, Guang; Xu, Wentao; Zhao, Xiaoqi; Dai, Pengfei

2018-06-01

There is a wide support that the Inner Mongolia Palaeo-uplift on the northern margin of the North China Craton has undergone an uplifting history. However, when and how did the uplift occurred keeps controversial. Extensive field-based structural, metamorphic, geochemical, geochronological and geophysical investigations on the Inner Mongolia Palaeo-uplift, which suggested that the Inner Mongolia Palaeo-uplift was an uplifted region since the Early Precambrian or range from Late Carboniferous-Early Jurassic. The geochemical characteristics of the Late Paleozoic to Early Mesozoic intrusive rocks indicated that the Inner Mongolia Palaeo-uplift was an Andean-type continental margin that is the extensional tectonic setting. To address the spatial and temporal development of the Inner Mongolia Palaeo-uplift, we have carried out provenance analysis of Permian sedimentary rocks which collected from the Panyangshan basin along the northern margin of the North China Craton. The QFL diagram revealed a dissected arc-recycled orogenic tectonic setting. Moreover, the framework grains are abundant with feldspar (36-50%), indicating the short transport distance and unstable tectonic setting. Detrital zircon U-Pb analysis ascertained possible provenance information: the Precambrian basement ( 2490 and 1840 Ma) and continental arc magmatic action ( 279 and 295 Ma) along the northern margin of the North China Craton. The projection in rose diagrams of the mean palaeocurrent direction, revealing the SSW and SSE palaeoflow direction, also shows the provenance of the Panyangshan basin sources mainly from the Inner Mongolia Palaeo-uplift. The andesite overlying the Naobaogou Formation has yielded U-Pb age of 277.3 ± 1.4 Ma. The additional dioritic porphyry dike intruded the Naobaogou and Laowopu Formations, which has an emplacement age of 236 ± 1 Ma. The above data identify that the basin formed ranges from Early Permian to Middle Triassic (277-236 Ma). Accordingly, the Inner Mongolia

Sedimentary record of late Paleozoic to Recent tectonism in central Asia — analysis of subsurface data from the Turan and south Kazak domains

NASA Astrophysics Data System (ADS)

Thomas, J. C.; Cobbold, P. R.; Shein, V. S.; Le Douaran, S.

1999-11-01

The Turan and south Kazak domains (TSK) are in central Asia, between the Caspian Sea and the Tien Shan. The area is covered by sediments, deposited since the Late Permian during a series of tectonic events closely related to the history of two oceanic domains, Paleotethys and Neotethys. Sedimentary basins on the TSK therefore provide constraints on the tectonic development of the southern margin of Eurasia since the Late Permian. Our study is based on structure-contour maps and isopach maps of five key stratigraphic markers, of Late Permian to Tertiary age. Isopach maps help locate major faults and delimit sedimentary basins, providing information on vertical motions and, in some instances, horizontal motions. Subsidence associated with extension appears to have dominated the TSK, from the Late Permian to the Eocene. The extension may have been of back-arc type in southern Eurasia, next to the active margin, where the Paleotethys and Neotethys successively subducted toward the north. Here, sedimentary basins are both wide and deep (up to 15 km). During the Mesozoic, two compressional events of regional significance occurred in association with accretion of continental blocks at the southern margin of Eurasia. The first one, at the end of the Triassic, led to strong selective inversion of basins over the Turan domain. The second one, during the Late Jurassic-Early Cretaceous, had weaker effects. Since the Oligocene, following collision of both India and Arabia with Eurasia, inversion has become more generalized and compressional basins have formed on the TSK. Throughout the entire history of development of the TSK, from the Late Permian to the Tertiary, structures of Paleozoic and early Mesozoic age have exerted a strong control on sedimentation and especially on the location of depocenters. The south Kazak domain has registered little subsidence, in comparison with the Turan domain, where some basins have become very deep.

Early Triassic development of a foreland basin in the Canadian high Arctic: Implications for a Pangean Rim of Fire

NASA Astrophysics Data System (ADS)

Hadlari, Thomas; Dewing, Keith; Matthews, William A.; Alonso-Torres, Daniel; Midwinter, Derrick

2018-06-01

Following the amalgamation of Laurasia and Gondwana to form Pangea, some Triassic tectonic models show an encircling arc system called the "Pangean Rim of Fire". Here we show that the stratigraphy and Early Triassic detrital zircon provenance of the Sverdrup Basin in the Canadian Arctic is most consistent with deposition in a retro-arc foreland basin. Late Permian and Early Triassic volcanism was accompanied by relatively high rates of subsidence leading to a starved basin with volcanic input from a magmatic arc to the northwest. The mostly starved basin persisted through the Middle and Late Triassic with nearly continuous input of volcanic ash recorded as bentonites on the northwestern edge of the basin. In the latest Triassic it is interpreted that decreasing subsidence and a significant influx of sand-grade sediment when the arc was exhumed led to filling of the basin at the end of an orogenic cycle. Combined with other hints of Early Triassic arc activity along the western margin of Laurentia we propose that the Pangean Rim of Fire configuration spanned the entire Triassic. This proposed configuration represents the ring of external subduction zones that some models suggest are necessary for the breakup of supercontinents such as Pangea.

Abiotic and biotic responses to Milankovitch-forced megamonsoon and glacial cycles recorded in South China at the end of the Late Paleozoic Ice Age

NASA Astrophysics Data System (ADS)

Fang, Qiang; Wu, Huaichun; Hinnov, Linda A.; Tian, Wenqian; Wang, Xunlian; Yang, Tianshui; Li, Haiyan; Zhang, Shihong

2018-04-01

At the end of the Late Paleozoic Ice Age (LPIA) from late Early Permian to early Late Permian, the global climate was impacted by a prevailing megamonsoon and Gondwanan deglaciation. To better understand the abiotic and biotic responses to Milankovitch-forced climate changes during this time period, multi-element X-ray fluorescence (XRF) geochemistry analyses were conducted on 948 samples from the late Early-late Middle Permian Maokou Formation at Shangsi, South China. The Fe/Ti, S/Ti, Ba/Ti and Ca time series, which were calibrated with an existing "floating" astronomical time scale (ATS), show the entire suite of Milankovitch rhythms including 405 kyr long eccentricity, 128 and 95 kyr short eccentricity, 33 kyr obliquity and 20 kyr precession. Spectral coherency and cross-phase analysis reveals that chemical weathering (monitored by Fe/Ti) and upwelling (captured by S/Ti and Ba/Ti) are nearly antiphase in the precession band, which suggests a contrast between summer and winter monsoon intensities. Strong obliquity signal in the Ba/Ti series is proposed to derive from changes in thermohaline circulation intensity from glaciation dynamics in southern Gondwana. The abundance of foraminifer, brachiopod and ostracod faunas within the Maokou Formation were mainly controlled by the 1.1 Myr obliquity modulation cycle. The obliquity-forced high-nutrient and oxygen-depleted conditions generally produced a benthic foraminifer bloom, but threatened the brachiopod and ostracod faunas.

Terrestrial Origin of Viviparity in Mesozoic Marine Reptiles Indicated by Early Triassic Embryonic Fossils

PubMed Central

Motani, Ryosuke; Jiang, Da-yong; Tintori, Andrea; Rieppel, Olivier; Chen, Guan-bao

2014-01-01

Viviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia), which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic). This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction. PMID:24533127

Assessment of continuous oil resources in the Wolfcamp shale of the Midland Basin, Permian Basin Province, Texas, 2016

USGS Publications Warehouse

Gaswirth, Stephanie B.

