Astronomical pacing of the global silica cycle recorded in Mesozoic bedded cherts.

PubMed

Ikeda, Masayuki; Tada, Ryuji; Ozaki, Kazumi

2017-06-07

The global silica cycle is an important component of the long-term climate system, yet its controlling factors are largely uncertain due to poorly constrained proxy records. Here we present a ∼70 Myr-long record of early Mesozoic biogenic silica (BSi) flux from radiolarian chert in Japan. Average low-mid-latitude BSi burial flux in the superocean Panthalassa is ∼90% of that of the modern global ocean and relative amplitude varied by ∼20-50% over the 100 kyr to 30 Myr orbital cycles during the early Mesozoic. We hypothesize that BSi in chert was a major sink for oceanic dissolved silica (DSi), with fluctuations proportional to DSi input from chemical weathering on timescales longer than the residence time of DSi (<∼100 Kyr). Chemical weathering rates estimated by the GEOCARBSULFvolc model support these hypotheses, excluding the volcanism-driven oceanic anoxic events of the Early-Middle Triassic and Toarcian that exceed model limits. We propose that the Mega monsoon of the supercontinent Pangea nonlinearly amplified the orbitally paced chemical weathering that drove BSi burial during the early Mesozoic greenhouse world.

Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls.

PubMed

Danise, Silvia; Higgs, Nicholas D

2015-04-01

We report fossil traces of Osedax, a genus of siboglinid annelids that consume the skeletons of sunken vertebrates on the ocean floor, from early-Late Cretaceous (approx. 100 Myr) plesiosaur and sea turtle bones. Although plesiosaurs went extinct at the end-Cretaceous mass extinction (66 Myr), chelonioids survived the event and diversified, and thus provided sustenance for Osedax in the 20 Myr gap preceding the radiation of cetaceans, their main modern food source. This finding shows that marine reptile carcasses, before whales, played a key role in the evolution and dispersal of Osedax and confirms that its generalist ability of colonizing different vertebrate substrates, like fishes and marine birds, besides whale bones, is an ancestral trait. A Cretaceous age for unequivocal Osedax trace fossils also dates back to the Mesozoic the origin of the entire siboglinid family, which includes chemosynthetic tubeworms living at hydrothermal vents and seeps, contrary to phylogenetic estimations of a Late Mesozoic-Cenozoic origin (approx. 50-100 Myr). © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Pre-mesozoic palinspastic reconstruction of the eastern great basin (Western United States).

PubMed

Levy, M; Christie-Blick, N

1989-09-29

The Great Basin of the western United States has proven important for studies of Proterozoic and Paleozoic geology [2500 to 245 million years ago (Ma)] and has been central to the development of ideas about the mechanics of crustal shortening and extension. An understanding of the deformational history of this region during Mesozoic and Cenozoic time (245 Ma to the present) is required for palinspastic reconstruction of now isolated exposures of older geology in order to place these in an appropriate regional geographic context. Considerable advances in unraveling both the crustal shortening that took place during Mesozoic to early Cenozoic time (especially from about 150 to 50 Ma) and the extension of the past 37 million years have shown that earlier reconstructions need to be revised significantly. A new reconstruction is developed for rocks of middle Proterozoic to Early Cambrian age based on evidence that total shortening by generally east-vergent thrusts and folds was at least 104 to 135 kilometers and that the Great Basin as a whole accommodated approximately 250 kilometers of extension in the direction 287 degrees +/- 12 degrees between the Colorado Plateau and the Sierra Nevada. Extension is assumed to be equivalent at all latitudes because available paleomagnetic evidence suggests that the Sierra Nevada experienced little or no rotation with respect to the extension direction since the late Mesozoic. An estimate of the uncertainty in the amount of extension obtained from geological and paleomagnetic uncertainties increases northward from +/-56 kilometers at 36 degrees 30N to (-87)(+108) kilometers at 40 degrees N. On the basis of the reconstruction, the original width of the preserved part of the late Proterozoic and Early Cambrian basin was about 150 to 300 kilometers, about 60 percent of the present width, and the basin was oriented slightly more north-south with respect to present-day coordinates.

Mesozoic dinosaurs from Brazil and their biogeographic implications.

PubMed

Bittencourt, Jonathas S; Langer, Max C

2011-03-01

The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.

Early Mesozoic paleogeography and tectonic evolution of the western United States: Insights from detrital zircon U-Pb geochronology, Blue Mountains Province, northeastern Oregon

USGS Publications Warehouse

LaMaskin, Todd A.; Vervoort, J.D.; Dorsey, R.J.; Wright, J.E.

2011-01-01

This study assesses early Mesozoic provenance linkages and paleogeographic-tectonic models for the western United States based on new petrographic and detrital zircon data from Triassic and Jurassic sandstones of the "Izee" and Olds Ferry terranes of the Blue Mountains Province, northeastern Oregon. Triassic sediments were likely derived from the Baker terrane offshore accretionary subduction complex and are dominated by Late Archean (ca. 2.7-2.5 Ga), Late Paleoproterozoic (ca. 2.2-1.6 Ga), and Paleozoic (ca. 380-255 Ma) detrital zircon grains. These detrital ages suggest that portions of the Baker terrane have a genetic affinity with other Cordilleran accretionary subduction complexes of the western United States, including those in the Northern Sierra and Eastern Klamath terranes. The abundance of Precambrian grains in detritus derived from an offshore complex highlights the importance of sediment reworking. Jurassic sediments are dominated by Mesozoic detrital ages (ca. 230-160 Ma), contain significant amounts of Paleozoic (ca. 290, 380-350, 480-415 Ma), Neoproterozoic (ca. 675-575 Ma), and Mesoproterozoic grains (ca. 1.4-1.0 Ga), and have lesser quantities of Late Paleoproterozoic grains (ca. 2.1-1.7 Ga). Detrital zircon ages in Jurassic sediments closely resemble well-documented age distributions in transcontinental sands of Ouachita-Appalachian provenance that were transported across the southwestern United States and modified by input from cratonal, miogeoclinal, and Cordilleran-arc sources during Triassic and Jurassic time. Jurassic sediments likely were derived from the Cordilleran arc and an orogenic highland in Nevada that yielded recycled sand from uplifted Triassic backarc basin deposits. Our data suggest that numerous Jurassic Cordilleran basins formed close to the Cordilleran margin and support a model for moderate post-Jurassic translation (~400 km) of the Blue Mountains Province. ?? 2011 Geological Society of America.

Isotopic and paleomagnetic constraints on the Mesozoic tectonic evolution of south China

NASA Astrophysics Data System (ADS)

Gilder, Stuart A.; Gill, James; Coe, Robert S.; Zhao, Xixi; Liu, Zhongwei; Wang, Genxian; Yuan, Kuirong; Liu, Wenlong; Kuang, Guodun; Wu, Haoruo

1996-07-01

In order to better constrain the paleogeographic evolution of south China we measured Sm-Nd and Rb-Sr isotopic compositions for 23 Mesozoic granites that crop out throughout the area. Tightly grouped neodymium depleted mantle model ages (1.4 ± 0.3 Ga) suggest the region is underlain by relatively homogeneous Proterozoic crust and fail to define crustal provinces. Neither the isotopic nor geologic data suggest that a Mesozoic suture exists. However, granites possessing anomalously high Sm (>8 ppm) and Nd (>45 ppm) concentrations, relatively high initial epsilon neodymium (-4 to -8), and high but variable initial 87Sr/86Sr (0.759 to 0.713) form a northeast trending zone that coincides with two prominent Mesozoic basins. Southeast of the zone lie the majority of Mesozoic intrusives and Upper Triassic to Lower Cretaceous extensional basins found in south China. Mesozoic paleomagnetic poles are well clustered northwest of the zone. Pre-Cretaceous poles southeast of it are discordant with respect to those from the northwest. The only recognized tectonostratigraphic terrane in south China lies southeast of the zone. The terrane is bordered by a northeast trending sinistral fault that was active in the Mesozoic. Other faults in south China have similar attitudes, ages, and sense of shear. Together, the observations suggest that the Mesozoic tectonic regime in south China consisted of strike-slip activity plus concomitant rifting as terranes or fragments of similar crust were transported north along sinistral faults. The zone, defined by the granites enriched in Nd and Sm, demarcates displaced terranes to the southeast from relatively stable land to the northwest.

A Temnospondyl Trackway from the Early Mesozoic of Western Gondwana and Its Implications for Basal Tetrapod Locomotion

PubMed Central

Marsicano, Claudia A.; Wilson, Jeffrey A.; Smith, Roger M. H.

2014-01-01

Background Temnospondyls are one of the earliest radiations of limbed vertebrates. Skeletal remains of more than 190 genera have been identified from late Paleozoic and early Mesozoic rocks. Paleozoic temnospondyls comprise mainly small to medium sized forms of diverse habits ranging from fully aquatic to fully terrestrial. Accordingly, their ichnological record includes tracks described from many Laurasian localities. Mesozoic temnospondyls, in contrast, include mostly medium to large aquatic or semi-aquatic forms. Exceedingly few fossil tracks or trackways have been attributed to Mesozoic temnospondyls, and as a consequence very little is known of their locomotor capabilities on land. Methodology/Principal Findings We report a ca. 200 Ma trackway, Episcopopus ventrosus, from Lesotho, southern Africa that was made by a 3.5 m-long animal. This relatively long trackway records the trackmaker dragging its body along a wet substrate using only the tips of its digits, which in the manus left characteristic drag marks. Based on detailed mapping, casting, and laser scanning of the best-preserved part of the trackway, we identified synapomorphies (e.g., tetradactyl manus, pentadactyl pes) and symplesiomorphies (e.g., absence of claws) in the Episcopopus trackway that indicate a temnospondyl trackmaker. Conclusions/Significance Our analysis shows that the Episcopopus trackmaker progressed with a sprawling posture, using a lateral-sequence walk. Its forelimbs were the major propulsive elements and there was little lateral bending of the trunk. We suggest this locomotor style, which differs dramatically from the hindlimb-driven locomotion of salamanders and other extant terrestrial tetrapods can be explained by the forwardly shifted center of mass resulting from the relatively large heads and heavily pectoral girdles of temnospondyls. PMID:25099971

A Mesozoic gliding mammal from northeastern China.

PubMed

Meng, Jin; Hu, Yaoming; Wang, Yuanqing; Wang, Xiaolin; Li, Chuankui

2006-12-14

Gliding flight has independently evolved many times in vertebrates. Direct evidence of gliding is rare in fossil records and is unknown in mammals from the Mesozoic era. Here we report a new Mesozoic mammal from Inner Mongolia, China, that represents a previously unknown group characterized by a highly specialized insectivorous dentition and a sizable patagium (flying membrane) for gliding flight. The patagium is covered with dense hair and supported by an elongated tail and limbs; the latter also bear many features adapted for arboreal life. This discovery extends the earliest record of gliding flight for mammals to at least 70 million years earlier in geological history, and demonstrates that early mammals were diverse in their locomotor strategies and lifestyles; they had experimented with an aerial habit at about the same time as, if not earlier than, when birds endeavoured to exploit the sky.

A bottom-up perspective on ecosystem change in Mesozoic oceans

PubMed Central

Follows, Michael J.

2016-01-01

Mesozoic and Early Cenozoic marine animals across multiple phyla record secular trends in morphology, environmental distribution, and inferred behaviour that are parsimoniously explained in terms of increased selection pressure from durophagous predators. Another systemic change in Mesozoic marine ecosystems, less widely appreciated than the first, may help to explain the observed animal record. Fossils, biomarker molecules, and molecular clocks indicate a major shift in phytoplankton composition, as mixotrophic dinoflagellates, coccolithophorids and, later, diatoms radiated across shelves. Models originally developed to probe the ecology and biogeography of modern phytoplankton enable us to evaluate the ecosystem consequences of these phytoplankton radiations. In particular, our models suggest that the radiation of mixotrophic dinoflagellates and the subsequent diversification of marine diatoms would have accelerated the transfer of primary production upward into larger size classes and higher trophic levels. Thus, phytoplankton evolution provides a mechanism capable of facilitating the observed evolutionary shift in Mesozoic marine animals. PMID:27798303

A bottom-up perspective on ecosystem change in Mesozoic oceans.

PubMed

Knoll, Andrew H; Follows, Michael J

2016-10-26

Mesozoic and Early Cenozoic marine animals across multiple phyla record secular trends in morphology, environmental distribution, and inferred behaviour that are parsimoniously explained in terms of increased selection pressure from durophagous predators. Another systemic change in Mesozoic marine ecosystems, less widely appreciated than the first, may help to explain the observed animal record. Fossils, biomarker molecules, and molecular clocks indicate a major shift in phytoplankton composition, as mixotrophic dinoflagellates, coccolithophorids and, later, diatoms radiated across shelves. Models originally developed to probe the ecology and biogeography of modern phytoplankton enable us to evaluate the ecosystem consequences of these phytoplankton radiations. In particular, our models suggest that the radiation of mixotrophic dinoflagellates and the subsequent diversification of marine diatoms would have accelerated the transfer of primary production upward into larger size classes and higher trophic levels. Thus, phytoplankton evolution provides a mechanism capable of facilitating the observed evolutionary shift in Mesozoic marine animals. © 2016 The Authors.

Sedimentary facies and depositional environments of early Mesozoic Newark Supergroup basins, eastern North America

USGS Publications Warehouse

Smoot, J.P.

1991-01-01

The early Mesozoic Newark Supergroup consists of continental sedimentary rocks and basalt flows that occupy a NE-trending belt of elongate basins exposed in eastern North America. The basins were filled over a period of 30-40 m.y. spanning the Late Triassic to Early Jurassic, prior to the opening of the north Atlantic Ocean. The sedimentary rocks are here divided into four principal lithofacies. The alluvial-fan facies includes deposits dominated by: (1) debris flows; (2) shallow braided streams; (3) deeper braided streams (with trough crossbeds); or (4) intense bioturbation or hyperconcentrated flows (tabular, unstratified muddy sandstone). The fluvial facies include deposits of: (1) shallow, ephemeral braided streams; (2) deeper, flashflooding, braided streams (with poor sorting and crossbeds); (3) perennial braided rivers; (4) meandering rivers; (5) meandering streams (with high suspended loads); (6) overbank areas or local flood-plain lakes; or (7) local streams and/or colluvium. The lacustrine facies includes deposits of: (1) deep perennial lakes; (2) shallow perennial lakes; (3) shallow ephemeral lakes; (4) playa dry mudflats; (5) salt-encrusted saline mudflats; or (6) vegetated mudflats. The lake margin clastic facies includes deposits of: (1) birdfoot deltas; (2) stacked Gilbert-type deltas; (3) sheet deltas; (4) wave-reworked alluvial fans; or (5) wave-sorted sand sheets. Coal deposits are present in the lake margin clastic and the lacustrine facies of Carnian age (Late Triassic) only in basins of south-central Virginia and North and South Carolina. Eolian deposits are known only from the basins in Nova Scotia and Connecticut. Evaporites (and their pseudomorphs) occur mainly in the northern basins as deposits of saline soils and less commonly of saline lakes, and some evaporite and alkaline minerals present in the Mesozoic rocks may be a result of later diagenesis. These relationships suggest climatic variations across paleolatitudes, more humid to the

Evolution of Northeastern Mexico during the early Mesozoic: potential areas for research and exploration José Rafael Barboza-Gudiño

NASA Astrophysics Data System (ADS)

Barboza-Gudiño, R.

2013-05-01

The lower Mesozoic succession of central and northeastern Mexico was deposited in a late Paleozoic-early Mesozoic remnant basin, formed at the westernmost culmination of the Ouachita-Marathon geosuture, after closure of the Rheic Ocean. Triassic fluvial deposits of El Alamar Formation (El Alamar River) are distributed in Tamaulipas and Nuevo Leon as remnants of a continental succession deposited close to the western margin of equatorial Pangea, such fluvial systems flowed to the ocean, located to the west and contributed to construction of the so-called Potosí submarine fan (Zacatecas Formation). Petrographic, geochemical, and detrital zircon geochronology studies indicate that both, marine and continental Triassic successions, come from a continental block and partially from a recycled orogen, showing grenvillian (900-1300 Ma) and Pan-African (500-700 Ma) zircon age populations, typical for peri-gondwanan blocks, in addition to zircons from the Permo-Triassic East Mexico arc (240-280 Ma). The absence of detrital zircons from the southwestern North American craton, represent a strong argument against left lateral displacement of Mexico to the southwest during the Jurassic up to their actual position, as proposed by the Mojave-Sonora megashear hypothesis. Towards the end of the Triassic or in earliest Jurassic time, began the subduction along the western margin of Pangea, which causes deformation of the Late Triassic Zacatecas Formation and subsequent magmatism in the continental Jurassic arc known as "Nazas Arc ", whose remnants are now exposed in central- to northeastern Mexico. Wide distributed in northern Mexico occurred also deposition of a red bed succession, overlying or partially interstratified with the Early to Middle Jurassic volcanic rocks of the Nazas Formation. To the west and southwest, such redbeds change transitionally to marine and marginal sedimentary facies which record sedimentation at the ancient paleo-pacific margin of Mexico (La Boca and

Melting of subducted continental crust: Geochemical evidence from Mesozoic granitoids in the Dabie-Sulu orogenic belt, east-central China

NASA Astrophysics Data System (ADS)

Zhao, Zi-Fu; Liu, Zhi-Bin; Chen, Qi

2017-09-01

Syn-collisional and postcollisional granitoids are common in collisional orogens, and they were primarily produced by partial melting of subducted continental crust. This is exemplified by Mesozoic granitoids from the Dabie-Sulu orogenic belt in east-central China. These granitoids were emplaced in small volumes in the Late Triassic (200-206 Ma) and the Late Jurassic (146-167 Ma) but massively in the Early Cretaceous (111-143 Ma). Nevertheless, all of them exhibit arc-like trace element distribution patterns and are enriched in Sr-Nd-Hf isotope compositions, indicating their origination from the ancient continental crust. They commonly contain relict zircons with Neoproterozoic and Triassic U-Pb ages, respectively, consistent with the protolith and metamorphic ages for ultrahigh-pressure (UHP) metaigneous rocks in the Dabie-Sulu orogenic belt. Some granitoids show low zircon δ18O values, and SIMS in-situ O isotope analysis reveals that the relict zircons with Neoproterozoic and Triassic U-Pb ages also commonly exhibit low δ18O values. Neoproterozoic U-Pb ages and low δ18O values are the two diagnostic features that distinguish the subducted South China Block from the obducted North China Block. Thus, the magma source of these Mesozoic granitoids has a genetic link to the subducted continental crust of the South China Block. On the other hand, these granitoids contain relict zircons with Paleoproterozoic and Archean U-Pb ages, which are present in both the South and North China Blocks. Taken together, the Mesozoic granitoids in the Dabie-Sulu orogenic belt and its hanging wall have their magma sources that are predominated by the continental crust of the South China Block with minor contributions from the continental crust of the North China Block. The Triassic continental collision between the South and North China Blocks brought the continental crust into the thickened orogen, where they underwent the three episodes of partial melting in the Late Triassic, Late

A comparative study of diversification events: the early Paleozoic versus the Mesozoic

NASA Technical Reports Server (NTRS)

Erwin, D. H.; Valentine, J. W.; Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)

1987-01-01

We compare two major long-term diversifications of marine animal families that began during periods of low diversity but produced strikingly different numbers of phyla, classes, and orders. The first is the early-Paleozoic diversification (late Vendian-Ordovician; 182 MY duration) and the other the Mesozoic phase of the post-Paleozoic diversification (183 MY duration). The earlier diversification was associated with a great burst of morphological invention producing many phyla, classes, and orders and displaying high per taxon rates of family origination. The later diversification lacked novel morphologies recognized as phyla and classes, produced fewer orders, and displayed lower per taxon rates of family appearances. The chief difference between the diversifications appears to be that the earlier one proceeded from relatively narrow portions of adaptive space, whereas the latter proceeded from species widely scattered among adaptive zones and representing a variety of body plans. This difference is believed to explain the major differences in the products of these great radiations. Our data support those models that hold that evolutionary opportunity is a major factor in the outcome of evolutionary processes.

Mesozoic black shales, source mixing and carbon isotopes

NASA Astrophysics Data System (ADS)

Suan, Guillaume

2016-04-01

Over the last decades, considerable attention has been devoted to the paleoenvironmental and biogeochemical significance of Mesozoic black shales. Black shale-bearing successions indeed often display marked changes in the organic carbon isotope composition (δ13Corg), which have been commonly interpreted as evidence for dramatic perturbations of global carbon budgets and CO2 levels. Arguably the majority of these studies have discarded some more "local" explanations when interpreting δ13Corg profiles, most often because comparable profiles occur on geographically large and distant areas. Based on newly acquired data and selected examples from the literature, I will show that the changing contribution of organic components with distinct δ13C signatures exerts a major but overlooked influence of Mesozoic δ13Corg profiles. Such a bias occurs across a wide spectrum of sedimentological settings and ages, as shown by the good correlation between δ13Corg values and proxies of kerogen proportions (such as rock-eval, biomarker, palynofacies and palynological data) recorded in Mesozoic marginal to deep marine successions of Triassic, Jurassic and Cretaceous age. In most of these successions, labile, 12C-enriched amorphous organic matter of marine origin dominates strata deposited under anoxic conditions, while oxidation-resistant, 13C-rich terrestrial particles dominate strata deposited under well-oxygenated conditions. This influence is further illustrated by weathering profiles of Toarcian (Lower Jurassic) black shales from France, where weathered areas dominated by refractory organic matter show dramatic 13C-enrichment (and decreased total organic carbon and pyrite contents) compared to non-weathered portions of the same horizon. The implications of these results for chemostratigraphic correlations and pCO2 reconstructions of Mesozoic will be discussed, as well as strategies to overcome this major bias.

The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution

PubMed Central

Brocklehurst, Neil; Upchurch, Paul; Mannion, Philip D.; O'Connor, Jingmai

2012-01-01

Many palaeobiological analyses have concluded that modern birds (Neornithes) radiated no earlier than the Maastrichtian, whereas molecular clock studies have argued for a much earlier origination. Here, we assess the quality of the fossil record of Mesozoic avian species, using a recently proposed character completeness metric which calculates the percentage of phylogenetic characters that can be scored for each taxon. Estimates of fossil record quality are plotted against geological time and compared to estimates of species level diversity, sea level, and depositional environment. Geographical controls on the avian fossil record are investigated by comparing the completeness scores of species in different continental regions and latitudinal bins. Avian fossil record quality varies greatly with peaks during the Tithonian-early Berriasian, Aptian, and Coniacian–Santonian, and troughs during the Albian-Turonian and the Maastrichtian. The completeness metric correlates more strongly with a ‘sampling corrected’ residual diversity curve of avian species than with the raw taxic diversity curve, suggesting that the abundance and diversity of birds might influence the probability of high quality specimens being preserved. There is no correlation between avian completeness and sea level, the number of fluviolacustrine localities or a recently constructed character completeness metric of sauropodomorph dinosaurs. Comparisons between the completeness of Mesozoic birds and sauropodomorphs suggest that small delicate vertebrate skeletons are more easily destroyed by taphonomic processes, but more easily preserved whole. Lagerstätten deposits might therefore have a stronger impact on reconstructions of diversity of smaller organisms relative to more robust forms. The relatively poor quality of the avian fossil record in the Late Cretaceous combined with very patchy regional sampling means that it is possible neornithine lineages were present throughout this interval but

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.

Mesozoic evolution of northeast African shelf margin, Libya and Egypt

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

Aadland, R.K.; Schamel, S.

1989-03-01

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. The 250 km-wide and highly differentiated Mesozoic passive margin in the Western Desert region of Egypt is developed above a broad northwest-trending Late Carboniferous basement arch. In northeastern Libya, in contrast, the passive margin is restricted to just the northernmost Cyrenaica platform, where subsidence was extremely rapid in the Jurassic and Early Cretaceous. The boundary between the Western Desertmore » basin and the Cyrenaica platform is controlled by the western flank of the basement arch. In the middle Cretaceous (100-90 Ma), subsidence accelerated over large areas of the Western desert, further enhancing a pattern of east-west-trending subbasins. This phase of rapid subsidence was abruptly ended about 80 Ma by the onset of structural inversion that uplifted the northern Cyrenaica shelf margin and further differentiated the Western Desert subbasin along a northeasterly trend.« less

Hotspots, polar wander, Mesozoic convection and the geoid

NASA Astrophysics Data System (ADS)

Anderson, D. L.

1981-11-01

The geoid bears little relation to present tectonic features of the earth other than trenches. The Mesozoic supercontinent of Pangea, however, apparently occupied a central position in the Atlantic-African geoid high. This and the equatorial Pacific geoid high contain most of the world's hotspots. The plateaus and rises in the western Pacific formed in the Pacific geoid high and this may have been the early Mesozoic position of Pacifica, the fragments of which are now the Pacific rim portions of the continents. Geoid highs which are unrelated to present subduction zones may be the former sites of continental aggregations and mantle insulation and, therefore, hotter than normal mantle. The pent-up heat causes rifts and hotspots and results in extensive uplift, magmatism, fragmentation and dispersal of the continents and the subsequent formation of plateaus, aseismic ridges and seamount chains. Convection in the uppermantle would then be due to lateral temperature gradients as well as heating from below and would be intrinsically episodic.

Hotspots, polar wander, Mesozoic convection and the geoid

NASA Technical Reports Server (NTRS)

Anderson, D. L.

1981-01-01

The geoid bears little relation to present tectonic features of the earth other than trenches. The Mesozoic supercontinent of Pangea, however, apparently occupied a central position in the Atlantic-African geoid high. This and the equatorial Pacific geoid high contain most of the world's hotspots. The plateaus and rises in the western Pacific formed in the Pacific geoid high and this may have been the early Mesozoic position of Pacifica, the fragments of which are now the Pacific rim portions of the continents. Geoid highs which are unrelated to present subduction zones may be the former sites of continental aggregations and mantle insulation and, therefore, hotter than normal mantle. The pent-up heat causes rifts and hotspots and results in extensive uplift, magmatism, fragmentation and dispersal of the continents and the subsequent formation of plateaus, aseismic ridges and seamount chains. Convection in the uppermantle would then be due to lateral temperature gradients as well as heating from below and would be intrinsically episodic.

The geology and Mesozoic collisional history of the Cordillera Real, Ecuador

NASA Astrophysics Data System (ADS)

Aspden, John A.; Litherland, Martin

1992-04-01

The geology of the metamorphic rocks of the Cordillera Real of Ecuador is described in terms of five informal lithotectonic divisions. We deduce that during the Mesozoic repeated accretionary events occurred and that dextral transpression has been of fundamental importance in determining the tectonic evolution of this part of the Northern Andes. The oldest event recognised, of probable Late Triassic age, may be related to the break-up of western Gondwana and generated a regional belt of 'S-type' plutons. During the Jurassic, major calc-alkaline batholiths were intruded. Following this, in latest Jurassic to Early Cretaceous time, a volcano-sedimentary terrane, of possible oceanic or marginal basin origin (the Alao division), and the most westerly, gneissic Chaucha-Arenillas terrane, were accreted to continental South America. The accretion of the oceanic Western Cordillera took place in latest Cretaceous to earliest Tertiary time. This latter event coincided with widespread thermal disturbance, as evidenced by the large number of young K-Ar mineral ages recorded from the Cordillera Real.

The inheritance of a Mesozoic landscape in western Scandinavia

PubMed Central

Fredin, Ola; Viola, Giulio; Zwingmann, Horst; Sørlie, Ronald; Brönner, Marco; Lie, Jan-Erik; Grandal, Else Margrethe; Müller, Axel; Margreth, Annina; Vogt, Christoph; Knies, Jochen

2017-01-01

In-situ weathered bedrock, saprolite, is locally found in Scandinavia, where it is commonly thought to represent pre-Pleistocene weathering possibly associated with landscape formation. The age of weathering, however, remains loosely constrained, which has an impact on existing geological and landscape evolution models and morphotectonic correlations. Here we provide new geochronological evidence that some of the low-altitude basement landforms on- and offshore southwestern Scandinavia are a rejuvenated geomorphological relic from Mesozoic times. K-Ar dating of authigenic, syn-weathering illite from saprolitic remnants constrains original basement exposure in the Late Triassic (221.3±7.0–206.2±4.2 Ma) through deep weathering in a warm climate and subsequent partial mobilization of the saprolitic mantle into the overlying sediment cascade system. The data support the bulk geomorphological development of west Scandinavia coastal basement rocks during the Mesozoic and later, long-lasting relative tectonic stability. Pleistocene glaciations played an additional geomorphological role, selectively stripping the landscape from the Mesozoic overburden and carving glacial landforms down to Plio–Pleistocene times. Saprolite K-Ar dating offers unprecedented possibilities to study past weathering and landscape evolution processes. PMID:28452366

A transitional alkalic dolerite dike suite of Mesozoic age in Southeastern New England

NASA Astrophysics Data System (ADS)

Hermes, O. Don; Rao, J. M.; Dickenson, M. P.; Pierce, T. A.

1984-12-01

Dike rocks from the New England platform of Rhode Island and adjacent Massachusetts consist of premetamorphic and post-metamorphic suites. The older group includes metamorphosed dolerite, minette, and schistose dioritic rocks. Post-metamorphic dikes consist of dolerite and sparse monchiquite. The post-metamorphic dolerites are of comparable age to the Eastern North American dolerite suite associated with the Mesozoic basins along the eastern seaboard of North America. However, the southeastern New England dolerites exhibit mineralogy and chemistry more typical of a transitional alkalic suite compared to the more subalkalic tholeiitic dolerites of the Eastern North American suite. Both suites are compatible with a rift tectonic setting, but the more alkalic dolerites may represent a deeper source of small volume melts compared to the Eastern North American dolerites. These more alkaline melts may have concentrated at local centers, or they may be typical of flank dolerites as opposed to the less alkalic varieties that occur within the central axial rift.

Paleozoic and Lower Mesozoic magmas from the eastern Klamath Mountains (North California) and the geodynamic evolution of northwestern America

NASA Astrophysics Data System (ADS)

Lapierre, H.; Brouxel, M.; Albarede, F.; Coulin, C.; Lecuyer, C.; Martin, P.; Mascle, G.; Rouer, O.

1987-09-01

The Paleozoic to Early Mesozoic geology of the eastern Klamath Mountains (N California) is characterized by three major magmatic events of Ordovician, Late Ordovician to Early Devonian, and Permo-Triassic ages. The Ordovician event is represented by a calc-alkalic island-arc sequence (Lovers Leap Butte sequence) developed in the vicinity of a continental margin. The Late Ordovician to Early Devonian event consists of the 430-480 Ma old Trinity ophiolite formed during the early development of a marginal basin, and a series of low-K tholeiitic volcanic suites (Lovers Leap Basalt—Keratophyre unit, Copley and Balaklala Formations) belonging to intraoceanic island-arcs. Finally, the Permo-Triassic event gave rise to three successives phases of volcanic activity (Nosoni, Dekkas and Bully Hill) represented by the highly differentiated basalt-to-rhyolite low-K tholeiitic series of mature island-arcs. The Permo-Triassic sediments are indicative of shallow to moderate depth in an open, warm sea. The geodynamic evolution of the eastern Klamath Mountains during Paleozoic to Early Mesozoic times is therefore constrained by the geological, petrological and geochemical features of its island-arcs and related marginal basin. A consistent plate-tectonic model is proposed for the area, consisting of six main stages: (1) development during Ordovician times of a calc-alkalic island-arc in the vicinity of a continental margin; (2) extrusion during Late Ordovician to Silurian times of a primitive basalt-andesite intraoceanic island-arc suite, which terminated with boninites, the latter suggest rifting in the fore-arc, followed by the breakup of the arc; (3) opening and development of the Trinity back-arc basin around 430-480 Ma ago; (4) eruption of the Balaklala Rhyolite either in the arc or in the fore-arc, ending in Early Devonian time with intrusion of the 400 Ma Mule Mountain stock; (5) break in volcanic activity from the Early Devonian to the Early Permian; and (6) development of

Extensive crustal melting during craton destruction: Evidence from the Mesozoic magmatic suite of Junan, eastern North China Craton

NASA Astrophysics Data System (ADS)

Yang, Fan; Santosh, M.; Tang, Li

2018-05-01

The cratonic destruction associated with the Pacific plate subduction beneath the eastern North China Craton (NCC) shows a close relationship with the widespread magmatism during the Late Mesozoic. Here we investigate a suite of intrusive and extrusive magmatic rocks from the Junan region of the eastern NCC in order to evaluate the role of extensive crustal melting related to decratonization. We present petrological, geochemical, zircon U-Pb geochronological and Lu-Hf isotopic data to evaluate the petrogenesis, timing and tectonic significance of the Early Cretaceous magmatism. Zircon grains in the basalt from the extrusive suite of Junan show multiple populations with Neoproterozoic and Early Paleozoic xenocrystic grains ranging in age from 764 Ma to 495 Ma as well as Jurassic grains with an age range of 189-165 Ma. The dominant population of magmatic zircon grains in the syenite defines three major age peaks of 772 Ma, 132 Ma and 126 Ma. Zircons in the granitoids including alkali syenite, monzonite and granodiorite yield a tightly restricted age range of 124-130 Ma representing their emplacement ages. The Neoproterozoic (841-547 Ma) zircon grains from the basalt and the syenite possess εHf(t) values of -22.9 to -8.4 and from -18.8 to -17.3, respectively. The Early Paleozoic (523-494 Ma) zircons from the basalt and the syenite also show markedly negative εHf(t) values of -22.7 to -18.0. The dominant population of Early Cretaceous (134-121 Ma) zircon grains presented in all the samples also displays negative εHf(t) values range from -31.7 to -21.1, with TDM of 1653-2017 Ma and TDMC in the range of 2193-3187 Ma. Accordingly, the Lu-Hf data suggest that the parent magma was sourced through melting of Mesoarchean to Paleoproterozoic basement rocks. Geochemical data on the Junan magmatic suite display features similar to those associated with the arc magmatic rocks involving subduction-related components, with interaction of fluids and melts in the suprasubduction

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

Chaotic evolution of the long-period Milankovitch cycle during the early Mesozoic: independent evidences from the Newark lacustrine sequence (North America) and the pelagic bedded chert sequence (Japan)

NASA Astrophysics Data System (ADS)

Ikeda, M.; Olsen, P. E.; Tada, R.

2012-12-01

The correlation of Earth's orbital parameters with climatic variations has been used to generate astronomically calibrated geologic time scales of high accuracy. However, because of the chaotic behavior of the solar planets, the orbital models have a large uncertainty beyond several tens of million years in the past. This chaotic behavior also causes the long-period astronomical cycles (> 0.5 Myr periodicity) to modulate their frequency and amplitude. In other words, their modulation patterns could be potential constraints for the orbital models. Here we report the first geologic constraints on the timing of frequency transition and amplitude modulation of the ~ 2 Myr long eccentricity cycles during the early Mesozoic. We examined the lake level records of the early Mesozoic Newark lacustrine sequence in North America and the biogenic silica burial rate of the pelagic bedded chert sequence in the Inuyama area, Japan, which are proven to be reflect the astronomical cycle (Olsen, 1986; Olsen and Kent, 1996; Ikeda et al., 2010). The time scales of the two sequences were orbitally calibrated with the end-Triassic mass extinction interval as the age anchor, covering ~ 30 Myr and ~ 65 Myr, respectively (Olsen et al., 2011; Ikeda et al., 2010, in prep). We find that the frequency modulation of ~ 2 Myr cycle between 2.4 Myr to 1.6 Myr cycle have occurred at least the Middle to Late Triassic. In addition, the ~ 2 Myr cycle modulate its amplitude with ~ 10 Myr periodicity with in-phase relation between the two. Similar modulation patterns of ~ 2 Myr cycles from the two independent geologic records indicate convincing evidences for the chaotic behavior of the Solar planets. Because these modulation patterns are different from the results of the orbital models by Laskar et al. (2004, 2011), our records will provide the new and challenging constraints for the orbital models in terms of chaotic behavior of Solar planets.

Near-Stasis in the Long-Term Diversification of Mesozoic Tetrapods

PubMed Central

Benson, Roger B. J.; Butler, Richard J.; Alroy, John; Mannion, Philip D.; Carrano, Matthew T.; Lloyd, Graeme T.

2016-01-01

How did evolution generate the extraordinary diversity of vertebrates on land? Zero species are known prior to ~380 million years ago, and more than 30,000 are present today. An expansionist model suggests this was achieved by large and unbounded increases, leading to substantially greater diversity in the present than at any time in the geological past. This model contrasts starkly with empirical support for constrained diversification in marine animals, suggesting different macroevolutionary processes on land and in the sea. We quantify patterns of vertebrate standing diversity on land during the Mesozoic–early Paleogene interval, applying sample-standardization to a global fossil dataset containing 27,260 occurrences of 4,898 non-marine tetrapod species. Our results show a highly stable pattern of Mesozoic tetrapod diversity at regional and local levels, underpinned by a weakly positive, but near-zero, long-term net diversification rate over 190 million years. Species diversity of non-flying terrestrial tetrapods less than doubled over this interval, despite the origins of exceptionally diverse extant groups within mammals, squamates, amphibians, and dinosaurs. Therefore, although speciose groups of modern tetrapods have Mesozoic origins, rates of Mesozoic diversification inferred from the fossil record are slow compared to those inferred from molecular phylogenies. If high speciation rates did occur in the Mesozoic, then they seem to have been balanced by extinctions among older clades. An apparent 4-fold expansion of species richness after the Cretaceous/Paleogene (K/Pg) boundary deserves further examination in light of potential taxonomic biases, but is consistent with the hypothesis that global environmental disturbances such as mass extinction events can rapidly adjust limits to diversity by restructuring ecosystems, and suggests that the gradualistic evolutionary diversification of tetrapods was punctuated by brief but dramatic episodes of radiation

Early Mesozoic rift basin architecture and sediment routing system in the Moroccan High Atlas

NASA Astrophysics Data System (ADS)

Perez, N.; Teixell, A.; Gomez, D.

2016-12-01

Late Permian to Triassic extensional systems associated with Pangea breakup governed the structural framework and rift basin architecture that was inherited by Cenozoic High Atlas Mountains in Morocco. U-Pb detrital zircon geochronologic and mapping results from Permo-Triassic deposits now incorporated into the High Atlas Mountains provide new constraints on the geometry and interconnectivity among synextensional depocenters. U-Pb detrital zircon data provide provenance constraints of Permo-Triassic deposits, highlighting temporal changes in sediment sources and revealing the spatial pattern of sediment routing along the rift. We also characterize the U-Pb detrital zircon geochronologic signature of distinctive interfingering fluvial, tidal, and aeolian facies that are preferentially preserved near the controlling normal faults. These results highlight complex local sediment mixing patterns potentially linked to the interplay between fault motion, eustatic, and erosion/transport processes. We compare our U-Pb geochronologic results with existing studies of Gondwanan and Laurentian cratonic blocks to investigate continent scale sediment routing pathways, and with analogous early Mesozoic extensional systems situated in South America (Mitu basin, Peru) and North America (Newark Basin) to assess sediment mixing patterns in rift basins.

The first iguanian lizard from the Mesozoic of Africa

NASA Astrophysics Data System (ADS)

Apesteguía, Sebastián; Daza, Juan D.; Simões, Tiago R.; Rage, Jean Claude

2016-09-01

The fossil record shows that iguanian lizards were widely distributed during the Late Cretaceous. However, the biogeographic history and early evolution of one of its most diverse and peculiar clades (acrodontans) remain poorly known. Here, we present the first Mesozoic acrodontan from Africa, which also represents the oldest iguanian lizard from that continent. The new taxon comes from the Kem Kem Beds in Morocco (Cenomanian, Late Cretaceous) and is based on a partial lower jaw. The new taxon presents a number of features that are found only among acrodontan lizards and shares greatest similarities with uromastycines, specifically. In a combined evidence phylogenetic dataset comprehensive of all major acrodontan lineages using multiple tree inference methods (traditional and implied weighting maximum-parsimony, and Bayesian inference), we found support for the placement of the new species within uromastycines, along with Gueragama sulamericana (Late Cretaceous of Brazil). The new fossil supports the previously hypothesized widespread geographical distribution of acrodontans in Gondwana during the Mesozoic. Additionally, it provides the first fossil evidence of uromastycines in the Cretaceous, and the ancestry of acrodontan iguanians in Africa.

Preliminary Depositional and Provenance Records of Mesozoic Basin Evolution and Cenozoic Shortening in the High Andes, La Ramada Fold-Thrust Belt, Southern-Central Andes (32-33°S)

NASA Astrophysics Data System (ADS)

Mackaman-Lofland, C.; Horton, B. K.; Fuentes, F.; Constenius, K. N.; McKenzie, R.; Alvarado, P. M.