2017-03-06

The U.S. Geological Survey completed a geology-based assessment of undiscovered, technically recoverable continuous petroleum resources in the Wolfcamp shale in the Midland Basin part of the Permian Basin Province of west Texas. This is the first U.S. Geological Survey evaluation of continuous resources in the Wolfcamp shale in the Midland Basin. Since the 1980s, the Wolfcamp shale in the Midland Basin has been part of the “Wolfberry” play. This play has traditionally been developed using vertical wells that are completed and stimulated in multiple productive stratigraphic intervals that include the Wolfcamp shale and overlying Spraberry Formation. Since the shift to horizontal wells targeting the organic-rich shale of the Wolfcamp, more than 3,000 horizontal wells have been drilled and completed in the Midland Basin Wolfcamp section. The U.S. Geological Survey assessed technically recoverable mean resources of 20 billion barrels of oil and 16 trillion cubic feet of associated gas in the Wolfcamp shale in the Midland Basin.

The Permian Whitehill Formation (Karoo Basin, South Africa): deciphering the complexity and potential of an unconventional gas resource

NASA Astrophysics Data System (ADS)

Götz, Annette E.

2014-05-01

A key energy policy objective of the South African government is to diversify its energy mix from coal which constitutes 85% of the current mix. Gas will play a key role in the future South African economy with demand coming from electricity generation and gas-to-liquids projects. A study on world shale reserves conducted by the Energy Information Agency (EIA) in 2011 concluded that there could be as much as 485 Tcf recoverable reserves of shale gas in the South African Karoo Basin. However, the true extent and commercial viability is still unknown, due to the lack of exploration drilling and modern 3D seismic. The present study compiles existing data from literature review and new data from outcrop analogue studies on the Permian Whitehill Formation, the main target formation for future shale gas production, including thickness, depth, maturity, TOC, lithologies, sedimentary and organic facies, and dolerite occurrence to provide a first reference dataset for further investigations and resource estimates.

Petrochemistry and zircon U-Pb geochronology of granitic rocks in the Wang Nam Khiao area, Nakhon Ratchasima, Thailand: Implications for petrogenesis and tectonic setting

NASA Astrophysics Data System (ADS)

Fanka, Alongkot; Tsunogae, Toshiaki; Daorerk, Veerote; Tsutsumi, Yukiyasu; Takamura, Yusuke; Sutthirat, Chakkaphan

2018-05-01

Carboniferous biotite granite, Late Permian hornblende granite, and Triassic biotite-hornblende granite, all of which belong to the Eastern Granite Belt, expose in the Wang Nam Khiao area, Nakhon Ratchasima, northeastern Thailand. The Carboniferous biotite granite is dominated by quartz, K-feldspar, plagioclase, and biotite. The Late Permian hornblende granite contains dominant assemblages of plagioclase, quartz, K-feldspar, hornblende, and minor amount of biotite, while the Triassic biotite-hornblende granite consists of quartz, plagioclase, K-feldspar with small amounts of biotite, and hornblende. The REE patterns with steep decrease from light to heavy REE together with the LILE (e.g. K, Sr) enrichment and depletion of some particular HFSE (e.g. Nb, Ti) indicate low degree of partial melting. Mineral chemistry of biotite and hornblende in the granites reflects crystallization from hydrous calc-alkaline arc-derived magmas possibly formed by subduction. Amphibole-plagioclase thermometry and Al-in-hornblende barometry indicate that the Late Permian hornblende granite and the Triassic biotite-hornblende granite may have equilibrated at 3.0-5.8 kbar/700-820 °C and 2.0-3.2 kbar/600-750 °C, respectively, in the middle-upper crust (about 10-15 km depth). Zircon U-Pb geochronology of the Carboniferous biotite granite, Late Permian hornblende granite and Triassic biotite-hornblende granite yielded intrusion ages of 314.6-284.9 Ma, 253.4 Ma, and 237.8 Ma, respectively, which implies multiple episodes of arc-magmatism formed by Palaeo-Tethys subduction beneath Indochina Terrane during Late Carboniferous/Early Permian, Late Permian and Middle Triassic.

Constraints on Late Paleozoic Ocean Response to Climate Change Based on Brachiopod δ11B and 87Sr/86Sr

NASA Astrophysics Data System (ADS)

Legett, S. A.; Rasbury, T.; Grossman, E. L.; Hemming, G.

2017-12-01

In order to understand the possible effects of climate change on present day oceans, it is important to determine how marine systems responded to climate change in the past. This study uses δ11B values from well-preserved Carboniferous and Permian brachiopods as well as models to examine chemical trends in seawater and how these relate to long- and short-term climate changes. Our results show that δ11B rises rapidly going into the Carboniferous from a low of 10‰ to a high of 17‰ and remains relatively stable through the Carboniferous, despite the initiation of glaciation in the Mid Carboniferous. At the Carboniferous-Permian boundary, δ11B declines into the Early Permian before reaching a low at the Sakmarian. This decline in δ11B is coincident with the decrease in 87Sr/86Sr through this interval, which corresponds to evidence for aridity going into the Permian. We hypothesize that a reduction in silicate weathering drives an increase in atmospheric pCO2 and a subsequent lowering of ocean pH going into the Permian. This is consistent with our interpretation of the Carboniferous-Permian boundary, as a major mechanism for controlling seawater boron isotope composition is the adsorption of borate on clays, removing isotopically light boron and thus leaving seawater boron isotopically heavy. Therefore, at lower pH seawater should become isotopically lighter as this mechanism for removal is reduced. These hypotheses are supported by our initial modeling results of the B and Sr isotopic budgets of the ocean during the Late Paleozoic.

Early Triassic wrinkle structures on land: stressed environments and oases for life

NASA Astrophysics Data System (ADS)

Chu, Daoliang; Tong, Jinnan; Song, Haijun; Benton, Michael J.; Bottjer, David J.; Song, Huyue; Tian, Li

2015-06-01

Wrinkle structures in rocks younger than the Permian-Triassic (P-Tr) extinction have been reported repeatedly in marine strata, but rarely mentioned in rocks recording land. Here, three newly studied terrestrial P-Tr boundary rock succession in North China have yielded diverse wrinkle structures. All of these wrinkles are preserved in barely bioturbated shore-shallow lacustrine siliciclastic deposits of the Liujiagou Formation. Conversely, both the lacustrine siliciclastic deposits of the underlying Sunjiagou Formation and the overlying Heshanggou Formation show rich bioturbation, but no wrinkle structures or other microbial-related structures. The occurrence of terrestrial wrinkle structures in the studied sections reflects abnormal hydrochemical and physical environments, presumably associated with the extinction of terrestrial organisms. Only very rare trace fossils occurred in the aftermath of the P-Tr extinction, but most of them were preserved together with the microbial mats. This suggests that microbial mats acted as potential oases for the surviving aquatic animals, as a source of food and oxygen. The new finds suggests that extreme environmental stresses were prevalent both in the sea and on land through most of the Early Triassic.

Rapid enhancement of chemical weathering recorded by extremely light seawater lithium isotopes at the Permian-Triassic boundary

NASA Astrophysics Data System (ADS)

Sun, He; Xiao, Yilin; Gao, Yongjun; Zhang, Guijie; Casey, John F.; Shen, Yanan

2018-04-01

Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian–Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light δ7Li to the ocean realm. The seawater Li isotope excursion started ≥300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered CO2 release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction.

Late Paleozoic fusulinids from Sonora, Mexcio: importance for interpretation of depositional settings, biogeography, and paleotectonics

USGS Publications Warehouse

Stevens, Calvin H.; Poole, Forrest G.; Amaya-Martínez, Ricardo

2014-01-01

Three sets of fusulinid faunas in Sonora, Mexico, discussed herein, record different depositional and paleotectonic settings along the southwestern margin of Laurentia (North America) during Pennsylvanian and Permian time. The settings include: offshelf continental rise and ocean basin (Rancho Nuevo Formation in the Sonora allochthon), shallow continental shelf (La Cueva Limestone), and foredeep basin on the continental shelf (Mina México Formation). Our data represent 41 fusulinid collections from 23 localities with each locality providing one to eight collections.Reworked fusulinids in the Middle and Upper Pennsylvanian part of the Rancho Nuevo Formation range in age from Desmoinesian into Virgilian (Moscovian-Gzhelian). Indigenous Permian fusulinids in the La Cueva Limestone range in age from middle or late Wolfcampian to middle Leonardian (late Sakmarian-late Artinskian), and reworked Permian fusulinids in the Mina México Formation range in age from early to middle Leonardian (middle-late Artinskian). Conodonts of Guadalupian age occur in some turbidites in the Mina México Formation, indicating the youngest foredeep deposit is at least Middle Permian in age. Our fusulinid collections indicate a hiatus of at least 10 m.y. between the youngest Pennsylvanian (Virgilian) rocks in the Sonora allochthon and the oldest Permian (middle Wolfcampian) rocks in the region.Most fusulinid faunas in Sonora show affinities to those of West Texas, New Mexico, and Arizona; however, some genera and species are similar to those in southeastern California. As most species are similar to those east of the southwest-trending Transcontinental arch in New Mexico and Arizona, this arch may have formed a barrier preventing large-scale migration and mixing of faunas between the southern shelf of Laurentia in northwestern Mexico and the western shelf in the southwestern United States.The Sonora allochthon, consisting of pre-Permian (Lower Ordovician to Upper Pennsylvanian) deep

Some contrasting biostratigraphic links between the Baker and Olds Ferry Terranes, eastern Oregon

USGS Publications Warehouse

Nestell, Merlynd K.; Blome, Charles D.

2016-01-01

New stratigraphic and paleontologic data indicate that ophiolitic melange windows in the Olds Ferry terrane of eastern Oregon contain limestone blocks and chert that are somewhat different in age than those present in the adjacent Baker terrane melange. The melange windows in the Olds Ferry terrane occur as inliers in the flyschoid Early and Middle Jurassic age Weatherby Formation, which depositionally overlies the contact between the melange-rich Devonian to Upper Triassic rocks of the Baker terrane on the north, and Upper Triassic and Early Jurassic volcanic arc rocks of the Huntington Formation on the south. The Baker terrane and Huntington Formation represent fragments of a subduction complex and related volcanic island arc, whereas the Weatherby Formation consists of forearc basin sedimentary deposits. The tectonic blocks in the melange windows of the Weatherby Formation (in the Olds Ferry terrane) are dated by scarce biostratigraphic evidence as Upper Pennsylvanian to Lower Permian and Upper Triassic. In contrast, tectonic blocks of limestone in theBaker terrane yield mostly fusulinids and small foraminifers of Middle Pennsylvanian Moscovian age at one locality.Middle Permian (Guadalupian) Tethyan fusulinids and smaller foraminifers (neoschwagerinids and other Middle Permian genera) are present at a few other localities. Late Triassic conodonts and bryozoans are also present in a few of the Baker terrane tectonic blocks. These limestone blocks are generally embedded in Permian and Triassic radiolarian bearing chert or argillite. Based on conodont, radiolarian and fusulinid data, the age limits of the meange blocks in the Weatherby Formation range from Pennsylvanian to Late Triassic.

Specialised emission pattern of leaf trace in a late Permian (253 million-years old) conifer

PubMed Central

Wei, Hai-Bo; Feng, Zhuo; Yang, Ji-Yuan; Chen, Yu-Xuan; Shen, Jia-Jia; He, Xiao-Yuan

2015-01-01

Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith, primary and secondary xylems. A complete leaf traces emission pattern of a conifer is presented for the first time from the late Palaeozoic. Three to five monarch leaf traces are grouped in clusters, arranged in a helical phyllotaxis. The leaf traces in each cluster can be divided into upper, middle and lower portions, and initiate at the pith periphery and cross the wood horizontally. The upper leaf trace increases its diameter during the first growth increment and then diminishes completely, which indicates leaf abscission at the end of the first year. The middle trace immediately bifurcates once or twice to form two or three vascular bundles. The lower trace persists as a single bundle during its entire length. The intricate leaf trace dynamics indicates this fossil plant had a novel evolutionary habit by promoting photosynthetic capability for the matured plant. PMID:26198410

Water Issues Related to Transitioning from Conventional to Unconventional Oil Production in the Permian Basin.

PubMed

Scanlon, Bridget R; Reedy, Robert C; Male, Frank; Walsh, Mark

2017-09-19

The Permian Basin is being transformed by the "shale revolution" from a major conventional play to the world's largest unconventional play, but water management is critical in this semiarid region. Here we explore evolving issues associated with produced water (PW) management and hydraulic fracturing water demands based on detailed well-by-well analyses. Our results show that although conventional wells produce ∼13 times more water than oil (PW to oil ratio, PWOR = 13), this produced water has been mostly injected back into pressure-depleted oil-producing reservoirs for enhanced oil recovery. Unconventional horizontal wells use large volumes of water for hydraulic fracturing that increased by a factor of ∼10-16 per well and ∼7-10 if normalized by lateral well length (2008-2015). Although unconventional wells have a much lower PWOR of 3 versus 13 from conventional wells, this PW cannot be reinjected into the shale reservoirs but is disposed into nonproducing geologic intervals that could result in overpressuring and induced seismicity. The potential for PW reuse from unconventional wells is high because PW volumes can support hydraulic fracturing water demand based on 2014 data. Reuse of PW with minimal treatment (clean brine) can partially mitigate PW injection concerns while reducing water demand for hydraulic fracturing.

Biotic and environmental changes in the Permian Triassic boundary interval recorded on a western Tethyan ramp in the Bükk Mountains, Hungary

NASA Astrophysics Data System (ADS)

Haas, János; Demény, Attila; Hips, Kinga; Zajzon, Norbert; Weiszburg, Tamás G.; Sudar, Milan; Pálfy, József

2007-01-01

Complete, continuous marine Permian-Triassic (P-T) boundary sections in the Bükk Mountains, Northern Hungary, represent a ramp setting on the margin of the western Tethys. The Upper Permian succession comprises limestone rich in calcareous algae, foraminifera, and skeletal fragments of metazoans. A significant reduction of biogenic components occurs in the topmost limestone layers below the "boundary shale bed" (BSB). It coincides with the beginning of a gradual negative shift in δ13C carb values that continues into the BSB. The BSB consists predominantly of marly siltstones that are similar to the insoluble residue of the underlying limestone. A second biotic decline is recorded in the upper-third of the BSB, where the continuous negative shift in δ13C values is superimposed by a sharp and quasi-symmetric negative peak. The δ13C peak is confined to the shale bed and is not correlated with the lithological change, therefore diagenetic or other secondary effects are ruled out. The carbon isotope signal reflects primary processes related to significant changes in environmental conditions. Correlation and comparison of sedimentological, biotic, geochemical and mineralogical features of the studied sections in the Bükk Mountains with other Tethyan P—T sections in the Southern Alps, Dinarides, Iran, Kasmir (India) and southern China are discussed. The continuous shift in δ13C values is most probably related to a decrease in bioproductivity, whereas the sharp peak is attributed to an addition of C strongly depleted in 13C isotope to the ocean-atmosphere system. The most plausible model is a massive release of methane from gas-hydrate dissociation. This event led to the extinction of the already impoverished biota. Scarcity of metazoans and prolonged unfavourable environmental conditions gave rise to a bloom of microbial communities. Mineralogical and geochemical analyses failed to reveal any evidence for extraterrestrial effects or synchronous volcanism were

Early Triassic environmental dynamics and microbial development during the Smithian-Spathian transition (Lower Weber Canyon, Utah, USA)

NASA Astrophysics Data System (ADS)

Grosjean, Anne-Sabine; Vennin, Emmanuelle; Olivier, Nicolas; Caravaca, Gwénaël; Thomazo, Christophe; Fara, Emmanuel; Escarguel, Gilles; Bylund, Kevin G.; Jenks, James F.; Stephen, Daniel A.; Brayard, Arnaud