2015-12-01

The Argentinian Andes define key examples of retroarc shortening and basin evolution above a zone of active subduction. The La Ramada fold-thrust belt (RFTB) in the High Andes provides insights into the relative influence and temporal records of diverse convergent margin processes (e.g. flat-slab subduction, convergent wedge dynamics, structural inversion). The RFTB contains Mesozoic extensional basin strata deformed by later Andean shortening. New detrital zircon U-Pb analyses of Mesozoic rift sediments reveal: (1) a dominant Permo-Triassic age signature (220-280 Ma) associated with proximal sources of effective basement (Choiyoi Group) during Triassic synrift deposition; (2) upsection younging of maximum depositional ages from Late Triassic through Early Cretaceous (230 to 100 Ma) with the increasing influence of western Andean arc sources; and (3) a significant Late Cretaceous influx of Paleozoic (~350-550 Ma) and Proterozoic (~650-1300 Ma) populations during the earliest shift from back-arc post-extensional subsidence to upper-plate shortening. The Cenozoic detrital record of the Manantiales foreland basin (between the Frontal Cordillera and Precordillera) records RFTB deformation prior to flat-slab subduction. A Permo-Triassic Choiyoi age signature dominates the Miocene succession, consistent with sources in the proximal Espinacito range. Subordinate Mesozoic (~80-250 Ma) to Proterozoic (~850-1800 Ma) U-Pb populations record exhumation of the Andean magmatic arc and recycling of different structural levels in the RFTB during thrusting/inversion of Mesozoic rift basin strata and subjacent Paleozoic units. Whereas maximum depositional ages of sampled Manantiales units cluster at 18-20 Ma, the Estancia Uspallata basin (~50 km to the south) shows consistent upsection younging of Cenozoic populations attributed to proximal volcanic centers. Ongoing work will apply low-temperature thermochronology to pinpoint basin accumulation histories and thrust timing.

Late Mesozoic-Cenozoic intraplate magmatism in Central Asia and its relation with mantle diapirism: Evidence from the South Khangai volcanic region, Mongolia

NASA Astrophysics Data System (ADS)

Yarmolyuk, Vladimir V.; Kudryashova, Ekaterina A.; Kozlovsky, Alexander M.; Lebedev, Vladimir A.; Savatenkov, Valery M.

2015-11-01

The South Khangai volcanic region (SKVR) comprises fields of Late Mesozoic-Cenozoic volcanic rocks scattered over southern and central Mongolia. Evolution of the region from the Late Jurassic to the Late Cenozoic includes 13 successive igneous episodes that are more or less evenly distributed in time. Major patterns in the distribution of different-aged volcanic complexes were controlled by a systematic temporal migration of volcanic centers over the region. The total length of their trajectory exceeds 1600 km. Principle characteristics of local magmatism are determined. The composition of igneous rocks varies from basanites to rhyolites (predominantly, high-K rocks), with geochemistry close to that of OIB. The rock composition, however, underwent transformations in the Mesozoic-Cenozoic. Rejuvenation of mafic rocks is accompanied by decrease in the contents of HREE and increase of Nb and Ta. According to isotope data, the SKVR magmatic melts were derived from three isotope sources that differed in the Sr, Nd, and Pb isotopic compositions and successively alternated in time. In the Early Cretaceous, the predominant source composition was controlled by interaction of the EMII- and PREMA-type mantle materials. The PREMA-type mantle material dominated quantitatively in the Late Cretaceous and initial Early Cenozoic. From the latest Early Cenozoic to Late Cenozoic, the magma source also contained the EMI-type material along with the PREMA-type. The structural fabric, rock composition, major evolutionary pattern, and inner structure of SKVR generally comply with the criteria used to distinguish the mantle plume-related regions. Analogous features can be seen in other regions of recent volcanism in Central Asia (South Baikal, Udokan, Vitim, and Tok Stanovik). The structural autonomy of these regions suggests that distribution of the Late Mesozoic-Cenozoic volcanism in Central Asia was controlled by a group of relatively small hot finger-type mantle plumes associated with

Diverse transitional giant fleas from the Mesozoic era of China.

PubMed

Huang, Diying; Engel, Michael S; Cai, Chenyang; Wu, Hao; Nel, André

2012-02-29

Fleas are one of the major lineages of ectoparasitic insects and are now highly specialized for feeding on the blood of birds or mammals. This has isolated them among holometabolan insect orders, although they derive from the Antliophora (scorpionflies and true flies). Like most ectoparasitic lineages, their fossil record is meagre and confined to Cenozoic-era representatives of modern families, so that we lack evidence of the origins of fleas in the Mesozoic era. The origins of the first recognized Cretaceous stem-group flea, Tarwinia, remains highly controversial. Here we report fossils of the oldest definitive fleas--giant forms from the Middle Jurassic and Early Cretaceous periods of China. They exhibit many defining features of fleas but retain primitive traits such as non-jumping hindlegs. More importantly, all have stout and elongate sucking siphons for piercing the hides of their hosts, implying that these fleas may be rooted among the pollinating 'long siphonate' scorpionflies of the Mesozoic. Their special morphology suggests that their earliest hosts were hairy or feathered 'reptilians', and that they radiated to mammalian and bird hosts later in the Cenozoic.

Late Mesozoic and possible early Tertiary accretion in western Washington State: the Helena-Haystack melange and the Darrington- Devils Mountain fault zone

USGS Publications Warehouse

Tabor, R.W.

1994-01-01

The Helena-Haystack melange (HH melange) and coincident Darrington-Devils Mountain fault zone (DDMFZ) in northwestern Washington separate two terranes, the northwest Cascade System (NWCS) and the western and eastern melange belts (WEMB). The two terranes of Paleozoic and Mesozoic rocks superficially resemble each other but record considerable differences in structural and metamorphic history. The HH melange is a serpentinite-matrix melange containing blocks of adjacent terranes but also exotic blocks. The HH melange must have formed between early Cretaceous and late middle Eocene time, because it contains tectonic clasts of early Cretaceous Shuksan Greenschist and is overlain by late middle Eocene sedimentary and volcanic rocks. The possible continuation of the DDMFZ to the northwest as the San Juan and the West Coast faults on Vancouver Island suggests that the structure has had a major role in the emplacement of all the westernmost terranes in the Pacific Northwest. -from Author

Mesozoic evolution of the northeast African shelf margin, Libya and Egypt

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

Aadland, R.K.; Schamel, S.

1988-08-01

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. Isopach and structural maps, cross sections, and sediment accumulation (geohistory) curves constructed from 89 wells in the Western Desert and 27 wells in northeastern Libya depict the structural and stratigraphic development of the northeast African shelf margin.

Strontium and oxygen isotopic variations in Mesozoic and Tertiary plutons of central Idaho

USGS Publications Warehouse

Fleck, R.J.; Criss, R.E.

1985-01-01

Regional variations in initial 87Sr/86Sr ratios (ri) of Mesozoic plutons in central Idaho locate the edge of Precambrian continental crust at the boundary between the late Paleozoic-Mesozoic accreted terranes and Precambrian sialic crust in western Idaho. The ri values increase abruptly but continuously from less than 0.704 in the accreted terranes to greater than 0.708 across a narrow, 5 to 15 km zone, characterized by elongate, lens-shaped, highly deformed plutons and schistose metasedimentary and metavolcanic units. The chemical and petrologic character of the plutons changes concomitantly from ocean-arc-type, diorite-tonalite-trondhjemite units to a weakly peraluminous, calcic to calcalkalic tonalite-granodiorite-granite suite (the Idaho batholith). Plutons in both suites yield Late Cretaceous ages, but Permian through Early Cretaceous bodies are confined to the accreted terranes and early Tertiary intrusions are restricted to areas underlain by Precambrian crust. The two major terranes were juxtaposed between 75 and 130 m.y. ago, probably between 80 and 95 m.y. Oxygen and strontium isotopic ratios and Rb and Sr concentrations of the plutonic rocks document a significant upper-crustal contribution to the magmas that intrude Precambrian crust. Magmas intruding the arc terranes were derived from the upper mantle/subducted oceanic lithosphere and may have been modified by anatexis of earlier island-arc volcanic and sedimentary units. Plutons near the edge of Precambrian sialic crust represent simple mixtures of the Precambrian wall-rocks with melts derived from the upper mantle or subducted oceanic lithosphere with ri of 0.7035. Rb/Sr varies linearly with ri, producing "pseudoisochrons" with apparent "ages" close to the age of the wall rocks. Measured ??18O values of the wall rocks are less than those required for the assimilated end-member by Sr-O covariation in the plutons, however, indicating that wall-rock ??18O was reduced significantly by exchange with

Paleozoic and Mesozoic deformations in the central Sierra Nevada, California

USGS Publications Warehouse

Nokleberg, Warren J.; Kistler, Ronald Wayne

1980-01-01

Analysis of structural and stratigraphic data indicates that several periods of regional deformation, consisting of combined folding, faulting, cataclasis, and regional metamorphism, occurred throughout the central Sierra Nevada during Paleozoic and Mesozoic time. The oldest regional deformation occurred alono northward trends during the Devonian and Mississippian periods in most roof pendants containing lower Paleozoic metasedimentary rocks at the center and along the crest of the range. This deformation is expressed in some roof pendants by an angular unconformity separating older thrice-deformed from younger twice-deformed Paleozoic metasedimentary rocks. The first Mesozoic deformation, which consisted of uplift and erosion and was accompanied by the onset of Andean-type volcanism during the Permian and Triassic, is expressed by an angular unconformity in several roof pendants from the Saddlebag Lake to the Mount Morrison areas. This unconformity is defined by Permian and Triassic andesitic to rhyolitic metavolcanic rocks unconformably overlying more intensely deformed Pennsylvanian, Permian(?), and older metasedimentary rocks. A later regional deformation occurred during the Triassic along N. 20?_30? W. trends in Permian and Triassic metavolcanic rocks of the Saddlebag Lake and Mount Dana roof pendants, in upper Paleozoic rocks of the Pine Creek roof pendant, and in the Calaveras Formation of the western metamorphic belt; the roof pendants are crosscut by Upper Triassic granitic rocks of the Lee Vining intrusive epoch. A still later period of Early and Middle Jurassic regional deformation occurred along N. 30?-60? E. trends in upper Paleozoic rocks of the Calaveras Formation of the western metamorphic belt. A further period of deformation was the Late Jurassic Nevadan orogeny, which occurred along N. 20?_40? W. trends in Upper Jurassic rocks of the western metamorphic belt that are crosscut by Upper Jurassic granitic rocks of the Yosemite intrusive epoch

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

Buried Mesozoic rift basins of Moroccan Atlantic continental margin

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

Mohamed, N.; Jabour, H.; El Mostaine, M.

1995-08-01

The Atlantic continental margin is the largest frontier area for oil and gas exploration in Morocco. Most of the activity has been concentrated where Upper Jurassic carbonate rocks have been the drilling objectives, with only one significant but non commercial oil discovery. Recent exploration activities have focused on early Mesozoic Rift basins buried beneath the post-rift sediments of the Middle Atlantic coastal plain. Many of these basins are of interest because they contain fine-grained lacustrine rocks that have sufficient organic richness to be classified as efficient oil prone source rock. Location of inferred rift basins beneath the Atlantic coastal plainmore » were determined by analysis of drilled-hole data in combination with gravity anomaly and aeromagnetic maps. These rift basins are characterized by several half graben filled by synrift sediments of Triassic age probably deposited in lacustrine environment. Coeval rift basins are known to be present in the U.S. Atlantic continental margin. Basin modeling suggested that many of the less deeply bored rift basins beneath the coastal plain are still within the oil window and present the most attractive exploration targets in the area.« less

Predator-induced macroevolutionary trends in Mesozoic crinoids

PubMed Central

Gorzelak, Przemysław; Salamon, Mariusz A.; Baumiller, Tomasz K.

2012-01-01

Sea urchins are a major component of recent marine communities where they exert a key role as grazers and benthic predators. However, their impact on past marine organisms, such as crinoids, is hard to infer in the fossil record. Analysis of bite mark frequencies on crinoid columnals and comprehensive genus-level diversity data provide unique insights into the importance of sea urchin predation through geologic time. These data show that over the Mesozoic, predation intensity on crinoids, as measured by bite mark frequencies on columnals, changed in step with diversity of sea urchins. Moreover, Mesozoic diversity changes in the predatory sea urchins show a positive correlation with diversity of motile crinoids and a negative correlation with diversity of sessile crinoids, consistent with a crinoid motility representing an effective escape strategy. We contend that the Mesozoic diversity history of crinoids likely represents a macroevolutionary response to changes in sea urchin predation pressure and that it may have set the stage for the recent pattern of crinoid diversity in which motile forms greatly predominate and sessile forms are restricted to deep-water refugia. PMID:22509040

New evidence for late mesozoic-early Cenozoic evolution of the Chilean Andes in the upper Tinguiririca valley (35 °S), central Chile

NASA Astrophysics Data System (ADS)

Charrier, Reynaldo; Wyss, AndréR.; Flynn, John J.; Swisher, Carl C.; Norell, Mark A.; Zapatta, Franyo; McKenna, Malcolm C.; Novacek, Michael J.

1996-11-01

New geologic, paleontologic and isotopic geochronometric results from the Termas del Flaco region in the upper Tinguiririca River valley in central Chile demand considerable revision of the accepted geotectonic history of the Andean Main Range in this region. A diverse, transitional Eocene-Oligocene aged, land-mammal fauna was recovered from several sites in volcaniclastic sediments of the Coya-Machalí (=Abanico) Formation. Major results of our study include: 1) The 1000 + m thick studied deposits, previously attributed to the Cretaceous Colimapu Formation, belong to the Coya-Machalí (=Abanico) Formation. Radioisotopic data from levels immediately above (31.5 Ma) and below (37.S Ma) the fossiliferous horizon indicate a latest Eocene to early Oligocene age for the basal part of the formation and the fauna contained in it. 2) The fossiliferous unit rests with slight angular offset on different Mesozoic units: "Brownish-red Clastic Unit" (BRCU) and Baños del Flaco Formation; in a limited area it also overlies a white tuff dated at 104 Ma. 3) The contacts just discussed (none of which is attributable to faulting), demonstrate the existence of two, or possibly three, unconformities in the region. 4) Sedimentological criteria argue against reference of the BRCU to the Colimapu Formation, and imply correlation of the former unit to basal levels with in the late Cretaceous Neuquén Group of western Argentina. 5) The Coya-Machalí Formation, previously viewed as representing the western volcanic equivalent of Riográndico Supercycle deposits of western Argentino, is likely coeval to much younger units in that region such as the Agua de la Piedra Formation. 6) Paleomagnetic results from the fossil producing horizon indicate about 20 ° of post-early Oligocene, counterclockwise rotation. 7) Fossil mammals from the Coya-Machalí Formation near Termas del Flaco represent a distinct biochronologic interval not heretofore clearly recognized from elsewhere on the continent

The fragmentation of Pangaea and Mesozoic terrestrial vertebrate biodiversity

PubMed Central

2016-01-01

During the Mesozoic (242–66 million years ago), terrestrial regions underwent a massive shift in their size, position and connectivity. At the beginning of the era, the land masses were joined into a single supercontinent called Pangaea. However, by the end of the Mesozoic, terrestrial regions had become highly fragmented, both owing to the drifting apart of the continental plates and the extremely high sea levels that flooded and divided many regions. How terrestrial biodiversity was affected by this fragmentation and large-scale flooding of the Earth's landmasses is uncertain. Based on a model using the species–area relationship (SAR), terrestrial vertebrate biodiversity would be expected to nearly double through the Mesozoic owing to continental fragmentation, despite a decrease of 24% in total terrestrial area. Previous studies of Mesozoic vertebrates have generally found increases in terrestrial diversity towards the end of the era, although these increases are often attributed to intrinsic or climatic factors. Instead, continental fragmentation over this time may largely explain any observed increase in terrestrial biodiversity. This study demonstrates the importance that non-intrinsic effects can have on the taxonomic success of a group, and the importance of geography to understanding past biodiversity. PMID:27651536

Distribution and character of upper mesozoic subduction complexes along the west coast of North America

USGS Publications Warehouse

Jones, D.L.; Blake, M.C.; Bailey, E.H.; McLaughlin, R.J.

1978-01-01

Structurally complex sequences of sedimentary, volcanic, and intrusive igneous rocks characterize a nearly continuous narrow band along the Pacific coast of North America from Baja California, Mexico to southern Alaska. They occur in two modes: (1) as complexly folded but coherent sequences of graywacke and argillite that locally exhibit blueschist-grade metamorphism, and (2) as melanges containing large blocks of graywacke, chert, volcanic and plutonic rocks, high-grade schist, and limestone in a highly sheared pelitic, cherty, or sandstone matrix. Fossils from the coherent graywacke sequences range in age from late Jurassic to Eocene; fossils from limestone blocks in the melanges range in age from mid-Paleozoic to middle Cretaceous. Fossils from the matrix surrounding the blocks, however, are of Jurassic, Cretaceous, and rarely, Tertiary age, indicating that fossils from the blocks cannot be used to date the time of formation of the melanges. Both the deformation of the graywacke, with accompanying blueschist metamorphism, as well as the formation of the melanges, are believed to be the result of late Mesozoic and early Tertiary subduction. The origin of the melanges, particularly the emplacement of exotic tectonic blocks, is not understood. ?? 1978.

The fragmentation of Pangaea and Mesozoic terrestrial vertebrate biodiversity.

PubMed

Vavrek, Matthew J

2016-09-01

During the Mesozoic (242-66 million years ago), terrestrial regions underwent a massive shift in their size, position and connectivity. At the beginning of the era, the land masses were joined into a single supercontinent called Pangaea. However, by the end of the Mesozoic, terrestrial regions had become highly fragmented, both owing to the drifting apart of the continental plates and the extremely high sea levels that flooded and divided many regions. How terrestrial biodiversity was affected by this fragmentation and large-scale flooding of the Earth's landmasses is uncertain. Based on a model using the species-area relationship (SAR), terrestrial vertebrate biodiversity would be expected to nearly double through the Mesozoic owing to continental fragmentation, despite a decrease of 24% in total terrestrial area. Previous studies of Mesozoic vertebrates have generally found increases in terrestrial diversity towards the end of the era, although these increases are often attributed to intrinsic or climatic factors. Instead, continental fragmentation over this time may largely explain any observed increase in terrestrial biodiversity. This study demonstrates the importance that non-intrinsic effects can have on the taxonomic success of a group, and the importance of geography to understanding past biodiversity. © 2016 The Author(s).

Mesozoic-Early Cenozoic Retroarc Basin Evolution in Response to Changing Tectonic Regimes, Southern Central Andes

NASA Astrophysics Data System (ADS)

Mackaman-Lofland, C.; Horton, B. K.; Fuentes, F.; Constenius, K. N.; Stockli, D. F.

2017-12-01

Spatial and temporal variations in pre-Andean deformation, inherited lithospheric discontinuities, and subduction geometry have been documented for the southern Central Andes (27-40°S). However, the influence of inherited crustal structures and changing subduction zone dynamics on along-strike (N-S) and across-strike (E-W) variations in upper-plate deformation and basin evolution remains poorly understood. The La Ramada Basin in the High Andes at 32°S preserves the northernmost succession correlated with the well-studied Neuquen Basin to the south. New maximum depositional ages and provenance information provided by detrital zircon U-Pb geochronology refine the chronostratigraphic and provenance framework of La Ramada Basin deposits and improve reconstructions of structural activity and subsidence mechanisms during polyphase basin evolution. Updated along- and across-strike comparisons with Neuquen and intraplate depocenters provide an unparalleled opportunity to examine long-term fluctuations in stress regime, modes of variable plate coupling, structural reactivation, and basin evolution. Zircon U-Pb age distributions constrain Mesozoic-Cenozoic ages of La Ramada clastic units and identify a previously unrecognized period of Paleogene nonmarine deposition. Late Triassic-Jurassic synrift and post-rift deposits record sediment derivation from the eastern half-graben footwall and western Andean volcanic arc during periods of slab rollback and thermal subsidence. Uplift of the Coastal Cordillera and introduction of Coastal Cordillera sediment at 107 Ma represents the first signature of initial Andean uplift associated with accumulation in the La Ramada Basin. Finally, newly identified Paleogene extensional structures and intra-arc deposits in the western La Ramada Basin are correlated with the extensional Abanico Basin system ( 28°S-44°S) to the west in Chile. Development and inversion of this system of intra-arc depocenters suggests that shortening and uplift in

Atlas of Mesozoic and Cenozoic Coastlines

NASA Astrophysics Data System (ADS)

Smith, A. G.; Smith, D. G.; Funnell, B. M.

2004-03-01

The inferred positions of global paleoshorelines through the 240 million years of the Mesozoic and Cenozoic are presented within this atlas. Thirty-one maps, generally corresponding to stratigraphic stages, provide a snapshot of the continents and their shorelines at approximately 8 million year intervals. The maps provide a representation of the gross changes in the distribution of land and sea throughout the Mesozoic and Cenozoic plotted on Mollweide projections of paleocontinental reconstruction. They do not distinguish between well and poorly defined shorelines, but the information sources are set out in a bibliography numbering more than 2000 primary paleographic references. This is a global compilation that presents the first attempt at delineating global shorelines at stage level, and which represents many years of work sponsored by British Petroleum International (BPI), and work by BPI themselves between 1981 and 1987.

Challenge for Mesozoic hydrocarbon exploration in the Eastern Indonesia

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

Abdullah, S.; Rukmiati, M.G.; Sitompul, N.

1996-12-31

The eastern part of Indonesia covers approximately 3 million square kilometers, 35 percent being landmass and 65 percent covered by ocean. Only three of 38 sedimentary basins are producing hydrocarbon (Salawati, Bintuni, and Seram Basins). Oil and gas have discovered in the Lariang, Bone, Timor, Banggai, Sula and Biak Basins, however the discoveries have not developed yet. Hydrocarbon systems in Northern Australia and Papua New Guinea give the major contributions to the geological idea of Pre-Tertiary section in the less explored area in the Eastern Indonesia. The Triassic-Middle Jurassic marine carbonaceous shale sequences are the main hydrocarbon source rock inmore » the Irian Jaya and surrounding area (Buton, gula and Seram basins). The main Mesozoic reservoir are the Kembelangan Formation in the Bintuni Basin of Irian Jaya and Bobong Formation in the North Sula Region. Exploration play types in the Eastern Indonesia can be divided into five types: 1 - Peri Cratonic, 2 - Marginal Rift Graben, 3 - Thrust Fold Belt Island Arc, 4 - Early Collision and 5 -Microcontinental Block - Advanced Collision. Recent discoveries through Mesozoic section in Eastern Indonesia are: Roabiba-1 (1990) in Bintuni Basin-Irian Jaya (Kambelangan Formation); Loku- 1 (1990) in North Sula region (Pre-Tertiary sediments); Oseil-1 (1993/94) in Bula-Seram Basin (Jurassic Manusela Formation); Elang-1 (1 994); Kakaktua-1 (1994) and Laminaria-1 in North Bonaparte Basin (Upper Jurassic Sands).« less

Long lasting paleolandscapes stability of the French Massif Central during the Mesozoic

NASA Astrophysics Data System (ADS)

Ricordel-Prognon, C.; Thiry, M.; Theveniaut, H.; Lagroix, F.

2009-04-01

Cretaceous) in the northern parts of the massif (Ricordel et al., 2005; Ricordel, 2007;). These new ages, fairly older than the expected ones, bring considerable changes in the palaeogeographic evolution of the Massif Central during Mesozoic and Cenozoic. Basement rocks (granites, gneiss, rhyolites and even Permo-Carboniferous sediments) show often pinkish facies throughout the Massif Central. It has been shown that these pink facies are albitised (mainly pseudomorphic replacement of the primary plagioclases into albite and alteration of the biotite into chlorite) (Schmitt, 1992; Parcerisa et al., 2009). These albitised facies are arranged in a clear succession against (?) the Triassic unconformity that gives significant constraints about their development in relation with the Triassic palaeosurface. Secondary albite and chlorite contain minute hematite inclusions, which have been dated, using paleomagnetism, to be Triassic in age (245 Ma) (Ricordel et al., 2007). Given that the alterations are of the same age as the unconformity, it then follows that the albitised facies be related to the Triassic palaeosurface and be used to track back the Triassic palaeosurface through wide crystalline areas, even far away from the Mesozoic cover. Palaeomagnetic analyses allowed dating a large range of paleoweathering features for which no objective datings were previously available. Spatial and temporal distributions of the paleoweathering features and related unconformities provide key arguments to unravel the geodynamic evolution of the Massif Central. Triassic, Late Jurassic and Tertiary unconformities are superimposed on large areas of the Massif Centrall. This implies very little erosion of the crystalline basement since Triassic time, as shown by the widespread preservation of the Triassic albitized facies. Since the red kaolinitic paleosols of Late Jurassic/Early Cretaceous age rest directly on the basement rocks, large areas of the Massif Central were uncovered at this period

Extreme Mesozoic crustal thinning in the Eastern Iberia margin: The example of the Columbrets Basin (Valencia Trough)

NASA Astrophysics Data System (ADS)

Mohn, G.; Etheve, N.; Frizon de Lamotte, D.; Roca, E.; Tugend, J.; Gómez-Romeu, J.

2017-12-01

Eastern Iberia preserves a complex succession of Mesozoic rifts partly or completely inverted during the Late Cretaceous and Cenozoic in relation with Africa-Eurasia convergence. Notably, the Valencia Trough, classically viewed as part of the Cenozoic West Mediterranean basins, preserves in its southwestern part a thick Mesozoic succession (locally »10km thick) over a highly thinned continental basement (locally only »3,5km thick). This sub-basin referred to as the Columbrets Basin, represents a Late Jurassic-Early Cretaceous hyper-extended rift basin weakly overprinted by subsequent events. Its initial configuration is well preserved allowing us to unravel its 3D architecture and tectono-stratigraphic evolution in the frame of the Mesozoic evolution of eastern Iberia. The Columbrets Basin benefits from an extensive dataset combining high resolution reflection seismic profiles, drill holes, refraction seismic data and Expanding Spread Profiles. Its Mesozoic architecture is controlled by interactions between extensional deformation and halokinesis involving the Upper Triassic salt. The thick uppermost Triassic to Cretaceous succession describes a general synclinal shape, progressively stretched and dismembered towards the basin borders. The SE-border of the basin is characterized by a large extensional detachment fault acting at crustal scale and interacting locally with the Upper Triassic décollement. This extensional structure accommodates the exhumation of the continental basement and part of the crustal thinning. Eventually our results highlight the complex interaction between extreme crustal thinning and occurrence of a pre-rift salt level for the deformation style and tectono-stratigraphic evolution of hyper-extended rift basins.

Late Mesozoic tectonics of the Southern-Thai Peninsula: from transpression to basins opening

NASA Astrophysics Data System (ADS)

Sautter, Benjamin; Pubellier, Manuel; Menier, David

2015-04-01

The petroleum basins of the Southern Thailand Peninsula are poorly known and their final geometry is controlled by the Tertiary stress variations applied on pre-existing Paleozoic and Mesozoic basement structures. From the end of Mesozoic times, the arrival of Indian plate was accomodated by transpressionnal deformation along the Western Margin of Sunda Plate. Evidences of this strain are the motions along several regional strike Slip Faults (Sagaing, Three Pagodas, Mae Ping, Red River, Ranong and Klong Marui Faults) as well as compressional features (folds and thrusts) evidenced onshore. Due to changes in the boundary forces, these structures were reactivated during the Tertiary, leading to the opening of basins in this part of Sundaland. We present a structural analysis based on geomorphology, fieldwork and seismic interpretation of the Southern Thai Peninsula with emphasis on the deformation's style onshore from Ranong to Satun and offshore from Eastern Mergui to Songhkla. By analyzing morphostructures and drainage anomalies from Digital Elevation Model (SRTM and ASTER), we highlight a predominance of N-S structures in the Southern Thai Peninsula: both in the granitic belt and in the sedimentary cover. The Triassic-Jurassic (Indosinian) post-collision granitic belt is intensely fractured, with 2 penetrative directions: N140 and N50. On both sides, the sedimentary units appear folded at a large wavelength (~20km). On most of the studied outcrops, Triassic to Early Cretaceous series are gently tilted and weakly fractured whereas the Paleozoic ones shows intense fracturation and steep dipping beds. Moreover, all the Paleozoic stratas display a constant N-S S1 which does not appear in the Mezosoic sediments. Althought most of the post-Mesozoic sediments do not crop out due to thick vegetal cover, several Tertiary basins can be easily seen from seismic data both onshore and offshore. These data suggest that rifting started in the Eocene and was accommodated by large

The Early Mesozoic volcanic arc of western North America in northeastern Mexico

NASA Astrophysics Data System (ADS)

Barboza-Gudiño, José Rafael; Orozco-Esquivel, María Teresa; Gómez-Anguiano, Martín; Zavala-Monsiváis, Aurora

2008-02-01

Volcanic successions underlying clastic and carbonate marine rocks of the Oxfordian-Kimmeridgian Zuloaga Group in northeastern Mexico have been attributed to magmatic arcs of Permo-Triassic and Early Jurassic ages. This work provides stratigraphic, petrographic geochronological, and geochemical data to characterize pre-Oxfordian volcanic rocks outcropping in seven localities in northeastern Mexico. Field observations show that the volcanic units overlie Paleozoic metamorphic rocks (Granjeno schist) or Triassic marine strata (Zacatecas Formation) and intrude Triassic redbeds or are partly interbedded with Lower Jurassic redbeds (Huizachal Group). The volcanic rocks include rhyolitic and rhyodacitic domes and dikes, basaltic to andesitic lava flows and breccias, and andesitic to rhyolitic pyroclastic rocks, including breccias, lapilli, and ashflow tuffs that range from welded to unwelded. Lower-Middle Jurassic ages (U/Pb in zircon) have been reported from only two studied localities (Huizachal Valley, Sierra de Catorce), and other reported ages (Ar/Ar and K-Ar in whole-rock or feldspar) are often reset. This work reports a new U/Pb age in zircon that confirms a Lower Jurassic (193 Ma) age for volcanic rocks exposed in the Aramberri area. The major and trace element contents of samples from the seven localities are typical of calc-alkaline, subduction-related rocks. The new geochronological and geochemical data, coupled with the lithological features and stratigraphic positions, indicate volcanic rocks are part of a continental arc, similar to that represented by the Lower-Middle Jurassic Nazas Formation of Durango and northern Zacatecas. On that basis, the studied volcanic sequences are assigned to the Early Jurassic volcanic arc of western North America.

Testing the Mojave-Sonora megashear hypothesis: Evidence from Paleoproterozoic igneous rocks and deformed Mesozoic strata in Sonora, Mexico

USGS Publications Warehouse

Amato, J.M.; Lawton, T.F.; Mauel, D.J.; Leggett, W.J.; Gonzalez-Leon, C. M.; Farmer, G.L.; Wooden, J.L.

2009-01-01

U-Pb ages and Nd isotope values of Proterozoic rocks in Sonora, Mexico, indicate the presence of Caborca-type basement, predicted to lie only south of the Mojave-Sonora mega-shear, 40 km north of the postulated megashear. Granitoids have U-Pb zircon ages of 1763-1737 Ma and 1076 Ma, with ??Nd(t) values from +1.4 to -4.3, typical of the Caborca block. Lower Jurassic strata near the Proterozoic rocks contain large granitic clasts with U-Pb ages and ??Nd(t) values indistinguishable from those of Caborcan basement. Caborca-type basement was thus present at this location north of the megashear by 190 Ma, the depositional age of the Jurassic strata. The Proterozoic rocks are interpreted as parautochthonous, exhumed and juxtaposed against the Mesozoic section by a reverse fault that formed a footwall shortcut across a Jurassic normal fault. Geochronology, isotope geochemistry, and structural geology are therefore inconsistent with Late Jurassic megashear displacement and require either that no major transcurrent structure is present in Sonora or that strike-slip displacement occurred prior to Early Jurassic time. ?? 2009 The Geological Society of America.

Mesozoic lacewings from China provide phylogenetic insight into evolution of the Kalligrammatidae (Neuroptera).

PubMed

Yang, Qiang; Wang, Yongjie; Labandeira, Conrad C; Shih, Chungkun; Ren, Dong

2014-06-09

The Kalligrammatidae are distinctive, large, conspicuous, lacewings found in Eurasia from the Middle Jurassic to mid Early Cretaceous. Because of incomplete and often inadequate fossil preservation, an absence of detailed morphology, unclear relationships, and unknown evolutionary trends, the Kalligrammatidae are poorly understood. We describe three new subfamilies, four new genera, twelve new species and four unassigned species from the late Middle Jurassic Jiulongshan and mid Early Cretaceous Yixian Formations of China. These kalligrammatid taxa exhibit diverse morphological characters, such as mandibulate mouthparts in one major clade and siphonate mouthparts in the remaining four major clades, the presence or absence of a variety of distinctive wing markings such as stripes, wing spots and eyespots, as well as multiple major wing shapes. Based on phylogenetic analyses, the Kalligrammatidae are divided into five principal clades: Kalligrammatinae Handlirsch, 1906, Kallihemerobiinae Ren & Engel, 2008, Meioneurinae subfam. nov., Oregrammatinae subfam. nov. and Sophogrammatinae subfam. nov., each of which is accorded subfamily-level status. Our results show significant morphological and evolutionary differentiation of the Kalligrammatidae family during a 40 million-year-interval of the mid Mesozoic. A new phylogeny and classification of five subfamilies and their constituent genera is proposed for the Kalligrammatidae. These diverse, yet highly specialized taxa from northeastern China suggest that eastern Eurasia likely was an important diversification center for the Kalligrammatidae. Kalligrammatids possess an extraordinary morphological breadth and panoply of adaptations during the mid-Mesozoic that highlight our conclusion that their evolutionary biology is much more complex than heretofore realized.

Mesozoic rift basins in western desert of Egypt, their southern extension and impact on future exploration

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

Taha, M.A.

1988-08-01

Rift basins are a primary target of exploration in east, central, and west Africa. These intracratonic rift basins range in age from the Triassic to the Neogene and are filled with lagoonal-lacustrine sand-shale sequences. Several rift basins may be present in the Western Desert of Egypt. In the northeastern African platform, the Mesozoic Tethyan strand lines were previously interpreted to have limited southern extension onto the continent. This concept, based upon a relatively limited amount of subsurface data, has directed and focused the exploration for oil and gas to the northernmost 120 km of the Western Desert of Egypt. Recentmore » well and geophysical data indicate a southerly extension of mesozoic rift basins several hundred kilometers inland from the Mediterranean Sea. Shushan/Faghur and Abu Gharadig/Bahrein basins may represent subparallel Mesozoic basins, trending northeast-southwest. Marine Oxfordian-Kimmeridgian sediments were recently reported from wells drilled approximately 500 km south of the present-day Mediterranean shoreline. The link of these basins with the Sirte basin to the southwest in Libya is not well understood. Exploration is needed to evaluate the hydrocarbon potential of such basins.« less

Naturally occurring contaminants in the Piedmont and Blue Ridge crystalline-rock aquifers and Piedmont Early Mesozoic basin siliciclastic-rock aquifers, eastern United States, 1994–2008

USGS Publications Warehouse

Chapman, Melinda J.; Cravotta, Charles A.; Szabo, Zoltan; Lindsay, Bruce D.

2013-01-01

Groundwater quality and aquifer lithologies in the Piedmont and Blue Ridge Physiographic Provinces in the eastern United States vary widely as a result of complex geologic history. Bedrock composition (mineralogy) and geochemical conditions in the aquifer directly affect the occurrence (presence in rock and groundwater) and distribution (concentration and mobility) of potential naturally occurring contaminants, such as arsenic and radionuclides, in drinking water. To evaluate potential relations between aquifer lithology and the spatial distribution of naturally occurring contaminants, the crystalline-rock aquifers of the Piedmont and Blue Ridge Physiographic Provinces and the siliciclastic-rock aquifers of the Early Mesozoic basin of the Piedmont Physiographic Province were divided into 14 lithologic groups, each having from 1 to 16 lithochemical subgroups, based on primary rock type, mineralogy, and weathering potential. Groundwater-quality data collected by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program from 1994 through 2008 from 346 wells and springs in various hydrogeologic and land-use settings from Georgia through New Jersey were compiled and analyzed for this study. Analyses for most constituents were for filtered samples, and, thus, the compiled data consist largely of dissolved concentrations. Concentrations were compared to criteria for protection of human health, such as U.S. Environmental Protection Agency (USEPA) drinking water maximum contaminant levels and secondary maximum contaminant levels or health-based screening levels developed by the USGS NAWQA Program in cooperation with the USEPA, the New Jersey Department of Environmental Protection, and Oregon Health & Science University. Correlations among constituent concentrations, pH, and oxidation-reduction (redox) conditions were used to infer geochemical controls on constituent mobility within the aquifers. Of the 23 trace-element constituents evaluated

Diverse ages and origins of basement complexes, Luzon, Philippines

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

Geary, E.E.; Harrison, T.M.; Heizler, M.

1988-04-01

Geological field investigations and /sup 40/Ar//sup 39/Ar ages from two basement complexes in southeast Luzon document the first known occurrences of pre-Late Cretaceous age rocks in the eastern Philippines. However, individual components within the two complexes vary in age from Late Jurassic (Caramoan basement complex) to Early Cretaceous and early Miocene (Camarines Norte-Calaguas Islands basement complex). These and other data show that southeast Luzon basement complexes are genetically diverse, and they indicate that the concept of an old, autochthonous basement in the Philippines is open to question. This supports the hypothesis that the Philippine Archipelago is an amalgamation of allochthonousmore » Mesozoic and Cenozoic island-arc, ocean-basin, and continental fragments that were assembled during the Tertiary.« less

Spatial and temporal distribution of Mesozoic adakitic rocks along the Tan-Lu fault, Eastern China: Constraints on the initiation of lithospheric thinning

NASA Astrophysics Data System (ADS)

Gu, Hai-Ou; Xiao, Yilin; Santosh, M.; Li, Wang-Ye; Yang, Xiaoyong; Pack, Andreas; Hou, Zhenhui

2013-09-01

The Mesozoic tectonics in East China is characterized by significant lithospheric thinning of the North China Craton, large-scale strike-slip movement along the Tan-Lu fault, and regional magmatism with associated metallogeny. Here we address the possible connections between these three events through a systematic investigation of the geochemistry, zircon geochronology and whole rock oxygen isotopes of the Mesozoic magmatic rocks distributed along the Tan-Lu fault in the Shandong province. The characteristic spatial and temporal distributions of high-Mg adakitic rocks along the Tan-Lu fault with emplacement ages of 134-128 Ma suggest a strong structural control for the emplacement of these intrusions, with magma generation possibly associated with the subduction of the Pacific plate in the early Cretaceous. The low-Mg adakitic rocks (127-120 Ma) in the Su-Lu orogenic belt were formed later than the high-Mg adakitic rocks, whereas in the Dabie orogenic belt, most of the low-Mg adakitic rocks (143-129 Ma) were generated earlier than the high-Mg adakitic rocks. Based on available data, we suggest that the large scale strike-slip tectonics of the Tan-Lu fault in the Mesozoic initiated cratonic destruction at the south-eastern margin of the North China Craton, significantly affecting the lower continental crust within areas near the fault. This process resulted in crustal fragments sinking into the asthenosphere and reacting with peridotites, which increased the Mg# of the adakitic melts, generating the high-Mg adakitic rocks. The gravitationally unstable lower continental crust below the Tan-Lu fault in the Su-Lu orogenic belt triggered larger volume delamination of the lower continental crust or foundering of the root.

Neoproterozoic, Paleozoic, and Mesozoic granitoid magmatism in the Qinling Orogen, China: Constraints on orogenic process

NASA Astrophysics Data System (ADS)

Wang, Xiaoxia; Wang, Tao; Zhang, Chengli

2013-08-01

The Qinling Orogen is one of the main orogenic belts in Asia and is characterized by multi-stage orogenic processes and the development of voluminous magmatic intrusions. The results of zircon U-Pb dating indicate that granitoid magmatism in the Qinling Orogen mainly occurred in four distinct periods: the Neoproterozoic (979-711 Ma), Paleozoic (507-400 Ma), and Early (252-185 Ma) and Late (158-100 Ma) Mesozoic. The Neoproterozoic granitic magmatism in the Qinling Orogen is represented by strongly deformed S-type granites emplaced at 979-911 Ma, weakly deformed I-type granites at 894-815 Ma, and A-type granites at 759-711 Ma. They can be interpreted as the products of respectively syn-collisional, post-collisional and extensional setting, in response to the assembly and breakup of the Rodinia supercontinent. The Paleozoic magmatism can be temporally classified into three stages of 507-470 Ma, 460-422 Ma and ˜415-400 Ma. They were genetically related to the subduction of the Shangdan Ocean and subsequent collision of the southern North China Block and the South Qinling Belt. The 507-470 Ma magmatism is spatially and temporally related to ultrahigh-pressure metamorphism in the studied area. The 460-422 Ma magmatism with an extensive development in the North Qinling Belt is characterized by I-type granitoids and originated from the lower crust with the involvement of mantle-derived magma in a collisional setting. The magmatism with the formation age of ˜415-400 Ma only occurred in the middle part of the North Qinling Belt and is dominated by I-type granitoid intrusions, and probably formed in the late-stage of a collisional setting. Early Mesozoic magmatism in the study area occurred between 252 and 185 Ma, with the cluster in 225-200 Ma. It took place predominantly in the western part of the South Qinling Belt. The 250-240 Ma I-type granitoids are of small volume and show high Sr/Y ratios, and may have been formed in a continental arc setting related to subduction

An integrated geophysical study on the Mesozoic strata distribution and hydrocarbon potential in the South China Sea

NASA Astrophysics Data System (ADS)

Hu, Weijian; Hao, Tianyao; Jiang, Weiwei; Xu, Ya; Zhao, Baimin; Jiang, Didi

2015-11-01

A series of drilling, dredge, and seismic investigations indicate that Mesozoic sediments exist in the South China Sea (SCS) which shows a bright prospect for oil and gas exploration. In order to study the distribution of Mesozoic strata and their residual thicknesses in the SCS, we carried out an integrated geophysical study based mainly on gravity data, gravity basement depth and distribution of residual Mesozoic thickness in the SCS were obtained using gravity inversion constrained with high-precision drilling and seismic data. In addition, the fine deep crustal structures and distribution characteristics of Mesozoic thicknesses of three typical profiles were obtained by gravity fitting inversion. Mesozoic strata in the SCS are mainly distributed in the south and north continental margins, and have been reformed by the later tectonic activities. They extend in NE-trending stripes are macro-controlled by the deep and large NE-trending faults, and cut by the NW-trending faults which were active in later times. The offset in NW direction of Mesozoic strata in Nansha area of the southern margin are more obvious as compared to the north margin. In the Pearl River Mouth Basin and Southwest Taiwan Basin of the north continental margin the Mesozoic sediments are continuously distributed with a relatively large thickness. In the Nansha area of the south margin the Mesozoic strata are discontinuous and their thicknesses vary considerably. According to the characteristics of Mesozoic thickness distribution and hydrocarbon potential analyses from drilling and other data, Dongsha Uplift-Chaoshan Depression, Southwest Taiwan Basin-Peikang Uplift and Liyue Bank have large thickness of the Mesozoic residual strata, have good hydrocarbon genesis capability and complete source-reservoir-cap combinations, show a bright prospect of Mesozoic oil/gas resources.

A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds.

PubMed

Knoll, Fabien; Chiappe, Luis M; Sanchez, Sophie; Garwood, Russell J; Edwards, Nicholas P; Wogelius, Roy A; Sellers, William I; Manning, Phillip L; Ortega, Francisco; Serrano, Francisco J; Marugán-Lobón, Jesús; Cuesta, Elena; Escaso, Fernando; Sanz, Jose Luis

2018-03-05

Fossils of juvenile Mesozoic birds provide insight into the early evolution of avian development, however such fossils are rare. The analysis of the ossification sequence in these early-branching birds has the potential to address important questions about their comparative developmental biology and to help understand their morphological evolution and ecological differentiation. Here we report on an early juvenile enantiornithine specimen from the Early Cretaceous of Europe, which sheds new light on the osteogenesis in this most species-rich clade of Mesozoic birds. Consisting of a nearly complete skeleton, it is amongst the smallest known Mesozoic avian fossils representing post-hatching stages of development. Comparisons between this new specimen and other known early juvenile enantiornithines support a clade-wide asynchronous pattern of osteogenesis in the sternum and the vertebral column, and strongly indicate that the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.

Mesozoic lacewings from China provide phylogenetic insight into evolution of the Kalligrammatidae (Neuroptera)

PubMed Central

2014-01-01

Background The Kalligrammatidae are distinctive, large, conspicuous, lacewings found in Eurasia from the Middle Jurassic to mid Early Cretaceous. Because of incomplete and often inadequate fossil preservation, an absence of detailed morphology, unclear relationships, and unknown evolutionary trends, the Kalligrammatidae are poorly understood. Results We describe three new subfamilies, four new genera, twelve new species and four unassigned species from the late Middle Jurassic Jiulongshan and mid Early Cretaceous Yixian Formations of China. These kalligrammatid taxa exhibit diverse morphological characters, such as mandibulate mouthparts in one major clade and siphonate mouthparts in the remaining four major clades, the presence or absence of a variety of distinctive wing markings such as stripes, wing spots and eyespots, as well as multiple major wing shapes. Based on phylogenetic analyses, the Kalligrammatidae are divided into five principal clades: Kalligrammatinae Handlirsch, 1906, Kallihemerobiinae Ren & Engel, 2008, Meioneurinae subfam. nov., Oregrammatinae subfam. nov. and Sophogrammatinae subfam. nov., each of which is accorded subfamily-level status. Our results show significant morphological and evolutionary differentiation of the Kalligrammatidae family during a 40 million-year-interval of the mid Mesozoic. Conclusion A new phylogeny and classification of five subfamilies and their constituent genera is proposed for the Kalligrammatidae. These diverse, yet highly specialized taxa from northeastern China suggest that eastern Eurasia likely was an important diversification center for the Kalligrammatidae. Kalligrammatids possess an extraordinary morphological breadth and panoply of adaptations during the mid-Mesozoic that highlight our conclusion that their evolutionary biology is much more complex than heretofore realized. PMID:24912379

A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds

DOE PAGES

Knoll, Fabien; Chiappe, Luis M.; Sanchez, Sophie; ...

2018-03-05

Fossils of juvenile Mesozoic birds provide insight into the early evolution of avian development, however such fossils are rare. The analysis of the ossification sequence in these early-branching birds has the potential to address important questions about their comparative developmental biology and to help understand their morphological evolution and ecological differentiation. Here we report on an early juvenile enantiornithine specimen from the Early Cretaceous of Europe, which sheds new light on the osteogenesis in this most species-rich clade of Mesozoic birds. Consisting of a nearly complete skeleton, it is amongst the smallest known Mesozoic avian fossils representing post-hatching stages ofmore » development. Finally, comparisons between this new specimen and other known early juvenile enantiornithines support a clade-wide asynchronous pattern of osteogenesis in the sternum and the vertebral column, and strongly indicate that the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.« less

A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds

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

Knoll, Fabien; Chiappe, Luis M.; Sanchez, Sophie

Fossils of juvenile Mesozoic birds provide insight into the early evolution of avian development, however such fossils are rare. The analysis of the ossification sequence in these early-branching birds has the potential to address important questions about their comparative developmental biology and to help understand their morphological evolution and ecological differentiation. Here we report on an early juvenile enantiornithine specimen from the Early Cretaceous of Europe, which sheds new light on the osteogenesis in this most species-rich clade of Mesozoic birds. Consisting of a nearly complete skeleton, it is amongst the smallest known Mesozoic avian fossils representing post-hatching stages ofmore » development. Finally, comparisons between this new specimen and other known early juvenile enantiornithines support a clade-wide asynchronous pattern of osteogenesis in the sternum and the vertebral column, and strongly indicate that the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.« less

Reconstruction of crustal blocks of California on the basis of initial strontium isotopic compositions of Mesozoic granitic rocks

USGS Publications Warehouse

Kistler, Ronald Wayne; Peterman, Zell E.

1978-01-01

Initial 87Sr/ 86 Sr was determined for samples of Mesozoic granitic rocks in the vicinity of the Garlock fault zone in California. These data along with similar data from the Sierra Nevada and along the San Andreas fault system permit a reconstruction of basement rocks offset by the Cenozoic lateral faulting along both the San Andreas and Garlock fault systems. The location of the line of initial 87Sr/ 86 Sr = 0.7060 can be related to the edge of the Precambrian continental crust in the western United States. Our model explains the present configuration of the edge of Precambrian continental crust as the result of two stages of rifting that occurred about 1,250 to 800 m.y. ago, during Belt sedimentation, and about 600 to 350 m.y. ago, prior to and during the development of the Cordilleran geosyncline and to left-lateral translation along a locus of disturbance identified in the central Mojave Desert. The variations in Rb, Sr, and initial 87Sr/ 86 Sr of the Mesozoic granitic rocks are interpreted as due to variations in composition and age of the source materials of the granitic rocks. The variations of Rb, Sr, and initial 87Sr/ 86 Sr in Mesozoic granitic rocks, the sedimentation history during the late Precambrian and Paleozoic, and the geographic position of loci of Mesozoic magmatism in the western United States are related to the development of the continental margin and different types of lithosphere during rifting.

Toward a continuous 405-kyr-calibrated Astronomical Time Scale for the Mesozoic Era

NASA Astrophysics Data System (ADS)

Hinnov, Linda; Ogg, James; Huang, Chunju

2010-05-01

Mesozoic cyclostratigraphy is being assembled into a continuous Astronomical Time Scale (ATS) tied to the Earth's cyclic orbital parameters. Recognition of a nearly ubiquitous, dominant ~400-kyr cycling in formations throughout the era has been particularly striking. Composite formations spanning contiguous intervals up to 50 myr clearly express these long-eccentricity cycles, and in some cases, this cycling is defined by third- or fourth-order sea-level sequences. This frequency is associated with the 405-kyr orbital eccentricity cycle, which provides a basic metronome and enables the extension of the well-defined Cenozoic ATS to scale the majority of the Mesozoic Era. This astronomical calibration has a resolution comparable to the 1% to 0.1% precision for radioisotope dating of Mesozoic ash beds, but with the added benefit of providing continuous stratigraphic coverage between dated beds. Extended portions of the Mesozoic ATS provide solutions to long-standing geologic problems of tectonics, eustasy, paleoclimate change, and rates of seafloor spreading.

Palaeointensity determinations and rock magnetic properties on basalts from Shatsky Rise: new evidence for a Mesozoic dipole low

NASA Astrophysics Data System (ADS)

Carvallo, C.; Camps, P.; Ooga, M.; Fanjat, G.; Sager, W. W.

2013-03-01

IODP Expedition 324 cored igneous rocks from Shatsky Rise, an oceanic plateau in the northwest Pacific Ocean that formed mainly during late Jurassic and Early Cretaceous times. We selected 60 samples from 3 different holes for Thellier-Thellier palaeointensity determinations. Induced and remanent magnetization curves measured at low- and high-temperature suggest a diverse and complex magnetic mineralogy, with large variations in Ti content and oxidation state. Hysteresis and FORC measurements show that most samples contain single-domain magnetic grains. After carrying out the palaeointensity determinations, only 9 samples satisfied all reliability criteria. These gave palaeointensity values between 16.5 and 21.5 μT, which correspond to average VDM values of (4.9 ± 0.2) × 1022 Am2 for an estimated age of 140-142 Ma. This value is lower than that for the recent field, which agrees with the hypothesis of a Mesozoic Dipole Low.

Timing of Exhumation of the Mesozoic Blue Nile Rift, Ethiopia: A New Study from Apatite Fission Track Thermochronology

NASA Astrophysics Data System (ADS)

Gani, N. D.; Bowden, S. M.

2017-12-01

At present, tectonic features of Ethiopia are dominated by the 2.5 km high Ethiopian Plateau, and the NE-SW striking continental rift, the East African Rift System (EARS) that dissected the plateau into the northwest and southeast plateaus. The stress direction of the EARS is nearly perpendicular to the stress direction of the Mesozoic rifts of the Central African Rift System (CARS), located mostly in Sudan, Ethiopia and Kenya. During the Gondwana splitting in Mesozoic, active lithospheric extension within the CARS resulted in several NW-SE striking continental rifts including the Blue Nile, Muglad, Melut and Anza that are well documented in Sudan and Kenya, from a combination of geophysical and drill core analysis and field investigations. However, the timing and evolution of the poorly documented Blue Nile Rift in Ethiopia, now hidden in the subsurface of the Ethiopian Plateau and the EARS, is largely unknown. This study investigates, for the first time, the timing of tectono-thermal evolution of the Blue Nile Rift from cooling ages deduced from apatite fission track (AFT) thermochronology to understand the rift flank exhumation. Here, we report the AFT results from basement samples collected in a vertical transect from the Ethiopian Plateau. The fission track ages of the samples show a general trend of increasing cooling ages with elevations. The time-temperature simulations of the fission track ages illustrate that the cooling started at least 80 Ma ago with a significant amount of rapid cooling between 80 and 70 Ma, followed by a slow cooling after 70 Ma and then another accelerated cooling starting around 10 Ma. The Cretaceous rapid cooling event likely related to the flank uplift of the Blue Nile Rift and associated faulting, during which much of the exhumation occurred. Today, the Blue Nile Rift is buried under the thick cover of Mesozoic sedimentary rocks and Cenozoic volcanics. The late Neogene rapid cooling agrees well with our previous thermal model

Evidence for rapid climate change in the Mesozoic-Palaeogene greenhouse world.

PubMed

Jenkyns, Hugh C

2003-09-15

The best-documented example of rapid climate change that characterized the so-called 'greenhouse world' took place at the time of the Palaeocene-Eocene boundary: introduction of isotopically light carbon into the ocean-atmosphere system, accompanied by global warming of 5-8 degrees C across a range of latitudes, took place over a few thousand years. Dissociation, release and oxidation of gas hydrates from continental-margin sites and the consequent rapid global warming from the input of greenhouses gases are generally credited with causing the abrupt negative excursions in carbon- and oxygen-isotope ratios. The isotopic anomalies, as recorded in foraminifera, propagated downwards from the shallowest levels of the ocean, implying that considerable quantities of methane survived upward transit through the water column to oxidize in the atmosphere. In the Mesozoic Era, a number of similar events have been recognized, of which those at the Triassic-Jurassic boundary, in the early Toarcian (Jurassic) and in the early Aptian (Cretaceous) currently carry the best documentation for dramatic rises in temperature. In these three examples, and in other less well-documented cases, the lack of a definitive time-scale for the intervals in question hinders calculation of the rate of environmental change. However, comparison with the Palaeocene-Eocene thermal maximum (PETM) suggests that these older examples could have been similarly rapid. In both the early Toarcian and early Aptian cases, the negative carbon-isotope excursion precedes global excess carbon burial across a range of marine environments, a phenomenon that defines these intervals as oceanic anoxic events (OAEs). Osmium-isotope ratios ((187)Os/(188)Os) for both the early Toarcian OAE and the PETM show an excursion to more radiogenic values, demonstrating an increase in weathering and erosion of continental crust consonant with elevated temperatures. The more highly buffered strontium-isotope system ((87)Sr/(86)Sr

The pre-Mesozoic tectonic unit division of the Xing-Meng orogenic belt (XMOB)

NASA Astrophysics Data System (ADS)

Xu, Bei; Zhao, Pan

2014-05-01

According to the viewpoint that the paleo-Asian ocean closed by the end of early Paleozoic and extended during the late Paleozoic, a pre-Mesozoic tectonic unit division has been suggested. Five blocks and four sutures have been recognized in the pre-Devonia stage, the five blocks are called Erguna (EB), Xing'an (XB), Airgin Sum-Xilinhot (AXB), Songliao-Hunshandak (SHB) and Jiamusi (JB) blocks and four sutures, Xinlin-Xiguitu (XXS), Airgin Sum-Xilinhot-Heihe (AXHS), Ondor Sum-Jizhong-Yanji (OJYS) and Mudanjiang (MS) sutures. The EB contains the Precambrian base with the ages of 720-850Ma and ɛHf(T)=+2.5to +8.1. The XB is characterized by the Paleoproterozoic granitic gneiss with ɛHf(T)=-3.9 to -8.9. Several ages from 1150 to 1500 Ma bave been acquired in the AXB, proving presence of old block that links with Hutag Uul block in Mongolia to the west. The Paleoproterozoic (1.8-1.9Ga) and Neoproterozoic (750-850Ma) ages have been reported from southern and eastern parts of the SHB, respectively. As a small block in east margin of the XMOB, the JB outcrops magmatite and granitic gneiss bases with ages of 800-1000Ma. The XXS is marked by blueschists with zircon ages of 490-500Ma in Toudaoqiao village, ophiolites in Xiguitu County and granite with ages of about 500Ma along the northern segment of XXS. The AXHS is characterized by the early Paleozoic arc magmatic rocks with ages from 430Ma to 490Ma, mélange and the late Devonia molass basins, which indicates a northward subduction of the SHB beneath the AXB during the early-middle Paleozoic. The OJYS is composed of the early Paleozoic volcanic rocks, diorites and granites with ages of 425-475Ma, blueschists, ophiolitic mélange, the late Silurian flysch and Early-Middle Devonian molasses in western segment, granites (420-450Ma) in middle segment, and plagiogranites (443Ma) and the late Silurian molasses in eastern segment. This suture was caused by a southward subduction of the SHB beneath the North China block. The MS

Paleozoic-Mesozoic boundary in the Berry Creek Quadrangle, northwestern Sierra Nevada, California

USGS Publications Warehouse

Hietanen, Anna Martta

1977-01-01

Structural and petrologic studies in the Berry Creek quadrangle at the north end of the western metamorphic belt of the Sierra Nevada have yielded new information that helps in distinguishing between the chemically similar Paleozoic and Mesozoic rocks. The distinguishing features are structural and textural and result from different degrees of deformation. Most Paleozoic rocks are strongly deformed and thoroughly recrystallized. Phenocrysts in meta volcanic rocks are granulated and drawn out into lenses that have sutured outlines. In contrast, the phenocrysts in the Mesozoic metavolcanic rocks show well-preserved straight crystal faces, are only slightly or not at all granulated, and contain fewer mineral inclusions than do those in the Paleozoic rocks. The groundmass in the Paleozoic rocks is recrystallized to a fairly coarse grained albite-epidote-amphibole-chlorite rock, whereas in the Mesozoic rocks the groundmass is a very fine grained feltlike mesh with only spotty occurrence of well-recrystallized finegrained albite-epidote-chlorite-actinolite rock. Primary minerals, such as augite, are locally preserved in the Mesozoic rocks but are altered to a mixture of amphibole, chlorite, and epidote in the Paleozoic rocks. In the contact aureoles of the plutons, and within the Big Bend fault zone, which crosses the area parallel to the structural trends, all rocks are thoroughly recrystallized and strongly deformed. Identification of the Paleozoic and Mesozoic rocks in these parts of the area was based on the continuity of the rock units in the field and on gradual changes in microscopic textures toward the plutons.

First identifiable Mesozoic harvestman (Opiliones: Dyspnoi) from Cretaceous Burmese amber

PubMed Central

Giribet, Gonzalo; Dunlop, Jason A

2005-01-01

Two inclusions in a piece of Upper Cretaceous (Albian) Burmese amber from Myanmar are described as a harvestman (Arachnida: Opiliones), Halitherses grimaldii new genus and species. The first Mesozoic harvestman to be named can be referred to the suborder Dyspnoi for the following reasons: prosoma divided into two regions, the posterior formed by the fusion of the meso- and metapeltidium; palp lacking a terminal claw, with clavate setae, and tarsus considerably shorter than the tibia. The bilobed, anteriorly projecting ocular tubercle is reminiscent of that of ortholasmatine nemastomatids. The status of other Mesozoic fossils referred to Opiliones is briefly reviewed. PMID:16024358

High-pressure amphibolite facies dynamic metamorphism and the Mesozoic tectonic evolution of an ancient continental margin, east- central Alaska

USGS Publications Warehouse

Dusel-Bacon, C.; Hansen, V.L.; Scala, J.A.

1995-01-01

Ductilely deformed amphibolite facies tectonites comprise two adjacent terranes in east-central Alaska: the northern, structurally higher Taylor Mountain terrane and the southern, structurally lower Lake George subterrane of the Yukon-Tanana terrane. The pressure, temperature, kinematic and age data are interpreted to indicate that the metamorphism of the Taylor Mountain terrane and Lake George subterrane took place during different phases of a latest Palaeozoic through early Mesozoic shortening episode resulting from closure of an ocean basin now represented by klippen of the Seventymile-Slide Mountain terrane. High- to intermediate-pressure metamorphism of the Taylor Mountain terrane took place within a SW-dipping (present-day coordinates) subduction system. High- to intermediate-pressure metamorphism of the Lake George subterrane and the structural contact zone occurred during NW-directed overthrusting of the Taylor Mountain, Seventymile-Slide Mountain and Nisutlin terranes, and imbrication of the continental margin in Jurassic time. -from Authors

Palinspastic reconstruction of Lower Mesozoic stratigraphic sequences near the latitude of Las Vegas: Implications for the entire Great Basin

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

Marzolf, J.E.

1993-04-01

On the Colorado Plateau, lower Mesozoic stratigraphy is subdivided by regional unconformities into the Lower Triassic Moenkopi, Upper Triassic Chinle, Lower and Middle( ) Jurassic Glen Canyon, and Middle Jurassic lower San Rafael tectonosequences. Palinspastic reconstruction for Cenozoic extensional and mesozoic compressional deformations near the latitude of Las Vegas indicates the Moenkopi tectono-sequence constructed a passive-margin-like architecture of modest width overlapping folded. Thrust-faulted, and intruded Permian strata, with state boundaries fixed relative to the Colorado Plateau, comparison of the location of the Early Triassic shelf-slope break near latitude 36[degree] with the palinspastically restored location of the shelf-slope break in southeasternmore » Idaho implies strata of the Moenkopi tectonosequence in the Mesozoic marine province of northwest NV lay in western utah in the Early Triassic. This reconstruction: suggests that the Galconda and Last Chance faults are part of the same thrust system; aligns late Carnian paleovalleys of the chinle tectonosequence on the Colorado Plateau with a coeval northwest-trending paleovalley cut across the Star Pea, and the Norian Cottonwood paleovalley with the coeval Grass Valley delta; defines a narrow, northward deepening back-arc basin in which the Glen Canyon tectonosequence was deposited; aligns east-facing half grabens along the back side of the arc from the Cowhole Mountains to the Clan Alpine Range; projects the volcan-arc/back-arc transition from northwest Arizona to the east side of the Idaho batholith; and predicts the abrupt facies change from silicic volcanics to marine strata of the lower San Rafael sequence lay in western Utah. The paleogeographic was altered in the late Bathonian to Callovian by back-arc extension north of a line extending from Cedar City, UT to Mina, NV. The palinspastic reconstruction implies the Paleozoic was tectonically stacked at the close of the Paleozoic.« less

Mesozoic units in SE Rhodope (Bulgaria): new structural and petrologic data and geodynamic implications for the Early Jurassic to Mid-Cretaceous evolution of the Vardar ocean basin

NASA Astrophysics Data System (ADS)

Bonev, N.; Stampfli, G.

2003-04-01

. Immobile trace element discrimination of both rock types constrains the volcanic (oceanic)-arc origin. They generally show low total REE concentrations (LREE>HREE) with enrichment of LIL elements relative to the HFS elements, and also very low Nb and relatively high Ce content consistent with an island-arc tectonic setting. We consider that the Meliata-Maliac ocean northern passive margin could be the source provenance for the Upper Permian clastics and Middle-Upper Triassic limestone blocks within the olistostromic melange-like unit, whereas turbidites and magmatic blocks may originate in an island arc-accretionary complex that relates to the southward subduction of the Maliac ocean under the supra-subduction back-arc Vardar ocean/island arc system. These new structural and petrologic data allow to precise the tectonic setting of the Mesozoic units and their geodynamic context in the frame of the Early Jurassic to Late Cretaceous evolution of the Vardar ocean.

The Mesozoic palaeo-relief and immature front belt of northern Tianshan

NASA Astrophysics Data System (ADS)

Chen, K.; Gumiaux, C.; Augier, R.; Chen, Y.; Wang, Q.

2012-04-01

The modern Tianshan (central Asia) extends east-west on about 2500 km long with an average of more than 2000 m in altitude. At first order, the finite structure of this range obviously displays a crust-scale 'pop-up' of Palaeozoic rocks surrounded by two Cenozoic foreland basins. Up to now, this range is regarded as a direct consequence of the Neogene to recent reactivation of a Palaeozoic belt due to the India - Asia collision. This study focuses on the structure of the northern front area of Tianshan and is mainly based on field structural works. In particular, relationships in between sedimentary cover and basement units allow discussing the tectonic and morphological evolution of the northern Tianshan during Mesozoic and Cenozoic times. The study area is about 250 km long, from Wusu to Urumqi, along the northern piedmont of the Tianshan. Continental sedimentary series of the basin as well as structure of the cover/basement interface can well be observed along several incised valleys. Sedimentological observations argue for a limited transport distance for Lower and Uppermost Jurassic deposits that are preserved within intra-mountainous basins or within the foreland basin, along the range front. Moreover, some of the studied geological sections show that Triassic to Jurassic sedimentary series can be continuously followed from the basin to the range where they unconformably overlie the Carboniferous basement. Such onlap type structures of the Jurassic series, on top of the Palaeozoic rock units, can also be observed at more local-scale (~a few 100 m). At different scales, our observations thus clearly evidence i) the existence of a substantial relief during Mesozoic times and ii) very limited deformation, after Mesozoic, along some segments of the northern range front. Yet, thrusting of the Palaeozoic basement on the Mesozoic or Cenozoic sedimentary series of the basin is also well exposed along some other river valleys. As a consequence, the northern front of

Deformation style of the Mesozoic sedimentary rocks in southern Thailand

NASA Astrophysics Data System (ADS)

Kanjanapayont, Pitsanupong

2014-10-01

Mesozoic sedimentary rocks in southern Thailand are widespread from NNE-SSW and N-S in Chumphon and Trang provinces. The Mesozoic stratigraphic units are the marine Triassic Sai Bon Formation and the non-marine Jurassic-Cretaceous Thung Yai Group, the latter subdivided into Khlong Min, Lam Thap, Sam Chom, and Phun Phin Formations. These units overlie Permian carbonate rocks with an angular unconformity, and are overlain unconformably by Cenozoic units and the Quaternary sediments. The Mesozoic rocks have been folded to form two huge first-ordered syncline or synclinoria, the Chumphon and Surat Thani-Krabi-Trang synclinoria. These synclinoria are elongated in NNE-SSW to N-S direction, and incorporate asymmetric lower-order parasitic folds. The folds have moderately to steeply dipping eastward limbs and more gently dipping westward limbs. These folds were transected by brittle fractures in four major directions. These geologic structures indicate WNW-ESE to E-W contraction with top-to-the-east simple shear at some time before the deposition of the Cenozoic sedimentary units. No major deformation has affected the rocks subsequently, apart from the formation of the fault-controlled Cenozoic basins.

Lithostratigraphic and biostratigraphic evidence for brief and synchronous Early Mesozoic basalt eruption over the Maghreb (Northwest Africa)

NASA Astrophysics Data System (ADS)

Et-Touhami, M.; Et-Touhami, M.; Olsen, P. E.; Puffer, J.

2001-05-01

Previously very sparse biostratigraphic data suggested that the Early Mesozoic tholeiitic effusive and intrusive magmatism in the various basins of the Maghreb occurred over a long time (Ladinian-Hettangian). However, a detailed comparison of the stratigraphy underlying, interbedded with, and overlying the basalts in these basins shows not only remarkable similarities with each other, but also with sequences in the latest Triassic and earliest Jurassic of eastern North America. There, the sequences have been shown to be cyclical, controlled by Milankovitch-type climate cycles; the same seems to be true in at least part of the Maghreb. Thus, the Moroccan basins have cyclical sequences surrounding and interbedded with one or two basaltic units. In the Argana and Khemisset basins the Tr-J boundary is identified by palynology to be below the lowest basalt, and the remarkably close lithological similarity between the pre-basalt sequence in the other Moroccan basins and to the North American basins - especially the Fundy basin - suggests a tight correlation in time. Likewise, the strata above the lowest basalt in Morocco show a similar pattern to what is seen above the lowest basalt formation in eastern North America, as do the overlying sequences. Furthermore, geochemistry on basalts in the Argana, Bou Fekrane, Khemisset, and Iouawen basins indicate they are high-Ti quartz-normative tholeiites as are the Orange Mountain Basalt (Fundy basin) and the North Mountain Basalt (Newark basin). The remarkable lithostratigraphic similarity across the Maghreb of these strata suggest contemporaneous and synchronous eruption over a time span of less than 200 ky, based on Milankovitch calibration, and within a ~20 ky interval after the Triassic-Jurassic boundary. Differences with previous interpretations of the biostratigraphy can be rationalized as a result of: 1, an over-reliance on comparisons with northern European palynology; 2, over-interpretation of poorly preserved fossils

The subduction-accretion history of the Bangong-Nujiang Ocean: Constraints from provenance and geochronology of the Mesozoic strata near Gaize, central Tibet

NASA Astrophysics Data System (ADS)

Li, Shun; Ding, Lin; Guilmette, Carl; Fu, Jiajun; Xu, Qiang; Yue, Yahui; Henrique-Pinto, Renato

2017-04-01

The Mesozoic strata, within the Bangong-Nujiang suture zone in central Tibet, recorded critical information about the subduction-accretion processes of the Bangong-Nujiang Ocean prior to the Lhasa-Qiangtang collision. This paper reports detailed field observations, petrographic descriptions, sandstone detrital zircon U-Pb ages and Hf isotopic analyses from an accretionary complex (preserved as Mugagangri Group) and the unconformably overlying Shamuluo Formation near Gaize. The youngest detrital zircon ages, together with other age constraints from literature, suggest that the Mugagangri Group was deposited during late Triassic-early Jurassic, while the Shamuluo Formation was deposited during late Jurassic-early Cretaceous. Based on the differences in lithology, age and provenance, the Mugagangri Group is subdivided into the upper, middle and lower subunits. These units are younging structurally downward/southward, consistent with models of progressive off-scrapping and accretion in a southward-facing subduction complex. The upper subunit, comprising mainly quartz-sandstone and siliceous mud/shale, was deposited in abyssal plain environment close to the Qiangtang passive margin during late Triassic, with sediments derived from the southern Qiangtang block. The middle and lower subunits comprise mainly lithic-quartz-sandstone and mud/shale, containing abundant ultramafic/ophiolitic fragments. The middle subunit, of late Triassic-early Jurassic age, records a transition in tectono-depositional setting from abyssal plain to trench-wedge basin, with sudden influx of sediments sourced from the central Qiangtang metamorphic belt and northern Qiangtang magmatic belt. The appearance of ultramafic/ophiolitic fragments in the middle subunit reflects the subduction initiation. The lower subunit was deposited in a trench-wedge basin during early Jurassic, with influx of Jurassic-aged zircons originating from the newly active southern Qiangtang magmatic arc. The lower subunit

Blueschist metamorphism and its tectonic implication of Late Paleozoic-Early Mesozoic metabasites in the mélange zones, central Inner Mongolia, China

NASA Astrophysics Data System (ADS)

Zhang, Jinrui; Wei, Chunjing; Chu, Hang

2015-01-01

Blueschists in central Inner Mongolia are distributed as layers and blocks in mélanges including the southern zone in Ondor Sum area and the northern zone in Manghete and Naomuhunni areas. They have been attributed to the subduction of Early Paleozoic oceanic crust. Blueschists from Ondor Sum and Naomuhunni are characterized by occurrence of sodic amphibole coexisting with epidote, albite, chlorite, calcic amphibole (in Ondor Sum) and muscovite (in Naomuhunni). Blueschists in Manghete contain porphyroblastic albite with inclusions of garnet and epidote in a matrix dominated by calcic-sodic amphibole, epidote, chlorite, albite and muscovite. Phase equilibria modeling for three blueschist samples using pseudosection suggest that the AlM2 contents in sodic amphibole can be used as a good barometer in the limited assemblage involving sodic amphibole + actinolite + epidote + chlorite + albite + quartz under pressures <4-6 kbar, while this barometer is largely influenced by temperature and bulk Fe2O3 contents in the actinolite-absent assemblage sodic amphibole + epidote + chlorite + albite + quartz of higher pressure and the AlM2 contents are not pressure-controlled in the albite-absent assemblage sodic amphibole + epidote + chlorite + quartz under pressures > 7-10 kbar. In the sodic amphibole-bearing assemblages, the NaM4 contents in sodic amphibole mainly decrease as temperature rises, being a potential thermometry. The calculated pseudosections constrain the P-T conditions of blueschists to be 3.2-4.2 kbar/355-415 °C in Ondor Sum, 8.2-9.0 kbar/455 °C-495 °C in Manghete and 6.6-8.1 kbar/420-470 °C in Naomuhunni. These P-T estimates indicate a rather high geothermal gradient of 18-25 °C/km for the blueschist metamorphism, being of intermediate P/T facies series. Available zircon U-Pb age data suggests that the protoliths of blueschists were formed later than Late Paleozoic-Early Mesozoic and metamorphosed soon afterwards. An alternative interpretation for the

Brittle Deformation in the Ordos Basin in response to the Mesozoic destruction of the North China Craton

NASA Astrophysics Data System (ADS)

Wang, Q.; Jiang, L.

2012-12-01

strata were developed in the beginning of Cretaceous. It seems that the western NCC experienced only uplift that recorded a weak N-S extension and E-W compression during the Early Cretaceous when the NCC experienced destruction. Conclusions: 1. The Cretaceous uplift ceased the "natural test of mechanical property" of the strata in the Ordos Basin. The difference in burying depth of the strata caused the vertical difference in joints development. 2. Joints in the interior of the Ordos Basin indicate a N-S extension and E-W compression with the sigma 1 vertical in the Early Cretaceous, as implying a regional uplift in the western NCC during its Mesozoic destruction.

Late Mesozoic deformations of the Verkhoyansk-Kolyma orogenic belt, Northeast Russia

NASA Astrophysics Data System (ADS)

Fridovsky, Valery

2016-04-01

The Verkhoyansk-Kolyma orogenic belt marks the boundary between the Kolyma-Omolon superterrane (microcontinent) and the submerged eastern margin of the North Asian craton. The orogenic system is remark able for its large number of economically viable gold deposits (Natalka, Pavlik, Rodionovskoe, Drazhnoe, Bazovskoe, Badran, Malo-Tarynskoe, etc.). The Verkhoyansk - Kolyma orogenic belt is subdivided into Kular-Nera and the Polousny-Debin terranes. The Kular-Nera terrane is mainly composed of the Upper Permian, Triassic, and Lower Jurassic black shales that are metamorphosed at lower greenschist facies conditions. The Charky-Indigirka and the Chai-Yureya faults separate the Kular-Nera from the Polousny-Debin terrane that is predominantly composed of the Jurassic flyschoi dturbidites. The deformation structure of the region evolved in association with several late Mesozoic tectonic events that took place in the north-eastern part ofthe Paleo-Pacific. In Late Jurassic-Early Cretaceous several generations of fold and thrust systems were formed due to frontal accretion of the Kolyma-Omolon superterrane to the eastern margin of the North Asian craton.Thrusting and folding was accompanied by granitic magmatism, metamorphic reworking of the Late Paleozoic and the Early Mesozoic sedimentary rocks, and formation of Au-Sn-W mineralization. Three stages of deformation related to frontal accretion can be distinguished. First stage D1 has developed in the north-eastern part of the Verkhoyansk - Kolyma orogenic belt. Early tight and isoclinal folds F1 and assosiated thrusts are characteristic of D1. Major thrusts, linear concentric folds F2 and cleavage were formed during D2. The main ore-controlling structures are thrust faults forming imbricate fan systems. Frontal and oblique ramps and systems of bedding and cross thrusts forming duplexes are common. It is notable that mineralized tectonized zones commonly develop along thrusts at the contacts of rocks of contrasting competence

The Mesozoic and Palaeozoic granitoids of north-western New Guinea

NASA Astrophysics Data System (ADS)

Jost, Benjamin M.; Webb, Max; White, Lloyd T.

2018-07-01

A large portion of the Bird's Head Peninsula of NW New Guinea is an inlier that reveals the pre-Cenozoic geological history of the northern margin of eastern Gondwana. The peninsula is dominated by a regional basement high exposing Gondwanan ('Australian') Palaeozoic metasediments intruded by Palaeozoic and Mesozoic granitoids. Here, we present the first comprehensive study of these granitoids, including field and petrographic descriptions, bulk rock geochemistry, and U-Pb zircon age data. We further revise and update previous subdivisions of granitoids in the area. Most granitoids were emplaced as small to medium-scale intrusions during two episodes in the Devonian-Carboniferous and the Late Permian-Triassic, separated by a period of apparent magmatic quiescence. The oldest rocks went unrecognised until this study, likely due to the younger intrusive events resetting the K-Ar isotopic system used in previous studies. Most of the Palaeozoic and Mesozoic granitoids are peraluminous and in large parts derived from partial melts of the country rock. This is corroborated by local migmatites and country rock xenoliths. Although rare, metaluminous and mafic rocks show that partial melts of mantle-derived material played a minor role in granitoid petrogenesis, especially during the Permian-Triassic. The Devonian-Carboniferous granitoids and associated volcanics are locally restricted, whereas the Permian-Triassic intrusions are found across NW New Guinea and further afield. The latter were likely part of an extensive active continental margin above a subduction system spanning the length of what is now New Guinea and potentially extending southward through eastern Australia and Antarctica.

Molecular clocks indicate turnover and diversification of modern coleoid cephalopods during the Mesozoic Marine Revolution

PubMed Central

Fuchs, Dirk; Winkelmann, Inger E.; Gilbert, M. Thomas P.; Pankey, M. Sabrina; Ribeiro, Ângela M.; Kocot, Kevin M.; Halanych, Kenneth M.; Oakley, Todd H.; da Fonseca, Rute R.

2017-01-01

Coleoid cephalopod molluscs comprise squid, cuttlefish and octopuses, and represent nearly the entire diversity of modern cephalopods. Sophisticated adaptations such as the use of colour for camouflage and communication, jet propulsion and the ink sac highlight the unique nature of the group. Despite these striking adaptations, there are clear parallels in ecology between coleoids and bony fishes. The coleoid fossil record is limited, however, hindering confident analysis of the tempo and pattern of their evolution. Here we use a molecular dataset (180 genes, approx. 36 000 amino acids) of 26 cephalopod species to explore the phylogeny and timing of cephalopod evolution. We show that crown cephalopods diverged in the Silurian–Devonian, while crown coleoids had origins in the latest Palaeozoic. While the deep-sea vampire squid and dumbo octopuses have ancient origins extending to the Early Mesozoic Era, 242 ± 38 Ma, incirrate octopuses and the decabrachian coleoids (10-armed squid) diversified in the Jurassic Period. These divergence estimates highlight the modern diversity of coleoid cephalopods emerging in the Mesozoic Marine Revolution, a period that also witnessed the radiation of most ray-finned fish groups in addition to several other marine vertebrates. This suggests that that the origin of modern cephalopod biodiversity was contingent on ecological competition with marine vertebrates. PMID:28250188

The age of the Keystone thrust: laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada

USGS Publications Warehouse

Fleck, R.J.; Carr, M.D.

1990-01-01

Nonmarine sedimentary and volcaniclastic foreland-basin deposits in the Spring Mountains are cut by the Contact and Keystone thrusts. These synorogenic deposits, informally designated the Lavinia Wash sequence by Carr (1980), previously were assigned a Late Jurassic to Early Cretaceous(?) age. New 40Ar.39Ar laser-fusion and incremental-heating studies of a tuff bed in the Lavinia Wash sequence support a best estimate age of 99.0 ?? 0.4 Ma, indicating that the Lavinia Wash sequence is actually late Early Cretaceous in age and establishing a maximum age for final emplacement of the Contact and Keystone thrust plates consistent with the remainder of the Mesozoic foreland thrust belt. -from Authors

Mesozoic cyclostratigraphy, the 405-kyr orbital eccentricity metronome, and the Astronomical Time Scale (Invited)

NASA Astrophysics Data System (ADS)

Hinnov, L.; Ogg, J. G.

2009-12-01

Mesozoic cyclostratigraphy from around the world is being assessed to construct a continuous Astronomical Time Scale (ATS) based on Earth’s cyclic orbital parameters. The recognition of a prevalent sedimentary cycling with a ~400-kyr period associated with forcing by the stable 405-kyr orbital eccentricity variation is an important development. Numerous formations spanning 10 to 20 myr (and longer) intervals in the Cretaceous, Jurassic and Triassic clearly express this dominant cycle and provide a robust basis for 405-kyr-scale calibration of the ATS. This 405-kyr metronome will enable extension of the well-defined Cenozoic ATS for scaling of the past quarter-billion years of Earth history. This astronomical calibration has a resolution comparable to the 1% to 0.1% precision for radioisotope dating of Mesozoic ash beds, with the added benefit of providing continuous stratigraphic coverage between dated beds. Extended portions of the Mesozoic ATS have already provided new insights into long-standing geologic problems of seafloor spreading, tectonics, eustasy, and paleoclimate change. Ongoing work is focused on closing gaps in coverage and on collecting duplicate cyclostratigraphic records for the entire Mesozoic Era.

Selected chemical analyses of water from formations of Mesozoic and Paleozoic age in parts of Oklahoma, northern Texas, and Union County, New Mexico

USGS Publications Warehouse

Parkhurst, R.S.; Christenson, S.C.

1987-01-01

Hydrochemical data were compiled into a data base as part of the Central Midwest Regional Aquifer System Analysis project. The data consist of chemical analyses of water samples collected from wells that are completed in formations of Mesozoic and Paleozoic age. The data base includes data from the National Water Data Storage and Retrieval System, the Petroleum Data System, the National Uranium Resource Evaluation, and selected publications. Chemical analyses were selected for inclusion within the hydrochemical data base if the total concentration of the cations differed from the total 10 percent or less of the total concentration of all ions. Those analyses which lacked the necessary data for an ionic balance were included if the ratios of dissolved-solids concentration to specific conductance were between 0.55 and 0.75. The tabulated chemical analyses, grouped by county, and a statistical summary of the analyses, listed by geologic unit, are presented.

Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau: Constraints from detrital zircon U-Pb ages and fission-track ages of the Triassic sedimentary sequence

NASA Astrophysics Data System (ADS)

Tang, Yan; Zhang, Yunpeng; Tong, Lili

2018-01-01

The Zoige depression is an important depocenter within the northeast Songpan-Ganzi flysch basin, which is bounded by the South China, North China and Qiangtang Blocks and forms the northeastern margin of the Tibetan Plateau. This paper discusses the sediment provenance and Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau, using the detrital zircon U-Pb ages and apatite fission-track data from the Middle to Late Triassic sedimentary rocks in the area. The U-Pb ages of the Middle to Late Triassic zircons range from 260-280 Ma, 429-480 Ma, 792-974 Ma and 1800-2500 Ma and represent distinct source region. Our new results demonstrate that the detritus deposited during the Middle Triassic (Ladinian, T2zg) primarily originated from the Eastern Kunlun and North Qinling Orogens, with lesser contributions from the North China Block. By the Late Triassic (early Carnian, T3z), the materials at the southern margin of the North China Block were generally transported westward to the basin along a river network that flowed through the Qinling region between the North China and South China Blocks: this interpretation is supported by the predominance of the bimodal distribution of 1.8 Ga and 2.5 Ga age peaks and a lack of significant Neoproterozoic zircon. Since the Late Triassic (middle Carnian, T3zh), considerable changes have occurred in the source terranes, such as the cessation of the Eastern Kunlun Orogen and North China Block sources and the rise of the northwestern margin of the Yangtze Block and South Qinling Orogen. These drastic changes are compatible with a model of a sustained westward collision between the South China and North China Blocks during the late Triassic and the clockwise rotation of the South China Block progressively closed the basin. Subsequently, orogeny-associated folds have formed in the basin since the Late Triassic (late Carnian), and the study area was generally subjected to uplifting and

Mesozoic Magmatism and Base-Metal Mineralization in the Fortymile Mining District, Eastern Alaska - Initial Results of Petrographic, Geochemical, and Isotopic Studies in the Mount Veta Area

USGS Publications Warehouse

Dusel-Bacon, Cynthia; Slack, John F.; Aleinikoff, John N.; Mortensen, James K.

2009-01-01

We present here the initial results of a petrographic, geochemical, and isotopic study of Mesozoic intrusive rocks and spatially associated Zn-Pb-Ag-Cu-Au prospects in the Fortymile mining district in the southern Eagle quadrangle, Alaska. Analyzed samples include mineralized and unmineralized drill core from 2006 and 2007 exploration by Full Metal Minerals, USA, Inc., at the Little Whiteman (LWM) and Fish prospects, and other mineralized and plutonic samples collected within the mining district is part of the USGS study. Three new ion microprobe U-Pb zircon ages are: 210 +- 3 Ma for quartz diorite from LWM, 187 +- 3 Ma for quartz monzonite from Fish, and 70.5 +- 1.1 Ma for altered rhyolite porphyry from Fish. We also present 11 published and unpublished Mesozoic thermal ionization mass spectrometric U-Pb zircon and titanite ages and whole-rock geochemical data for the Mesozoic plutonic rocks. Late Triassic and Early Jurassic plutons generally have intermediate compositions and are slightly foliated, consistent with synkinematic intrusion. Several Early Jurassic plutons contain magmatic epidote, indicating emplacement of the host plutons at mesozonal crustal depths of greater than 15 km. Trace-element geochemical data indicate an arc origin for the granitoids, with an increase in the crustal component with time. Preliminary study of drill core from the LWM Zn-Pb-Cu-Ag prospect supports a carbonate-replacement model of mineralization. LWM massive sulfides consist of sphalerite, galena, and minor pyrite and chalcopyrite, in a gangue of calcite and lesser quartz; silver resides in Sb-As-Ag sulfosalts and pyrargyrite, and probably in submicroscopic inclusions within galena. Whole-rock analyses of LWM drill cores also show elevated In, an important metal in high-technology products. Hypogene mineralized rocks at Fish, below the secondary Zn-rich zone, are associated with a carbonate host and also may be of replacement origin, or alternatively, may be a magnetite

A Glimpse at Late Mesozoic to Early Tertiary Offshore Stratigraphy from Wilkes Land, East Antarctica: Results of Strategic Dredging of the Mertz-Ninnis Trough

NASA Astrophysics Data System (ADS)

Schrum, H.; Domack, E.; Desantis, L.; Leventer, A.; McMullen, K.; Escutia, C.

2004-12-01

infilling a rifted basin of late Cretaceous age. Seaward dipping reflectors above the syn-rift strata represent post-rift deposits ranging from Paleogene to Quaternary. Included within this stratigraphy are lithified diamictites containing Mesozoic palynomorphs in addition to palynomorphs of Early Tertiary age (including dinoflagellates). Seaward dipping reflectors in the deep axis of the Mertz-Ninnis Trough were not sampled directly by our dredges, but are believed to be Lower Cretaceous siltstones by extrapolation to core DF-79-38, 100 km along strike to the southeast (Domack et al., 1980). Furthermore, the thermal maturity of the lignite samples recovered in our collections suggests that the coal is of Early Tertiary age, as are numerous organic-rich mudstones, which contain Paleogene palynomorphs. These results indicate that sedimentary strata in this portion of the Wilkes Land Margin contain significantly thick (greater than 2.7 km) post-rift (drift phase) marine sequences of both pre- and synglacial character. Strategic dredging is a promising methodology by which to sample stratigraphic succession in a cost effective manner along the East Antarctic margin in the absence of, or preparation for, International Ocean Drilling Projects on the shelf. Domack, E. W., Fairchild, W. W., and Anderson, J. B. (1980) Lower Cretaceous sediment from the East Antarctic continental shelf, Nature, 287, 625-626.

Mesozoic contractile and extensional structures in the Boyer Gap area, northern Dome Rock Mountains, Arizona

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

Boettcher, S.S.

1993-04-01

Mesozoic polyphase contractile and superposed ductile extensional structures affect Proterozoic augen gneiss, Paleozoic metasedimentary rocks, and Jurassic granitoids in the Boyer Gap area of the northern Dome Rock Mtns, W-central Arizona. The nappe-style contractile structures are preserved in the footwall of the Tyson Thrust shear zone, which is one of the structurally lowest thrust faults in the E-trending Jurassic and Cretaceous Maria fold and thrust belt. Contractile deformation preceded emplacement of Late Cretaceous granite (ca 80 Ma, U-Pb zircon) and some may be older than variably deformed Late Jurassic leucogranite. Specifically, detailed structural mapping reveals the presence of a km-scalemore » antiformal syncline that apparently formed as a result of superposition of tight to isoclinal, south-facing folds on an earlier, north-facing recumbent fold. The stratigraphic sequence of metamorphosed Paleozoic cratonal strata is largely intact in the northern Dome Rock Mtns, such that overturned and upright stratigraphic units can be distinguished. A third phase of folding in the Boyer Gap area is distinguished by intersection lineations that are folded obliquely across the hinges of open to tight, sheath folds. The axial planes of the sheet folds are subparallel to the mylonitic foliation in top-to-the-northeast extensional shear zones. The timing of ductile extensional structures in the northern Dome Rock is constrained by [sup 40]Ar/[sup 39]Ar isochron ages of 56 Ma and 48 Ma on biotite from mylonitic rocks in both the hanging wall and footwall of the Tyson Thrust shear zone. The two early phases of folding are the dominant mechanism by which shortening was accommodated in the Boyer Gap area, as opposed to deformation along discrete thrust faults with large offset. All of the ductile extensional structures are spectacularly displayed at an outcrop scale but are not of sufficient magnitude to obliterate the km-scale Mesozoic polyphase contractile

High-precision 40Ar/39Ar age for the Jehol Biota

NASA Astrophysics Data System (ADS)

Chang, S.; Zhang, H.; Renne, P. R.; Fang, Y.

2008-12-01

Abundant fossils of the terrestrial Jehol Biota, including plants, insects, dinosaurs, birds, mammals and freshwater invertebrates, were discovered from the Yixian Formation and the overlying Jiufotang Formation in Inner Mongolia, Hebei Province and Liaoning Province, northeastern China. Because of the exceptional preservation of fossils, the Jehol Biota is one of the most important Mesozoic fossil outcrops and referred to as a "Mesozoic Pompeii". The Jehol Biota has provided a rare opportunity to address questions about the origin of birds, the evolution of feathers and flight, the early diversification of angiosperms and the timing of the radiation of placental mammals. The Tuchengzi Formation, which lies unconformably just below the Yixian Formation and consists mainly of variegated sandstones, is less fossiliferous than the two overlying formations. However, dinosaur tracks, silicified wood and compressed plants are found in this formation. A systematic 40Ar/39Ar dating of the Yixian and the Jiufotang formations was undertaken to provide a framework for understanding the timing and duration of the Jehol Biota and evolutionary events represented within it. Furthermore, determining the absolute age of the Tuchengzi Formation provides information to interpret abundant dinosaur tracks within and provide better age constrains for the beginning of the Jehol Biota. Here we present robust high-precision 40Ar/39Ar data for six tuff samples and two basalt samples collected from the Tuchengzi, the Yixian and the Jiufotang formations near the classic outcrops in western Liaoning, NE China. We obtain an age of 139.5 ± 1.0 Ma for the uppermost Tuchengzi Formation, an age of 129.7 ± 0.5 Ma for a basaltic lava from the bottom of the Yixian Formation and an age of 122.1 ± 0.3 Ma for a tuff from the base of the overlying Jiufotang Formation. Our data indicate that the Yixian Formation was deposited during the Early Cretaceous, the Barremian to early Aptian, within a time span

Field guide to the Mesozoic arc and accretionary complex of South-Central Alaska, Indian to Hatcher Pass

USGS Publications Warehouse

Karl, Susan M.; Oswald, P.J.; Hults, Chad P.

2015-01-01

This field trip traverses exposures of a multi-generation Mesozoic magmatic arc and subduction-accretion complex that had a complicated history of magmatic activity and experienced variations in composition and deformational style in response to changes in the tectonic environment. This Mesozoic arc formed at an unknown latitude to the south, was accreted to North America, and was subsequently transported along faults to its present location (Plafker and others, 1989; Hillhouse and Coe, 1994). Some of these faults are still active. Similar tectonic, igneous, and sedimentary processes to those that formed the Mesozoic arc complex persist today in southern Alaska, building on, and deforming the Mesozoic arc. The rocks we will see on this field trip provide insights on the three-dimensional composition of the modern arc, and the processes involved in the evolution of an arc and its companion accretionary complex.

Geologic and Geochronologic Studies of the Early Proterozoic Kanektok Metamorphic Complex of Southwestern Alaska

USGS Publications Warehouse

Turner, Donald L.; Forbes, Robert B.; Aleinikoff, John N.; McDougall, Ian; Hedge, Carl E.; Wilson, Frederic H.; Layer, Paul W.; Hults, Chad P.

2009-01-01

The Kanektok complex of southwestern Alaska appears to be a rootless terrane of early Proterozoic sedimentary, volcanic, and intrusive rocks which were metamorphosed to amphibolite and granulite facies and later underwent a pervasive late Mesozoic thermal event accompanied by granitic plutonism and greenschist facies metamorphism of overlying sediments. The terrane is structurally complex and exhibits characteristics generally attributed to mantled gneiss domes. U-Th-Pb analyses of zircon and sphene from a core zone granitic orthogneiss indicate that the orthogneiss protolith crystallized about 2.05 b.y. ago and that the protolithic sedimentary, volcanic and granitic intrusive rocks of the core zone were metamorphosed to granulite and amphibolite facies about 1.77 b.y. ago. A Rb-Sr study of 13 whole-rock samples also suggests metamorphism of an early Proterozoic [Paleoproterozoic] protolith at 1.77 Ga, although the data are scattered and difficult to interpret. Seventy-seven conventional 40K/40Ar mineral ages were determined for 58 rocks distributed throughout the outcrop area of the complex. Analysis of the K-Ar data indicate that nearly all of these ages have been totally or partially reset by a pervasive late Mesozoic thermal event accompanied by granitic plutonism and greenschist facies metamorphism. Several biotites gave apparent K-Ar ages over 2 Ga. These ages appear to be controlled by excess radiogenic 40Ar produced by the degassing protolith during the 1.77 Ga metamorphism and incorporated by the biotites when they were at temperatures at which Ar could diffuse through the lattice. Five amphibolites yielded apparent Precambrian 40K/40Ar hornblende ages. There is no evidence that these hornblende ages have been increased by excess argon. The oldest 40K/40Ar hornblende age of 1.77 Ga is identical to the sphene 207Pb/206Pb orthogneiss age and to the Rb-Sr 'isochron' age for six of the 13 whole-rock samples. The younger hornblende ages are interpreted as

Age and tectonic setting of the Mesozoic McCoy Mountains Formation in western Arizona, USA

USGS Publications Warehouse

Spencer, J.E.; Richard, S.M.; Gehrels, G.E.; Gleason, J.D.; Dickinson, W.R.

2011-01-01

The McCoy Mountains Formation consists of Upper Jurassic to Upper Cretaceous siltstone, sandstone, and conglomerate exposed in an east-west-trending belt in southwestern Arizona and southeastern California. At least three different tectonic settings have been proposed for McCoy deposition, and multiple tectonic settings are likely over the ~80 m.y. age range of deposition. U-Pb isotopic analysis of 396 zircon sand grains from at or near the top of McCoy sections in the southern Little Harquahala, Granite Wash, New Water, and southern Plomosa Mountains, all in western Arizona, identifi ed only Jurassic or older zircons. A basaltic lava fl ow near the top of the section in the New Water Mountains yielded a U-Pb zircon date of 154.4 ?? 2.1 Ma. Geochemically similar lava fl ows and sills in the Granite Wash and southern Plomosa Mountains are inferred to be approximately the same age. We interpret these new analyses to indicate that Mesozoic clastic strata in these areas are Upper Jurassic and are broadly correlative with the lowermost McCoy Mountains Formation in the Dome Rock, McCoy, and Palen Mountains farther west. Six samples of numerous Upper Jurassic basaltic sills and lava fl ows in the McCoy Mountains Formation in the Granite Wash, New Water, and southern Plomosa Mountains yielded initial ??Nd values (at t = 150 Ma) of between +4 and +6. The geochemistry and geochronology of this igneous suite, and detrital-zircon geochronology of the sandstones, support the interpretation that the lower McCoy Mountains Formation was deposited during rifting within the western extension of the Sabinas-Chihuahua-Bisbee rift belt. Abundant 190-240 Ma zircon sand grains were derived from nearby, unidentifi ed Triassic magmatic-arc rocks in areas that were unaffected by younger Jurassic magmatism. A sandstone from the upper McCoy Mountains Formation in the Dome Rock Mountains (Arizona) yielded numerous 80-108 Ma zircon grains and almost no 190-240 Ma grains, revealing a major

Timing and implications for the late Mesozoic geodynamic settings of eastern North China Craton: Evidences from K-Ar dating age and sedimentary-structural characteristics records of Lingshan Island, Shandong Province

NASA Astrophysics Data System (ADS)

Li, Jie; Jin, Aiwen; Hou, Guiting

2017-12-01

The Lingshan Island in Shandong Province in the eastern North China Craton, well known for the Late Mesozoic multi-scale slide-slump structures is related to paleo-earthquake. Terrigenous clastic rocks, volcanic clastic rocks and volcanic lavas are extensively exposed in the Lingshan Island and its adjacent regions of the Shandong Province, which led to fierce debates on their ages, sedimentary characteristics and tectono-sedimentary evolution. In this contribution, we present the characteristics of the Late Mesozoic stratigraphy in the Lingshan Island. Whole-rock K-Ar dating of dyke at Beilaishi and rhyolites at Laohuzui of the Lingshan Island yielded ages of 159 Ma and 106-92 Ma which coincides with the Laiyang Period rifting and the Qingshan Period rifting in the Jiaolai Basin, respectively. On the basis of the analysis to the Late Mesozoic sedimentary environment of `flysch' and `molasse'-like formations as well as tectonic stress fields reconstruction, four episodes of the tectono-sedimentary evolution were established in the Lingshan Island and its adjacent regions in the eastern North China Craton. They consist of two episodes of extensional events for the syn-rift, and two episodes of compression events for the inversion of the post-rift. The entire episodes can be summarized as follows: (1) the first syn-rift NW-SE extension in Laiyang Period can be identified by the `flysch' formation (Unit 1) and by emplacement of the NE-trending dyke in the Laiyang Group. This syn-rift episode can be related to the NW-SE post-orogenic extension resulted from the gravity collapse of the thickened lithosphere along the Sulu Orogen. (2) The first post-rift NW-SE inversion, which was caused by the NW-directed subduction of Izanaqi Plate, can be well documented by the `X' type conjugate joints as well as slide slump folds in Unit 1. (3) The second syn-rift NW-SE extension in Qingshan Period is characterized by rhyolite rocks (Unit 2). This syn-rift episode can be considered

The Miocene mammal Necrolestes demonstrates the survival of a Mesozoic nontherian lineage into the late Cenozoic of South America

PubMed Central

Rougier, Guillermo W.; Wible, John R.; Beck, Robin M. D.; Apesteguía, Sebastian

2012-01-01

The early Miocene mammal Necrolestes patagonensis from Patagonia, Argentina, was described in 1891 as the only known extinct placental “insectivore” from South America (SA). Since then, and despite the discovery of additional well-preserved material, the systematic status of Necrolestes has remained in flux, with earlier studies leaning toward placental affinities and more recent ones endorsing either therian or specifically metatherian relationships. We have further prepared the best-preserved specimens of Necrolestes and compared them with newly discovered nontribosphenic Mesozoic mammals from Argentina; based on this, we conclude that Necrolestes is related neither to marsupials nor placentals but is a late-surviving member of the recently recognized nontherian clade Meridiolestida, which is currently known only from SA. This conclusion is supported by a morphological phylogenetic analysis that includes a broad sampling of therian and nontherian taxa and that places Necrolestes within Meridiolestida. Thus, Necrolestes is a remnant of the highly endemic Mesozoic fauna of nontribosphenic mammals in SA and extends the known record of meridiolestidans by almost 45 million years. Together with other likely relictual mammals from earlier in the Cenozoic of SA and Antarctica, Necrolestes demonstrates the ecological diversity of mammals and the mosaic pattern of fauna replacement in SA during the Cenozoic. In contrast to northern continents, the Cenozoic faunal history of SA was characterized by a long period of interaction between endemic mammalian lineages of Mesozoic origin and metatherian and eutherian lineages that probably dispersed to SA during the latest Cretaceous or earliest Paleocene. PMID:23169652

Mesozoic invasion of crust by MORB-source asthenospheric magmas, U.S. Cordilleran interior

NASA Astrophysics Data System (ADS)

Leventhal, Janet A.; Reid, Mary R.; Montana, Art; Holden, Peter

1995-05-01

Mafic and ultramafic xenoliths entrained in lavas of the Cima volcanic field have Nd and Sr isotopic ratios indicative of a source similar to that of mid-ocean ridge basalt (MORB). Nd and Sr internal isochrons demonstrate a Late Cretaceous intrusion age. These results, combined with evidence for emplacement in the lower crust and upper mantle, indicate invasion of the lower crust by asthenospheric magmas in the Late Cretaceous. Constituting the first prima facie evidence for depleted-mantle magmatism in the Basin and Range province prior to late Cenozoic volcanism, these results lend key support to models suggesting crustal heating by ascent of asthenosphere in the Mesozoic Cordilleran interior.

Early to Middle Jurassic tectonic evolution of the Bogda Mountains, Northwest China: Evidence from sedimentology and detrital zircon geochronology

NASA Astrophysics Data System (ADS)

Ji, Hongjie; Tao, Huifei; Wang, Qi; Qiu, Zhen; Ma, Dongxu; Qiu, Junli; Liao, Peng

2018-03-01

The Bogda Mountains, as an important intracontinental orogenic belt, are situated in the southern part of the Central Asian Orogenic Belt (CAOB), and are a key area for understanding the Mesozoic evolution of the CAOB. However, the tectonic evolution of the Bogda Mountains remains controversial during the Mesozoic Era, especially the Early to Middle Jurassic Periods. The successive Lower to Middle Jurassic strata are well preserved and exposed along the northern flank of the Western Bogda Mountains and record the uplift processes of the Bogda Mountains. In this study, we analysed sedimentary facies combined with detrital zircon U-Pb geochronology at five sections of Lower to Middle Jurassic strata to detect the tectonic evolution and changes of provenance in the Bogda area. During Early to Middle Jurassic times, the fluvial, deltaic and lacustrine environments dominated in the western section of the Bogda area. The existence of Early Triassic peak age indicates that the Bogda Mountains did not experience uplift during the period of early Badaowan Formation deposition. The Early Triassic to Late Permian granitoid plutons and Carboniferous volcanic rocks from the Barkol and Santanghu areas were the main provenances. The significant change in the U-Pb age spectrum implies that the Eastern Bogda Mountains initiated uplift in the period of late Badaowan Formation deposition, and the Eastern Junggar Basin and the Turpan-Hami Basin were partially partitioned. The Eastern Bogda Mountains gradually became the major provenance. From the period of early Sangonghe to early Toutunhe Formations deposition, the provenance of the sediments and basin-range frame were similar to that of late Badaowan. However, the Eastern Bogda Mountains suffered intermittent uplift three times, and successive denudation. The uplifts respectively happened in early Sangonghe, late Sangonghe to early Xishanyao, and late Xishanyao to early Toutunhe. During the deposition stage of Toutunhe Formation, a

Do schizophrenia patients age early?

PubMed

Shivakumar, Venkataram; Kalmady, Sunil V; Venkatasubramanian, Ganesan; Ravi, Vasanthapuram; Gangadhar, Bangalore N

2014-08-01

The etiopathogenesis of schizophrenia is poorly understood. Within the proposed "neurodegeneration paradigm", observations have been put forth for "accelerated aging" in this disorder. This proposition is largely based on the neuroscience research that demonstrates progressive changes in brain as well as other systemic abnormalities supportive of faster aging process in patients with this disorder. In this review, we have summarized the literature related to the concept of early aging in schizophrenia. These studies include P300 abnormalities & visual motion discrimination, neuroimaging findings, telomere dynamics as well as neuropathology of related brain regions. We also propose a role of vitamin D, neuroimmunological changes and elevated oxidative stress as well as mitochondrial dysfunction in addition to the above factors with 'vitamin-D deficiency' as the central paradox. Put together, the evidence supporting early aging in schizophrenia is compelling and this requires further systematic studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Mesozoic intracontinental underthrust in the SE margin of the North China Block: Insights from the Xu-Huai thrust-and-fold belt

NASA Astrophysics Data System (ADS)

Shu, Liangshu; Yin, Hongwei; Faure, Michel; Chen, Yan

2017-06-01

The Xu-Huai thrust-and-fold belt, located in the southeastern margin of the North China Block, consists mainly of thrust and folded pre-Mesozoic strata. Its geodynamic evolution and tectonic setting are topics of long debate. This paper provides new evidence from geological mapping, structural analysis, and making balance cross-sections, with restoration of cross-sections. Results suggest that this belt was subjected to two-phase deformation, including an early-phase regional-scale NW-ward thrust and fold, and a late-phase extension followed by the emplacement of dioritic, monzodioritic porphyrites dated at 131-135 Ma and locally strike-slip shearing. According to the mapping, field observations and drill-hole data, three structural units were distinguished, namely, (1) the pre-Neoproterozoic crystalline basement in the eastern segment, (2) the nappe unit or the thrust-and-fold zone in the central segment, which is composed of Neoproterozoic to Ordovician carbonate rocks and Carboniferous-Permian coal-bearing rocks, about 2600 m thick, and (3) the western frontal zone. A major decollement fault has also been identified in the base of the nappe unit, on which dozen-meter to km-scale thrust-and-fold bodies were commonly developed. All pre-Mesozoic depositional sequences were involved into a widespread thrust and fold event. Six uncompetent-rock layers with biostratigraphic ages (Nanjing University, 1996) have been recognized, and each uncompetent-rock layer occurred mainly in the top of the footwall, playing an important role in the development of the Xu-Huai thrust-and-fold belt. Geometry of the major decollement fault suggests that the nappe unit of this belt was rooted in its eastern side, near the Tan-Lu Fault Zone. Two geological cross-sections were chosen for structural balancing and restoration. From the balanced cross-sections, ramp-flat and imbricated faults as well as fault-related folds were identified. A shortening of 20.6-29.6 km was obtained from

Paleomagnetic data from Sarawak, Malaysia (Borneo) and the late Mesozoic and Cenozoic tectonics of Sundaland

NASA Astrophysics Data System (ADS)

Schmidtke, Eric A.; Fuller, Michael D.; Haston, Roger B.

1990-02-01

Paleomagnetic data from 231 samples from 31 sites in rocks of Upper Jurassic to Miocene age in Sarawak (Malaysian Borneo) reveal a trend of increasing counterclockwise (CCW) declination deflection with age. Six sites in Tertiary hypabyssal intrusions show 8° to 52° of CCW deflection. The intrusion deflected 52° CCW was K-Ar dated at 26 m.y. (Upper Oligocene), while one deflected 22° CCW gives a 17 m. y. age (Lower Miocene). Three sites in the Upper Eocene to Miocene(?) Silantek Formation show an average 40° of CCW deflection. Prefolding directions, showing 90° of CCW deflection, are isolated in 4 sites (including two positive fold tests) in Upper Jurassic and Cretaceous rocks of the Bau Limestone and Pedawan Formations. A postfolding, Cenozoic remagnetization with an average of 60° of CCW deflection is found in five Bau Limestone sites. Three sites in the Upper Jurassic Kedadom Formation show an average of 50° of CCW deflection. CCW declination deflections found in Mesozoic and Cenozoic rocks as far as 400 km east and 150 km south of Sarawak, in Kalimantan (Indonesian Borneo), also fit the trend of deflection versus age. On the basis of the regional consistency of declination deflection versus age, along with geologic evidence the data are considered to be evidence of a regional (rather than a local block or distributed shear) rotation. The domain of CCW rotation extends into West Malaysia, suggesting that West Borneo and the Malay Peninsula may have been a stable block during the latest Cretaceous and Cenozoic. West Malaysia and Borneo may have had different histories in the rest of the Mesozoic. The data imply up to 108° CCW rotation of Borneo with respect to stable Eurasia, sometime during the Cretaceous and Cenozoic. Cenozoic rotation may also have occurred between Indochina and Borneo. The sense of rotation shown by the data does not support the "propagating extrusion tectonics" model for Cenozoic Southeast Asia.

Reconstruction of an early Paleozoic continental margin based on the nature of protoliths in the Nome Complex, Seward Peninsula, Alaska

USGS Publications Warehouse

Till, Alison B.; Dumoulin, Julie A.; Ayuso, Robert A.; Aleinikoff, John N.; Amato, Jeffrey M.; Slack, John F.; Shanks, W.C. Pat

2014-01-01

The Nome Complex is a large metamorphic unit that sits along the southern boundary of the Arctic Alaska–Chukotka terrane, the largest of several micro continental fragments of uncertain origin located between the Siberian and Laurentian cratons. The Arctic Alaska–Chukotka terrane moved into its present position during the Mesozoic; its Mesozoic and older movements are central to reconstruction of Arctic tectonic history. Accurate representation of the Arctic Alaska–Chukotka terrane in reconstructions of Late Proterozoic and early Paleozoic paleogeography is hampered by the paucity of information available. Most of the Late Proterozoic to Paleozoic rocks in the Alaska–Chukotka terrane were penetratively deformed and recrystallized during the Mesozoic deformational events; primary features and relationships have been obliterated, and age control is sparse. We use a variety of geochemical, geochronologic, paleontologic, and geologic tools to read through penetrative deformation and reconstruct the protolith sequence of part of the Arctic Alaska–Chukotka terrane, the Nome Complex. We confirm that the protoliths of the Nome Complex were part of the same Late Proterozoic to Devonian continental margin as weakly deformed rocks in the southern and central part of the terrane, the Brooks Range. We show that the protoliths of the Nome Complex represent a carbonate platform (and related rocks) that underwent incipient rifting, probably during the Ordovician, and that the carbonate platform was overrun by an influx of siliciclastic detritus during the Devonian. During early phases of the transition to siliciclastic deposition, restricted basins formed that were the site of sedimentary exhalative base-metal sulfide deposition. Finally, we propose that most of the basement on which the largely Paleozoic sedimentary protolith was deposited was subducted during the Mesozoic.

Indo-Burma Range: a belt of accreted microcontinents, ophiolites and Mesozoic-Paleogene flyschoid sediments

NASA Astrophysics Data System (ADS)

Acharyya, S. K.

2015-07-01

This study provides an insight into the lithotectonic evolution of the N-S trending Indo-Burma Range (IBR), constituting the southern flank of the Himalayan syntaxis. Paleogene flyschoid sediments (Disang-Barail) that represent a shallow marine to deltaic environment mainly comprise the west-central sector of IBR, possibly resting upon a continental base. On the east, these sequences are tectonically flanked by the Eocene olistostromal facies of the Disang, which developed through accretion of trench sediments during the subduction. The shelf and trench facies sequences of the Disang underwent overthrusting from the east, giving rise to two ophiolite suites ( Naga Hills Lower Ophiolite ( NHLO) and Victoria Hills Upper Ophiolite ( VHUO), but with different accretion history. The ophiolite and ophiolite cover rock package were subsequently overthrusted by the Proterozoic metamorphic sequence, originated from the Burmese continent. The NHLO suite of Late Jurassic to Early Eocene age is unconformably overlain by mid-Eocene shallow marine ophiolite-derived clastics. On the south, the VHUO of Mesozoic age is structurally underlain by continental metamorphic rocks. The entire package in Victoria Hills is unconformably overlain by shallow marine Late Albian sediments. Both the ophiolite suites and the sandwiched continental metamorphic rocks are thrust westward over the Paleogene shelf sediments. These dismembered ophiolites and continental metamorphic rocks suggest thin-skinned tectonic detachment processes in IBR, as reflected from the presence of klippe of continental metamorphic rocks over the NHLO and the flyschoid Disang floor sediments and half windows exposing the Disang beneath the NHLO.

The newfoundland basin - Ocean-continent boundary and Mesozoic seafloor spreading history

NASA Technical Reports Server (NTRS)

Sullivan, K. D.

1983-01-01

It is pointed out that over the past 15 years there has been considerable progress in the refinement of predrift fits and seafloor spreading models of the North Atlantic. With the widespread acceptance of these basic models has come increasing interest in resolution of specific paleogeographic and kinematic problems. Two such problems are the initial position of Iberia with respect to North America and the geometry and chronology of early (pre-80 m.y.) relative motions between these two plates. The present investigation is concerned with geophysical data from numerous Bedford Institute/Dalhousie University cruises to the Newfoundland Basin which were undrtaken to determine the location of the ocean-continent boundary (OCB) and the Mesozoic spreading history on the western side. From the examination of magnetic data in the Newfoundland Basin, the OCB east of the Grand Banks is defined as the seaward limit of the 'smooth' magnetic domain which characterizes the surrounding continental shelves. A substantial improvement in Iberia-North America paleographic reconstructions is achieved.

Mesozoic Deformation and Its Geological Significance in the Southern Margin of the South China Sea

NASA Astrophysics Data System (ADS)

Zhu, Rongwei; Liu, Hailing; Yao, Yongjian; Wang, Yin

2018-05-01

The pre-Eocene history of the region around the present South China Sea is not well known. New multi-channel seismic profiles provide valuable insights into the probable Mesozoic history of this region. Detailed structural and stratigraphic interpretations of the multi-channel seismic profiles, calibrated with relevant drilling and dredging data, show major Mesozoic structural features. A structural restoration was done to remove the Cenozoic tectonic influence and calculate the Mesozoic tectonic compression ratios. The results indicate that two groups of compressive stress with diametrically opposite orientations, S(S)E-N(N)W and N(N)W-S(S)E, were active during the Mesozoic. The compression ratio values gradually decrease from north to south and from west to east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate at which the Nansha block drifted northward in the late Jurassic to late Cretaceous. The Nansha block drifted northward until it collided and sutured with the southern China margin. The opening of the present South China Sea may be related to this suture zone, which was a tectonic zone of weakness.

Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

NASA Astrophysics Data System (ADS)

Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

2015-04-01

The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary

Paleozoic subduction complex and Paleozoic-Mesozoic island-arc volcano-plutonic assemblages in the northern Sierra terrane

USGS Publications Warehouse

Hanson, Richard E.; Girty, Gary H.; Harwood, David S.; Schweickert, Richard A.

2000-01-01

This field trip provides an overview of the stratigraphic and structural evolution of the northern Sierra terrane, which forms a significant part of the wall rocks on the western side of the later Mesozoic Sierra Nevada batholith in California. The terrane consists of a pre-Late Devonian subduction complex (Shoo Fly Complex) overlain by submarine arc-related deposits that record the evolution of three separate island-arc systems in the Late Sevonian-Early Mississippian, Permian, and Late Triassic-Jurassic. The two Paleozoic are packages and the underlying Shoo Fly Complex have an important bearing on plate-tectonic processes affecting the convergent margin outboard of the Paleozoic Cordilleran miogeocline, although their original paleogeographic relations to North America are controversial. The third arc package represents an overlap assemblage that ties the terrane to North America by the Late Triassic and helps constrain the nature and timing of Mesozoic orogenesis. Several of the field-trip stops examine the record of pre-Late Devonian subduction contained in the Shoo Fly Complex, as well as the paleovolcanology of the overlying Devonian to Jurassic arc rocks. Excellent glaciated exposures provide the opportunity to study a cross section through a tilted Devonian volcano-plutonic association. Additional stops focus on plutonic rocks emplaced during the Middle Jurassic arc magmatism in the terrane, and during the main pulse of Cretaceous magmatism in the Sierra Nevada batholith to the east.

Early-Life Intelligence Predicts Midlife Biological Age

PubMed Central

Caspi, Avshalom; Belsky, Daniel W.; Harrington, Honalee; Houts, Renate; Israel, Salomon; Levine, Morgan E.; Sugden, Karen; Williams, Benjamin; Poulton, Richie; Moffitt, Terrie E.

2016-01-01

Objectives: Early-life intelligence has been shown to predict multiple causes of death in populations around the world. This finding suggests that intelligence might influence mortality through its effects on a general process of physiological deterioration (i.e., individual variation in “biological age”). We examined whether intelligence could predict measures of aging at midlife before the onset of most age-related disease. Methods: We tested whether intelligence assessed in early childhood, middle childhood, and midlife predicted midlife biological age in members of the Dunedin Study, a population-representative birth cohort. Results: Lower intelligence predicted more advanced biological age at midlife as captured by perceived facial age, a 10-biomarker algorithm based on data from the National Health and Nutrition Examination Survey (NHANES), and Framingham heart age (r = 0.1–0.2). Correlations between intelligence and telomere length were less consistent. The associations between intelligence and biological age were not explained by differences in childhood health or parental socioeconomic status, and intelligence remained a significant predictor of biological age even when intelligence was assessed before Study members began their formal schooling. Discussion: These results suggest that accelerated aging may serve as one of the factors linking low early-life intelligence to increased rates of morbidity and mortality. PMID:26014827

Mesozoic to Cenozoic tectonic transition process in Zhanhua Sag, Bohai Bay Basin, East China

NASA Astrophysics Data System (ADS)

Cheng, Yanjun; Wu, Zhiping; Lu, Shunan; Li, Xu; Lin, Chengyan; Huang, Zheng; Su, Wen; Jiang, Chao; Wang, Shouye

2018-04-01

The Zhanhua sag is part of the Bohai Bay intracontinental basin system that has developed since the Mesozoic in East China. The timing of this basin system coincides with the final assembly of East Asia and the development of Western Pacific-type plate margin. Here we use 3-D seismic and core log data to investigate the evolution of this basin and discuss its broad tectonic settings. Our new structural study of Zhanhua sag suggests that there are four major tectonic transitions occurred in the Bohai Bay Basin during Mesozoic and Cenozoic: (1) The first tectonic transition was from stable Craton to thrusting during the Triassic, mainly caused by the South China Block's subduction northward beneath the North China Block, which induced the formation of the NW-striking thrust faults. (2) The second tectonic transition was mainly characterized by a change from compression to extension, which can be further divided into two-stages. At the first stage, two episodes of NW-SE shortening occurred in East Asia during Early-Middle Jurassic and Late Jurassic-earliest Cretaceous, respectively. At the second stage, the extension and left-lateral shearing took place during Early Cretaceous while compression occurred during Late Cretaceous. The NW-striking thrust faults changed to normal faults and the NNE-striking left-lateral strike-slip faults started to influence the eastern part of the basin. (3) The third transition occurred when the NW-SE extension and NNE-striking right-lateral shearing started to form during Paleogene, and the peak deformation happen around 40 Ma due to the change of the subduction direction of Pacific Plate relative to Eurasia Plate. The NE-striking normal faults are the main structure, and the pre-existing NNE-striking strike-slip faults changed from left-lateral to right-lateral. (4) The fourth transition saw the regional subsidence during Neogene, which was probably caused by the India-Asia "Hard collision" between 25 and 20 Ma.

Anomalous isotopic compositions of Sr, Ar and O in the Mesozoic diabase dikes of Liberia, West Africa

NASA Astrophysics Data System (ADS)

Mauche, Renée; Faure, Gunter; Jones, Lois M.; Hoefs, Jochen

1989-01-01

The Mesozoic diabase dikes of Liberia are tholeiites whose 87Sr/86Sr and 87Rb/86Sr ratios scatter widely on the Rb-Sr isochron diagram. The problem is attributed to differences in the initial 87Sr/86Sr ratios of these rocks which range from 0.70311 to 0.70792, assuming a uniform age of 186 Ma for the dikes and using λ(87Rb)=1.42 × 10-11y-1. The range of values is similar to that observed in the Mesozoic basalt flows and dikes of other Gondwana continents. New whole-rock K-Ar dates confirm previous conclusions that the diabase dikes in the Liberian and Pan-African age provinces of Liberia absorbed extraneous 40Ar after intrusion. Only the dikes in the Paynesville Sandstone have K-Ar dates that range from 117 Ma to 201 Ma and may not contain extraneous 40Ar. However, dikes from all three age provinces of Liberia have elevated initial 87Sr/86Sr ratios. These results indicate that contamination with radiogenic 87Sr occurred primarily before intrusion of the magma whereas the addition of extraneous 40Ar occurred after emplacement and reflects the age and mineral composition of the country rock. The δ 18O values of the Liberian diabase range from +5.6/% to +9.10/% and correlate positively with initial 87Sr/86Sr ratios. The data can be modeled by fractional crystallization and simultaneous assimilation of crustal rocks by the magma. However, samples containing amphibole and biotite replacing pyroxene deviate from the Sr-O isotope trajectories of the model and appear to have been depleted in 18O and enriched in 87Sr by interactions with groundwater at high temperature.

Rapid middle Miocene collapse of the Mesozoic orogenic plateau in north-central Nevada

USGS Publications Warehouse

Colgan, Joseph P.; Henry, Christopher D.

2009-01-01

The modern Sierra Nevada and Great Basin were likely the site of a high-elevation orogenic plateau well into Cenozoic time, supported by crust thickened during Mesozoic shortening. Although crustal thickening at this scale can lead to extension, the relationship between Mesozoic shortening and subsequent formation of the Basin and Range is difficult to unravel because it is unclear which of the many documented or interpreted extensional episodes was the most significant for net widening and crustal thinning. To address this problem, we integrate geologic and geochronologic data that bear on the timing and magnitude of Cenozoic extension along an ???200km east-west transect south of Winnemucca, Battle Mountain, and Elko, Nevada. Pre-Cenozoic rocks in this region record east-west Palaeozoic and Mesozoic compression that continued into the Cretaceous. Little to no tectonism and no deposition followed until intense magmatism began in the Eocene. Eocene and Oligocene ash-flow tuffs flowed as much as 200km down palaeovalleys cut as deeply as 1.5km into underlying Palaeozoic and Mesozoic rocks in a low-relief landscape. Eocene sedimentation was otherwise limited to shallow lacustrine basins in the Elko area; extensive, thick clastic deposits are absent. Minor surface extension related to magmatism locally accompanied intense Eocene magmatism, but external drainage and little or no surface deformation apparently persisted regionally until about 16-17Ma. Major upper crustal extension began across the region ca. 16-17Ma, as determined by cross-cutting relationships, low-temperature thermochronology, and widespread deposition of clastic basin fill. Middle Miocene extension was partitioned into high-strain (50-100%) domains separated by largely unextended crustal blocks, and ended by 10-12Ma. Bimodal volcanic rocks that erupted during middle Miocene extension are present across most of the study area, but are volumetrically minor outside the northern Nevada rift. The modern

Early-Life Intelligence Predicts Midlife Biological Age.