2018-01-01

The Early Triassic biotic recovery following the end-Permian mass extinction is well documented in the Smithian-Spathian Thaynes Group of the western USA basin. This sedimentary succession is commonly interpreted as recording harsh conditions of various shallow marine environments where microbial structures flourished. However, recent studies questioned the relevance of the classical view of long-lasting deleterious post-crisis conditions and suggested a rapid diversification of some marine ecosystems during the Early Triassic. Using field and microfacies analyses, we investigate a well-preserved Early Triassic marine sedimentary succession in Lower Weber Canyon (Utah, USA). The identification of microbial structures and their depositional settings provide insights on factors controlling their morphologies and distribution. The Lower Weber Canyon sediments record the vertical evolution of depositional environments from a middle Smithian microbial and dolosiliciclastic peritidal system to a late Smithian-early Spathian bioclastic, muddy mid ramp. The microbial deposits are interpreted as Microbially Induced Sedimentary Structures (MISS) that developed either (1) in a subtidal mid ramp where microbial wrinkles and chips are associated with megaripples characterizing hydrodynamic conditions of lower flow regime, or (2) in protected areas of inter- to subtidal inner ramp where they formed laminae and domal structures. Integrated with other published data, our investigations highlight that the distribution of these microbial structures was influenced by the combined effects of bathymetry, hydrodynamic conditions, lithology of the substrat physico-chemical characteristics of the depositional environment and by the regional relative sea-level fluctuations. Thus, we suggest that local environmental factors and basin dynamics primarily controlled the modalities of microbial development and preservation during the Early Triassic in the western USA basin.

New Postcranial Material of the Early Caseid Casea broilii Williston, 1910 (Synapsida: Caseidae) with a Review of the Evolution of the Sacrum in Paleozoic Non-Mammalian Synapsids

PubMed Central

LeBlanc, Aaron R. H.; Reisz, Robert R.

2014-01-01

Here we use the description of a new specimen of the small caseid synapsid Casea broilii that preserves the sacral, pelvic and hind limb regions in great detail and in three dimensions, as a unique opportunity to reevaluate the early stages in the evolution of the sacrum in the lineage that led to mammals. We place this new material in the context of sacral evolution in early caseid synapsids and conclude that the transition from two to three sacral vertebrae occurred in small-bodied species, suggesting that it was not an adaptation to heavy weight bearing. Furthermore, we compare descriptions of sacral anatomy among known early synapsids, including caseids, ophiacodontids, edaphosaurids, varanopids, and sphenacodontians and review sacral evolution in early synapsids. Based on the descriptions of new species of caseids, edaphosaurids, and varanopids over the past several decades, it is clear that a sacrum consisting of three vertebrae evolved independently at least four times in synapsids during the Late Carboniferous and Early Permian. Furthermore, similarities in the morphologies of the sacral vertebrae and ribs of these early synapsids lead us to conclude that an anterior caudal vertebra had been incorporated into the sacral series convergently in these groups. Given the repeated acquisition of a three-vertebra sacrum in early synapsids and no apparent link to body size, we argue that this sacral anatomy was related to more efficient terrestrial locomotion than to increased weight bearing. PMID:25545624

Geochemical effects of CO2 injection on produced water chemistry at an enhanced oil recovery site in the Permian Basin of northwest Texas, USA: Preliminary geochemical and Li isotope results

NASA Astrophysics Data System (ADS)

Pfister, S.; Gardiner, J.; Phan, T. T.; Macpherson, G. L.; Diehl, J. R.; Lopano, C. L.; Stewart, B. W.; Capo, R. C.

2014-12-01

Injection of supercritical CO2 for enhanced oil recovery (EOR) presents an opportunity to evaluate the effects of CO2 on reservoir properties and formation waters during geologic carbon sequestration. Produced water from oil wells tapping a carbonate-hosted reservoir at an active EOR site in the Permian Basin of Texas both before and after injection were sampled to evaluate geochemical and isotopic changes associated with water-rock-CO2 interaction. Produced waters from the carbonate reservoir rock are Na-Cl brines with TDS levels of 16.5-34 g/L and detectable H2S. These brines are potentially diluted with shallow groundwater from earlier EOR water flooding. Initial lithium isotope data (δ7Li) from pre-injection produced water in the EOR field fall within the range of Gulf of Mexico Coastal sedimentary basin and Appalachian basin values (Macpherson et al., 2014, Geofluids, doi: 10.1111/gfl.12084). Pre-injection produced water 87Sr/86Sr ratios (0.70788-0.70795) are consistent with mid-late Permian seawater/carbonate. CO2 injection took place in October 2013, and four of the wells sampled in May 2014 showed CO2 breakthrough. Preliminary comparison of pre- and post-injection produced waters indicates no significant changes in the major inorganic constituents following breakthrough, other than a possible drop in K concentration. Trace element and isotope data from pre- and post-breakthrough wells are currently being evaluated and will be presented.

Paleomagnetism and tectonics of the Southern Tarim Basin, northwestern China

NASA Astrophysics Data System (ADS)

Gilder, Stuart; Zhao, Xixi; Coe, Robert; Meng, Zifang; Courtillot, Vincent; Besse, Jean

1996-10-01

We report Late Carboniferous, Permian, and early Tertiary paleomagnetic data from the southern Tarim basin. Prefolding magnetizations were isolated in each case. The Late Carboniferous-Permian and early Tertiary poles lie at 64.6°N, 166.5°E, A95 = 6.3° and 58.1°N, 202.0°E, A95 = 12.7°, respectively. The Late Jurassic to early Tertiary (J3-E1) paleolatitudes of Tarim and several basins throughout central Asia are similar, yet significantly (10° to 20°) shallower than those predicted by the Eurasian apparent polar wander path. Resolving this discrepancy remains a major problem in Asian paleomagnetism. Discordance of the late Paleozoic poles from Tarim and Siberia suggest that Tarim has rotated about 30° counterclockwise with respect to Siberia since the Permian. Where paleomagnetic samples of both Late Carboniferous to Early Triassic (C3-T1) and J3-E1 ages were collected from the same area of Tarim, a great circle passes through the means of the poles and the sampling locality. This suggests that (1) only a difference in inclination (and not declination) distinguishes the two data sets, and (2) vertical axis block rotations of the C3-E1 strata occurred after E1. Although based on data of lesser quality, the mean Early to Middle Jurassic (J1-2) pole from Tarim differs significantly from the Eurasian reference pole, requiring radical tectonic solutions to resolve them. The Tarim J1-2 pole is indistinguishable from both the mean J3-E1 and C3-T1 poles. The similarity of all the poles and the analogous tectonic setting of present-day central Asia to that of the late Paleozoic in eastern North America raises the question whether all the data from Tarim are overprinted.

Two-stage formation model of the Junggar basin basement: Constraints to the growth style of Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

He, Dengfa

2016-04-01

retro-arc or inter-arc basin belts from north to south, such as Santanghu-Suosuoquan-Emin, Wucaiwan-Dongdaohaizi-Mahu (Mahu block sunk as a bathyal basin during this phase) and Fukang-western well Pen1 sag accordingly. Thirdly, the closure of these retro-arc or inter-arc basins migrating gradually toward the south led to the collision and amalgamation between the above-mentioned island arcs during the Carboniferous, constituting the basic framework of the Junggar 'block'. Fourthly, the emplacement of large-scale mantle-derived magmas occurred in the latest Carboniferous to Early Permian. For instance, the well Mahu 5 penetrate the latest Carboniferous basalts with a thickness of over 20 m, and these mantle-derived magmas consolidated the above-mentioned island arc-collaged blocks. Therefore, the Junggar basin basement mainly comprises pre-Carboniferous collaged basement, and its formation is characterized by two-stage growth model, involving the Carboniferous lateral growth of island arcs and the latest Carboniferous to Early Permian vertical crustal growth related to emplacement and underplating of the mantle-derived magmas. In the Middle Permian, the Junggar Basin is dominated by a series of stable intra-continental sag basins from west to east, such as Mahu, Shawan, western Well Pen1, Dongdaohaizi-Wucaiwan-Dajing, Fukang-Jimusaer sag lake-basins and so on. The Middle Permian (e.g., Lower Wu'erhe, Lucaogou, and Pingdiquan Formations) thick source rocks developed in these basins, suggesting that the Junggar Basin had been entered 'intra-cratonic sag' basin evolution stage. Since then, no strong thermal tectonic event could result in crust growth. The present crustal thickness of Junggar Basin is 45-52 km, which was mainly formed before the latest Early Permian. Subsequently, the Junggar Basin experienced a rapid cooling process during the Late Permian to Triassic. These events constrain the formation timing of the Junggar basin basement to be before the latest Early

New whaitsioids (Therapsida: Therocephalia) from the Teekloof Formation of South Africa and therocephalian diversity during the end-Guadalupian extinction

PubMed Central

Smith, Roger M.H.