PubMed

Schaefer, Jonathan D; Caspi, Avshalom; Belsky, Daniel W; Harrington, Honalee; Houts, Renate; Israel, Salomon; Levine, Morgan E; Sugden, Karen; Williams, Benjamin; Poulton, Richie; Moffitt, Terrie E

2016-11-01

Early-life intelligence has been shown to predict multiple causes of death in populations around the world. This finding suggests that intelligence might influence mortality through its effects on a general process of physiological deterioration (i.e., individual variation in "biological age"). We examined whether intelligence could predict measures of aging at midlife before the onset of most age-related disease. We tested whether intelligence assessed in early childhood, middle childhood, and midlife predicted midlife biological age in members of the Dunedin Study, a population-representative birth cohort. Lower intelligence predicted more advanced biological age at midlife as captured by perceived facial age, a 10-biomarker algorithm based on data from the National Health and Nutrition Examination Survey (NHANES), and Framingham heart age (r = 0.1-0.2). Correlations between intelligence and telomere length were less consistent. The associations between intelligence and biological age were not explained by differences in childhood health or parental socioeconomic status, and intelligence remained a significant predictor of biological age even when intelligence was assessed before Study members began their formal schooling. These results suggest that accelerated aging may serve as one of the factors linking low early-life intelligence to increased rates of morbidity and mortality. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Final report. [Mesozoic tectonic history of the northeastern Great Basin (Nevada)

NASA Technical Reports Server (NTRS)

Zamudio, Joe

1993-01-01

In eastern Nevada and western Utah is an extensive terrane that has experienced a complex tectonic history of Mesozoic deformation and superposed Tertiary extension. The Mesozoic tectonic history of this area has been the subject of controversy for the past twenty or more years. The debate has centered on whether major Mesozoic geologic structures were due to compressional or extensional tectonic regimes. The goal of our research was to decipher the deformational history of the area by combining detailed geologic mapping, remote sensing data analysis, and U-Pb and K-Ar geochronology. This study area includes the Dolly Varden Mountains and adjacent Currie Hills, located in the semi-arid environment of the northeastern Great Basin in Nevada. Vegetation cover in the Dolly Varden Mountains typically ranges from about 10 percent to 50 percent, with some places along drainages and on high, north-facing slopes where vegetation cover approaches 100 percent. Sagebrush is found at less vegetated lower elevations, whereas pinon pine and juniper are prevalent above 2,000 meters. A variety of geologic materials is exposed in the study area. A sequence of Late Paleozoic and Triassic sedimentary rocks includes limestone, dolomite, chert, sandstone, siltstone and shale. A two-phase granitic stock, called the Melrose, intruded these rocks, resulting in metamorphism along the intrusive contact. Tertiary volcanic rocks cover most of the eastern part of the Dolly Varden Mountains and low-lying areas in the Currie Hills.

Zircon Hf-O isotopic constraints on the origin of Late Mesozoic felsic volcanic rocks from the Great Xing'an Range, NE China

NASA Astrophysics Data System (ADS)

Gong, Mingyue; Tian, Wei; Fu, Bin; Wang, Shuangyue; Dong, Jinlong

2018-05-01

The voluminous Late Mesozoic magmatism was related to extensive re-melting of juvenile materials that were added to the Central East Asia continent in Phanerozoic time. The most favoured magma generation mechanism of Late Mesozoic magmas is partial melting of underplated lower crust that had radiogenic Hf-Nd isotopic characteristics, but this mechanism faces difficulties when interpreting other isotopic data. The tectonic environment controlling the generation of the Late Mesozoic felsic magmas is also in dispute. In this study, we obtained new U-Pb ages, and geochemical and isotopic data of representative Jurassic (154.4 ± 1.5 Ma) and Cretaceous (140.2 ± 1.5 Ma) felsic volcanic samples. The Jurassic sample has inherited zircon cores of Permian age, with depleted mantle-like εHf(t) of +7.4 - +8.5, which is in contrast with those of the magmatic zircons (εHf(t) = +2.4 ± 0.7). Whereas the inherited cores and the magmatic zircons have identical mantle-like δ18O composition ranges (4.25-5.29‰ and 4.69-5.54‰, respectively). These Hf-O isotopic characteristics suggest a mixed source of enriched mantle materials rather than ancient crustal components and a depleted mantle source represented by the inherited Permian zircon core. This mechanism is manifested by the eruption of Jurassic alkaline basalts originated from an enriched mantle source. The Cretaceous sample has high εHf(t) of +7.0 - +10.5, suggesting re-melting of a mafic magma derived from a depleted mantle-source. However, the sub-mantle zircon δ18O values (3.70-4.58‰) suggest the depleted mantle-derived mafic source rocks had experienced high temperature hydrothermal alteration at upper crustal level. Therefore, the Cretaceous felsic magma, if not all, could be generated by re-melting of down-dropped supracrustal volcanic rocks that experienced high temperature oxygen isotope alteration. The two processes, enriched mantle-contribution and supracrustal juvenile material re-melting, are new

Presence of the dinosaur Scelidosaurus indicates Jurassic age for the Kayenta Formation (Glen Canyon Group, northern Arizona)

NASA Astrophysics Data System (ADS)

Padian, Kevin

1989-05-01

The Glen Canyon Group (Moenave, Wingate, Kayenta and Navajo Formations) of northern Arizona represents an extensive outcrop of early Mesozoic age terrestrial sediments. The age of these formations has long been disputed because independent stratigraphic data from marine tie-ins, paleobotanical and palynological evidence, and radiometric calibrations have been scanty or absent. The fauna of the Kayenta Formation in particular has been problematic because it has appeared to contain both typical Late Triassic and Early Jurassic taxa Here I report that the principal evidence for Late Triassic taxa, dermal scutes previously assigned to an aetosaur, in fact belongs to the thyreophoran ornithischian dinosaur Scelidosaurus, previously known only as a washed-in form found in marine sediments in the Early Jurassic of England. The presence of this dinosaur represents the first vertebrate biostratigraphic tie-in of the Glen Canyon Group horizons with reliably dated marine deposits in Europe. Together with revised systematic assessments of other vertebrates and independent evidence from fossil pollen, it supports an Early Jurassic age for the Kayenta Formation and most or all of the Glen Canyon Group.

Accessory Mineral Depth-Profiling Applied to the Corsican Lower Crust: A Continuous Thermal History of Mesozoic Continental Rifting

NASA Astrophysics Data System (ADS)

Seymour, N. M.; Stockli, D. F.; Beltrando, M.; Smye, A.

2015-12-01

Despite advances in understanding the structural development of hyperextended magma-poor rift margins, the temporal and thermal evolution of lithospheric hyperextension during rifting remains only poorly understood. In contrast to classic pure-shear models, multi-stage rift models that include depth-dependent thinning predict significant lower-crustal reheating during the necking phase due to buoyant rise of the asthenosphere. The Santa Lucia nappe of NE Corsica is an ideal laboratory to test for lower-crustal reheating as it preserves Permian lower crust exhumed from granulitic conditions during Mesozoic Tethyan rifting. This study presents the first use of apatite U-Pb depth-profile thermochronology in conjunction with novel rutile U-Pb and zircon U-Pb thermo- and geochronology to reconstruct a continuous t-T path to constrain the syn-rift thermal evolution of this exposed lower-crustal section. LASS-ICP-MS depth-profile analyses of zircon reveal thin (<10 μm) ~210-180 Ma overgrowths on 300-270 Ma cores in lower-crustal lithologies, indicative of renewed thermal activity during Mesozoic rifting. Cooling due to rapid rift margin exhumation is recorded by the topology of rutile and apatite depth profiles caused by thermally-activated volume diffusion at T >400°C. Lower-crustal rutile reveal a rounded progression from core plateaus at ~170 Ma to 150-145 Ma at the outer 8-10 μm of grains while middle-crustal apatite records 170 Ma cores grading to 140-135 Ma rims. Inverse modeling of rutile profiles suggests the lower crust cooled from 700°C at 200 Ma to 425°C at 140 Ma. Middle-crustal apatite yield a two-stage history, with rapid cooling from 500°C at 200 Ma to 420°C at ~180 Ma followed by slow cooling to 400°C by 160 Ma. Combined with zircon overgrowth ages, these data indicate the Santa Lucia nappe underwent a thermal pulse in the late Triassic-early Jurassic associated with depth-dependent thinning and hyperextension of the Corsican margin.

A Cretaceous eutriconodont and integument evolution in early mammals.

PubMed

Martin, Thomas; Marugán-Lobón, Jesús; Vullo, Romain; Martín-Abad, Hugo; Luo, Zhe-Xi; Buscalioni, Angela D

2015-10-15

The Mesozoic era (252-66 million years ago), known as the domain of dinosaurs, witnessed a remarkable ecomorphological diversity of early mammals. The key mammalian characteristics originated during this period and were prerequisite for their evolutionary success after extinction of the non-avian dinosaurs 66 million years ago. Many ecomorphotypes familiar to modern mammal fauna evolved independently early in mammalian evolutionary history. Here we report a 125-million-year-old eutriconodontan mammal from Spain with extraordinary preservation of skin and pelage that extends the record of key mammalian integumentary features into the Mesozoic era. The new mammalian specimen exhibits such typical mammalian features as pelage, mane, pinna, and a variety of skin structures: keratinous dermal scutes, protospines composed of hair-like tubules, and compound follicles with primary and secondary hairs. The skin structures of this new Mesozoic mammal encompass the same combination of integumentary features as those evolved independently in other crown Mammalia, with similarly broad structural variations as in extant mammals. Soft tissues in the thorax and abdomen (alveolar lungs and liver) suggest the presence of a muscular diaphragm. The eutriconodont has molariform tooth replacement, ossified Meckel's cartilage of the middle ear, and specialized xenarthrous articulations of posterior dorsal vertebrae, convergent with extant xenarthran mammals, which strengthened the vertebral column for locomotion.

Testing co-evolutionary hypotheses over geological timescales: interactions between Mesozoic non-avian dinosaurs and cycads.

PubMed

Butler, Richard J; Barrett, Paul M; Kenrick, Paul; Penn, Malcolm G

2009-02-01

The significance of co-evolution over ecological timescales is well established, yet it remains unclear to what extent co-evolutionary processes contribute to driving large-scale evolutionary and ecological changes over geological timescales. Some of the most intriguing and pervasive long-term co-evolutionary hypotheses relate to proposed interactions between herbivorous non-avian dinosaurs and Mesozoic plants, including cycads. Dinosaurs have been proposed as key dispersers of cycad seeds during the Mesozoic, and temporal variation in cycad diversity and abundance has been linked to dinosaur faunal changes. Here we assess the evidence for proposed hypotheses of trophic and evolutionary interactions between these two groups using diversity analyses, a new database of Cretaceous dinosaur and plant co-occurrence data, and a geographical information system (GIS) as a visualisation tool. Phylogenetic evidence suggests that the origins of several key biological properties of cycads (e.g. toxins, bright-coloured seeds) likely predated the origin of dinosaurs. Direct evidence of dinosaur-cycad interactions is lacking, but evidence from extant ecosystems suggests that dinosaurs may plausibly have acted as seed dispersers for cycads, although it is likely that other vertebrate groups (e.g. birds, early mammals) also played a role. Although the Late Triassic radiations of dinosaurs and cycads appear to have been approximately contemporaneous, few significant changes in dinosaur faunas coincide with the late Early Cretaceous cycad decline. No significant spatiotemporal associations between particular dinosaur groups and cycads can be identified - GIS visualisation reveals disparities between the spatiotemporal distributions of some dinosaur groups (e.g. sauropodomorphs) and cycads that are inconsistent with co-evolutionary hypotheses. The available data provide no unequivocal support for any of the proposed co-evolutionary interactions between cycads and herbivorous dinosaurs

Revisiting Mesozoic felsic intrusions in eastern South China: spatial and temporal variations and tectonic significance

NASA Astrophysics Data System (ADS)

Zhu, Kong-Yang; Li, Zheng-Xiang; Xia, Qun-Ke; Xu, Xi-Sheng; Wilde, Simon A.; Chen, Han-Lin

2017-12-01

Whole-rock and mineral geochemical data are used to place new constraints on the petrogenesis and tectonic setting of Mesozoic granitoids (including syenites) in eastern South China. In the Early Mesozoic, granitoids of variable compositions were intruded in the Cathaysia Block which by this time had developed a thickened and highly differentiated Paleoproterozoic crust through the influence of subduction. Late Triassic ( 225 Ma) syenites are significantly different from Jurassic-Cretaceous syenites in South China and from most trachytes (GEOROC database) in terms of their high Th/U, La/Nb and Gd/Yb ratios. Their low Rb contents, coupled with their high K/Rb and Nb/Ta, and low 87Sr/86Sr and 206Pb/204Pb ratios suggest a source that had undergone granulite-facies metamorphism at the base of thickened (> 45 km thick) continental crust where garnet and rutile are stable. The Late Triassic alkaline intrusions thus appear not to be related to continental rifting. Compared with the Late Triassic syenites, contemporaneous syenogranites have higher Ga/Al and Rb/K ratios and ISr values. Their Ga/Al ratios are positively correlated with ISr values, and their higher Ga/Al ratios likewise do not appear to be related to a rift setting but reflect the composition of the source. New Pb isotopic data from Cretaceous magmatic rocks reveal that 120-100 Ma I-type granitoids in Zhejiang Province were likely derived from mixing of three components: contemporaneous basaltic magma, an enriched crustal component and a depleted crustal component. Pb isotopes of both the I-type granitoids and the basalts become more radiogenic towards the coast, where the ca. 100 Ma intrusions dominate. Furthermore, zircon-melt partition of Ce and hornblende oxygen barometries indicate that the Early Cretaceous intrusions also became more oxidized towards the coast. In addition, the ca. 100 Ma granitoids have higher Gd/Yb and lower Fe/Mg ratios than those of the 120-110 Ma suite, implying crustal thickening

Tectono-sedimentary events and geodynamic evolution of the Mesozoic and Cenozoic basins of the Alpine Margin, Gulf of Tunis, north-eastern Tunisia offshore

NASA Astrophysics Data System (ADS)

Melki, Fetheddine; Zouaghi, Taher; Chelbi, Mohamed Ben; Bédir, Mourad; Zargouni, Fouad

2010-09-01

The structural pattern, tectono-sedimentary framework and geodynamic evolution for Mesozoic and Cenozoic deep structures of the Gulf of Tunis (north-eastern Tunisia) are proposed using petroleum well data and a 2-D seismic interpretation. The structural system of the study area is marked by two sets of faults that control the Mesozoic subsidence and inversions during the Paleogene and Neogene times: (i) a NE-SW striking set associated with folds and faults, which have a reverse component; and (ii) a NW-SE striking set active during the Tertiary extension episodes and delineating grabens and subsiding synclines. In order to better characterize the tectono-sedimentary evolution of the Gulf of Tunis structures, seismic data interpretations are compared to stratigraphic and structural data from wells and neighbouring outcrops. The Atlas and external Tell belonged to the southernmost Tethyan margin record a geodynamic evolution including: (i) rifting periods of subsidence and Tethyan oceanic accretions from Triassic until Early Cretaceous: we recognized high subsiding zones (Raja and Carthage domains), less subsiding zones (Gamart domain) and a completely emerged area (Raouad domain); (ii) compressive events during the Cenozoic with relaxation periods of the Oligocene-Aquitanian and Messinian-Early Pliocene. The NW-SE Late Eocene and Tortonian compressive events caused local inversions with sealed and eroded folded structures. During Middle to Late Miocene and Early Pliocene, we have identified depocentre structures corresponding to half-grabens and synclines in the Carthage and Karkouane domains. The north-south contractional events at the end of Early Pliocene and Late Pliocene periods are associated with significant inversion of subsidence and synsedimentary folded structures. Structuring and major tectonic events, recognized in the Gulf of Tunis, are linked to the common geodynamic evolution of the north African and western Mediterranean basins.

Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean

NASA Astrophysics Data System (ADS)

Zhang, Li-Yun; Ding, Lin; Pullen, Alex; Xu, Qiang; Liu, De-Liang; Cai, Fu-Long; Yue, Ya-Hui; Lai, Qing-Zhou; Shi, Ren-Deng; Ducea, Mihai N.; Kapp, Paul; Chapman, Alan

2014-03-01

A geologic investigation was undertaken in the Hoh-Xil-Songpan-Ganzi (HXSG) complex, northern Tibet in order to better understand magma genesis and evolution during the late stages of Paleo-Tethys ocean closure. The HXSG complex is composed of vast accumulations of Middle-Upper Triassic marine gravity flow deposits that were extensively intruded by igneous rocks. These early Mesozoic rocks exposed in this area record a rich history of accretionary tectonics during the amalgamation of the Tibetan Plateau terranes. Eight plutons sampled from the western HXSG complex yield zircon U-Pb ages that range from 225 to 193 Ma. Muscovite 40Ar/39Ar ages for the Hudongliang and Zhuonai Lake plutons yield ages of 210.7 ± 2.5 Ma and 212.7 ± 2.5 Ma, respectively. These plutonic rocks can be subdivided into two geochemically distinct groups. Group 1 (221-212 Ma: Dapeng Lake, Changhong Lake and Heishibei Lake plutons) is composed of high-K calc-alkaline rocks that have strongly fractionated REE patterns with high (La/Yb)N ratios (91-18) and generally lack Eu anomalies (Eu*/Eu = 1.02-0.68). Rocks in Group 1 display pronounced negative Nb-Ta and Ti anomalies on primitive mantle-normalized spidergrams. Group 1 rocks exhibit high Sr (782-240 ppm) and low Y (6.3-16.0 ppm) contents with high Sr/Y ratios (84-20). Based on Sr-Nd-Hf isotopic data (87Sr/86Sri = 0.7079-0.7090, ɛNd(t) = - 7.7-- 4.7, ɛHf(t) = - 5.7-- 0.8) and low MgO contents (MgO = 1.10-2.18%), Group 1 rocks are geochemically similar to adakitic rocks and were probably derived from partial melting of the downgoing Paleo-Tethys oceanic slab and overlying marine sediments. Group 2 plutons (225-193 Ma: Daheishan, Yunwuling, Zhuonai Lake, Malanshan and Hudongliang plutons) display lower P2O5 with increasing SiO2 and are medium-K to high-K I-type calc-alkaline bodies with low Sr (14-549 ppm) and high Y (22.3-10.5 ppm) contents. Group 2 rocks have variable fractionated REE patterns ((La/Yb)N = 3-38) and negative Eu anomalies (Eu

Exhumation history of the West Kunlun Mountains, northwestern Tibet: Evidence for a long-lived, rejuvenated orogen

NASA Astrophysics Data System (ADS)

Cao, Kai; Wang, Guo-Can; Bernet, Matthias; van der Beek, Peter; Zhang, Ke-Xin

2015-12-01

How and when the northwestern Tibetan Plateau originated and developed upon pre-existing crustal and topographic features is not well understood. To address this question, we present an integrated analysis of detrital zircon U-Pb and fission-track double dating of Cenozoic synorogenic sediments from the Kekeya and Sanju sections in the southwestern Tarim Basin. These data help establishing a new chronostratigraphic framework for the Sanju section and confirm a recent revision of the chronostratigraphy at Kekeya. Detrital zircon fission-track ages present prominent Triassic-Early Jurassic (∼250-170 Ma) and Early Cretaceous (∼130-100 Ma) static age peaks, and Paleocene-Early Miocene (∼60-21 Ma) to Eocene-Late Miocene (∼39-7 Ma) moving age peaks, representing source exhumation. Triassic-Early Jurassic static peak ages document unroofing of the Kunlun terrane, probably related to the subduction of Paleotethys oceanic lithosphere. In combination with the occurrence of synorogenic sediments on both flanks of the Kunlun terrane, these data suggest that an ancient West Kunlun range had emerged above sea level by Triassic-Early Jurassic times. Early Cretaceous fission-track peak ages are interpreted to document exhumation related to thrusting along the Tam Karaul fault, kinematically correlated to the Main Pamir thrust further west. Widespread Middle-Late Mesozoic crustal shortening and thickening likely enhanced the Early Mesozoic topography. Paleocene-Early Eocene fission-track peak ages are presumably partially reset. Limited regional exhumation indicates that the Early Cenozoic topographic and crustal pattern of the West Kunlun may be largely preserved from the Middle-Late Mesozoic. The Main Pamir-Tam Karaul thrust belt could be a first-order tectonic feature bounding the northwestern margin of the Middle-Late Mesozoic to Early Cenozoic Tibetan Plateau. Toward the Tarim basin, Late Oligocene-Early Miocene steady exhumation at a rate of ∼0.9 km/Myr is likely

Functional Morphometric Analysis of the Furcula in Mesozoic Birds

PubMed Central

Close, Roger A.; Rayfield, Emily J.

2012-01-01

The furcula displays enormous morphological and structural diversity. Acting as an important origin for flight muscles involved in the downstroke, the form of this element has been shown to vary with flight mode. This study seeks to clarify the strength of this form-function relationship through the use of eigenshape morphometric analysis coupled with recently developed phylogenetic comparative methods (PCMs), including phylogenetic Flexible Discriminant Analysis (pFDA). Additionally, the morphospace derived from the furculae of extant birds is used to shed light on possible flight adaptations of Mesozoic fossil taxa. While broad conclusions of earlier work are supported (U-shaped furculae are associated with soaring, strong anteroposterior curvature with wing-propelled diving), correlations between form and function do not appear to be so clear-cut, likely due to the significantly larger dataset and wider spectrum of flight modes sampled here. Interclavicular angle is an even more powerful discriminator of flight mode than curvature, and is positively correlated with body size. With the exception of the close relatives of modern birds, the ornithuromorphs, Mesozoic taxa tend to occupy unique regions of morphospace, and thus may have either evolved unfamiliar flight styles or have arrived at similar styles through divergent musculoskeletal configurations. PMID:22666324

Multiple Emplacement and Exhumation History of the Late Mesozoic Dayunshan-Mufushan Batholith in Southeast China and Its Tectonic Significance: 2. Magnetic Fabrics and Gravity Survey

NASA Astrophysics Data System (ADS)

Ji, Wenbin; Chen, Yan; Chen, Ke; Wei, Wei; Faure, Michel; Lin, Wei

2018-01-01

The Late Mesozoic magmatic province is a prominent feature of the South China Block (SCB). However, the tectonic regimes associated with the magmatism are still elusive. A combined anisotropy of magnetic susceptibility and gravity study has been carried out to determine the fabric patterns and shape at depth of the Dayunshan-Mufushan composite batholith in the north-central SCB. This is a companion paper to Part 1 that presented the structural and geochronological data of this batholith. The magnetic fabrics in the batholith interior predominantly reflect magma flow structures. Two distinct patterns of the magnetic lineations are defined, around NNE-SSW and WNW-ESE trends for the early-stage and late-stage intrusions of the batholith, respectively. The gravity survey reveals that the early-stage intrusion has a main feeder zone located below its northern part, while several linear feeder zones trending NNE-SSW are inferred for the late-stage intrusion. Integrating all results, a two-stage construction of the batholith with distinct tectonic regimes has been established. It is concluded that the early-stage intrusion experienced a southward magma transport during its emplacement, partially assisted by far-field compression from the north at ca. 150 Ma. Conversely, the emplacement and exhumation of the late-stage intrusion was accommodated by a NW-SE crustal stretching involving a lateral magma expansion above the multiple feeder zones (likely corresponding to extensional fractures) and ductile shearing during 132-95 Ma localized mainly along the Dayunshan detachment fault. Finally, we discuss the geodynamic linkage between the paleo-Pacific subduction and the Late Mesozoic tectonomagmatism in the SCB.

100-million-year dynasty of giant planktivorous bony fishes in the Mesozoic seas.

PubMed

Friedman, Matt; Shimada, Kenshu; Martin, Larry D; Everhart, Michael J; Liston, Jeff; Maltese, Anthony; Triebold, Michael

2010-02-19

Large-bodied suspension feeders (planktivores), which include the most massive animals to have ever lived, are conspicuously absent from Mesozoic marine environments. The only clear representatives of this trophic guild in the Mesozoic have been an enigmatic and apparently short-lived Jurassic group of extinct pachycormid fishes. Here, we report several new examples of these giant bony fishes from Asia, Europe, and North America. These fossils provide the first detailed anatomical information on this poorly understood clade and extend its range from the lower Middle Jurassic to the end of the Cretaceous, showing that this group persisted for more than 100 million years. Modern large-bodied, planktivorous vertebrates diversified after the extinction of pachycormids at the Cretaceous-Paleogene boundary, which is consistent with an opportunistic refilling of vacated ecospace.

Re-Os isotope evidence from Mesozoic and Cenozoic basalts for secular evolution of the mantle beneath the North China Craton

NASA Astrophysics Data System (ADS)

Huang, Feng; Xu, Ji-Feng; Liu, Yong-Sheng; Li, Jie; Chen, Jian-Lin; Li, Xi-Yao

2017-05-01

The mechanism and process of lithospheric thinning beneath the North China Craton (NCC) are still debated. A key criterion in distinguishing among the proposed mechanisms is whether associated continental basalts were derived from the thinning lithospheric mantle or upwelling asthenosphere. Herein, we investigate the possible mechanisms of lithospheric thinning based on a systematic Re-Os isotopic study of Mesozoic to Cenozoic basalts from the NCC. Our whole-rock Re-Os isotopic results indicate that the Mesozoic basalts generally have high Re and Os concentrations that vary widely from 97.2 to 839.4 ppt and 74.4 to 519.6 ppt, respectively. They have high initial 187Os/188Os ratios ranging from 0.1513 to 0.3805, with corresponding variable γOs(t) values (+20 to +202). In contrast, the Re-Os concentrations and radiogenic Os isotope compositions of the Cenozoic basalts are typically lower than those of the Mesozoic basalts. The lowest initial 187Os/188Os ratios of the Cenozoic basalts are 0.1465 and 0.1479, with corresponding γOs(t) values of +15 and +16, which are within the range of ocean island basalts. These new Re-Os isotopic results, combined with the findings of previous studies, indicate that the Mesozoic basalts were a hybrid product of the melting of pyroxenite and peridotite in ancient lithospheric mantle beneath the NCC. The Cenozoic basalts were derived mainly from upwelling asthenosphere mixed with small amounts of lithospheric materials. The marked differences in geochemistry between the Mesozoic and Cenozoic basalts suggest a greatly reduced involvement of lithospheric mantle as the magma source from the Mesozoic to the Cenozoic. The subsequent lithospheric thinning of the NCC and replacement by upwelling asthenospheric mantle resulted in a change to asthenosphere-derived Cenozoic basalts.

Tertiary or Mesozoic komatiites from Gorgona Island, Colombia: Field relations and geochemistry

NASA Astrophysics Data System (ADS)

Echeverría, Lina M.

1980-08-01

An exceptional occurrence of ultramafic lavas within the volcanic member of the Mesozoic (or younger) Gorgona Igneous Complex represents the first known komatiites of post-Precambrian age. Gorgona komatiites are virtually unaltered and display typical spinifex textures, with 7 10 cm long plates of olivine (Fo 88 to 91) surrounded by acicular aluminous augite, subordinate plagioclase (An 56 to 78), basaltic glass, and two spinel phases. The MgO contents of the komatiites range from 15 to 22 wt.%. Sr and Nd isotopic compositions are indicative of depletion of incompatible elements in the mantle source region, as is the case for “normal” mid-ocean ridge basalts. The komatiites are low in total REE abundances and extremely depleted in LREE. They represent primary melts generated by high degree of partial melting of the mantle. Eruption temperatures are estimated at 1,450° to 1,500° C.

Comparison of clay mineral stratigraphy to other proxy palaeoclimate indicators in the Mesozoic of NW Europe.

PubMed

Ruffell, Alastair; McKinley, Jennifer M; Worden, Richard H

2002-04-15

This paper reviews the opportunities and pitfalls associated with using clay mineralogical analysis in palaeoclimatic reconstructions. Following this, conjunctive methods of improving the reliability of clay mineralogical analysis are reviewed. The Mesozoic succession of NW Europe is employed as a case study. This demonstrates the relationship between clay mineralogy and palaeoclimate. Proxy analyses may be integrated with clay mineralogical analysis to provide an assessment of aridity-humidity contrasts in the hinterland climate. As an example, the abundance of kaolinite through the Mesozoic shows that, while interpretations may be difficult, the Mesozoic climate of NW Europe was subject to great changes in rates of continental precipitation. We may compare sedimentological (facies, mineralogy, geochemistry) indicators of palaeoprecipitation with palaeotemperature estimates. The integration of clay mineralogical analyses with other sedimentological proxy indicators of palaeoclimate allows differentiation of palaeoclimatic effects from those of sea-level and tectonic change. We may also observe how widespread palaeoclimate changes were; whether they were diachronous or synchronous; how climate, sea level and tectonics interact to control sedimentary facies and what palaeoclimate indicators are reliable.

Mesozoic Compressional Folds of the Nansha Waters, Southern South China Sea

NASA Astrophysics Data System (ADS)

Zhu, R.; Liu, H.; Yao, Y.; Wang, Y.

2017-12-01

As an important part of the South China Sea, the southern margin of the South China Sea is fundamental to understand the interaction of the Eurasian, Pacific and Indian-Australian plates and the evolution of the South China Sea. Some multi-channel seismic profiles of the Nansha waters together with published drillings and dredge data were correlated for interpretation. The strata of the study region can be divided into the upper, middle and lower structural layers. The upper and middle structural layers with extensional tectonics are Cenozoic; the lower structural layer suffered compression is Mesozoic. Further structural restoration was done to remove the Cenozoic tectonic influence and to calculate the Mesozoic tectonic compression ratios. The results indicate that two diametrically opposite orientations of compressive stress, S(S)E towards N(N)W orientation and N(N)W towards S(S)E orientation respectively, once existed in the lower structural layer of the study area and shared the same variation trend. The compression ratio values gradually decrease both from the north to the south and from the west to the east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate of the Nansha block drifted northward in Late Jurassic to Late Cretaceous, which had pushed the Nansha block drifted northward until it collided and sutured with the Southern China Margin. Thus the opening of the present-day South China Sea may be related to this suture zone, which was tectonically weakness zone.Key words: Mesozoic compression; structural restoration; proto-South China Sea; Nansha waters; Southern South China Sea; Acknowledgements: The work was granted by the National Natural Science Foundation of China (Grant Nos. 41476039, 91328205, 41576068 and 41606080).

Geochemistry, 40Ar/39Ar geochronology, and geodynamic implications of Early Cretaceous basalts from the western Qinling orogenic belt, China

NASA Astrophysics Data System (ADS)

Zhang, Feifei; Wang, Yuejun; Cawood, Peter A.; Dong, Yunpeng

2018-01-01

The Qinling-Dabie orogenic belt was formed by the collision of the North and South China Cratons during the Early Mesozoic and subsequently developed into an intracontinental tectonic process during late Mesozoic. Field investigations identified the presence of late Mesozoic basalts in the Duofutun and Hongqiang areas in the western Qinling orogenic belt. The petrogenesis of these basalts provides an important constraint on the late Mesozoic geodynamics of the orogen. The representative basaltic samples yield the 40Ar/39Ar plateau age of about 112 Ma. These samples belong to the alkaline series and have SiO2 ranging from 44.98 wt.% to 48.19 wt.%, Na2O + K2O from 3.44 wt% to 5.44 wt%, and MgO from 7.25 wt.% to 12.19 wt.%. They demonstrate the right-sloping chondrite-normalized REE patterns with negligible Eu anomalies (1.00-1.10) and PM-normalized patterns enriched in light rare earth element, large ion lithophile element and high field strength element, similar to those of OIB rocks. These samples additionally show an OIB-like Sr-Nd isotopic signature with εNd(t) values ranging from +6.13 to +10.15 and initial 87Sr/86Sr ratios from 0.7028 to 0.7039, respectively. These samples are geochemically subdivided into two groups. Group 1 is characterized by low Al2O3 and high TiO2 and P2O5 contents, as well as high La/Yb ratios (>20), being the product of the high-pressure garnet fractionation from the OIB-derived magma. Group 2 shows higher Al2O3 but lower P2O5 contents and La/Yb ratios (<20) than Group 1, originating from asthenospheric mantle with input of delaminated lithospheric component. In combination with available data, it is proposed for the petrogenetic model of the Early Cretaceous thickened lithospheric delamination in response to the asthenospheric upwelling along the western Qinling orogenic belt.

Early paleozoic gabbro-amphibolites in the structure of the Bureya Terrane (eastern part of the Central Asian Fold Belt): First geochronological data and tectonic position

NASA Astrophysics Data System (ADS)

Smirnov, Yu. V.; Sorokin, A. A.; Kudryashov, N. M.

2012-07-01

Resulting from U-Pb geochronological study, it has been found that the gabbro-amphibolites composing the Bureya (Turan) Terrane in the eastern part of the Central Asian Fold Belt are Early Paleozoic (Early Ordovician; 455 ± 1.5 Ma) in age rather than Late Proterozoic as was believed earlier. The gabbro-amphibolites and associated metabasalts are close to tholeiites of the intraoceanic island arcs in terms of the geochemical properties. It is suggested that the tectonic block composed of these rocks was initially a seafloor fragment that divided the Bureya and Argun terranes in the Early Paleozoic and was later tectonically incorporated into the modern structure of the Bureya Terrane as a result of Late Paleozoic and Mesozoic events.

Provenance of Mesozoic clastic rocks within the Bangong-Nujiang suture zone, central Tibet: Implications for the age of the initial Lhasa-Qiangtang collision

NASA Astrophysics Data System (ADS)

Li, Shun; Guilmette, Carl; Ding, Lin; Xu, Qiang; Fu, Jia-Jun; Yue, Ya-Hui

2017-10-01

The Bangong-Nujiang suture zone, separating the Lhasa and Qiangtang blocks of the Tibetan Plateau, is marked by remnants of the Bangong-Nujiang oceanic basin. In the Gaize area of central Tibet, Mesozoic sedimentary strata recording the evolution of the basin and subsequent collision between these two blocks include the Upper Triassic-Lower Jurassic turbidites of the Mugagangri Group, the Upper Jurassic-Lower Cretaceous sandstone-dominated Wuga and Shamuluo formations, and the Upper Cretaceous molasse deposits of the Jingzhushan Formation. The Shamuluo and Jingzhushan formations rest unconformably on the underlying Mugagangri Group and Wuga Formation, respectively. In this contribution, we analyze petrographic components of sandstones and U-Pb-Hf isotopic compositions of detrital zircons from the Wuga and Jingzhushan formations for the first time. Based on the youngest detrital zircon ages, the maximum depositional ages of the Wuga and Jingzhushan formations are suggested to be ∼147-150 Ma and ∼79-91 Ma, respectively. Petrographic and isotopic results indicate that sediments in the Wuga Formation were mainly sourced from the accretionary complex (preserved as the Mugagangri Group) in the north, while sediments in the Jingzhushan Formation have mixed sources from the Lhasa block, the Qiangtang block and the intervening suture zone. Provenance analysis, together with regional data, suggests that the Upper Jurassic-Lower Cretaceous Wuga and Shamuluo formations were deposited in a peripheral foreland basin and a residual-sea basin, respectively, in response to the Lhasa-Qiangtang collision, whereas the Upper Cretaceous Jingzhushan Formation reflects continental molasse deposition during the post-collisional stage. The development of the peripheral foreland basin evidenced by deposition of the Wuga Formation reveals that the age of the initial Lhasa-Qiangtang collision might be the latest Jurassic (∼150 Ma).

Phanerozoic polyphase orogenies recorded in the northeastern Okcheon Belt, Korea from SHRIMP U-Pb detrital zircon and K-Ar illite geochronologies

NASA Astrophysics Data System (ADS)

Jang, Yirang; Kwon, Sanghoon; Song, Yungoo; Kim, Sung Won; Kwon, Yi Kyun; Yi, Keewook

2018-05-01

We present the SHRIMP U-Pb detrital zircon and K-Ar illite 1Md/1M and 2M1 ages, suggesting new insight into the Phanerozoic polyphase orogenies preserved in the northeastern Okcheon Belt, Korea since the initial basin formation during Neoproterozoic rifting through several successive contractional orogens. The U-Pb detrital zircon ages from the Early Paleozoic strata of the Taebaeksan Zone suggest a Cambrian maximum deposition age, and are supported by trilobite and conodont biostratigraphy. Although the age spectra from two sedimentary groups, the Yeongwol and Taebaek Groups, show similar continuous distributions from the Late Paleoproterozoic to Early Paleozoic ages, a Grenville-age hiatus (1.3-0.9 Ga) in the continuous stratigraphic sequence from the Taebaek Group suggests the existence of different peripheral clastic sources along rifted continental margin(s). In addition, we present the K-Ar illite 1Md/1M ages of the fault gouges, which confirm fault formation/reactivation during the Late Cretaceous to Early Paleogene (ca. 82-62 Ma) and the Early Miocene (ca. 20-18 Ma). The 2M1 illite ages, at least those younger than the host rock ages, provide episodes of deformation, metamorphism and hydrothermal effects related to the tectonic events during the Devonian (ca.410 Ma) and Permo-Triassic (ca. 285-240 Ma). These results indicate that the northeastern Okcheon Belt experienced polyphase orogenic events, namely the Okcheon (Middle Paleozoic), Songrim (Late Paleozoic to Early Mesozoic), Daebo (Middle Mesozoic) and Bulguksa (Late Mesozoic to Early Cenozoic) Orogenies, reflecting the Phanerozoic tectonic evolution of the Korean Peninsula along the East Asian continental margin.

Constraints from Mesozoic siliciclastic cover rocks and satellite image analysis on the slip history of regional E-W faults in the southeast Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Tewksbury, Barbara J.; Mehrtens, Charlotte J.; Gohlke, Steven A.; Tarabees, Elhamy A.; Hogan, John P.

2017-12-01

In the southeast Western Desert of Egypt, a prominent set of E-W faults and co-located domes and basins involve sedimentary cover rock as young as the early Eocene. Although earlier Mesozoic slip on faults in southern Egypt has been widely mentioned in the literature and attributed to repeated reactivation of basement faults, evidence is indirect and based on the idea that regional stresses associated with tectonic events in the Syrian Arc would likely have reactivated basement faults in south Egypt in dextral strike slip during the Mesozoic as well as the Cenozoic. Here, we present direct evidence from the rock record for the sequence of development of features along these faults. Southwest of Aswan, a small structural dome in Mesozoic Nubia facies rocks occurs where the Seiyal Fault bends northward from west to east. The dome is cut by strands of the Seiyal Fault and a related set of cataclastic deformation bands showing dominantly right lateral strike slip, as well as by younger calcite veins with related patchy poikilotopic cement. High resolution satellite image analysis of the remote southwest Kharga Valley shows a similar sequence of events: older structural domes and basins located where E-W faults bend northward from west to east, right lateral offset of domes and basins along the E-W faults, and two sets of deformation band faults that lack co-located domes and basins. We suggest that field data, image analysis, and burial depth estimates are best explained by diachronous development of features along the E-W fault system. We propose that Late Mesozoic right lateral strike slip produced domes and basins in Nubia facies rocks in stepover regions above reactivated basement faults. We further suggest that the extensively linked segments of the E-W fault system in Nubia facies rocks, plus the deformation band systems, formed during the late Eocene when basement faults were again reactivated in dominantly right lateral strike slip.

Subduction history of the Paleo-Pacific plate beneath the Eurasian continent: Evidence from Mesozoic igneous rocks and accretionary complex in NE Asia

NASA Astrophysics Data System (ADS)

Xu, W.

2015-12-01

Mesozoic magmatisms in NE China can be subdivided into seven stages, i.e., Late Triassic, Early Jurassic, Middle Jurassic, Late Jurassic, early Early Cretaceous, late Early Cretaceous, and Late Cretaceous. Late Triassic magmatisms consist of calc-alkaline igneous rocks in the Erguna Massif, and bimodal igneous rocks in eastern margin of Eurasian continent. The former reveals southward subduction of the Mongol-Okhotsk oceanic plate, the latter reveals an extensional environment (Xu et al., 2013). Early Jurassic magmatisms are composed of calc-alkaline igneous rocks in the eastern margin of the Eurasian continent and the Erguna Massif, revealing westward subduction of the Paleo-pacific plate and southward subduction of the Mongol-Okhotsk oceanic plate (Tang et al., 2015), respectively. Middle Jurassic magmatism only occur in the Great Xing'an Range and the northern margin of the NCC, and consists of adakitic rocks that formed in crustal thickening, reflecting the closure of the Mongol-Okhotsk ocean (Li et al., 2015). Late Jurassic and early Early Cretaceous magmatisms only occur to the west of the Songliao Basin, and consist of trackyandesite and A-type of rhyolites, revealing an extensional environment related to delamination of thickened crust. The late Early Cretaceous magmatisms are widespread in NE China, and consist of calc-alkaline volcanics in eastern margin and bimodal volcanics in intracontinent, revealing westward subduction of the Paleo-pacific plate. Late Cretaceous magmatisms mainly occur to the east of the Songliao Basin, and consist of calc-alkaline volcanics in eastern margin and alkaline basalts in intracontinent (Xu et al., 2013), revealing westward subduction of the Paleo-pacific plate. The Heilongjiang complex with Early Jurassic deformation, together with Jurassic Khabarovsk complex in Russia Far East and Mino-Tamba complex in Japan, reveal Early Jurassic accretionary history. Additionally, the Raohe complex with the age of ca. 169 Ma was

Early Executive Function at Age Two Predicts Emergent Mathematics and Literacy at Age Five

PubMed Central

Mulder, Hanna; Verhagen, Josje; Van der Ven, Sanne H. G.; Slot, Pauline L.; Leseman, Paul P. M.

2017-01-01

Previous work has shown that individual differences in executive function (EF) are predictive of academic skills in preschoolers, kindergartners, and older children. Across studies, EF is a stronger predictor of emergent mathematics than literacy. However, research on EF in children below age three is scarce, and it is currently unknown whether EF, as assessed in toddlerhood, predicts emergent academic skills a few years later. This longitudinal study investigates whether early EF, assessed at two years, predicts (emergent) academic skills, at five years. It examines, furthermore, whether early EF is a significantly stronger predictor of emergent mathematics than of emergent literacy, as has been found in previous work on older children. A sample of 552 children was assessed on various EF and EF-precursor tasks at two years. At age five, these children performed several emergent mathematics and literacy tasks. Structural Equation Modeling was used to investigate the relationships between early EF and academic skills, modeled as latent factors. Results showed that early EF at age two was a significant and relatively strong predictor of both emergent mathematics and literacy at age five, after controlling for receptive vocabulary, parental education, and home language. Predictive relations were significantly stronger for mathematics than literacy, but only when a verbal short-term memory measure was left out as an indicator to the latent early EF construct. These findings show that individual differences in emergent academic skills just prior to entry into the formal education system can be traced back to individual differences in early EF in toddlerhood. In addition, these results highlight the importance of task selection when assessing early EF as a predictor of later outcomes, and call for further studies to elucidate the mechanisms through which individual differences in early EF and precursors to EF come about. PMID:29075209

Early Executive Function at Age Two Predicts Emergent Mathematics and Literacy at Age Five.

PubMed

Mulder, Hanna; Verhagen, Josje; Van der Ven, Sanne H G; Slot, Pauline L; Leseman, Paul P M

2017-01-01

Previous work has shown that individual differences in executive function (EF) are predictive of academic skills in preschoolers, kindergartners, and older children. Across studies, EF is a stronger predictor of emergent mathematics than literacy. However, research on EF in children below age three is scarce, and it is currently unknown whether EF, as assessed in toddlerhood, predicts emergent academic skills a few years later. This longitudinal study investigates whether early EF, assessed at two years, predicts (emergent) academic skills, at five years. It examines, furthermore, whether early EF is a significantly stronger predictor of emergent mathematics than of emergent literacy, as has been found in previous work on older children. A sample of 552 children was assessed on various EF and EF-precursor tasks at two years. At age five, these children performed several emergent mathematics and literacy tasks. Structural Equation Modeling was used to investigate the relationships between early EF and academic skills, modeled as latent factors. Results showed that early EF at age two was a significant and relatively strong predictor of both emergent mathematics and literacy at age five, after controlling for receptive vocabulary, parental education, and home language. Predictive relations were significantly stronger for mathematics than literacy, but only when a verbal short-term memory measure was left out as an indicator to the latent early EF construct. These findings show that individual differences in emergent academic skills just prior to entry into the formal education system can be traced back to individual differences in early EF in toddlerhood. In addition, these results highlight the importance of task selection when assessing early EF as a predictor of later outcomes, and call for further studies to elucidate the mechanisms through which individual differences in early EF and precursors to EF come about.

Early Children's Literature and Aging

ERIC Educational Resources Information Center

McGuire, Sandra L.

2016-01-01

Increased longevity is a worldwide phenomenon placing emphasis on the need for preparation for life's later years. Today's children will be the older adults of tomorrow. A resource that can help to educate them about aging and prepare them for the long life ahead is early children's literature (Preschool-Primary). This literature can provide…

Late Pan-African and early Mesozoic brittle compressions in East and Central Africa: lithospheric deformation within the Congo-Tanzania Cratonic area

NASA Astrophysics Data System (ADS)

Delvaux, D.; Kipata, M. L.; Macheyeki, A. S.

2012-04-01

Tectonic reconstructions leading to the formation of the Central-African part of Gondwana have so far not much taken into account constraints provided by the evolution of brittle structures and related stress field. This is largely because little is known on continental brittle deformation in Equatorial Africa before the onset of the Mesozoic Central-African and Late Cenozoic East-African rifts. We present a synthesis of fault-kinematic data and paleostress inversion results from field surveys covering parts of Tanzania, Zambia and the Democratic Republic of Congo. It is based on investigations along the eastern margin of the Tanzanian craton, in the Ubendian belt between the Tanzanian craton and Bangweulu block, in the Lufilian Arc between the Kalahari and Congo cratons and along the Congo intracratonic basin. Paleostress tensors were computed for a substantial database by interactive stress tensor inversion and data subset separation, and the relative succession of major brittle events established. Two of them appear to be of regional importance and could be traced from one region to the other. The oldest one is the first brittle event recorded after the paroxysm of the Terminal Pan-African event that led to the amalgamation Gondwana at the Precambrian-Cambrian transition. It is related to compressional deformation with horizontal stress trajectories fluctuating from an E-W compression in Central Tanzania to NE-SW in the Ubende belt and Lufilian Arc. The second event is a transpressional inversion with a consistent NW-SE compression that we relate to the far-field effects of the active margin south of Gondwana during the late Triassic - early Jurassic.

Organic geochemistry, lithology, and paleontology of Tertiary and Mesozoic rocks from wells on the Alaska Peninsula

USGS Publications Warehouse

McLean, Hugh James

1977-01-01

Core chips and drill cuttings from eight of the nine wells drilled along the Bering Sea lowlands of the Alaska Peninsula were subjected to lithologic and paleontologic analyses. Results suggest that at least locally, sedimentary rocks of Tertiary age contain oil and gas source and reservoir rocks capable of generating and accumulating liquid and gas hydrocarbons. Paleogene strata rich in organic carbon are immature. However, strata in offshore basins to the north and south may have been subjected to a more productive thermal environment. Total organic carbon content of fine grained Neogene strata appears to be significantly lower than in Paleogene rocks, possibly reflecting nonmarine or brackish water environments of deposition. Neogene sandstone beds locally yield high values of porosity and permeability to depths of about 8,000 feet (2,439 m). Below this depth, reservoir potential rapidly declines. The General Petroleum, Great Basins No. 1 well drilled along the shore of Bristol Bay reached granitic rocks. Other wells drilled closer to the axis of the present volcanic arc indicate that both Tertiary and Mesozoic sedimentary rocks have been intruded by dikes and sills of andesite and basalt. Although the Alaska Peninsula has been the locus of igneous activity throughout much of Mesozoic and Tertiary time, thermal maturity indicators such as vitrinite reflectance and coal rank suggest, that on a regional scale, sedimentary rocks have not been subjected to abnormally high geothermal gradients.

Mongolian Oil Shale, hosted in Mesozoic Sedimentary Basins

NASA Astrophysics Data System (ADS)

Bat-Orshikh, E.; Lee, I.; Norov, B.; Batsaikhan, M.

2016-12-01

Mongolia contains several Mesozoic sedimentary basins, which filled >2000 m thick non-marine successions. Late Triassic-Middle Jurassic foreland basins were formed under compression tectonic conditions, whereas Late Jurassic-Early Cretaceous rift valleys were formed through extension tectonics. Also, large areas of China were affected by these tectonic events. The sedimentary basins in China host prolific petroleum and oil shale resources. Similarly, Mongolian basins contain hundreds meter thick oil shale as well as oil fields. However, petroleum system and oil shale geology of Mongolia remain not well known due to lack of survey. Mongolian oil shale deposits and occurrences, hosted in Middle Jurassic and Lower Cretaceous units, are classified into thirteen oil shale-bearing basins, of which oil shale resources were estimated to be 787 Bt. Jurassic oil shale has been identified in central Mongolia, while Lower Cretaceous oil shale is distributed in eastern Mongolia. Lithologically, Jurassic and Cretaceous oil shale-bearing units (up to 700 m thick) are similar, composed mainly of alternating beds of oil shale, dolomotic marl, siltstone and sandstone, representing lacustrine facies. Both Jurassic and Cretaceous oil shales are characterized by Type I kerogen with high TOC contents, up to 35.6% and low sulfur contents ranging from 0.1% to 1.5%. Moreover, S2 values of oil shales are up to 146 kg/t. The numbers indicate that the oil shales are high quality, oil prone source rocks. The Tmax values of samples range from 410 to 447, suggesting immature to early oil window maturity levels. PI values are consistent with this interpretation, ranging from 0.01 to 0.03. According to bulk geochemistry data, Jurassic and Cretaceous oil shales are identical, high quality petroleum source rocks. However, previous studies indicate that known oil fields in Eastern Mongolia were originated from Lower Cretaceous oil shales. Thus, further detailed studies on Jurassic oil shale and its

Reinterpretation of Mesozoic and Cenozoic tectonic events, Mountain Pass area, northeastern San Bernardino County, California

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

Nance, M.A.

1993-04-01

Detailed mapping, stratigraphic structural analysis in the Mountain Pass area has resulted in a reinterpretation of Mesozoic and Cenozoic tectonic events in the area. Mesozoic events are characterized by north vergent folds and thrust faults followed by east vergent thrusting. Folding created two synclines and an anticline which were than cut at different stratigraphic levels by subsequent thrust faults. Thrusting created composite tectono-stratigraphic sections containing autochthonous, para-autothonous, and allochthonous sections. Normal faults cutting these composite sections including North, Kokoweef, White Line, and Piute fault must be post-thrusting, not pre-thrusting as in previous interpretations. Detailed study of these faults results inmore » differentiation of at least three orders of faults and suggest they represent Cenozoic extension correlated with regional extensional events between 11 and 19 my. Mesozoic stratigraphy reflects regional orogenic uplift, magmatic activity, and thrusting. Inclusion of Kaibab clasts in the Chinle, Kaibab and Chinle clasts in the Aztec, and Chinle, Aztec, and previously deposited Delfonte Volcanics clasts in the younger members of the Delfonte Volcanics suggest regional uplift prior to the thrusting of Cambrian Bonanza King over Delfonte Volcanics by the Mescal Thrust fault. The absence of clasts younger than Kaibab argues against pre-thrusting activity for the Kokoweef fault.« less

Children of Two to Three Years of Age in France: Early Childhood Settings and Age Divisions

ERIC Educational Resources Information Center

Garnier, Pascale; Rayna, Sylvie; Brougère, Gilles; Rupin, Pablo

2017-01-01

In a French early childhood care and education system that is strongly divided by age and institution, the current research studies the collective life of children at the pivotal age of two to three years of age in four different early childhood settings: (1) a group of "grands" (nursery) in a "crèche" (daycare centre), (2) a…

Successful Aging: Early Influences and Contemporary Characteristics

ERIC Educational Resources Information Center

Pruchno, Rachel A.; Wilson-Genderson, Maureen; Rose, Miriam; Cartwright, Francine

2010-01-01

Purpose: Positing that successful aging has independent, yet related, dimensions that are both objective and subjective, we examine how early influences and contemporary characteristics define 4 groups of people. Design and Methods: Data were gathered from 5,688 persons aged 50-74 years living in New Jersey who participated in telephone…

Paleomagnetic Constraints on the Tectonic History of the Mesozoic Ophiolite and Arc Terranes of Western Mexico

NASA Astrophysics Data System (ADS)

Boschman, L.; Van Hinsbergen, D. J. J.; Langereis, C. G.; Molina-Garza, R. S.; Kimbrough, D. L.

2017-12-01

The North American Cordillera has been shaped by a long history of accretion of arcs and other buoyant crustal fragments to the western margin of the North American Plate since the Early Mesozoic. Accretion of these terranes resulted from a complex tectonic history interpreted to include episodes of both intra-oceanic subduction within the Panthalassa/Pacific Ocean, as well as continental margin subduction along the western margin of North America. Western Mexico, at the southern end of the Cordillera, contains a Late Cretaceous-present day long-lived continental margin arc, as well as Mesozoic arc and SSZ ophiolite assemblages of which the origin is under debate. Interpretations of the origin of these subduction-related rock assemblages vary from far-travelled exotic intra-oceanic island arc character to autochthonous or parautochthonous extended continental margin origin. We present new paleomagnetic data from four localities: (1) the Norian SSZ Vizcaíno peninsula Ophiolite; (2) its Lower Jurassic sedimentary cover; and (3) Barremian and (4) Aptian sediments derived from the Guerrero arc. The data show that the Mexican ophiolite and arc terranes have a paleolatitudinal plate motion history that is equal to that of the North American continent. This suggests that these rock assemblages were part of the overriding plate and were perhaps only separated from the North American continent by temporal fore- or back-arc spreading. These spreading phases resulted in the temporal existence of tectonic plates between the North American and Farallon Plates, and upon closure of the basins, in the growth of the North American continent without addition of any far-travelled exotic terranes.

Paleoclimatic and paleolatitude settings of accumulation of radiolarian siliceous-volcanogenic sequences in the middle Mesozoic Pacific: Evidence from allochthons of East Asia

NASA Astrophysics Data System (ADS)

Vishnevskaya, V. S.; Filatova, N. I.

2017-09-01

Jurassic-Cretaceous siliceous-volcanogenic rocks from nappes of tectonostratigraphic sequences of the East Asia Middle Cretaceous Okhotsk-Koryak orogenic belt are represented by a wide range of geodynamic sedimentation settings: oceanic (near-spreading zones, seamounts, and deep-water basins), marginal seas, and island arcs. The taxonomic compositions of radiolarian communities are used as paleolatitude indicators in the Northern Pacific. In addition, a tendency toward climate change in the Mesozoic is revealed based on these communities: from the warm Triassic to the cold Jurassic with intense warming from the Late Jurassic to the Early Cretaceous. Cretaceous warming led to heating of ocean waters even at moderately high latitudes and to the development of Tethyan radiolarians there. These data are confirmed by a global Cretaceous temperature peak coinciding with a high-activity pulse of the planetary mantle superplume system, which created thermal anomalies and the greenhouse effect. In addition, the Pacific superplume attributed to this system caused accelerated movement of oceanic plates, which resulted in a compression setting on the periphery of the Pacific and the formation of the Okhotsk-Koryak orogenic belt on its northwestern framing in the Middle Cretaceous, where Mesozoic rocks of different geodynamic and latitudinal-climate settings were juxtaposed into allochthonous units.

Mesozoic paleogeography and paleoclimates - A discussion of the diverse greenhouse and hothouse conditions of an alien world

NASA Astrophysics Data System (ADS)

Holz, Michael

2015-08-01

The Mesozoic was the time of the break-up of Pangaea, with profound consequences not only for the paleocontinental configuration, but also for paleoclimates and for the evolution of life. Cool greenhouse conditions alternated with warm greenhouse and even hothouse conditions, with global average temperatures around 6-9 °C warmer than the present ones. There are only sparse and controversial evidence for polar ice; meanwhile, extensive evaporitic and desertic deposits are well described. Global sea levels were mainly high, and the content of atmospheric O2 was varying between 15 and 25%. These conditions make the Mesozoic Earth an alien world compared to present-day conditions. Degassing from volcanism linked to the rifting process of Pangaea and methane emissions from reptilian biotas were climate-controlling factors because they enhanced atmospheric CO2 concentrations up to 16 times compared to present-day levels. The continental break-up modified paleopositions and shoreline configurations of the landmasses, generating huge epicontinental seas and altering profoundly the oceanic circulation. The Mesozoic was also a time of important impact events as probable triggers for "impact winters"; and for the Era at least nine huge (diameter > 20 km) impact structures are known. This paper presents an abridged but updated overview of the Mesozoic paleogeographic and paleoclimatic variations, characterizing each period and sub-period in terms of paleoclimatic state and main tectonic and climatic events, and provides a brief geologic, stratigraphic, paleoclimatic and taphonomic characterization of dinosaur occurrences as recorded in the Brazilian continental basins.

Late Cretaceous tectonothermal evolution of the southern Lhasa terrane, South Tibet: Consequence of a Mesozoic Andean-type orogeny

NASA Astrophysics Data System (ADS)

Dong, Xin; Zhang, Ze-ming; Klemd, Reiner; He, Zhen-yu; Tian, Zuo-lin

2018-04-01

The Lhasa terrane of the southern Tibetan Plateau participated in a Mesozoic Andean-type orogeny caused by the northward subduction of the Neo-Tethyan oceanic lithosphere. However, metamorphic rocks, which can unravel details of the geodynamic evolution, are rare and only exposed in the south-eastern part of the Lhasa terrane. Therefore, we conducted a detailed petrological, geochemical and U-Pb zircon geochronological study of the late Cretaceous metamorphic rocks and associated gabbros from the Nyemo inlier of the southern Lhasa terrane. The Nyemo metamorphic rocks including gneisses, schists, marbles and calc-silicate rocks, experienced peak amphibolite-facies contact metamorphism under P-T conditions of 3.5-4.0 kbar and 642-657 °C with a very high geothermal gradient of 45-50 °C/km, revealing a distinct deflection from the steady-state geotherm during low-pressure metamorphism. Inherited magmatic zircon cores from the metamorphic rocks yielded protolith ages of 197-194 Ma, while overgrowth zircon rims yielded metamorphic ages of ca. 86 Ma. Whole-rock chemistry and zircon Hf isotopes suggest that the protoliths of the gneisses and schists are andesites and tuffs of the early Jurassic Sangri Group, which were derived from a depleted mantle source of a continental arc affinity. The coeval intimately-associated gabbro (ca. 86 Ma) crystallized under P-T conditions of 3.5-5.3 kbar and 914-970 °C, supplying the heat flux high enough to cause the contact metamorphism of the Sangri Group rock types. We propose that the intrusion of the gabbro and a simultaneous pressure increase of up to 4.0 kbar, which is related to crustal thickening due to crustal overthrusting and the intrusion of mafic material, resulted in the late Cretaceous metamorphism of the early Jurassic Sangri Group during an Andean-type orogeny. Furthermore the Nyemo metamorphic rocks, which have previously been considered to represent slivers of the Precambrian metamorphic basement of the Lhasa terrane

Origin and geodynamic significance of the early Mesozoic Weiya LP and HT granulites from the Chinese Eastern Tianshan

NASA Astrophysics Data System (ADS)

Mao, Ling-Juan; He, Zhen-Yu; Zhang, Ze-Ming; Klemd, Reiner; Xiang, Hua; Tian, Zuo-Lin; Zong, Ke-Qing

2015-12-01

The Chinese Tianshan in the southwestern part of the Central Asian Orogenic Belt (CAOB) is characterized by a variety of high-grade metamorphic rocks, which provide critical constraints for understanding the geodynamic evolution of the CAOB. In this paper, we present detailed petrological and zircon U-Pb geochronological studies of the Weiya low-pressure and high-temperature (LP-HT) granulites of the Chinese Eastern Tianshan. These granulites were previously considered to be a product of a regional metamorphic orogenic event. Due to different bulk-rock chemistries the Weiya granulites, which occur as lenses within the contact metamorphic aureole of the Weiya granitic ring complex, have a variety of felsic-pelitic and mafic granulites with different textural equilibrium mineral assemblages including garnet-cordierite-sillimanite-bearing granulites, cordierite-sillimanite-bearing granulites, cordierite-orthopyroxene-bearing granulites, and orthopyroxene-clinopyroxene-bearing granulites. Average P-T thermobarometric calculations and conventional geothermobarometry indicates that the Weiya granulites underwent early prograde metamorphism under conditions of 600-650 °C at 3.2-4.2 kbar and peak metamorphism of 750-840 °C at 2.9-6.3 kbar, indicating a rather high geothermal gradient of ca. 60 °C/km. Zircon U-Pb LA-ICP-MS dating revealed metamorphic ages between 244 ± 1 to 237 ± 3 Ma, which are in accordance with the crystallization age of the Weiya granitic ring complex. We suggest that the formation of the Weiya granulites was related to contemporaneous granitic magmatism instead of a regional metamorphic orogenic event. In addition, a Late Devonian metamorphic age of ca. 380 Ma was recorded in zircon mantle domains from two pelitic samples which is consistent with the metamorphic age of the Xingxingxia metamorphic complex in the Chinese Eastern Tianshan. This suggests that the mantle domains of the zircon grains of the Weiya granulites probably formed during the

The Late Oligocene to Early Miocene early evolution of rifting in the southwestern part of the Roer Valley Graben

NASA Astrophysics Data System (ADS)

Deckers, Jef

2016-06-01

The Roer Valley Graben is a Mesozoic continental rift basin that was reactivated during the Late Oligocene. The study area is located in the graben area of the southwestern part of the Roer Valley Graben. Rifting initiated in the study area with the development of a large number of faults in the prerift strata. Some of these faults were rooted in preexisting zones of weakness in the Mesozoic strata. Early in the Late Oligocene, several faults died out in the study area as strain became focused upon others, some of which were able to link into several-kilometer-long systems. Within the Late Oligocene to Early Miocene northwestward prograding shallow marine syn-rift deposits, the number of active faults further decreased with time. A relatively strong decrease was observed around the Oligocene/Miocene boundary and represents a further focus of strain onto the long fault systems. Miocene extensional strain was not accommodated by further growth, but predominantly by displacements along the long fault systems. Since the Oligocene/Miocene boundary coincides with a radical change in the European intraplate stress field, the latter might have contributed significantly to the simultaneous change of fault kinematics in the study area.

Mesozoic to Cenozoic magmatic history of the Pamir

NASA Astrophysics Data System (ADS)

Chapman, James B.; Scoggin, Shane H.; Kapp, Paul; Carrapa, Barbara; Ducea, Mihai N.; Worthington, James; Oimahmadov, Ilhomjon; Gadoev, Mustafo

2018-01-01

New geochronologic, geochemical, and isotopic data for Mesozoic to Cenozoic igneous rocks and detrital minerals from the Pamir Mountains help to distinguish major regional magmatic episodes and constrain the tectonic evolution of the Pamir orogenic system. After final accretion of the Central and South Pamir terranes during the Late Triassic to Early Jurassic, the Pamir was largely amagmatic until the emplacement of the intermediate (SiO2 > 60 wt.%), calc-alkaline, and isotopically evolved (-13 to -5 zircon εHf(t)) South Pamir batholith between 120-100 Ma, which is the most volumetrically significant magmatic complex in the Pamir and includes a high flux magmatic event at ∼105 Ma. The South Pamir batholith is interpreted as the northern (inboard) equivalent of the Cretaceous Karakoram batholith and the along-strike equivalent of an Early Cretaceous magmatic belt in the northern Lhasa terrane in Tibet. The northern Lhasa terrane is characterized by a similar high-flux event at ∼110 Ma. Migration of continental arc magmatism into the South Pamir terrane during the mid-Cretaceous is interpreted to reflect northward directed, low-angle to flat-slab subduction of the Neo-Tethyan oceanic lithosphere. Late Cretaceous magmatism (80-70 Ma) in the Pamir is scarce, but concentrated in the Central and northern South Pamir terranes where it is comparatively more mafic (SiO2 < 60 wt.%), alkaline, and isotopically juvenile (-2 to +2 zircon εHf(t)) than the South Pamir batholith. Late Cretaceous magmatism in the Pamir is interpreted here to be the result of extension associated with roll-back of the Neotethyan oceanic slab, which is consistent with similarly aged extension-related magmatism in the Karakoram terrane and Kohistan. There is an additional pulse of magmatism in the Pamir at 42-36 Ma that is geographically restricted (∼150 km diameter ellipsoidal area) and referred to as the Vanj magmatic complex. The Vanj complex comprises metaluminous, high-K calc-alkaline to

Field evidences for a Mesozoic palaeo-relief through the northern Tianshan

NASA Astrophysics Data System (ADS)

Gumiaux, Charles; Chen, Ke; Augier, Romain; Chen, Yan; Wang, Qingchen

2010-05-01

The modern Tianshan mountain belt, located in Central Asia, offers a natural laboratory to study orogenic processes linked with convergent geodynamical settings. Most of the previous studies either focused on the Paleozoic evolution of the range - subductions, arc accretions and continental collision - or on its Cenozoic intra-continental evolution linked with the India-Asia collision. At first order, the finite structure of this range obviously displays a remarkable uprising of Paleozoic "basement" rocks - as a crustal-scale ‘pop-up' - surrounded by two Cenozoic foreland basins. The present-day topography of the Tianshan is traditionally related to the latest intra-continental reactivation of the range. In contrast, the present field study of the northern Tianshan brings new and clear evidences for the existence of a significant relief, in this area, during Mesozoic times. The investigation zone is about 250 km long, from Wusu to Urumqi, along the northern flank of the Tianshan where the rivers deeply incised the topography. In such valleys, lithologies and structural relationships between Paleozoic basement rocks, Mesozoic and Cenozoic sedimentary series are particularly well exposed along several sections. Jurassic series are mostly characterized by coal-bearing, coarse-grained continental deposits. Within intra-mountain basins, sedimentary breccias, with clasts of Carboniferous basement rocks, have been locally found at the base of the series. This argues for the presence of a rather proximal palaeo-relief of basement rocks along the range front and the occurrence of proximal intra-mountain basins, during the Jurassic. Moreover, while a major thrust is mostly evoked between Jurassic deposits and the Paleozoic units, some of the studied sections show that the Triassic to Jurassic sedimentary series can be followed from the basin to the range. In these cases, the unconformity of the Mesozoic series on top of the Carboniferous basement has been locally clearly

Field guide to the Mesozoic accretionary complex along Turnagain Arm and Kachemak Bay, south-central Alaska

USGS Publications Warehouse

Bradley, Dwight C.; Kusky, Timothy M.; Karl, Susan M.; Haeussler, Peter J.

1997-01-01

Turnagain Arm, just east of Anchorage, provides a readily accessible, world-class cross section through a Mesozoic accretionary wedge. Nearly continuous exposures along the Seward Highway, the Alaska Railroad, and the shoreline of Turnagain Arm display the two main constituent units of the Chugach terrane: the McHugh Complex and Valdez Group. In this paper we describe seven bedrock geology stops along Turnagain Arm, and two others in the Chugach Mountains just to the north (Stops 1-7 and 9), which will be visited as part of the May, 1997 field trip of the Alaska Geological Society. Outcrops along Turnagain Arm have already been described in two excellent guidebook articles (Clark, 1981; Winkler and others 1984), both of which remain as useful and valid today as when first published. Since the early 1980's, studies along Turnagain Arm have addressed radiolarian ages of chert and conodont ages of limestone in the McHugh Complex (Nelson and others, 1986, 1987); geochemistry of basalt in the McHugh Complex (Nelson and Blome, 1991); post-accretion brittle faulting (Bradley and Kusky, 1990; Kusky and others, 1997); and the age and tectonic setting of gold mineralization (Haeussler and others, 1995). Highlights of these newer findings will described both in the text below, and in the stop descriptions.Superb exposures along the southeastern shore of Kachemak Bay show several other features of the McHugh Complex that are either absent or less convincing along Turnagain Arm. While none of these outcrops can be reached via the main road network, they are still reasonably accessible - all are within an hour by motorboat from Homer, seas permitting. Here, we describe seven outcrops along the shore of Kachemak Bay that we studied between 1989 and 1993 during geologic mapping of the Seldovia 1:250,000- scale quadrangle. These outcrops (Stops 61-67) will not be part of the 1997 itinerary, but are included here tor the benefit of those who may wish to visit them later.

Key goals and indicators for successful aging of adults with early-onset disability.

PubMed

LaPlante, Mitchell P

2014-01-01

Substantial improvements have occurred in the longevity of several groups of individuals with early-onset disabilities, with many now surviving to advanced ages. This paper estimates the population of adults aging with early-onset disabilities at 12-15 million persons. Key goals for the successful aging of adults with early-onset disabilities are discussed, emphasizing reduction in risks for aging-related chronic disease and secondary conditions, while promoting social participation and independence. However, indicators suggest that elevated risk factors for aging-related chronic diseases, including smoking, obesity, and inactivity, as well as barriers to prevention and the diminished social and economic situation of adults with disabilities are continuing impediments to successful aging that must be addressed. Increased provider awareness that people with early-onset disabilities are aging and can age successfully and the integration of disability and aging services systems are transformative steps that will help adults with early-onset disability to age more successfully. Copyright © 2014 Elsevier Inc. All rights reserved.

Geochemistry of Mesozoic plutons, southern Death Valley region, California: Insights into the origin of Cordilleran interior magmatism

USGS Publications Warehouse

Ramo, O.T.; Calzia, J.P.; Kosunen, P.J.

2002-01-01

Mesozoic granitoid plutons in the southern Death Valley region of southeastern California reveal substantial compositional and isotopic diversity for Mesozoic magmatism in the southwestern US Cordillera. Jurassic plutons of the region are mainly calc-alkaline mafic granodiorites with ??Ndi of -5 to -16, 87Sr/86Sri of 0.707-0.726, and 206Pb/204Pbi of 17.5-20.0. Cretaceous granitoids of the region are mainly monzogranites with ??Ndi of -6 to -19, 87Sr/86Sri of 0.707-0.723, and 206Pb/204Pbi of 17.4-18.6. The granitoids were generated by mixing of mantle-derived mafic melts and pre-existing crust - some of the Cretaceous plutons represent melting of Paleoproterozoic crust that, in the southern Death Valley region, is exceptionally heterogeneous. A Cretaceous gabbro on the southern flank of the region has an unuasually juvenile composition (??Ndi -3.2, 87Sr/86Sri 0.7060). Geographic position of the Mesozoic plutons and comparison with Cordillera plutonism in the Mojave Desert show that the Precambrian lithosphere (craton margin) in the eastern Mojave Desert region may consists of two crustal blocks separated by a more juvenile terrane.

Early-life inflammation, immune response and ageing.

PubMed

Khan, Imroze; Agashe, Deepa; Rolff, Jens

2017-03-15

Age-related diseases are often attributed to immunopathology, which results in self-damage caused by an inappropriate inflammatory response. Immunopathology associated with early-life inflammation also appears to cause faster ageing, although we lack direct experimental evidence for this association. To understand the interactions between ageing, inflammation and immunopathology, we used the mealworm beetle Tenebrio molitor as a study organism. We hypothesized that phenoloxidase, an important immune effector in insect defence, may impose substantial immunopathological costs by causing tissue damage to Malpighian tubules (MTs; functionally equivalent to the human kidney), in turn accelerating ageing. In support of this hypothesis, we found that RNAi knockdown of phenoloxidase (PO) transcripts in young adults possibly reduced inflammation-induced autoreactive tissue damage to MTs, and increased adult lifespan. Our work thus suggests a causative link between immunopathological costs of early-life inflammation and faster ageing. We also reasoned that if natural selection weakens with age, older individuals should display increased immunopathological costs associated with an immune response. Indeed, we found that while old infected individuals cleared infection faster than young individuals, possibly they also displayed exacerbated immunopathological costs (larger decline in MT function) and higher post-infection mortality. RNAi-mediated knockdown of PO response partially rescued MTs function in older beetles and resulted in increased lifespan after infection. Taken together, our data are consistent with a direct role of immunopathological consequences of immune response during ageing in insects. Our work is also the first report that highlights the pervasive role of tissue damage under diverse contexts of ageing and immune response. © 2017 The Author(s).

Early-life inflammation, immune response and ageing

PubMed Central

2017-01-01

Age-related diseases are often attributed to immunopathology, which results in self-damage caused by an inappropriate inflammatory response. Immunopathology associated with early-life inflammation also appears to cause faster ageing, although we lack direct experimental evidence for this association. To understand the interactions between ageing, inflammation and immunopathology, we used the mealworm beetle Tenebrio molitor as a study organism. We hypothesized that phenoloxidase, an important immune effector in insect defence, may impose substantial immunopathological costs by causing tissue damage to Malpighian tubules (MTs; functionally equivalent to the human kidney), in turn accelerating ageing. In support of this hypothesis, we found that RNAi knockdown of phenoloxidase (PO) transcripts in young adults possibly reduced inflammation-induced autoreactive tissue damage to MTs, and increased adult lifespan. Our work thus suggests a causative link between immunopathological costs of early-life inflammation and faster ageing. We also reasoned that if natural selection weakens with age, older individuals should display increased immunopathological costs associated with an immune response. Indeed, we found that while old infected individuals cleared infection faster than young individuals, possibly they also displayed exacerbated immunopathological costs (larger decline in MT function) and higher post-infection mortality. RNAi-mediated knockdown of PO response partially rescued MTs function in older beetles and resulted in increased lifespan after infection. Taken together, our data are consistent with a direct role of immunopathological consequences of immune response during ageing in insects. Our work is also the first report that highlights the pervasive role of tissue damage under diverse contexts of ageing and immune response. PMID:28275145

Mobile Learning and Early Age Mathematics

ERIC Educational Resources Information Center

Peled, Shir; Schocken, Shimon

2014-01-01

The ability to develop engaging simulations and constructive learning experiences using mobile devices is unprecedented, presenting a disruption in educational practices of historical proportions. In this paper we describe some of the unique virtues that mobile learning hold for early age mathematics education. In particular, we describe how…

Correspondence of Mesozoic Eustatic Sea-Level Change with Palaeoclimate Proxies: Evidence for Glacio-Eustasy?

NASA Astrophysics Data System (ADS)

Simmons, M.; Davies, A.; Gréselle, B.

2011-12-01

Large-scale changes in stratigraphic architecture and facies that are brought about by changes in relative sea-level have been the focus of much academic and industry study over the last few decades. The authors, plus numerous colleagues, have studied over 11,000 stratigraphic sections worldwide. By applying biostratigraphic and chemostratigraphic calibration in suitable locations from this dataset it is possible to demonstrate over 250 synchronous global sequence stratigraphic events in the Phanerozoic including over 100 in the Mesozoic. This then raises the question - what causes globally synchronous eustatic sea-level change? To answer this question requires an understanding of both the pace and amplitude of the observed eustatic sea-level change. In successions where duration can be deduced from orbital forcing cycles, our observed sea-level changes appear to be relatively rapid - less than 500,000 years, for example, for sea-level rises in the Late Jurassic. The amplitude of such rises is in the order of tens of metres. Such rates and amplitudes as inferred from our global model preclude tectonism as a primary driver and implicate glacio-eustacy as a key driving mechanism, even in supposed "greenhouse times". Given the clear economic importance of understanding the underlying mechanisms driving this eustatic change we have compiled records of key isotopic proxies through the entire Mesozoic in an effort to explore the relationship between global sea-level and palaeoclimate. Our research reveals a clear link between many large-scale maximum flooding events with known episodes of palaeoclimatic warming and between climatic cooling events and lowstand intervals, further implicating glacio-eustacy. In addition to the isotopic proxy evidence we have also compiled direct indicators for the occurrence of cold polar conditions, including the presence of ice sheets, in the Mesozoic (e.g. tillites, glendonites). This has been incorporated into plate tectonic

Small head circumference at birth and early age at adiposity rebound.

PubMed

Eriksson, J G; Kajantie, E; Lampl, M; Osmond, C; Barker, D J P

2014-01-01

The adiposity rebound is the age in childhood when body mass index is at a minimum before increasing again. The age at rebound is highly variable. An early age is associated with increased obesity in later childhood and adult life. We have reported that an early rebound is predicted by low weight gain between birth and 1 year of age and resulting low body mass index at 1 year. Here, we examine whether age at adiposity rebound is determined by influences during infancy or is a consequence of foetal growth. Our hypothesis was that measurements of body size at birth are related to age at adiposity rebound. Longitudinal study of 2877 children born in Helsinki, Finland, during 1934-1944. Early age at adiposity rebound was associated with small head circumference and biparietal diameter at birth, but not with other measurements of body size at birth. The mean age at adiposity rebound rose from 5.8 years in babies with a head circumference of ≤33 cm to 6.2 in babies with a head circumference of >36 cm (P for trend = 0.007). The association between thinness in infancy and early rebound became apparent at 6 months of age. It was not associated with adverse living conditions. In a simultaneous regression, small head circumference at birth, high mother's body mass index and tall maternal stature each had statistically significant trends with early adiposity rebound (P = 0.002, <0.001, 0.004). We hypothesize that the small head size at birth that preceded an early adiposity rebound was the result of inability to sustain a rapid intra-uterine growth trajectory initiated in association with large maternal body size. This was followed by catch-up growth in infancy, and we hypothesize that this depleted the infant's fat stores. © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

First early Mesozoic amber in the Western Hemisphere

USGS Publications Warehouse

Litwin, R.J.; Ash, S.R.

1991-01-01

Detrital amber pebbles and granules have been discovered in Upper Triassic strata on the Colorado Plateau. Although amber previously has been reported from Pennsylvanian, Jurassic, Cretaceous, and Tertiary strata, we know of no other reported Triassic occurrence in North America or the Western Hemisphere. The new discovered occurrences of amber are at two localities in the lower part of the Petrified Forest Member of the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona. The paper coals and carbonaceous paper shales containing the amber also contain fossil palynomorph assemblages that indicate a late Carnian age for these occurrences. -Authors

Lattice Modeling of Early-Age Behavior of Structural Concrete.

PubMed

Pan, Yaming; Prado, Armando; Porras, Rocío; Hafez, Omar M; Bolander, John E

2017-02-25

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential.

Lattice Modeling of Early-Age Behavior of Structural Concrete

PubMed Central

Pan, Yaming; Prado, Armando; Porras, Rocío; Hafez, Omar M.; Bolander, John E.

2017-01-01

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential. PMID:28772590

A tribosphenic mammal from the Mesozoic of Australia.

PubMed

Rich, T H; Vickers-Rich, P; Constantine, A; Flannery, T F; Kool, L; van Klaveren, N

1997-11-21

A small, well-preserved dentary of a tribosphenic mammal with the most posterior premolar and all three molars in place has been found in Aptian (Early Cretaceous) rocks of southeastern Australia. In most respects, dental and mandibular anatomy of the specimen is similar to that of primitive placental mammals. With the possible exception of a single tooth reported as Eocene in age, terrestrial placentals are otherwise unknown in Australia until the Pliocene. This possible Australian placental is similar in age to Prokennalestes from the late Aptian/early Albian Khoboor Beds of Mongolia, the oldest currently accepted member of the infraclass Placentalia.

Sedimentary facies analysis of the Mesozoic clastic rocks in Southern Peru (Tacna, 18°S): Towards a paleoenvironmental Redefinition and stratigraphic Reorganization

NASA Astrophysics Data System (ADS)

Alván, Aldo; Jacay, Javier; Caracciolo, Luca; Sánchez, Elvis; Trinidad, Inés

2018-07-01

The Mesozoic rocks of southern Peru comprise a Middle Jurassic to Early Cretaceous sedimentary sequence deposited during a time interval of approximately 34 Myr. In Tacna, these rocks are detrital and constitute the Yura Group (Callovian to Tithonian) and the Hualhuani Formation (Berriasian). Basing on robust interpretation of facies and petrographic analysis, we reconstruct the depositional settings of such units and provide a refined stratigraphic framework. Accordingly, nine types of sedimentary facies and six architectural elements are defined. They preserve the record of a progradational fluvial system, in which two styless regulated the dispersion of sediments: (i) a high-to moderate-sinuosity meandering setting (Yura Group), and a later (ii) incipient braided setting (Hualhuani Formation). The Yura Group (Callovian-Tithonian) represents the onset of floodplain deposits and lateral accretion of point-bar deposits sited on a semi-flat topography. Nonetheless, the progradational sequence was affected by at least two rapid marine ingressions occurred during Middle Callovian and Tithonian times. Such marine ingressions reveal the proximity of a shallow marine setting and incipient carbonate deposition. In response to increase in topographic gradient, the Hualhuani Formation (Berriasian) deposited as extensive multistory sandy channels. The mineralogy of the Mesozoic sediments suggests sediment supplies and intense recycling from a craton interior (i.e. Amazon Craton and/or plutonic sources) located eastward of the study area.

Petroleum geology of the mid-Atlantic continental margin, offshore Virginia

USGS Publications Warehouse

Bayer, K.C.; Milici, R.C.

1989-01-01

The Baltimore Canyon Trough, a major sedimentary basin on the Atlantic continental shelf, contains up to 18 km of Mesozoic and Cenozoic strata. The basin has been studied extensively by multichannel common depth point (CDP) seismic reflection profiles and has been tested by drilling for hydrocarbon resources in several places. The Mesozoic and Cenozoic strata contained in the basin were deposited in littoral to bathyal depositional settings and contain immature to marginally mature oil-prone and gas-prone kerogen. The more deeply buried strata of Early Mesozoic age are more likely to be thermally mature than are the younger strata with respect to hydrocarbon generation, but contain terrestrially derived coaly organic matter that would be prone to yield gas, rather than oil. An analysis of available CDP seismic reflection data has indicated that there are several potential hydrocarbon plays in the area offshore of Virginia. These include: (1) Lower Mesozoic synrift basins that appear similar to those exposed in the Appalachian Piedmont, (2) a stratigraphic updip pinchout of strata of Early Mesozoic age in the offshore region near the coast, (3) a deeply buried paleoshelf edge, where seismic reflectors dip sharply seaward; and (4) a Cretaceous/Jurassic shelf edge beneath the present continental rise. Of these, the synrift basins and Cretaceous/Jurassic shelf edge are considered to be the best targets for exploration. ?? 1989.

[Immune system aging rate in patients with early forms of chronic cerebrovascular diseases].

PubMed

Kochetkova, N G; Al'tman, D Sh; Teplova, S N

2009-01-01

Using the Bioage and Snake software the immune and cardiovascular system aging rate was diagnosed in patients having early forms of chronic cerebrovascular diseases (CCVD). The indicators of biological, cardiopulmonary and immunological age were studied in patients showing early symptoms of cerebrovascular insufficiency and dyscirculatory encephalopathy of the 1st stage. The rate of age-dependent physiological changes was diagnosed compared to general body aging rate. Some specific patterns of immune system aging were found in patients with early forms of CCVDs, the cardinal aging symptoms (heterotropia, heterochronia) were verified.