2017-01-01

Two new species of therocephalian therapsids are described from the upper Permian Teekloof Formation of the Karoo Basin, South Africa. They include two specimens of a whaitsiid, Microwhaitsia mendrezi gen. et sp. nov., and a single, small whaitsioid Ophidostoma tatarinovi gen. et sp. nov., which preserves a combination of primitive and apomorphic features. A phylogenetic analysis of 56 therapsid taxa and 136 craniodental and postcranial characters places the new taxa within the monophyletic sister group of baurioids—Whaitsioidea—with Microwhaitsia as a basal whaitsiid and Ophidostoma as an aberrant whaitsioid just outside the hofmeyriid+whaitsiid subclade. The new records support that whaitsioids were diverse during the early-late Permian (Wuchiapingian) and that the dichotomy between whaitsiid-line and baurioid-line eutherocephalians was established early on. The oldest Gondwanan whaitsiid Microwhaitsia and additional records from the lower strata of the Teekloof Formation suggest that whaitsioids had diversified by the early Wuchiapingian and no later than Pristerognathus Assemblage Zone times. Prior extinction estimates based on species counts are reflected in an analysis of origination/extinction rates, which imply increasing faunal turnover from Guadalupian to Lopingian (late Permian) times. The new records support a growing body of evidence that some key Lopingian synapsid clades originated near or prior to the Guadalupian-Lopingian boundary ca. 260–259 million years ago, but only radiated following the end-Guadalupian extinction of dinocephalians and basal therocephalian predators (long-fuse model). Ongoing collecting in older portions of the Teekloof Formation (e.g., Pristerognathus Assemblage Zone) will shed further light on early eutherocephalians during this murky but critical time in their evolutionary diversification. PMID:29018609

An exceptional fossil skull from South America and the origins of the archosauriform radiation

NASA Astrophysics Data System (ADS)

Pinheiro, Felipe L.; França, Marco A. G.; Lacerda, Marcel B.; Butler, Richard J.; Schultz, Cesar L.

2016-03-01

Birds, dinosaurs, crocodilians, pterosaurs and their close relatives form the highly diverse clade Archosauriformes. Archosauriforms have a deep evolutionary history, originating in the late Permian, prior to the end-Permian mass extinction, and radiating in the Triassic to dominate Mesozoic ecosystems. However, the origins of this clade and its extraordinarily successful body plan remain obscure. Here, we describe an exceptionally preserved fossil skull from the Lower Triassic of Brazil, representing a new species, Teyujagua paradoxa, transitional in morphology between archosauriforms and more primitive reptiles. This skull reveals for the first time the mosaic assembly of key features of the archosauriform skull, including the antorbital and mandibular fenestrae, serrated teeth, and closed lower temporal bar. Phylogenetic analysis recovers Teyujagua as the sister taxon to Archosauriformes, and is congruent with a two-phase model of early archosauriform evolution, in response to two mass extinctions occurring at the end of the Guadalupian and the Permian.

U.S. Geological Survey input-data forms for the assessment of the Spraberry Formation of the Midland Basin, Permian Basin Province, Texas, 2017

USGS Publications Warehouse

Marra, Kristen R.

2017-10-24

In 2017, the U.S. Geological Survey (USGS) completed an updated assessment of undiscovered, technically recoverable oil and gas resources in the Spraberry Formation of the Midland Basin (Permian Basin Province) in southwestern Texas (Marra and others, 2017). The Spraberry Formation was assessed using both the standard continuous (unconventional) and conventional methodologies established by the USGS for three assessment units (AUs): (1) Lower Spraberry Continuous Oil Trend AU, (2) Middle Spraberry Continuous Oil Trend AU, and (3) Northern Spraberry Conventional Oil AU. The revised assessment resulted in total estimated mean resources of 4,245 million barrels of oil, 3,112 billion cubic feet of gas, and 311 million barrels of natural gas liquids. The purpose of this report is to provide supplemental documentation of the input parameters used in the USGS 2017 Spraberry Formation assessment.

Body size reductions in nonmammalian eutheriodont therapsids (Synapsida) during the end-Permian mass extinction.

PubMed

Huttenlocker, Adam K

2014-01-01

The extent to which mass extinctions influence body size evolution in major tetrapod clades is inadequately understood. For example, the 'Lilliput effect,' a common feature of mass extinctions, describes a temporary decrease in body sizes of survivor taxa in post-extinction faunas. However, its signature on existing patterns of body size evolution in tetrapods and the persistence of its impacts during post-extinction recoveries are virtually unknown, and rarely compared in both geologic and phylogenetic contexts. Here, I evaluate temporal and phylogenetic distributions of body size in Permo-Triassic therocephalian and cynodont therapsids (eutheriodonts) using a museum collections-based approach and time series model fitting on a regional stratigraphic sequence from the Karoo Basin, South Africa. I further employed rank order correlation tests on global age and clade rank data from an expanded phylogenetic dataset, and performed evolutionary model testing using Brownian (passive diffusion) models. Results support significant size reductions in the immediate aftermath of the end-Permian mass extinction (ca. 252.3 Ma) consistent with some definitions of Lilliput effects. However, this temporal succession reflects a pattern that was underscored largely by Brownian processes and constructive selectivity. Results also support two recent contentions about body size evolution and mass extinctions: 1) active, directional evolution in size traits is rare over macroevolutionary time scales and 2) geologically brief size reductions may be accomplished by the ecological removal of large-bodied species without rapid originations of new small-bodied clades or shifts from long-term evolutionary patterns.

Integrating petroleum and sulfur data to map the Guadalupian-Ochoan (Middle to Upper Permian) Boundary of the Delaware Basis, Trans-Pecos, Texas

NASA Astrophysics Data System (ADS)

Dishron, Joseph B.

2011-12-01

The Delaware Basin of the Permian Basin is a classic intra-cratonic basin of West Texas and Southeast New Mexico. Hydrocarbon exploration and production have occurred in the region since the early 1920s, and, as a result, the formations related to these oil and gas reserves have been studied in great detail. Some formations in the Delaware Basin, however, have not been studied in such detail, and this thesis examines one, lesser-known unit that could have economic potential. The Lamar Limestone (Lamar Lime) of the Bell Canyon Formation has commonly been dismissed as a production interval; rather, it has been described as a source and seal rock for the Ramsey Sand of the lower Bell Canyon Formation. However, recent studies found that the Lamar Lime was contributing to production, and it has been described by Trentham (2006) as a potentia "mini Barnett" reservoir. The depths of these deposits are in a range that is ideal for oil accumulation. This study made use of data from wells and test holes drilled in the western Delaware Basin, Culberson County, Texas. Many oil and gas wells have been drilled in the western Delaware Basin, but they are concentrated in the north and east portions of Culberson County. In addition, sulfur wells were drilled in the area in the late 1960s and early 1970s. Analyses of the well logs of these wells and of core and outcrop studies were completed to gain a better understanding of the distribution and economic potential of the Lamar. Both datasets were combined to provide information not readily available in the oil and gas dataset. The Lamar Lime is an excellent marker bed because it underlies thick evaporites. The evaporite sequences are Ochoan in age, and, therefore, the contact of the Lamar Lime (Bell Canyon Formation) and the Castile Formation is the approximate boundary for the Guadalupian-Ochoan Series. The Castile Formation, the Salado Formation, and the Rustler Formation (from oldest to youngest) are the evaporite units that

Detrital zircon U-Pb geochronology and provenance of the Carboniferous-Permian glaciomarine pebbly slates in the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wang, Q.; Zhu, D.; Zhao, Z.; Chung, S.; Li, C.; Sui, Q.; Fu, X.; Mo, X.

2011-12-01

Glaciomarine diamictites (including pebbly slate, pebbly siltstone, and pebbly sandstone) in the Tibetan Plateau are widely interpreted to have been associated with the deglaciation of the Indian continent. Guiding by zircon cathodoluminescence images, we determined U-Pb ages for detrital zircons from five typical Carboniferous-Permian pebbly slate samples from the Qiangtang, Lhasa, and Tethyan Himalaya of the Tibetan Plateau. The age distributions of detrital zircons from two samples (180 analyses) from Qiwu and Gangma Tso of the Qiangtang Terrane are similar, with two main age peaks ca. 579 and ca. 816 Ma and one minor age peak ca. 2490 Ma. Two samples (177 analyses) from Jiangrang and Damxung of the Lhasa Terrane define similar age distributions with two main age peaks ca. 539 and ca. 1175 Ma. Ages of detrital zircons from one sample (110 analyses) from Kangmar of the Tethyan Himalaya display main age peaks ca. 535, ca. 949, and ca. 2490 Ma. The ca. 816-Ma detrital zircons from the Qiangtang Terrane were most likely derived from the Lesser Himalaya, and the ca. 950-Ma detrital zircons from the Tethyan Himalaya might have been sourced from the High Himalaya, Eastern Ghats Province of the Indian plate and the Rayner Province of East Antarctica. The distinctive ca. 1175-Ma age population characteristic of zircons in the pebbly slates from the Lhasa Terrane is identical to the detrital zircons from the late Paleozoic sandstones (Zhu et al., 2011a) and the inherited zircons from the Mesozoic peraluminous granites (Zhu et al., 2011b) in this terrane, but significantly absent in the pebbly slates from both the Qiangtang and the Tethyan Himalayan terranes. The ca. 1175-Ma detrital zircons in the Lhasa Terrane were most likely sourced from the Albany-Fraser-Wilkes in southwestern Australia and East Antarctica. These new data obtained in this study reveal a distinct difference of detrital zircon provenance for the coeval Carboniferous-Permian glaciomarine pebbly slates

Earth Observations taken by Expedition 30 crewmember

NASA Image and Video Library

2012-02-05

ISS030-E-090012 (5 Feb. 2012) --- The Parana River floodplain along the Mato Grosso–Sao Paulo border, Brazil is featured in this image photographed by an Expedition 30 crew member on the International Space Station. The Parana River appears as a wide, blue strip across this photograph, with muddy brown water of the smaller Verde River entering from the northwest (top left). An extensive wetland (dark green) occupies most of the left half of the image, where the floodplain of the river reaches a width of 11 kilometers. The thin line of a road crossing the floodplain also gives a sense of scale. Above the Parana–Verde confluence (center) the floodplain is much narrower. The floodplain is generated by sediments delivered by both rivers. Evidence for this is that the entire surface of the floodplain is crisscrossed by the wider traces of former Parana R. channels as well as numerous narrower traces of the Verde R. The floodplains along both rivers are bordered by numerous rectangular agricultural fields. Dominant crops along this part of the Parana River are coffee, corn and cotton. Turbid water, such as that in the Verde River, is common in most rivers that drain plowed agricultural land as some topsoil is washed into local rivers after rains. A long tendril of brown water extends from the Verde R. into the main channel of the Parana River where it hugs the west bank, remaining unmixed for many kilometers. This effectively shows the direction of river flow from orbit (right to left for the Parana, upper left to center for the Verde).

Paleozoic and mesozoic evolution of East-Central California

USGS Publications Warehouse

Stevens, C.H.; Stone, P.; Dunne, G.C.; Greene, D.C.; Walker, J.D.; Swanson, B.J.

1997-01-01

East-central California, which encompasses an area located on the westernmost part of sialic North America, contains a well-preserved record of Paleozoic and Mesozoic tectonic events that reflect the evolving nature of the Cordilleran plate margin to the west. After the plate margin was formed by continental rifting in the Neoproterozoic, sediments comprising the Cordilleran miogeocline began to accumulate on the subsiding passive margin. In east-central California, sedimentation did not keep pace with subsidence, resulting in backstepping of a series of successive carbonate platforms throughout the early and middle Paleozoic. This phase of miogeoclinal development was brought to a close by the Late Devonian-Early Mississippian Antler orogeny, during the final phase of which oceanic rocks were emplaced onto the continental margin. Subsequent Late Mississippian-Pennsylvanian faulting and apparent reorientation of the carbonate platform margin are interpreted to have been associated with truncation of the continental plate on a sinistral transform fault zone. In the Early Permian, contractional deformation in east-central California led to the development of a narrow, uplifted thrust belt flanked by marine basins in which thick sequences of deep-water strata accumulated. A second episode of contractional deformation in late Early Permian to earliest Triassic time widened and further uplifted the thrust belt and produced the recently identified Inyo Crest thrust, which here is correlated with the regionally significant Last Chance thrust. In the Late Permian, about the time of the second contractional episode, extensional faulting created shallow sedimentary basins in the southern Inyo Mountains. In the El Paso Mountains to the south, deformation and plutonism record the onset of subduction and arc magmatism in late Early Permian to earliest Triassic time along this part of the margin. Tectonism had ceased in most of east-central California by middle to late Early

Molybdenite Re-Os, zircon U-Pb dating and Lu-Hf isotopic analysis of the Xiaerchulu Au deposit, Inner Mongolia Province, China

NASA Astrophysics Data System (ADS)

Wang, Jia-xin; Nie, Feng-Jun; Zhang, Xue-ni; Jiang, Si-hong

2016-09-01

The Xiaerchulu Au deposit, located in the Southern Orogenic Belt (SOB) of Western Inner Mongolia (WIM), is hosted in an Early Permian (271-261 Ma) volcanic-plutonic sequence. Mineralization took place in silicified biotite granites or along the contact zone between the Neoproterozoic Baiyinbaolage Group and the biotite granite. In order to constrain the timing of the Xiaerchulu mineralization and discuss the petrogenesis of the hosting granites, molybdenite Re-Os, and zircon U-Pb and, Lu-Hf, and REE, geochemical, and Sr-Nd isotopic studies were completed in this study. We measured Re-Os isotopes of six molybdenite samples from the main ore body, which yielded a weighted average model age of 261.7 ± 1.5 Ma with a MSWD of 0.55, indicating that the time of mineralization was at ca. 262 Ma. High precision U-Pb dating for the studied granites yields Permian 206Pb/238U ages ranging from 271 to 269 Ma. These age data confirm that both the intrusion and related mineralization were initiated in Early Permian period. These granites are strongly peraluminous with A/CNK = 1.11-1.12, high SiO2-K2O contents, as well as containing biotite and muscovite, indicating a petrogenesis of typical S-type granites, the above consideration is also consistent with the result of discrimination diagrams. The Re contents of molybdenite, εNd(t), and zircon εHf(t), as well as the 176Hf/177Hf values of the granites, fall into the ranges from 1.153 to 2.740 μg/g, - 11.1 to - 9.3, - 8.8 to - 0.9, and 0.282358 to 0.282688, respectively. All of this evidence suggests that the metals were derived from a predominantly crustal source, the granites originated from crust in an extensional setting, and the rejuvenation of the continent may have play an important role during the ore-forming processes of the Early Permian epoch.

The Phuket Terrane: A Late Palaeozoic rift at the margin of Sibumasu

NASA Astrophysics Data System (ADS)

Ridd, Michael F.