Significance of zircon U-Pb ages from the Pescadero felsite, west-central California coast ranges

USGS Publications Warehouse

McLaughlin, Robert J.; Moore, Diane E.; ,; Martens, UWE C.; Clark, J.C.

2011-01-01

Weathered felsite is associated with the late Campanian–Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio–Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ∼185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ± prehnite ± laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe–reverse geometry (SHRIMP-RG) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefly Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86–90 Ma. Reflecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio–Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ∼100 km to the east in the Diablo Range–San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper

Mesozoic intra-arc tectonics in the NE Mojave Desert, CA

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

Stephens, K.A.; Schermer, E.R.; Walker, J.D.

1993-04-01

Field and U-Pb zircon geochronological data from the Tiefort Mts. (TM) and surrounding areas in the NE Mojave Desert provide new constraints on Precambrian to Paleozoic paleogeography and Mesozoic intra-arc tectonics. Amphibolite facies metasediments appear to correlate with lower Paleozoic miogeoclinal sequences. Coarse-grained K-feldspar augen gneiss occurs in sharp contact with the metasedimentary rocks; U-Pb dating yields a 1393[+-]12 Ma age. This gneiss is interpreted to represent cratonal basement of North America. A texturally and compositionally heterogeneous amphibolite-facies monzonitic complex which intrudes the basement and metasediments yields a mid-Jurassic age. Felsite and biotite granite that intrude the foliated monzonitic complexmore » locally contain the mylonitic fabric and appear to be syn-late kinematic. Undeformed pegmatite, granite, and microdiorite appear as dikes throughout the region. Vertical silicic dikes at southern TM trend N5-25E and are dated at 148[+-]14 Ma, coeval with the Independence dike swarm (IDS). Similar dikes that occur at TM trend N60-80E. Undeformed granite cross-cuts the foliated monzonite; some granitic rocks cut dikes of the IDs and are likely to be Cretaceous in age. The E- to SE-vergence and mid-late Jurassic age of ductile shear zones in the TM region are similar to that in nearby parts of the East Sierra Thrust System (ESTS). If NE and NNE dikes are IDS-equivalent, this implies clockwise, vertical-axis rotation of 30[degree]--90[degree] by younger structures. The authors interpret this to be related to late Cenozoic strike-slip faults. Restoration of folds and the IDS to the regional NW trend results in top to the E to NE sense of shear during Jurassic deformation. Deformation in the TM and areas to the north connects the ESTS from the Garlock fault to the central Mojave region indicating a region in which mid-crustal levels of the arc and cratonal basement experienced contractional tectonism during mid

Gratitude From Early Adulthood to Old Age.

PubMed

Allemand, Mathias; Hill, Patrick L

2016-02-01

Are there age differences in gratitude from early adulthood to old age? The current studies tested several ways by which an association between age and dispositional gratitude may present, by considering multiple measures on both fronts. We used data from three cross-sectional studies (total N = 1,736; total age range: 19-94). The results indicated that (a) age effects in gratitude are more likely to occur for subjective age in terms of future time perspective (i.e., people's perceptions of their remaining opportunities and time) than chronological age; (b) chronological age effects are more domain specific than general in nature; and (c) they are more likely to occur for the instrumental domain as compared to the interpersonal domain. Finally, the results indicated that (d) perceived future time, particularly with respect to remaining opportunities, mediates the relation between chronological age and general gratitude. Overall, the findings suggest that gratitude is subject to a variety of developmental influences across adulthood. © 2014 Wiley Periodicals, Inc.

A new, well-preserved genus and species of fossil Glaphyridae (Coleoptera, Scarabaeoidea) from the Mesozoic Yixian Formation of Inner Mongolia, China

PubMed Central

Yan, Zhuo; Nikolajev, Georgiy V.; Ren, Dong

2012-01-01

Abstract A new genus and species of fossil Glaphyridae, Cretohypna cristata gen. et sp. n., is described and illustrated from the Mesozoic Yixian Formation. This new genus is characterized by the large body; large and strong mandibles; short labrum; elytra without longitudinal carina; and male meso- and possible metatibia apically modified. A list of described fossil glaphyrids of the world is provided. This significant finding broadens the known diversity of Glaphyridae in the Mesozoic China. PMID:23372414

Hydrocarbons in New Guinea, controlled by basement fabric, Mesozoic extension and Tertiary convergent margin tectonics

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

Hill, K.C.; Kendrick, R.D.; Crowhurst, P.V.

1996-01-01

Most models for the tectonic evolution of New Guinea involve Early and Late Miocene arc-continent collisions, creating an orogenic belt. Structural trends and prospectivity are then analyzed in terms of belts across the country; the Fold Belt (with the discovered oil and gas fields), the Mobile Belt and the accreted arcs. This model inhibits realistic assessment of prospectivity. It now appears the Mobile Belt formed by Oligocene compression then by Early Miocene extension, related to slab-rollback, that unroofed metamorphic core complexes adjacent to starved half-grabens. The grabens filled in the Middle Miocene and were largely transported intact during the Pliocenemore » arc-collision. Early Miocene reefs and hypothesized starved basin source rocks create a viable play throughout northern New Guinea as in the Salawati Basin. The Pliocene clastic section is locally prospective due to overthrusting and deep burial. Within the Fold Belt, the site and types of oil and gas fields are largely controlled by the basement architecture. This controlled the transfer zones and depocentres during Mesozoic extension and the location of major basement uplifts during compression. In PNG, the Bosavi lineament separates an oil province from a gas province. In Irian Jaya the transition from a relatively competent sequence to a rifted sequence west of [approx]139[degrees]E may also be a gas-oil province boundary. Understanding, in detail, the compartmentalization of inverted blocks and areas of thin-skinned thrusting, controlled by the basement architecture, will help constrain hydrocarbon prospectivity.« less

Hydrocarbons in New Guinea, controlled by basement fabric, Mesozoic extension and Tertiary convergent margin tectonics

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

Hill, K.C.; Kendrick, R.D.; Crowhurst, P.V.

1996-12-31

Most models for the tectonic evolution of New Guinea involve Early and Late Miocene arc-continent collisions, creating an orogenic belt. Structural trends and prospectivity are then analyzed in terms of belts across the country; the Fold Belt (with the discovered oil and gas fields), the Mobile Belt and the accreted arcs. This model inhibits realistic assessment of prospectivity. It now appears the Mobile Belt formed by Oligocene compression then by Early Miocene extension, related to slab-rollback, that unroofed metamorphic core complexes adjacent to starved half-grabens. The grabens filled in the Middle Miocene and were largely transported intact during the Pliocenemore » arc-collision. Early Miocene reefs and hypothesized starved basin source rocks create a viable play throughout northern New Guinea as in the Salawati Basin. The Pliocene clastic section is locally prospective due to overthrusting and deep burial. Within the Fold Belt, the site and types of oil and gas fields are largely controlled by the basement architecture. This controlled the transfer zones and depocentres during Mesozoic extension and the location of major basement uplifts during compression. In PNG, the Bosavi lineament separates an oil province from a gas province. In Irian Jaya the transition from a relatively competent sequence to a rifted sequence west of {approx}139{degrees}E may also be a gas-oil province boundary. Understanding, in detail, the compartmentalization of inverted blocks and areas of thin-skinned thrusting, controlled by the basement architecture, will help constrain hydrocarbon prospectivity.« less

Digital surfaces and hydrogeologic data for the Mesozoic through early Tertiary rocks in the Southeastern Coastal Plain in parts of Mississippi, Alabama, Georgia, South Carolina, and Florida

USGS Publications Warehouse

Cannon, Debra M.; Bellino, Jason C.; Williams, Lester J.

2012-01-01

A digital dataset of hydrogeologic data for Mesozoic through early Tertiary rocks in the Southeastern Coastal Plain was developed using data from five U.S. Geological Survey (USGS) reports published between 1951 and 1996. These reports contain maps and data depicting the extent and elevation of the Southeast Coastal Plain stratigraphic and hydrogeologic units in Florida and parts of Mississippi, Alabama, Georgia, and South Carolina. The reports are: Professional Paper 1410-B (Renken, 1996), Professional Paper 1088 (Brown and others, 1979), Professional Paper 524-G (Applin and Applin, 1967), Professional Paper 447 (Applin and Applin, 1965), and Circular 91 (Applin, 1951). The digital dataset provides hydrogeologic data for the USGS Energy Resources Program assessment of potential reservoirs for carbon sequestration and for the USGS Groundwater Resource Program assessment of saline aquifers in the southeastern United States. A Geographic Information System (ArcGIS 9.3.1) was used to construct 33 digital (raster) surfaces representing the top or base of key stratigraphic and hydrogeologic units. In addition, the Geographic Information System was used to generate 102 geo-referenced scanned maps from the five reports and a geo-database containing structural and thickness contours, faults, extent polygons, and common features. The dataset also includes point data of well construction and stratigraphic elevations and scanned images of two geologic cross sections and a nomenclature chart.

Age at Menarche Is Associated with Divergent Alcohol Use Patterns in Early Adolescence and Early Adulthood

ERIC Educational Resources Information Center

Richards, Meghan A.; Oinonen, Kirsten A.

2011-01-01

A cross-sectional retrospective design was employed to examine the relationship between age at menarche (AAM) and alcohol use patterns from middle childhood (age 7) to early adulthood in 265 University-aged women. Earlier menarche was associated with: (a) earlier ages at first drink and first intoxication, (b) greater use between ages 9 and 14…

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

Time-slice maps showing age, distribution, and style of deformation in Alaska north of 60° N.

USGS Publications Warehouse

Moore, Thomas E.; Box, Stephen E.

2016-08-29

The structural architecture of Alaska is the product of a complex history of tectonism that occurred along the Cordilleran and Arctic margins of North America through interactions with ancient and modern ocean plates and with continental elements derived from Laurentia, Siberia, and Baltica. To unravel the tectonic history of Alaska, we constructed maps showing the age, distribution, structural style, and kinematics of contractional and penetrative extensional deformation in Alaska north of latitude 60° N. at a scale of 1:5,000,000. These maps use the Geologic Map of the Arctic (Harrison and others, 2011) as a base map and follow the guidelines in the Tectonic Map of the Arctic project (Petrov and others, 2013) for construction, including use of the International Commission on Stratigraphy time scale (Cohen and others, 2013) divided into 20 time intervals. We find evidence for deformation in 14 of the 20 time intervals and present maps showing the known or probable extent of deformation for each time interval. Maps and descriptions of deformational style, age constraints, kinematics, and information sources for each deformational episode are discussed in the text and are reported in tabular form. This report also contains maps showing the lithologies and structural geology of Alaska, a terrane map, and the distribution of tectonically important units including post-tectonic sedimentary basins, accretionary complexes, ophiolites, metamorphic rocks.These new maps show that most deformational belts in Alaska are relatively young features, having developed during the late Mesozoic and Cenozoic. The oldest episode of deformation recognized anywhere in Alaska is found in the basement of the Farewell terrane (~1.75 Ga). Paleozoic and early Mesozoic deformational events, including Devonian deformation in the Arctic Alaska terrane, Pennsylvanian deformation in the Alexander terrane, Permian deformation in the Yukon Composite (Klondike orogeny) and Farewell terranes (Browns

Assessment of undiscovered oil and gas resources of the East Coast Mesozoic basins of the Piedmont, Blue Ridge Thrust Belt, Atlantic Coastal Plain, and New England Provinces, 2011

USGS Publications Warehouse

Milici, Robert C.; Coleman, James L.; Rowan, Elisabeth L.; Cook, Troy A.; Charpentier, Ronald R.; Kirschbaum, Mark A.; Klett, Timothy R.; Pollastro, Richard M.; Schenk, Christopher J.

2012-01-01

During the early opening of the Atlantic Ocean in the Mesozoic Era, numerous extensional basins formed along the eastern margin of the North American continent from Florida northward to New England and parts of adjacent Canada. The basins extend generally from the offshore Atlantic continental margin westward beneath the Atlantic Coastal Plain to the Appalachian Mountains. Using a geology-based assessment method, the U.S. Geological Survey estimated a mean undiscovered natural gas resource of 3,860 billion cubic feet and a mean undiscovered natural gas liquids resource of 135 million barrels in continuous accumulations within five of the East Coast Mesozoic basins: the Deep River, Dan River-Danville, and Richmond basins, which are within the Piedmont Province of North Carolina and Virginia; the Taylorsville basin, which is almost entirely within the Atlantic Coastal Plain Province of Virginia and Maryland; and the southern part of the Newark basin (herein referred to as the South Newark basin), which is within the Blue Ridge Thrust Belt Province of New Jersey. The provinces, which contain these extensional basins, extend across parts of Georgia, South Carolina, North Carolina, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, and Massachusetts.

Suicide in Elementary School-Aged Children and Early Adolescents.

PubMed

Sheftall, Arielle H; Asti, Lindsey; Horowitz, Lisa M; Felts, Adrienne; Fontanella, Cynthia A; Campo, John V; Bridge, Jeffrey A

2016-10-01

Suicide in elementary school-aged children is not well studied, despite a recent increase in the suicide rate among US black children. The objectives of this study were to describe characteristics and precipitating circumstances of suicide in elementary school-aged children relative to early adolescent decedents and identify potential within-group racial differences. We analyzed National Violent Death Reporting System (NVDRS) surveillance data capturing suicide deaths from 2003 to 2012 for 17 US states. Participants included all suicide decedents aged 5 to 14 years (N = 693). Age group comparisons (5-11 years and 12-14 years) were conducted by using the χ 2 test or Fisher's exact test, as appropriate. Compared with early adolescents who died by suicide, children who died by suicide were more commonly male, black, died by hanging/strangulation/suffocation, and died at home. Children who died by suicide more often experienced relationship problems with family members/friends (60.3% vs 46.0%; P = .02) and less often experienced boyfriend/girlfriend problems (0% vs 16.0%; P < .001) or left a suicide note (7.7% vs 30.2%; P < .001). Among suicide decedents with known mental health problems (n = 210), childhood decedents more often experienced attention-deficit disorder with or without hyperactivity (59.3% vs 29.0%; P = .002) and less often experienced depression/dysthymia (33.3% vs 65.6%; P = .001) compared with early adolescent decedents. These findings raise questions about impulsive responding to psychosocial adversity in younger suicide decedents, and they suggest a need for both common and developmentally-specific suicide prevention strategies during the elementary school-aged and early adolescent years. Further research should investigate factors associated with the recent increase in suicide rates among black children. Copyright © 2016 by the American Academy of Pediatrics.

Suicide in Elementary School-Aged Children and Early Adolescents

PubMed Central

Sheftall, Arielle H.; Asti, Lindsey; Horowitz, Lisa M.; Felts, Adrienne; Fontanella, Cynthia A.; Campo, John V.

2016-01-01

BACKGROUND AND OBJECTIVES: Suicide in elementary school–aged children is not well studied, despite a recent increase in the suicide rate among US black children. The objectives of this study were to describe characteristics and precipitating circumstances of suicide in elementary school–aged children relative to early adolescent decedents and identify potential within-group racial differences. METHODS: We analyzed National Violent Death Reporting System (NVDRS) surveillance data capturing suicide deaths from 2003 to 2012 for 17 US states. Participants included all suicide decedents aged 5 to 14 years (N = 693). Age group comparisons (5–11 years and 12–14 years) were conducted by using the χ2 test or Fisher’s exact test, as appropriate. RESULTS: Compared with early adolescents who died by suicide, children who died by suicide were more commonly male, black, died by hanging/strangulation/suffocation, and died at home. Children who died by suicide more often experienced relationship problems with family members/friends (60.3% vs 46.0%; P = .02) and less often experienced boyfriend/girlfriend problems (0% vs 16.0%; P < .001) or left a suicide note (7.7% vs 30.2%; P < .001). Among suicide decedents with known mental health problems (n = 210), childhood decedents more often experienced attention-deficit disorder with or without hyperactivity (59.3% vs 29.0%; P = .002) and less often experienced depression/dysthymia (33.3% vs 65.6%; P = .001) compared with early adolescent decedents. CONCLUSIONS: These findings raise questions about impulsive responding to psychosocial adversity in younger suicide decedents, and they suggest a need for both common and developmentally-specific suicide prevention strategies during the elementary school–aged and early adolescent years. Further research should investigate factors associated with the recent increase in suicide rates among black children. PMID:27647716

Preterm birth-associated cost of early intervention services: an analysis by gestational age.

PubMed

Clements, Karen M; Barfield, Wanda D; Ayadi, M Femi; Wilber, Nancy

2007-04-01

Characterizing the cost of preterm birth is important in assessing the impact of increasing prematurity rates and evaluating the cost-effectiveness of therapies to prevent preterm delivery. To assess early intervention costs that are associated with preterm births, we estimated the program cost of early intervention services for children who were born in Massachusetts, by gestational age at birth. Using the Pregnancy to Early Life Longitudinal Data Set, birth certificates for infants who were born in Massachusetts between July 1999 and June 2000 were linked to early intervention claims through 2003. We determined total program costs, in 2003 dollars, of early intervention and mean cost per surviving infant by gestational age. Costs by plurality, eligibility criteria, provider discipline, and annual costs for children's first 3 years also were examined. Overall, 14,033 of 76,901 surviving infants received early intervention services. Program costs totaled almost $66 million, with mean cost per surviving infant of $857. Mean cost per infant was highest for children who were 24 to 31 weeks' gestational age ($5393) and higher for infants who were 32 to 36 weeks' gestational age ($1578) compared with those who were born at term ($725). Cost per surviving infant generally decreased with increasing gestational age. Among children in early intervention, mean cost per child was higher for preterm infants than for term infants. At each gestational age, mean cost per surviving infant was higher for multiples than for singletons, and annual early intervention costs were higher for toddlers than for infants. Compared with their term counterparts, preterm infants incurred higher early intervention costs. This information along with data on birth trends will inform budget forecasting for early intervention programs. Costs that are associated with early childhood developmental services must be included when considering the long-term costs of prematurity.

Late Proterozoic-Paleozoic evolution of the Arctic Alaska-Chukotka terrane based on U-Pb igneous and detrital zircon ages: Implications for Neoproterozoic paleogeographic reconstructions

USGS Publications Warehouse

Amato, J.M.; Toro, J.; Miller, E.L.; Gehrels, G.E.; Farmer, G.L.; Gottlieb, E.S.; Till, A.B.

2009-01-01

The Seward Peninsula of northwestern Alaska is part of the Arctic Alaska-Chukotka terrane, a crustal fragment exotic to western Laurentia with an uncertain origin and pre-Mesozoic evolution. U-Pb zircon geochronology on deformed igneous rocks reveals a previously unknown intermediate-felsic volcanic event at 870 Ma, coeval with rift-related magmatism associated with early breakup of eastern Rodinia. Orthogneiss bodies on Seward Peninsula yielded numerous 680 Ma U-Pb ages. The Arctic Alaska-Chukotka terrane has pre-Neoproterozoic basement based on Mesoproterozoic Nd model ages from both 870 Ma and 680 Ma igneous rocks, and detrital zircon ages between 2.0 and 1.0 Ga in overlying cover rocks. Small-volume magmatism occurred in Devonian time, based on U-Pb dating of granitic rocks. U-Pb dating of detrital zircons in 12 samples of metamorphosed Paleozoic siliciclastic cover rocks to this basement indicates that the dominant zircon age populations in the 934 zircons analyzed are found in the range 700-540 Ma, with prominent peaks at 720-660 Ma, 620-590 Ma, 560-510 Ma, 485 Ma, and 440-400 Ma. Devonian- and Pennsylvanian-age peaks are present in the samples with the youngest detrital zircons. These data show that the Seward Peninsula is exotic to western Laurentia because of the abundance of Neoproterozoic detrital zircons, which are rare or absent in Lower Paleozoic Cordilleran continental shelf rocks. Maximum depositional ages inferred from the youngest detrital age peaks include latest Proterozoic-Early Cambrian, Cambrian, Ordovician, Silurian, Devonian, and Pennsylvanian. These maximum depositional ages overlap with conodont ages reported from fossiliferous carbonate rocks on Seward Peninsula. The distinctive features of the Arctic Alaska-Chukotka terrane include Neoproterozoic felsic magmatic rocks intruding 2.0-1.1 Ga crust overlain by Paleozoic carbonate rocks and Paleozoic siliciclastic rocks with Neoproterozoic detrital zircons. The Neoproterozoic ages are

Age of acquisition in sport: starting early matters.

PubMed

Hernandez, Arturo E; Mattarella-Micke, Andrew; Redding, Richard W T; Woods, Elizabeth A; Beilock, Sian

2011-01-01

Although the age at which a skill is learned (age of acquisition [AoA]) is one of the most studied predictors of success in domains ranging from language to music, very little work has focused on this factor in sports. In order to uncover how the age at which a skill is learned relates to how athletes cognitively represent that skill, we asked a group of skilled golfers who learned to play golf before (early learners) or after (late learners) the age of 10 to take a series of putts on an indoor putting green. Golfers putted in isolation (single-task condition), while monitoring a stream of words presented over a loudspeaker (dual-task condition), or while being instructed to attend to specific aspects of their golf swing (skill-focused condition). Early and late learners putted equally well in the single-task and dual-task conditions. However, in the skill-focused condition, golfers who learned earlier performed worse than those who learned later. The results are consistent with the notion that AoA influences the manner in which sports, like other domains such as language and music, are represented in memory.

Geochronology and geochemistry of Mesozoic intrusive rocks in the Xing'an Massif of NE China: Implications for the evolution and spatial extent of the Mongol-Okhotsk tectonic regime

NASA Astrophysics Data System (ADS)

Li, Yu; Xu, Wen-Liang; Tang, Jie; Pei, Fu-Ping; Wang, Feng; Sun, Chen-Yang

2018-04-01

This study presents new zircon U-Pb-Hf and whole-rock geochemical data for intrusive rocks in the Xing'an Massif of NE China, with the aim of furthering our understanding of the evolution and spatial influence of the Mongol-Okhotsk tectonic regime. Zircon U-Pb dating indicates that five stages of Mesozoic magmatism are recorded in the Xing'an Massif, namely during the Middle Triassic ( 237 Ma), the Late Triassic ( 225 Ma), the Early Jurassic ( 178 Ma), the Middle Jurassic ( 168 Ma), and the late Early Cretaceous ( 130 Ma). The Middle Triassic-Early Jurassic intrusive rocks in the Xing'an Massif are dominantly granodiorites, monzogranites, and syenogranites that formed from magma generated by partial melting of newly accreted continental crust. Geochemistry of the Middle Triassic-Early Jurassic granitoid suites of the Xing'an Massif indicates their formation at an active continental margin setting, related to the southwards subduction of the Mongol-Okhotsk oceanic plate. The Middle Jurassic monzogranites in the Xing'an Massif are geochemically similar to adakites and have εHf(t) values (+3.8 to +5.8) and Hf two-stage model ages (TDM2; 979-850 Ma) that are indicative of derivation from magma generated by partial melting of thickened juvenile lower crust. The Middle Jurassic monzogranites formed in a compressional setting related to the closure of the Mongol-Okhotsk Ocean. The late Early Cretaceous intrusive rocks in the Xing'an Massif are dominated by A-type granitoids that are associated with bimodal volcanic rocks, suggesting their formation in an extensional environment related to either (i) delamination of a previously thickened region of the crust, associated with the Mongol-Okhotsk tectonic regime; (ii) the subduction of the Paleo-Pacific Plate; or (iii) the combined influence of these two tectonic regimes.

Telomere length and early severe social deprivation: linking early adversity and cellular aging

PubMed Central

Drury, SS; Theall, K; Gleason, MM; Smyke, AT; De Vivo, I; Wong, JYY; Fox, NA; Zeanah, CH; Nelson, CA

2012-01-01

Accelerated telomere length attrition has been associated with psychological stress and early adversity in adults; however, no studies have examined whether telomere length in childhood is associated with early experiences. The Bucharest Early Intervention Project is a unique randomized controlled trial of foster care placement compared with continued care in institutions. As a result of the study design, participants were exposed to a quantified range of time in institutional care, and represented an ideal population in which to examine the association between a specific early adversity, institutional care and telomere length. We examined the association between average relative telomere length, telomere repeat copy number to single gene copy number (T/S) ratio and exposure to institutional care quantified as the percent of time at baseline (mean age 22 months) and at 54 months of age that each child lived in the institution. A significant negative correlation between T/S ratio and percentage of time was observed. Children with greater exposure to institutional care had significantly shorter relative telomere length in middle childhood. Gender modified this main effect. The percentage of time in institutional care at baseline significantly predicted telomere length in females, whereas the percentage of institutional care at 54 months was strongly predictive of telomere length in males. This is the first study to demonstrate an association between telomere length and institutionalization, the first study to find an association between adversity and telomere length in children, and contributes to the growing literature linking telomere length and early adversity. PMID:21577215

Early cretaceous topographic growth of the Lhasaplano, Tibetan plateau: Constraints from the Damxung conglomerate

NASA Astrophysics Data System (ADS)

Wang, Jian-Gang; Hu, Xiumian; Garzanti, Eduardo; Ji, Wei-Qiang; Liu, Zhi-Chao; Liu, Xiao-Chi; Wu, Fu-Yuan

2017-07-01

Constraining the timing of early topographic growth on the Tibetan plateau is critical for any models of India-Asia collision, Himalayan orogeny and subsequent plateau development in the Cenozoic. Stratigraphic, sedimentological and provenance analysis of the Lower Cretaceous red-beds of the Damxung Conglomerate provide new key information to reconstruct the paleogeography and the tectonic evolution of the Lhasa terrane at the time. The over 700-m-thick Damxung Conglomerate documents distal alluvial fan to braidplain sedimentation passing upward to proximal alluvial fan sedimentation. Deposition began near sea level, as documented by limestone beds occurring at the base of the unit. Zircon U-Pb dating of interbedded tuff layers constrain deposition age at ca. 111 Ma. Abundance of volcanic clasts, Cretaceous U-Pb ages and Hf isotopes of detrital zircons yielding mainly negative ɛHf(t) values together with paleocurrent data indicate an active volcanic source located in the North Lhasa subterrane. Pre-Mesozoic-aged zircon, recycled quartz and (meta) sedimentary rock fragments increase up-section, indicating progressive erosional exhumation of the Paleozoic sedimentary/metasedimentary basement. The Damxung Conglomerate thus records a significant uplift and unroofing stage in the source region, implying initial topographic growth on the Lhasa terrane at early Albian time. Early Cretaceous topographic growth on the Lhasa terrane is supported by the stratigraphic record in the Linzhou basin, the Xigaze forearc basin and the southern Nima basin. In contrast, marine strata in the central-western Lhasa terrane lasted until the early Cenomanian (ca. 96 Ma), indicating diachronous marine regression on the Lhasa terrane from east to west.

Modeling old-age wealth with endogenous early-life outcomes: The case of Mexico

PubMed Central

DeGraff, Deborah S.; Wong, Rebeca

2014-01-01

This paper contributes to the literature on the life course and aging by examining the association between early-life outcomes and late-life well being, using data from the Mexican Health and Aging Study. Empirical research in this area has been challenged by the potential endogeneity of the early-life outcomes of interest, an issue which most studies ignore or downplay. Our contribution takes two forms: (1) we examine in detail the potential importance of two key life-cycle outcomes, age at marriage (a measure of family formation) and years of educational attainment (a measure of human capital investment) for old-age wealth, and (2) we illustrate the empirical value of past context variables that could help model the association between early-life outcomes and late-life well being. Our illustrative approach, matching macro-level historical policy and census variables to individual records to use as instruments in modeling the endogeneity of early-life behaviors, yields a statistically identified two-stage model of old-age wealth with minimum bias. We use simulations to show that the results for the model of wealth in old age are meaningfully different when comparing the approach that accounts for endogeneity with an approach that assumes exogeneity of early-life outcomes. Furthermore, our results suggest that in the Mexican case, models which ignore the potential endogeneity of early-life outcomes are likely to under-estimate the effects of such variables on old-age wealth. PMID:25170434

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

Depositional systems and stratigraphy of Paleozoic and Lower Mesozoic rocks in outcrop, Tassili region, southwest Algeria

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

Hertig, S.P.; Tye, R.S.; Coffield, D.Q.

1991-08-01

Paleozoic to Lower Mesozoic strata of the southeastern Algerian Tassili are traditionally subdivided by regionally extensive unconformities such as the Pan African, Taconic, Caledonian, and Hercynian. Using outcrop data from southeastern Algeria, this classic approach is modified by reinterpreting the genesis of these unconformities and rock sequences. Five prominent sequences, defined within the Paleozoic and lower Mesozoic section, usually consist of a succession of lowstand, transgressive, and highstand system tracts separated by sequence boundaries or transgressive surfaces. The Pan-African, Taconic, Caledonian, and Hercynian unconformities are sequence boundaries. Important sequence boundaries also occur within the Ordovician and Silurian sections. These sequencesmore » correlate with subsurface data in the Illizi basin and provide a framework for renewed exploration in the subsurface of the Algerian Sahara, where more than 30 billion bbl of recoverable oil and oil equivalent have been generated and trapped.« less

Where Is ELSA? The Early to Late Shift in Aging

PubMed Central

Buchler, Norbou; Dobbins, Ian G.; Cabeza, Roberto

2012-01-01

Studies of cognitive and neural aging have recently provided evidence of a shift from an early- to late-onset cognitive control strategy, linked with temporally extended activity in the prefrontal cortex (PFC). It has been uncertain, however, whether this age-related shift is unique to PFC and executive control tasks or whether the functional location might vary depending on the particular cognitive processes that are altered. The present study tested whether an early-to-late shift in aging (ELSA) might emerge in the medial temporal lobes (MTL) during a protracted context memory task comprising both anticipatory cue (retrieval preparation) and retrieval probe (retrieval completion) phases. First, we found reduced MTL activity in older adults during the early retrieval preparation phase coupled with increased MTL activity during the late retrieval completion phase. Second, we found that functional connectivity between MTL and PFC regions was higher during retrieval preparation in young adults but higher during retrieval completion in older adults, suggesting an important interactive relationship between the ELSA pattern in MTL and PFC. Taken together, these results critically suggest that aging results in temporally lagged activity even in regions not typically associated with cognitive control, such as the MTL. PMID:22114083

Palaeozoic and Mesozoic tectonic implications of Central Afghanistan

NASA Astrophysics Data System (ADS)

Sliaupa, Saulius; Motuza, Gediminas

2017-04-01

The field and laboratory studies were carried out in Ghor Province situated in the central part of Afghanistan. It straddles juxtaposition of the Tajik (alternatively, North Afghanistan) and Farah Rod blocks separated by Band-e-Bayan zone. The recent studies indicate that Band-e-Bayan zone represents highly tectonised margin of the Tajik block (Motuza, Sliaupa, 2016). The Band-e-Bayan zone is the most representative in terms of sedimentary record. The subsidence trends and sediment lithologies suggest the passive margin setting during (Cambrian?) Ordovician to earliest Carboniferous times. A change to the foredeep setting is implied in middle Carboniferous through Early Permian; the large-thickness flysh-type sediments were derived from continental island arc provenance, as suggested by chemical composition of mudtstones. This stage can be correlated to the amalgamation of the Gondwana supercontinent. The new passive-margin stage can be inferred in the Band-e-Bayan zone and Tajik blocks in the Late Permian throughout the early Late Triassic that is likely related to breaking apart of Gondwana continent. A collisional event is suggested in latest Triassic, as seen in high-rate subsidence associating with dramatic change in litholgies, occurrence of volcanic rocks and granidoid intrusions. The continental volcanic island arc derived (based on geochemical indices) terrigens prevail at the base of Jurassic that were gradually replaced by carbonate platform in the Middle Jurassic pointing to cessation of the tectonic activity. A new tectonic episode (no deposition; and folding?) took place in the Tajik and Band-e-Bayan zone in Late Jurassic. The geological section of the Farah Rod block, situated to the south, is represented by Jurassic and Cretaceous sediments overlain by sporadic Cenozoic volcanic-sedimentary succession. The lower part of the Mesozoic succession is composed of terrigenic sediments giving way to upper Lower Cretaceous shallow water carbonates implying

Analysis, prediction, and case studies of early-age cracking in bridge decks

NASA Astrophysics Data System (ADS)

ElSafty, Adel; Graeff, Matthew K.; El-Gharib, Georges; Abdel-Mohti, Ahmed; Mike Jackson, N.

2016-06-01

Early-age cracking can adversely affect strength, serviceability, and durability of concrete bridge decks. Early age is defined as the period after final setting, during which concrete properties change rapidly. Many factors can cause early-age bridge deck cracking including temperature change, hydration, plastic shrinkage, autogenous shrinkage, and drying shrinkage. The cracking may also increase the effect of freeze and thaw cycles and may lead to corrosion of reinforcement. This research paper presents an analysis of causes and factors affecting early-age cracking. It also provides a tool developed to predict the likelihood and initiation of early-age cracking of concrete bridge decks. Understanding the concrete properties is essential so that the developed tool can accurately model the mechanisms contributing to the cracking of concrete bridge decks. The user interface of the implemented computer Excel program enables the user to input the properties of the concrete being monitored. The research study and the developed spreadsheet were used to comprehensively investigate the issue of concrete deck cracking. The spreadsheet is designed to be a user-friendly calculation tool for concrete mixture proportioning, temperature prediction, thermal analysis, and tensile cracking prediction. The study also provides review and makes recommendations on the deck cracking based mainly on the Florida Department of Transportation specifications and Structures Design Guidelines, and Bridge Design Manuals of other states. The results were also compared with that of other commercially available software programs that predict early-age cracking in concrete slabs, concrete pavement, and reinforced concrete bridge decks. The outcome of this study can identify a set of recommendations to limit the deck cracking problem and maintain a longer service life of bridges.

pre-Mesozoic evolution of the basement of the Catalan Coastal Ranges: implications from geochemical and Sm-Nd isotope data of the Palaeozoic succession of the Collserola Range

NASA Astrophysics Data System (ADS)

Vilà, Miquel; Pin, Christian

2016-04-01

neighbouring terrains of SW Europe. There is a small decrease of the ɛNdT with decreasing age of sedimentation, from the Cambro-Ordovician to the Carboniferous, suggesting an increase of the amount of more 'juvenile' material. The presence of small volumes of alkaline basaltic rocks provides evidence for the input of juvenile material in the Early Palaeozoic basin and suggests that an extensional tectonic regime prevailed during the Cambro-Ordovician sedimentation. From a geodynamic point of view, overall, the analysis of the data evokes that the Palaeozoic rocks of the Catalan Coastal Ranges were part of the Northern Gondwana passive margin before the closure of the Rheic Ocean and the subsequent Variscan orogeny.

The role of Mesozoic sedimentary basin tapers on the formation of Cenozoic crustal shortening structures and foredeep in the western Sichuan Basin, China

NASA Astrophysics Data System (ADS)

Wang, M.

2017-12-01

The foreland basin records important clues of tectonic and sedimentary process of mountain-building, thus to explore its dynamic mechanism on the formation is an important issue of the mountain-basin interaction. The Longmen Shan fold-and-thrust belt and its adjacent Sichuan basin located in the eastern margin of Tibetan Plateau, are one of the most-concerned regions of studying modern mountain-building and seismic process, and are also a natural laboratory of studying the dynamics of the formation and development of foreland basin. However, it still need further explore on the mechanics of the development of the Cenozoic foreland basin and thrust-belts in the western Sichuan Basin. The Longmen Shan thrust belt has experienced multi-stages of tectonics evolution, foreland basin formation and topography growth since Late Triassic, and whether the early formed basin architecture and large Mesozoic sedimentary basin taper can influence the formation and development of the Cenozoic foreland basin and thrust belts? To solve these issues, this project aim to focus on the Cenozoic foreland basin and internal crustal shortening structures in the western Sichuan basin, on the basis of growth critical wedge taper theory. We will reconstruct the shape of multi-phases of sedimentary basin tapers, the temporal-spatial distribution of crustal shortening and thrusting sequences, and analyze the control mechanism of Mesozoic sedimentary basin taper on the formation of Cenozoic foreland basins, and final explore the interaction between the tectonics geomorphology, stress field and dynamic propagation of foreland basin.

A drowned Mesozoic bird breeding colony from the Late Cretaceous of Transylvania.

PubMed

Dyke, Gareth; Vremir, Mátyás; Kaiser, Gary; Naish, Darren

2012-06-01

Despite a rapidly improving fossil record, the reproductive biology of Mesozoic birds remains poorly known: only a handful of undisputed, isolated Cretaceous eggs (some containing embryonic remains) are known. We report here the first fossil evidence for a breeding colony of Mesozoic birds, preserved at the Late Cretaceous (Maastrichtian) Oarda de Jos (Od) site in the Sebeş area of Transylvania, Romania. A lens of calcareous mudstone with minimum dimensions of 80 cm length, 50 cm width and 20 cm depth contains thousands of tightly packed, morphologically homogenous eggshell fragments, seven near-complete eggs and neonatal and adult avialan skeletal elements. Eggshell forms 70-80 % of the matrix, and other fossils are entirely absent. The bones exhibit clear characters of the Cretaceous avialan clade Enantiornithes, and the eggshell morphology is also consistent with this identification. Both taphonomy and lithology show that the components of this lens were deposited in a single flood event, and we conclude that it represents the drowned remains of a larger enantiornithine breeding colony, swamped by rising water, washed a short distance and deposited in a shallow, low-energy pond. The same fate often befalls modern bird colonies. Such a large concentration of breeding birds suggests aquatic feeding in this species, augments our understanding of enantiornithine biology and shows that colonial nesting was not unique to crown birds.

Accretion of a Small Continental Fragment to a Larger Continental Plate: Mesozoic Ecuador as a Case-Study Area

NASA Astrophysics Data System (ADS)

Massonne, H.

2013-05-01

Only a few regions on Earth are appropriate to study processes that have happened in deeper crustal levels during the accretion of a microplate to a larger continental plate. Ecuador is one of these regions where in middle Mesozoic times a small continental fragment collided with the South-American plate. Along the suture between both plates, which occurs close to the present volcanic belt of Ecuador, high-pressure (HP) metamorphic rocks developed. These rocks, which are metapelites, metabasites, and metagranitoids, record processes during the microcontinent-continent collision (Massonne and Toulkeridis, 2012, Int. Geol. Rev. 54). The pressures, determined for the HP rocks, were as high as 14 kbar at temperatures somewhat above 500°C. The HP stage was followed by slight heating at the early exhumation. Peak temperatures up to 560°C were reached at pressures ≥10 kbar. This HP metamorphism was caused by the collision of the microplate with the South-American plate resulting in crustal thickening. The ascent of the HP rocks occurred in an exhumation channel. Before the collision, an oceanic basin existed between these plates. Probably, it was narrow as eclogite bodies are lacking in the N-S trending HP belt of Ecuador. Such bodies, especially if the eclogites had experienced pressures in excess of 20 kbar, are markers of a collision of major continental plates in Phanerozoic times with originally extended oceanic basins between these plates. In a more global context, the narrow ocean between the microplate and the South American continent is assumed to have been the westernmost portion of the Neo-Tethys which had extended to completely separate the two major fragments of former Pangaea before the opening of the southern Atlantic Ocean. This opening caused the closure of the narrow Neo-Tethys segment between the colliding microplate and the South American plate. This segment was bordered by E-W trending transform faults. A fault system (La Palma - El Guayabo fault

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.

Largest known Mesozoic multituberculate from Eurasia and implications for multituberculate evolution and biology.

PubMed

Xu, Li; Zhang, Xingliao; Pu, Hanyong; Jia, Songhai; Zhang, Jiming; Lü, Junchang; Meng, Jin

2015-10-22

A new multituberculate, Yubaartar zhongyuanensis gen. and sp. nov., is reported from the Upper Cretaceous of Luanchuan County, Henan Province, China. The holotype of the new taxon is a partial skeleton with nearly complete cranium and associated lower jaws with in situ dentitions. The new species is the southern-most record of a Late Cretaceous multituberculate from outside of the Mongolian Plateau in Asia and represents the largest known Mesozoic multituberculate from Eurasia. The new specimen displays some intriguing features previously unknown in multituberculates, such as the first evidence of replacement of the ultimate upper premolar and a unique paleopathological case in Mesozoic mammals in which the animal with a severely broken right tibia could heal and survive in natural condition. The phylogenetic analysis based on craniodental characters places Yubaartar as the immediate outgroup of Taeniolabidoidea, a group consisting of a North American clade and an Asian clade. This relationship indicates at least a faunal interchange of multituberculates before the K-Pg transition. The new evidence further supports the hypothesis that disparity in dental complexity, which relates to animal diets, increased with generic richness and disparity in body size, and that an adaptive shift towards increased herbivory across the K-Pg transitional interval.

Early-life stress and reproductive cost: A two-hit developmental model of accelerated aging?