2009-09-01

It is widely accepted that Sibumasu rifted from Gondwana in the Late Palaeozoic. But the rifts themselves have not previously been documented in Southeast Asia. This paper identifies the pre-Middle Permian Kaeng Krachan Group of Upper Peninsular Thailand as the infill of one such rift, which is given the name Phuket Terrane. Indirect evidence suggests the rift-infill is several kilometres thick and glacially-influenced diamictites are conspicuous in the succession. There are significant similarities with the >3 km thick pre-Middle Permian rift-infill of the Carnarvon Basin of Western Australia. East of the Khlong Marui Fault belt the succession is thinner and diamictites are a minor component. A tectono-stratigraphic model is proposed involving Gondwana glaciers dropping their load at the (present) western margin of the Phuket Terrane from where it was re-sedimented in the rapidly subsiding marine rift basin. It is suggested that the Khlong Marui Fault formed part of the eastern boundary of the rift system. The Three Pagodas Fault belt similarly juxtaposes different pre-Middle Permian successions. Rifting ceased in the Early Permian and a passive margin formed as the Mesotethys ocean widened, the upper part of the Kaeng Krachan Group and the overlying Ratburi Limestone representing the post-rift sequence.

Palaeogeographic evolution of the central segment of the South Atlantic during Early Cretaceous times: palaeotopographic and geodynamic implications

NASA Astrophysics Data System (ADS)

Chaboureau, A. C.; Guillocheau, F.; Robin, C.; Rohais, S.; Moulin, M.; Aslanian, D.

2012-04-01

The tectonic and sedimentary evolution of the Early Cretaceous rift of the central segment of the South Atlantic Ocean is debated. Our objective is to better constraint the timing of its evolution by drawing palaeogeographic and deformation maps. Eight palaeogeographic and deformations maps were drawn from the Berriasian to the Middle-Late Aptian, based on a biostratigraphic (ostracodes and pollens) chart recalibrated on absolute ages (chemostratigraphy, interstratified volcanics, Re-Os dating of the organic matter). The central segment of the South Atlantic is composed of two domains that have a different history in terms of deformation and palaeogeography. The southern domain includes Namibe, Santos and Campos Basins. The northern domain extends from Espirito Santo and North Kwanza Basins, in the South, to Sergipe-Alagoas and North Gabon Basins to the North. Extension started in the northern domain during Late Berriasian (Congo-Camamu Basin to Sergipe-Alagoas-North Gabon Basins) and migrated southward. At that time, the southern domain was not a subsiding domain. This is time of emplacement of the Parana-Etendeka Trapp (Late Hauterivian-Early Barremian). Extension started in this southern domain during Early Barremian. The brittle extensional period is shorter in the South (5-6 Ma, Barremian to base Aptian) than in the North (19 to 20 Myr, Upper Berriasian to Base Aptian). From Late Berriasian to base Aptian, the northern domain evolves from a deep lake with lateral highs to a shallower one, organic-rich with no more highs. The lake migrates southward in two steps, until Valanginian at the border between the northern and southern domains, until Early Barremian, North of Walvis Ridge. The Sag phase is of Middle to Late Aptian age. In the southern domain, the transition between the brittle rift and the sag phase is continuous. In the northern domain, this transition corresponds to a hiatus of Early to Middle Aptian age, possible period of mantle exhumation. Marine

Inconsistencies between Pangean reconstructions and basic climate controls.

PubMed

Rowe, Clinton M; Loope, David B; Oglesby, Robert J; Van der Voo, Rob; Broadwater, Charles E

2007-11-23

The supercontinent Pangea dominated our planet from the Permian into the Jurassic. Paleomagnetic reconstructions have been used to estimate the latitudinal position of Pangea during this 100-million-year period. Atmospheric circulation, recorded by eolian sandstones in the southwestern United States, shows a broad sweep of northeasterly winds over their northernmost extent, curving to become northwesterly in the south: This evidence is consistent with paleomagnetic reconstructions of the region straddling the equator in the Early Permian but is at odds with its northward movement to about 20 degrees N by the Early Jurassic. At least one of the following scenarios must be true: The latitude based on paleomagnetism is incorrect; the interpretation of how winds shaped the dunes is mistaken; the basic climate controls in the Jurassic were different from those of today; or the paleogeographic reconstructions available are insufficient to adequately reproduce the wind fields responsible for dune formation.

Syndepositional tectonics recorded by soft-sediment deformation and liquefaction structures (continental Lower Permian sediments, Southern Alps, Northern Italy): Stratigraphic significance

NASA Astrophysics Data System (ADS)

Berra, F.; Felletti, F.

2011-04-01

The Lower Permian succession of the Central Southern Alps (Lombardy, Northern Italy) was deposited in fault-controlled continental basins, probably related to transtensional tectonics. We focussed our study on the stratigraphic record of the Lower Permian Orobic Basin, which consists of a 1000 m thick succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo Formation, PDV) resting on the underlying prevailing pyroclastic flows of the Cabianca Volcanite. The PDV consists of a lower part (composed of conglomerates passing laterally to sandstones and distally to silt and shales), a middle part (pelitic, with carbonates) and an upper part (alternating sandstone, silt and volcanic flows). Syndepositional tectonics during the deposition of the PDV is recorded by facies distribution, thickness changes and by the presence of deformation and liquefaction structures interpreted as seismites. Deformation is recorded by both ductile structures (ball-and-pillow, plastic intrusion, disturbed lamination, convolute stratification and slumps) and brittle structures (sand dykes and autoclastic breccias). Both the sedimentological features and the geodynamic setting of the depositional basin confidently support the interpretation of the described deformation features as related to seismic shocks. The most significant seismically-induced deformation is represented by a slumped horizon (about 4 m thick on average) which can be followed laterally for more than 5 km. The slumped bed consists of playa-lake deposits (alternating pelites and microbial carbonates, associated with mud cracks and vertebrate tracks). The lateral continuity and the evidence of deposition on a very low-angle surface along with the deformation/liquefaction of the sediments suggest that the slump was triggered by a high-magnitude earthquake. The stratigraphic distribution of the seismites allows us to identify time intervals of intense seismic activity

Integrated biostratigraphy of foraminifers, radiolarians and conodonts in shallow and deep water Middle Permian (Capitanian) deposits of the "Rader slide", Guadalupe Mountains, West Texas

USGS Publications Warehouse

Nestell, M.K.; Nestell, G.P.; Wardlaw, B.R.; Sweatt, M.J.

2006-01-01

A diverse assemblage of microfossils is present in a 6m thick sequence of three debris flow deposits interbedded with thin turbidite limestone beds and fine grained siliciclastics exposed above the megaconglomerate in a section (known as the "Rader Slide" in numerous guidebook stops) of the Rader Limestone Member of the Bell Canyon Formation of Capitanian age (Middle Permian) in the Guadalupe Mountains of West Texas. Each debris flow, derived from nearby Capitan Reef shelf-margin and slope deposits, contains a distinct microfossil assemblage. Small foraminifers and fusulinaceans, conodonts, radiolarians, sponge spicules, fish dermal plates and teeth, and other fragmental fossils are present in this sequence. Conodonts are relatively scarce in the first (or lowest) debris flow, except in its upper part, but they are common to abundant in the other two debris flows, and very abundant in several of the thin turbidite limestone beds. All of the conodonts present appear to be morphotypes of one population of the species Jinogondolella postserrata, except for one new conodont species, and the Jinogondolella postserrata Zone is clearly documented in this sequence. The debris flows contain the fusulinaceans Rauserella, rare Codonofusiella, Polydiexodina, Leella? and various species of the small foraminifers Globivalvulina, Hemigordius, Baisalina, Abadehella, Deckerella, Neoendothyranella, Vachardella, Geinitzina, and Polarisella. Some of the thin turbidite limestone beds contain a foraminiferal assemblage similar to that found in the debris flows, but with lower diversity. Many small foraminiferal species appear to be endemic, although a few are closely related to species known in Permian age strata in Italy, Greenland, the Russian Far East, northeastern part of Russia (Omolon massif), and the Zechstein of Germany and the Baltic area. Two thin limestone beds above the second debris flow contain primarily radiolarian species known from the Follicucullus japonicus Zone of

Provenance of Permian-Triassic Gondwana Sequence Units Accreted to the Banda Arc: Constraints from U/Pb and Hf Analysis of Zircons and Igneous Geochemistry

NASA Astrophysics Data System (ADS)

Flores, J. A.; Spencer, C. J.; Harris, R. A.; Hoiland, C.

2011-12-01

Analysis of zircons from Australian affinity Permo-Triassic units of the Timor region yield age distributions with large peaks at 230-400 Ma and 1750-1900 Ma (n=435). Similar zircon age peaks are also found in rocks from NE Australia and the eastern Cimmerian block. It is likely that these terranes, which are now widely separated, were once part of the northern edge of Gondwana near what is now the NW margin of Australia. The Cimmerian Block was removed from Gondwana during Early Permian rifting and initiation of the Neo-Tethys Ocean. Hf analysis of zircon from the Aileu Complex in Timor and Kisar shows bimodal (juvenial and evolved) magmatism in the Gondwana Sequence of NW Australia at ~300 Ma. The magmatic event produced basalt with rift valley and ocean floor geochemical affinities, and rhyolite. Similar rock types and isotopic signatures are also found in Permo-Triassic igneous units throughout the Cimmerian continental block. The part of the Cimmerian Block with zircon distributions most like the Gondwana Sequence of NW Australia is the terranes of northern Tibet and Malaysia. The large 1750-1900 Ma zircon peak is much more wide spread, and appears in terranes from Baoshan (SW China) to Borneo. The Permo-Triassic rocks of the Timor region fill syn-rift intracratonic basins that successfully rifted in the Jurassic to form the NW margin of Australia. This passive continental margin first entered the Sunda Trench in the Timor region at around 8 Ma causing the Permo-Triassic rocks to accrete to the edge of the Asian Plate and emerge as a series of mountainous islands in the young collision zone. Eventually, the Australian continental margin will collide with the southern edge of the Asian plate and these Gondwana terranes will rejoin. However, it may be difficult to reconstruct the various ventures of they made over the past 300 Ma.

Geochronological study of zircons from continental crust rocks in the Frido Unit (southern Apennines)

NASA Astrophysics Data System (ADS)

Laurita, Salvatore; Prosser, Giacomo; Rizzo, Giovanna; Langone, Antonio; Tiepolo, Massimo; Laurita, Alessandro

2015-01-01

Zircon crystals have been separated from gneisses and metagranitoids of the Pollino area (southern Apennines) in order to unravel the origin of these crustal slices within the ophiolite-bearing Frido Unit. The morphology of the zircon has been investigated by SEM, and the internal structure was revealed by cathodoluminescence. Data obtained by U/Pb dating have been used to deduce the age and significance of the different crystallization stages of zircon, connected to the evolutionary stages of the continental crust (Late Paleozoic-Early Mesozoic). Zircons in gneisses are characterized by inherited cores of magmatic origin, bordered by metamorphic rims. Inherited zircons generally show Paleoproterozoic to Ordovician ages, indicating the provenance of the sedimentary protolith from different sources. The exclusive presence of Late Neoproterozoic zircon cores in leucocratic gneisses may suggest a different magmatic source possibly connected to Pan-African events. Late Carboniferous-Early Permian ages are found mainly in zircon rims of metamorphic origin. These are similar to the emplacement ages of protolith of the metagranites in the middle crust portion. Late Carboniferous-Early Permian metamorphism and magmatism testify the extensional collapse of the Hercynian belt, recorded in European, particularly, in the Corsica-Sardinia block and in Calabria. Late Permian-Triassic ages have been detected in zircon rims from gneisses and metagranitoids. These younger ages appear related to deformation and emplacement of albite-quartz veins in both lithologies, and are related to an extensional episode predating the Middle Triassic to Middle Jurassic rifting in the Tethyan domain, followed by Middle to Late Jurassic spreading.

Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

USGS Publications Warehouse

Zheng, Lingyun; Liu, Gaisheng; Chou, C.-L.; Qi, C.; Zhang, Y.

2007-01-01

The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals. ?? 2007 Elsevier Ltd. All rights reserved.

An archosauromorph dominated ichnoassemblage in fluvial settings from the late Early Triassic of the Catalan Pyrenees (NE Iberian Peninsula).

PubMed

Mujal, Eudald; Fortuny, Josep; Bolet, Arnau; Oms, Oriol; López, José Ángel

2017-01-01

The vertebrate recovery after the end-Permian mass extinction can be approached through the ichnological record, which is much more abundant than body fossils. The late Olenekian (Early Triassic) tetrapod ichnoassemblage of the Catalan Pyrenean Basin is the most complete and diverse of this age from Western Tethys. This extensional basin, composed of several depocenters, was formed in the latest phases of the Variscan orogeny (Pangea breakup) and was infilled by braided and meandering fluvial systems of the red-beds Buntsandstein facies. Abundant and diverse tetrapod ichnites are recorded in these facies, including Prorotodactylus mesaxonichnus isp. nov. (tracks possibly produced by euparkeriids), cf. Rotodactylus, at least two large chirotheriid morphotypes (archosauriform trackmakers), Rhynchosauroides cf. schochardti, two other undetermined Rhynchosauroides forms, an undetermined Morphotype A (archosauromorph trackmakers) and two types of Characichnos isp. (swimming traces, here associated to archosauromorph trackmakers). The Pyrenean ichnoassemblage suggests a relatively homogeneous ichnofaunal composition through the late Early Triassic of Central Pangea, characterized by the presence of Prorotodactylus and Rotodactylus. Small archosauromorph tracks dominate and present a wide distribution through the different fluviatile facies of the Triassic Pyrenean Basin, with large archosaurian footprints being present in a lesser degree. Archosauromorphs radiated and diversified through the Triassic vertebrate recovery, which ultimately lead to the archosaur and dinosaur dominance of the Mesozoic.

The elemental geochemistry of Lower Triassic shallow-marine carbonates from central Saudi Arabia: Implications for redox conditions in the immediate aftermath of the latest Permian mass extinction

NASA Astrophysics Data System (ADS)

Eltom, Hassan A.; Abdullatif, Osman M.; Babalola, Lamidi O.

2018-03-01

The southern margin of the Tethys Ocean was occupied by a broad, shallow continental shelf during the Permian-Triassic boundary interval, with the area of present-day Saudi Arabia located from 10° to 30° south of the paleo-equator. The strata deposited in modern Saudi Arabia in the aftermath of the latest Permian mass extinction (LPME) are dominated by oolitic microbialite limestone (OML), which are overlain by skeletal oolitic limestones (SOL) capped by dolostones and dolomitic limestones (DDL). This succession reflects changes in depositional setting, which can be potentially tied to redox conditions using redox sensitive trace elements and rare earth elements (REEs). Statistical analyses reveals that trace elements and REEs are associated with detrital material, and possibly with diagenetic minerals as well. Proxies such as the Y/Ho, Pr/Pr*, Smn/Ybn, Lan/Smn and Lan/Ybn ratios indicate that REEs do not record a seawater-like pattern, and cannot be used as redox indicator. The presence of a normal marine fauna implies oxic conditions during deposition of the DDL and SOL units. However, the OML unit, which represents the immediate aftermath of LPME, lacks both a normal marine fauna and reliable geochemical signals, making it difficult to infer redox conditions in the depositional environment. Similar to published data from sections that reflect shallow marine condition in the LPME of the Tethys Ocean, chemical index of alteration values are consistently high throughout the study succession, suggesting globally intense chemical weathering in the aftermath of the LPME. As a result, geochemical redox proxies in shallow marine carbonates of the Tethys Ocean are likely to be contaminated by detrital material that have been generated by chemical weathering, and thus, other methods are required to determine depositional redox conditions.

Discovery of abundant cellulose microfibers encased in 250 Ma Permian halite: a macromolecular target in the search for life on other planets.