PubMed

Shalev, Idan; Belsky, Jay

2016-05-01

Two seemingly independent bodies of research suggest a two-hit model of accelerated aging, one highlighting early-life stress and the other reproduction. The first, informed by developmental models of early-life stress, highlights reduced longevity effects of early adversity on telomere erosion, whereas the second, informed by evolutionary theories of aging, highlights such effects with regard to reproductive cost (in females). The fact that both early-life adversity and reproductive effort are associated with shorter telomeres and increased oxidative stress raises the prospect, consistent with life-history theory, that these two theoretical frameworks currently informing much research are tapping into the same evolutionary-developmental process of increased senescence and reduced longevity. Here we propose a mechanistic view of a two-hit model of accelerated aging in human females through (a) early-life adversity and (b) early reproduction, via a process of telomere erosion, while highlighting mediating biological embedding mechanisms that might link these two developmental aging processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Total petroleum systems of the Bonaparte Gulf Basin area, Australia; Jurassic, Early Cretaceous-Mesozoic; Keyling, Hyland Bay-Permian; Milligans-Carboniferous, Permian

USGS Publications Warehouse

Bishop, M.G.

1999-01-01

The Bonaparte Gulf Basin Province (USGS #3910) of northern Australia contains three important hydrocarbon source-rock intervals. The oldest source-rock interval and associated reservoir rocks is the Milligans-Carboniferous, Permian petroleum system. This petroleum system is located at the southern end of Joseph Bonaparte Gulf and includes both onshore and offshore areas within a northwest to southeast trending Paleozoic rift that was initiated in the Devonian. The Milligans Formation is a Carboniferous marine shale that sources accumulations of both oil and gas in Carboniferous and Permian deltaic, marine shelf carbonate, and shallow to deep marine sandstones. The second petroleum system in the Paleozoic rift is the Keyling, Hyland Bay-Permian. Source rocks include Lower Permian Keyling Formation delta-plain coals and marginal marine shales combined with Upper Permian Hyland Bay Formation prodelta shales. These source-rock intervals provide gas and condensate for fluvial, deltaic, and shallow marine sandstone reservoirs primarily within several members of the Hyland Bay Formation. The Keyling, Hyland Bay-Permian petroleum system is located in the Joseph Bonaparte Gulf, north of the Milligans-Carboniferous, Permian petroleum system, and may extend northwest under the Vulcan graben sub-basin. The third and youngest petroleum system is the Jurassic, Early Cretaceous-Mesozoic system that is located seaward of Joseph Bonaparte Gulf on the Australian continental shelf, and trends southwest-northeast. Source-rock intervals in the Vulcan graben sub-basin include deltaic mudstones of the Middle Jurassic Plover Formation and organic-rich marine shales of the Upper Jurassic Vulcan Formation and Lower Cretaceous Echuca Shoals Formation. These intervals produce gas, oil, and condensate that accumulates in, shallow- to deep-marine sandstone reservoirs of the Challis and Vulcan Formations of Jurassic to Cretaceous age. Organic-rich, marginal marine claystones and coals of the

Early Parenthood and Coming of Age in the 1990s.

ERIC Educational Resources Information Center

Rosenheim, Margaret K., Ed.; Testa, Mark F., Ed.

This book examines how early parenthood differs historically, cross-nationally (in Korea and Sweden), and by class, race, and age in the United States. Contributors discuss how consequential is early parenthood for the future social and economic well-being of parents and children, whether postponing childbearing beyond the teenage years would…

Primary early correction of tetralogy of Fallot irrespective of age.

PubMed

Kantorova, Andrea; Zbieranek, Kai; Sauer, Henning; Lilje, Christian; Haun, Christoph; Hraska, Viktor

2008-04-01

The policy of early repair of patients with tetralogy of Fallot, irrespective of age, as opposed to initial palliation with a shunt, remains controversial. The aim of our study was to analyze the midterm outcome of primary early correction of tetralogy of Fallot. Between 1996 and 2005, a total of 61 consecutive patients less than 6 months of age underwent primary correction of tetralogy of Fallot in two institutions. The median age at surgery was 3.3 months, and 27 patients (44%) were younger than 3 months of age, including 12 (20%) newborns. We analyzed the patients in 2 groups: those younger than 3 months of age, and those aged between 3 and 6 months. There was one early (1.6%), and one late death. Actuarial survival was 98.4%, 96.7%, 96.7% at 1, 5, and 10 years respectively, with a median follow up of 4.5 years. There was no difference in survival, bypass time, lengths of ventilation, and hospital stay between the groups. A transjunctional patch was placed significantly more often in the patients younger than 3 months (p = 0.039), with no adverse effect on survival and morbidity during the follow-up. Freedom from reoperation was 98.2%, 92.2%, and 83% at 1, 5, and 10 years respectively, with no difference between the groups. Elective primary repair of tetralogy of Fallot in asymptomatic patients is delayed beyond 3 months of age. In symptomatic patients, primary repair of tetralogy of Fallot is performed irrespective of age, weight and preoperative state. This approach is safe, and provides an excellent midterm outcome with acceptable morbidity and rates of reintervention. The long-term benefits of this approach must be established by careful follow-up, with particular emphasis on arrhythmias, right ventricular function, and exercise performance.

Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic.

PubMed

Martinez, Mathieu; Dera, Guillaume

2015-10-13

Eccentricity, obliquity, and precession are cyclic parameters of the Earth's orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce "grand orbital cycles," but the behavior and the paleoenvironmental consequences of these cycles remain debated for the Mesozoic owing to the chaotic diffusion of the solar system in the past. Here, we test for these cycles from the Jurassic to the Early Cretaceous by analyzing new stable isotope datasets reflecting fluctuations in the carbon cycle and seawater temperatures. Our results document a prominent cyclicity of ∼9 My in the carbon cycle paced by changes in the seasonal dynamics of hydrological processes and long-term sea level fluctuations. These paleoenvironmental changes are linked to a great eccentricity cycle consistent with astronomical solutions. The orbital forcing signal was mainly amplified by cumulative sequestration of organic matter in the boreal wetlands under greenhouse conditions. Finally, we show that the ∼9-My cycle faded during the Pliensbachian, which could either reflect major paleoenvironmental disturbances or a chaotic transition affecting this cycle.

Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic

PubMed Central

Martinez, Mathieu; Dera, Guillaume

2015-01-01

Eccentricity, obliquity, and precession are cyclic parameters of the Earth’s orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce ‟grand orbital cycles,” but the behavior and the paleoenvironmental consequences of these cycles remain debated for the Mesozoic owing to the chaotic diffusion of the solar system in the past. Here, we test for these cycles from the Jurassic to the Early Cretaceous by analyzing new stable isotope datasets reflecting fluctuations in the carbon cycle and seawater temperatures. Our results document a prominent cyclicity of ∼9 My in the carbon cycle paced by changes in the seasonal dynamics of hydrological processes and long-term sea level fluctuations. These paleoenvironmental changes are linked to a great eccentricity cycle consistent with astronomical solutions. The orbital forcing signal was mainly amplified by cumulative sequestration of organic matter in the boreal wetlands under greenhouse conditions. Finally, we show that the ∼9-My cycle faded during the Pliensbachian, which could either reflect major paleoenvironmental disturbances or a chaotic transition affecting this cycle. PMID:26417080

Sub-basaltic Imaging of Ethiopian Mesozoic Sediments Using Surface Wave Dispersion

NASA Astrophysics Data System (ADS)

Mammo, T.; Maguire, P.; Denton, P.; Cornwell, D.

2003-12-01

The Ethiopia Afar Geoscientific Lithospheric Experiment (EAGLE) involved the deployment of a 400km NW-SE cross-rift profile across the Main Ethiopian Rift. The profile extended to about 150km on either side of the rift over the uplifted Ethiopian plateau characterized by voluminous Tertiary flood basalts covering a thick sequence of Mesozoic sediments. These consist of three major stratigraphic units, the Cretaceous Upper Sandstone (medium grained, friable and moderately to well-sorted) overlying the Jurassic Antalo limestone (with intercalations of marl, shale, mudstone and gypsum) above the Triassic Adigrat sandstone. These sediments are suggested to be approximately 1.5km thick at the north-western end of the profile, thickening to the south-east. They are considered a possible hydrocarbon reservoir and therefore crucial to the economy of Ethiopia. The EAGLE cross-rift profile included the deployment of 97 Guralp 6TD seismometers (30sec - 80Hz bandwidth) at a nominal 5km spacing. A 5.75 tonne explosion from the Muger quarry detonated specifically for the EAGLE project generated the surface waves used in this study. Preliminary processing involving the multiple filter technique has enabled the production of group velocity dispersion curves. These curves have been inverted to provide 1-D shear wave models, with the intention of providing an in-line cross-rift profile of Mesozoic sediment thickness. Preliminary results suggest that the sediments can be distinguished from both overlying plateau basalt and underlying basement, with their internal S-wave velocity structure possibly indicating that the three sediment units described above can be separately identified.

Search for clues to Mesozoic graben on Long Island

USGS Publications Warehouse

Rogers, W.B.; Aparisi, M.; Sirkin, L.

1989-01-01

The position of Long Island between the Hartford Basin of Connecticut and graben structures reported from seismic reflection studies offshore to the south of the island suggests the possibility that other grabens associated with the early Mesozoic rifting might be buried beneath central Long Island. The hypothesis that post-rift tectonic activity would be related to the rift grabens and that such activity would be expressed in the post-rift sedimentary deposits led to a study of the Cretaceous and Pleistocene section to seek clues for buried grabens on Long Island. The Pleistocene glacial deposits in central and eastern Long Island have been mapped and a pollen zonation in the Upper Cretaceous section in the central part established. This work, combined with literature research, suggests the following: 1. (1) In central Long Island, the spacing of wells which reach basement enables a NE- striking zone free of basement samples to be defined where a buried graben could occur. This zone is referred to as the "permissible zone" because within it the data permit the existence of a hidden graben. 2. (2) The abrupt changes in the thickness of some pollen zones in the Upper Cretaceous deposits of central Long Island may be related to Cretaceous faulting. 3. (3) Buried preglacial valleys, the confluence of glacial lobes and major glacial outwash channels seem concentrated in west central and central Long Island. The loci of these drainage features may reflect structural control by a basement depression. 4. (4) The "permissible zone" is aligned with the zone of structures in an offshore zone south of central Long Island and with the Hartford Basin in Connecticut. Geophysical anomalies also fit into this pattern. 5. (5) A definitive answer to the question of a buried graben on Long Island will require a seismic line across the "permissible zone", or further drilling. ?? 1989.

New Fossil Evidence on the Sister-Group of Mammals and Early Mesozoic Faunal Distributions

NASA Astrophysics Data System (ADS)

Shubin, Neil H.; Crompton, A. W.; Sues, Hans-Dieter; Olsen, Paul E.

1991-03-01

Newly discovered remains of highly advanced mammal-like reptiles (Cynodontia: Tritheledontidae) from the Early Jurassic of Nova Scotia, Canada, have revealed that aspects of the characteristic mammalian occlusal pattern are primitive. Mammals and tritheledontids share an homologous pattern of occlusion that is not seen in other cynodonts. The new tritheledontids represent the first definite record of this family from North America. The extreme similarity of North American and African tritheledontids supports the hypothesis that the global distribution of terrestrial tetrapods was homogeneous in the Early Jurassic. This Early Jurassic cosmopolitanism represents the continuation of a trend toward increased global homogeneity among terrestrial tetrapod communities that began in the late Paleozoic.

Early age damage quantification of actively restrained concrete using inverse analysis

NASA Astrophysics Data System (ADS)

Albanna, Ali

Early-age cracking can be a significant problem in concrete pavements, floors, and bridge decks. Cracking occurs when the volumetric changes associated with drying, hydration, and temperature reduction are prevented. Good knowledge about the characteristics of early age concrete is necessary to achieve reliable crack control. Volumetric changes due to shrinkage depend on the type of concrete and its components. It has been found that light weight aggregates can work as internal reservoir to supply the concrete matrix with water that is needed during the early age; this process is called internal curing. Also fibers can give more ductility to the concrete and produce less shrinkage. There is a need to better understand the effects of early age uniaxial restraint on long term concrete mechanical performance. In this study, two types of concrete were studied (high performance fiber reinforced concrete and ordinary concrete) under actively restrained loading conditions to assess the effect on the long term fracture toughness and energy. Single edge notched specimens having dimensions of 250 mm x 150 mm x 75 mm and a notch to depth ratio of 0.33 were caste and used in both direct tension and three point bending. The direct tension tests were carried out on a direct tension loading frame constructed in house that was supplied with two mechanical jacks and load cell.

Mesozoic mammals from Arizona: new evidence on Mammalian evolution.

PubMed

Jenkins, F A; Crompton, A W; Downs, W R

1983-12-16

Knowledge of early mammalian evolution has been based on Old World Late Triassic-Early Jurassic faunas. The discovery of mammalian fossils of approximately equivalent age in the Kayenta Formation of northeastern Arizona gives evidence of greater diversity than known previously. A new taxon documents the development of an angular region of the jaw as a neomorphic process, and represents an intermediate stage in the origin of mammalian jaw musculature.

Collapse of proteostasis represents an early molecular event in Caenorhabditis elegans aging.

PubMed

Ben-Zvi, Anat; Miller, Elizabeth A; Morimoto, Richard I

2009-09-01

Protein damage contributes prominently to cellular aging. To address whether this occurs at a specific period during aging or accumulates gradually, we monitored the biochemical, cellular, and physiological properties of folding sensors expressed in different tissues of C. elegans. We observed the age-dependent misfolding and loss of function of diverse proteins harboring temperature-sensitive missense mutations in all somatic tissues at the permissive condition. This widespread failure in proteostasis occurs rapidly at an early stage of adulthood, and coincides with a severely reduced activation of the cytoprotective heat shock response and the unfolded protein response. Enhancing stress responsive factors HSF-1 or DAF-16 suppresses misfolding of these metastable folding sensors and restores the ability of the cell to maintain a functional proteome. This suggests that a compromise in the regulation of proteostatic stress responses occurs early in adulthood and tips the balance between the load of damaged proteins and the proteostasis machinery. We propose that the collapse of proteostasis represents an early molecular event of aging that amplifies protein damage in age-associated diseases of protein conformation.

Zircon U-Pb age of the Pescadero felsite: A late Cretaceous igneous event in the forearc, west-central California Coast Ranges

USGS Publications Warehouse

Ernst, W.G.; Martens, U.C.; McLaughlin, R.J.; Clark, J.C.; Moore, Diane E.

2011-01-01

Weathered felsite is associated with the late Campanian-Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio-Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ~185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ?? prehnite ?? laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe-reverse geometry (SHRIMPRG) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefl y Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86-90 Ma. Refl ecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio-Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ~100 km to the east in the Diablo Range- San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper Cretaceous

An early Cambrian greenhouse climate.

PubMed

Hearing, Thomas W; Harvey, Thomas H P; Williams, Mark; Leng, Melanie J; Lamb, Angela L; Wilby, Philip R; Gabbott, Sarah E; Pohl, Alexandre; Donnadieu, Yannick

2018-05-01

The oceans of the early Cambrian (~541 to 509 million years ago) were the setting for a marked diversification of animal life. However, sea temperatures-a key component of the early Cambrian marine environment-remain unconstrained, in part because of a substantial time gap in the stable oxygen isotope (δ 18 O) record before the evolution of euconodonts. We show that previously overlooked sources of fossil biogenic phosphate have the potential to fill this gap. Pristine phosphatic microfossils from the Comley Limestones, UK, yield a robust δ 18 O signature, suggesting sea surface temperatures of 20° to 25°C at high southern paleolatitudes (~65°S to 70°S) between ~514 and 509 million years ago. These sea temperatures are consistent with the distribution of coeval evaporite and calcrete deposits, peak continental weathering rates, and also our climate model simulations for this interval. Our results support an early Cambrian greenhouse climate comparable to those of the late Mesozoic and early Cenozoic, offering a framework for exploring the interplay between biotic and environmental controls on Cambrian animal diversification.

Extension style in the Orphan Basin during the Mesozoic North Atlantic rifting

NASA Astrophysics Data System (ADS)

Gouiza, Mohamed; Hall, Jeremy

2013-04-01

The Orphan Basin, lying along the Newfoundland passive continental margin, has formed in Mesozoic time during the opening of the North Atlantic Ocean and the breakup of Iberia/Eurasia from North America. Regional deep seismic reflection profiles across the basin indicate that the Neoproterozoic basement has been affected by repeated extensional episodes between the Late Triassic/Jurassic and the Early Cretaceous. Deformation initiated in the eastern part of the Orphan basin in the Jurassic and migrated toward the west in the Early Cretaceous, resulting in numerous rift structures filled with Jurassic-Lower Cretaceous syn-rift successions and sealed by thick Upper Cretaceous-Cenozoic post-rift sediments. The seismic data show an extremely attenuated crust underneath the eastern and western part of the deep basin, forming two sub-basins associated with the development of rifting. The two sub-basins are separated by a wide structural high with a relatively thick crust and are bounded to the west by the continental shelf domain. Restoration of the Orphan Basin along a 2D crustal section (520 km long), yields a total amount of stretching of about 144 km, while the total crustal thinning indicates an extension of around 250 km, assuming mass conservation along the section and an initial crustal thickness of 28 km. Brittle deformation accommodated by normal faults is documented in the seismic profiles and affected essentially the present-day upper portion of the crust, and represents only 60% of the total extension which thinned the Orphan crust. The remaining crustal thinning must involve other deformation processes which are not (easily) recognizable in the seismic data. We propose two models that could explain discrepancies between brittle deformation and total crustal thinning during lithospheric extension. The first model assumes the reactivation of pre-rift inherited structures, which act as crustal-scale detachments during the early stages of rifting. The second

Geochemical and Nd-Sr isotopic constraints on the genesis of Mesozoic alkaline magmatism in Tu Le basin, Northern Vietnam

NASA Astrophysics Data System (ADS)

Tran, T. A.; Tran, T. H.; Lan, C. Y.; Chung, S. L.; Lo, C. H.; Wang, P. L.; Lee, T. Y.; Merztman, S. A.

2003-04-01

Mesozoic alkaline magmatism that occurred in the Tu Le basin, northern Vietnam, resulted in several igneous complexes composed of different lithologies. They are represented by the Suoi Be basalts, the Ban Hat gabbros, the Phu Sa Phin syenites, the Van Chan rhyolites and the Ngoi Thia rhyolites, which overall show a bimodal chemical composition. Ar-Ar dating and stratigraphic data indicate that the magmatism clustered in two periods, i.e., the middle-late Jurassic (176 - 145 Ma) and the late Cretaceous-earliest Tertiary (80 - 60 Ma), respectively. The Suoi Be basalts, the Ban Hat gabbros, the Van Chan rhyolites and some of the Phu Sa Phin syenites formed in the Jurassic stage, whilst the Ngoi Thia rhyolites and most of the Phu Sa Phin syenites formed in the Cretaceous stage. The mafic Jurassic magmas are silica-undersaturated (SiO_2 = 44-49 wt.%) and sodium-rich, with low MgO (˜7-3 wt.%) but high TiO_2 (3.6-2.0 wt.%). They exhibit various degrees of LREE-enrichment, with (La)N = 79-290, 5.5<(La/Yb)N<20 (chondrite-normalized) and without apparent Eu anomalies. On the other hand, the felsic magmas of Jurassic and Cretaceous ages show similar geochemical features, with SiO_2 = 62-78 wt.%, (Na_2O+K_2O) = 5.3-10.2 wt.%, significant Eu anomalies (Eu/Eu*= 0.1-0.54), and enrichments in the HFSE (Nb, Ta, Zr) and LILE (Rb, Th, U, K) along with pronounced depletions in Ba, Sr, P and Ti in the primitive mantle-normalized multi-element variation diagram. They are geochemically comparable to A-type granitoids. The mafic and felsic magmas have distinguishable Nd isotope ratios. In contrast to the Jurassic and Cretaceous felsic magmas that have uniform eNd(T) values (-1.5 to -2.8), the Jurassic mafic rocks are marked by more radiogenic and heterogenous eNd(T) values (-1.9 to -8.9), implying different magma sources and independent petrogenetic processes involved in generation of the Jurassic bimodal magmatism. Combining with relevant geological data from northern Vietnam and SW

Fossil evidence of avian crops from the Early Cretaceous of China

PubMed Central

Zheng, Xiaoting; Martin, Larry D.; Zhou, Zhonghe; Burnham, David A.; Zhang, Fucheng; Miao, Desui

2011-01-01

The crop is characteristic of seed-eating birds today, yet little is known about its early history despite remarkable discoveries of many Mesozoic seed-eating birds in the past decade. Here we report the discovery of some early fossil evidence for the presence of a crop in birds. Two Early Cretaceous birds, the basal ornithurine Hongshanornis and a basal avian Sapeornis, demonstrate that an essentially modern avian digestive system formed early in avian evolution. The discovery of a crop in two phylogenetically remote lineages of Early Cretaceous birds and its absence in most intervening forms indicates that it was independently acquired as a specialized seed-eating adaptation. Finally, the reduction or loss of teeth in the forms showing seed-filled crops suggests that granivory was possibly one of the factors that resulted in the reduction of teeth in early birds. PMID:21896733

Early-late life trade-offs and the evolution of ageing in the wild.

PubMed

Lemaître, Jean-François; Berger, Vérane; Bonenfant, Christophe; Douhard, Mathieu; Gamelon, Marlène; Plard, Floriane; Gaillard, Jean-Michel

2015-05-07

Empirical evidence for declines in fitness components (survival and reproductive performance) with age has recently accumulated in wild populations, highlighting that the process of senescence is nearly ubiquitous in the living world. Senescence patterns are highly variable among species and current evolutionary theories of ageing propose that such variation can be accounted for by differences in allocation to growth and reproduction during early life. Here, we compiled 26 studies of free-ranging vertebrate populations that explicitly tested for a trade-off between performance in early and late life. Our review brings overall support for the presence of early-late life trade-offs, suggesting that the limitation of available resources leads individuals to trade somatic maintenance later in life for high allocation to reproduction early in life. We discuss our results in the light of two closely related theories of ageing-the disposable soma and the antagonistic pleiotropy theories-and propose that the principle of energy allocation roots the ageing process in the evolution of life-history strategies. Finally, we outline research topics that should be investigated in future studies, including the importance of natal environmental conditions in the study of trade-offs between early- and late-life performance and the evolution of sex-differences in ageing patterns. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Early life determinants of frailty in old age: the Helsinki Birth Cohort Study.

PubMed

Haapanen, M J; Perälä, M M; Salonen, M K; Kajantie, E; Simonen, M; Pohjolainen, P; Eriksson, J G; von Bonsdorff, M B

2018-04-12

there is evidence suggesting that several chronic diseases have their origins in utero and that development taking place during sensitive periods may affect the aging process. We investigated whether early life determinants would be associated with frailty in old age. at a mean age of 71 years, 1,078 participants belonging to the Helsinki Birth Cohort Study were assessed for frailty according to the Fried frailty criteria. Early life measurements (birth weight, length, mother body mass index [BMI] and parity) were obtained from birth, child welfare and school health records. Multinomial regression analysis was used to assess the association between early life determinants and frailty in old age. weight, length and BMI at birth were all inversely associated with frailty in old age. A 1 kg increase in birth weight was associated with a lower relative risk ratio (RRR) of frailty (age and sex-adjusted RRR = 0.40, 95% CI: 0.19, 0.82) compared to non-frailty. Associations persisted after adjusting for several confounding factors. Compared to cohort members in the upper middle class, those who as adults worked as manual workers or belonged to the lower middle class, were at an increased risk of frailty. those who were small at birth were at an increased risk of developing frailty in old age, suggesting that frailty is at least partly programmed in early life. A less privileged socioeconomic status in adulthood was associated with an increased risk of frailty in old age.

Highly differentiated magmas linked with polymetallic mineralization: A case study from the Cuihongshan granitic intrusions, Lesser Xing'an Range, NE China

NASA Astrophysics Data System (ADS)

Fei, Xianghui; Zhang, Zhaochong; Cheng, Zhiguo; Santosh, M.; Jin, Ziliang; Wen, Bingbing; Li, Zixi; Xu, Lijuan

2018-03-01

The genetic link between granitoids and polymetallic skarn mineralization has remained equivocal. The Cuihongshan skarn-porphyry W-Mo-Pb-Zn-(Fe-Cu) deposit in the eastern part of the Central Asian Orogenic Belt provides a unique example to address this issue. The major rock types in the mine area are Early Paleozoic intrusions composed of biotite syenogranite and biotite porphyritic granite and Early Mesozoic intrusions represented by porphyritic quartz monzonite, biotite monzogranite, and porphyritic granite. The diagnostic mineralogical and geochemical features indicate that the rocks belong to A2-type granites. The Early Paleozoic suite shows zircon U-Pb ages of 501 Ma, and εHf(t) values of - 4.4 to + 2.7 and + 2.4 to + 7.6, respectively. In combination with their coherent geochemical trends, these rocks are inferred to be products of in-situ differentiation. Although the Mesozoic suite shows crystallization ages of 194-196 Ma, εHf(t) values are in the range of - 2.5 to + 7.5 for the porphyritic quartz monzonite, the - 1.8 to + 4.5 values for the monzogranite and the + 2.3 to + 8.0 range for the porphyritic granite. The porphyritic quartz monzonite displays distinct mineral assemblage and shows significant compositional gap with the other two lithofacies. In contrast, the monzogranite and porphyritic granite have similar geochemical features, and are thus inferred to be co-magmatic. Considering the high SiO2 contents, variable εHf(t) (- 4.4 to + 8.0) and εNd(t) values (- 8.4 to + 0.28) for the two suites, we infer that both episodes of granitoid magmatism resulted from partial melting of crustal materials with a mixed source containing varying proportions of juvenile and Precambrian crustal components. The Early Mesozoic porphyritic granite shows a highly evolved F-rich geochemical affinity, and experienced magma-fluid interaction. Cassiterite from the calcic skarn and the magnesian skarn that coexists with magnetite orebodies shows a mean U-Pb age of 195

Gestational age-dependent risk factors for preterm birth: associations with maternal education and age early in gestation.

PubMed

Auger, Nathalie; Abrahamowicz, Michal; Wynant, Willy; Lo, Ernest

2014-05-01

Preterm birth (PTB) before 37 weeks can occur over a wide range of gestational ages, but few studies have assessed if associations between risk factors and PTB vary over the duration of gestation. We sought to evaluate if associations between two major risk factors (maternal education and age) and PTB depend on gestational age at delivery. We estimated hazard ratios of PTB for education and age in a time-to-event analysis using a retrospective cohort of 223,756 live singleton births from the province of Québec, Canada for the years 2001-2005. Differences in hazards of maternal education and age with PTB were assessed over gestational age in a Cox proportional hazards model using linear and nonlinear time interaction terms, adjusting for maternal characteristics. Associations of PTB with lower (vs. higher) education and older (vs. younger) age strengthened progressively at earlier gestational ages, such that the risk of PTB for maternal education and age was not constant over the course of gestation. Associations of PTB with risk factors such as maternal low education and older age may be stronger early in gestation. Models that capture the time-dependent nature of PTB may be useful when the goal is to assess associations at low gestational ages, and to avoid masked or biased associations early in gestation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Boosting Early Development: The Mixed Effects of Kindergarten Enrollment Age

ERIC Educational Resources Information Center

Zhang, Jiahui; Xin, Tao

2012-01-01

This study aimed to investigate the effects of kindergarten enrollment age on four-year-old Chinese children's early cognition and problem behavior using multilevel models. The sample comprised of 1,391 pre-school children (the mean age is 4.58 years old) from 74 kindergartens in six different provinces. The results demonstrated curvilinear…

Organizations' Ways of Employing Early Retirees: The Role of Age-Based HR Policies.

PubMed

Oude Mulders, Jaap; Henkens, Kène; Schippers, Joop

2015-06-01

We examine whether from an organizational perspective it is possible to distinguish different ways of employing early retirees and explore how the employment of early retirees is related to the application of 4 age-based human resource (HR) policies, namely demotion, offering training opportunities to older workers, offering early retirement, and allowing flexible working hours. We perform a latent class analysis on a sample of 998 Dutch organizations in order to categorize them based on 3 dimensions of their employment of early retirees. We then run a multinomial logistic regression to relate the employment of early retirees to the 4 age-based HR policies. We distinguish 4 types of organizations based on their way of employing early retirees: nonusers (52.6%), users for mainly standard work (20.8%), users for mainly nonstandard work (9.8%), and users for standard and nonstandard work (16.7%). We find that organizations that apply demotion, offer early retirement, and allow flexible working hours are more likely to be users for mainly standard work. Also, organizations that do not offer early retirement are less likely to employ early retirees. Age-based HR policies, especially demotion, offering early retirement, and allowing flexible working hours, are conducive to the employment of early retirees for mainly standard work. Broader implementation of these policies may provide opportunities for older workers to make a more gradual transition from work to retirement. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Acoustic Emission Behavior of Early Age Concrete Monitored by Embedded Sensors.

PubMed

Qin, Lei; Ren, Hong-Wei; Dong, Bi-Qin; Xing, Feng

2014-10-02

Acoustic emission (AE) is capable of monitoring the cracking activities inside materials. In this study, embedded sensors were employed to monitor the AE behavior of early age concrete. Type 1-3 cement-based piezoelectric composites, which had lower mechanical quality factor and acoustic impedance, were fabricated and used to make sensors. Sensors made of the composites illustrated broadband frequency response. In a laboratory, the cracking of early age concrete was monitored to recognize different hydration stages. The sensors were also embedded in a mass concrete foundation to localize the temperature gradient cracks.

Paleozoic to early Cenozoic cooling and exhumation of the basement underlying the eastern Puna plateau margin prior to plateau growth

NASA Astrophysics Data System (ADS)

Insel, N.; Grove, M.; Haschke, M.; Barnes, J. B.; Schmitt, A. K.; Strecker, M. R.

2012-12-01

Constraining the pre-Neogene history of the Puna plateau is crucial for establishing the initial conditions that attended the early stage evolution of the southern extent of the Andean plateau. We apply high- to low-temperature thermochronology data from plutonic rocks in northwestern Argentina to quantify the Paleozoic, Mesozoic and early Tertiary cooling history of the Andean crust. U-Pb crystallization ages of zircons indicate that pluton intrusion occurred during the early mid-Ordovician (490-470 Ma) and the late Jurassic (160-150 Ma). Lower-temperature cooling histories from 40Ar/39Ar analyses of K-feldspar vary substantially. Basement rocks underlying the western Puna resided at temperatures below 200°C (<6 km depth) since the Devonian (˜400 Ma). In contrast, basement rocks underlying the southeastern Puna were hotter (˜200-300°C) throughout the Paleozoic and Jurassic and cooled to temperatures of <200°C by ˜120 Ma. The southeastern Puna basement records a rapid cooling phase coeval with active extension of the Cretaceous Salta rift at ˜160-100 Ma that we associate with tectonic faulting and lithospheric thinning. The northeastern Puna experienced protracted cooling until the late Cretaceous with temperatures <200°C during the Paleocene. Higher cooling rates between 78 and 55 Ma are associated with thermal subsidence during the postrift stage of the Salta rift and/or shortening-related flexural subsidence. Accelerated cooling and deformation during the Eocene was focused within a narrow zone along the eastern Puna/Eastern Cordillera transition that coincides with Paleozoic/Mesozoic structural and thermal boundaries. Our results constrain regional erosion-induced cooling throughout the Cenozoic to have been less than ˜150°C, which implies total Cenozoic denudation of <6-4 km.

The Association of Kindergarten Entry Age with Early Literacy Outcomes

ERIC Educational Resources Information Center

Huang, Francis L.; Invernizzi, Marcia A.

2012-01-01

The authors investigated whether age at kindergarten entry was associated with early literacy achievement gaps and if these gaps persisted over time. Using the kindergarten age eligibility cutoff date, they created 2 groups of students who represented the oldest and youngest children in a cohort of students in high-poverty, low-performing schools.…

Working Memory in Early-School-Age Children with Asperger's Syndrome

ERIC Educational Resources Information Center

Cui, Jifang; Gao, Dingguo; Chen, Yinghe; Zou, Xiaobing; Wang, Ya

2010-01-01

Using a battery of working memory span tasks and n-back tasks, this study aimed to explore working memory functions in early-school-age children with Asperger's syndrome (AS). Twelve children with AS and 29 healthy children matched on age and IQ were recruited. Results showed: (a) children with AS performed better in digit and word recall tasks,…

Early growth patterns are associated with intelligence quotient scores in children born small-for-gestational age.

PubMed

Varella, Marcia H; Moss, William J

2015-08-01

To assess whether patterns of growth trajectory during infancy are associated with intelligence quotient (IQ) scores at 4 years of age in children born small-for-gestational age (SGA). Children in the Collaborative Perinatal Project born SGA were eligible for analysis. The primary outcome was the Stanford-Binet IQ score at 4 years of age. Growth patterns were defined based on changes in weight-for-age z-scores from birth to 4 months and 4 to 12 months of age and consisted of steady, early catch-up, late catch-up, constant catch-up, early catch-down, late catch-down, constant catch-down, early catch-up & late catch-down, and early catch-down & late catch-up. Multivariate linear regression was used to assess associations between patterns of growth and IQ. We evaluated patterns of growth and IQ in 5640 children. Compared with children with steady growth, IQ scores were 2.9 [standard deviation (SD)=0.54], 1.5 (SD=0.63), and 2.2 (SD=0.9) higher in children with early catch-up, early catch-up and later catch-down, and constant catch-up growth patterns, respectively, and 4.4 (SD=1.4) and 3.9 (SD=1.5) lower in children with early catch-down & late catch-up, and early catch-down growth patterns, respectively. Patterns in weight gain before 4 months of age were associated with differences in IQ scores at 4 years of age, with children with early catch-up having slightly higher IQ scores than children with steady growth and children with early catch-down having slightly lower IQ scores. These findings have implications for early infant nutrition in children born SGA. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Regulation of body temperature by some Mesozoic marine reptiles.

PubMed

Bernard, Aurélien; Lécuyer, Christophe; Vincent, Peggy; Amiot, Romain; Bardet, Nathalie; Buffetaut, Eric; Cuny, Gilles; Fourel, François; Martineau, François; Mazin, Jean-Michel; Prieur, Abel

2010-06-11

What the body temperature and thermoregulation processes of extinct vertebrates were are central questions for understanding their ecology and evolution. The thermophysiologic status of the great marine reptiles is still unknown, even though some studies have suggested that thermoregulation may have contributed to their exceptional evolutionary success as apex predators of Mesozoic aquatic ecosystems. We tested the thermal status of ichthyosaurs, plesiosaurs, and mosasaurs by comparing the oxygen isotope compositions of their tooth phosphate to those of coexisting fish. Data distribution reveals that these large marine reptiles were able to maintain a constant and high body temperature in oceanic environments ranging from tropical to cold temperate. Their estimated body temperatures, in the range from 35 degrees +/- 2 degrees C to 39 degrees +/- 2 degrees C, suggest high metabolic rates required for predation and fast swimming over large distances offshore.

Early Childhood Predictors of School-Age Children's Reports of Sibling Relationships.

ERIC Educational Resources Information Center

Poris, Michelle P.

This study examined the associations between the early family environment, older siblings' early characteristics, and later sibling relationships. Participating were 37 families with infants and preschool-age older siblings who were observed in the laboratory at 3 time points and followed-up 3 years later. Findings indicated that parents' early…

School Age Outcomes of Children Diagnosed Early and Later with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Clark, Megan Louise Erin; Vinen, Zoe; Barbaro, Josephine; Dissanayake, Cheryl

2018-01-01

Early diagnosis of Autism Spectrum Disorder is considered best practice, increasing access to early intervention. Yet, many children are diagnosed after 3-years. The current study investigated the school age outcomes of children who received an early and later diagnosis of ASD. The cognitive and behavioural outcomes of children diagnosed early (n…

Erosional history of the Appalachians as recordeed in detrital zircon fission-track ages and lithic detritus in Atlantic Coastal Plain sediments

USGS Publications Warehouse

Naeser, C.W.; Naeser, N.D.; Edwards, Lucy E.; Weems, Robert E.; Southworth, C. Scott; Newell, Wayne L.

2016-01-01

Comparison of fission-track (FT) ages of detrital zircons recovered from Atlantic Coastal Plain sediments to FT ages of zircons from bedrock in source terranes in the Appalachians provides a key to understanding the provenance of the sediments and, in turn, the erosional and depositional history of the Atlantic passive margin.In Appalachian source terranes, the oldest zircon fission-track (ZFT) ages from bedrock in the western Appalachians (defined for this paper as the Appalachian Plateau, Valley and Ridge, and far western Blue Ridge) are notably older than the oldest ages from bedrock in the eastern Appalachians (Piedmont and main part of the Blue Ridge). The age difference is seen both in ZFT sample ages and in individual zircon grain ages and reflects differences in the thermotectonic history of the rocks. In the east, ZFT data indicate that the rocks cooled from temperatures high enough to partially or totally reset ZFT ages during the Paleozoic and (or) Mesozoic. The majority of the rocks are interpreted to have cooled through the ZFT closure temperature (∼235 °C) at various times during the late Paleozoic Alleghanian orogeny. In contrast, most of the rocks sampled in the western Appalachians have never been heated to temperatures high enough to totally reset their ZFT ages. Reflecting their contrasting thermotectonic histories, nearly 80 percent of the sampled western rocks yield one or more zircon grains with very old FT ages, in excess of 800 Ma; zircon grains yielding FT ages this old have not been found in rocks in the Piedmont and main part of the Blue Ridge. The ZFT data suggest that the asymmetry of zircon ages of exposed bedrock in the eastern and western Appalachians was in evidence by no later than the Early Cretaceous and probably by the Late Triassic.Detrital zircon suites from sands collected in the Atlantic Coastal Plain provide a record of detritus eroded from source terranes in the Appalachians during the Mesozoic and Cenozoic. In Virginia

Diversity of developmental patterns in achelate lobsters-today and in the Mesozoic.

PubMed

Haug, Joachim T; Audo, Denis; Charbonnier, Sylvain; Haug, Carolin

2013-11-01

Modern achelate lobsters, slipper and spiny lobsters, have a specific post-embryonic developmental pattern with the following phases: phyllosoma, nisto (slipper lobsters) or puerulus (spiny lobsters), juvenile and adult. The phyllosoma is a peculiar larva, which transforms through a metamorphic moult into another larval form, the nisto or puerulus which largely resembles the juvenile. Unlike the nisto and puerulus, the phyllosoma is characterised by numerous morphological differences to the adult, e.g. a thin head shield, elongate appendages, exopods on these appendages and a special claw. Our reinvestigation of the 85 million years old fossil "Eryoneicus sahelalmae" demonstrates that it represents an unusual type of achelatan lobster larva, characterised by a mixture of phyllosoma and post-phyllosoma characters. We ascribe it to its own genus: Polzicaris nov. gen. We study its significance by comparisons with other cases of Mesozoic fossil larvae also characterised by a mixture of characters. Accordingly, all these larvae are interpreted as ontogenetic intermediates between phyllosoma and post-phyllosoma morphology. Remarkably, most of the larvae show a unique mixture of retained larval and already developed post-larval features. Considering the different-and incompatible-mixture of characters of each of these larvae and their wide geographical and temporal distribution, we interpret all these larvae as belonging to distinct species. The particular character combinations in the different larvae make it currently difficult to reconstruct an evolutionary scenario with a stepwise character acquisition. Yet, it can be concluded that a larger diversity of larval forms and developmental patterns occurred in Mesozoic than in modern faunas.

Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating

PubMed Central

Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

2015-01-01

The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900–1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology. PMID:26488413

Proterozoic to Mesozoic evolution of North-West Africa and Peri-Gondwana microplates: Detrital zircon ages from Morocco and Canada

NASA Astrophysics Data System (ADS)

Marzoli, Andrea; Davies, Joshua H. F. L.; Youbi, Nasrrddine; Merle, Renaud; Dal Corso, Jacopo; Dunkley, Daniel J.; Fioretti, Anna Maria; Bellieni, Giuliano; Medina, Fida; Wotzlaw, Jörn-Frederik; McHone, Greg; Font, Eric; Bensalah, Mohamed Khalil

2017-05-01

The complex history of assemblage and disruption of continental plates surrounding the Atlantic Ocean is in part recorded by the distribution of detrital zircon ages entrained in continental sedimentary strata from Morocco (Central High Atlas and Argana basins) and Canada (Grand Manan Island, New Brunswick). Here we investigate detrital zircon from the latest Triassic (ca. 202 Ma) sedimentary strata directly underlying lava flows of the Central Atlantic magmatic province or interlayered within them. SHRIMP (Sensitive High-Resolution Ion MicroProbe) and LA-ICP-MS (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry) U-Pb ages for zircon range from Paleozoic to Archean with a dominant Neoproterozoic peak, and significant amounts of ca. 2 Ga zircon. These ages suggest a prevailing West African (Gondwanan) provenance at all sampling sites. Notably, the Paleoproterozoic zircon population is particularly abundant in central Morocco, north of the High Atlas chain, suggesting the presence of Eburnean-aged rocks in this part of the country, which is consistent with recent geochronologic data from outcropping rocks. Minor amounts of late Mesoproterozoic and early Neoproterozoic zircon ages (ca. 1.1-0.9 Ga) in Moroccan samples are more difficult to interpret. A provenance from Avalonia or Amazonia, as proposed by previous studies is not supported by the age distributions observed here. An involvement of more distal source regions, possibly located in north-eastern Africa (Arabian Nubian Shield) would instead be possible. Paleozoic zircon ages are abundant in the Canadian sample, pointing to a significant contribution from Hercynian aged source rocks. Such a signal is nearly absent in the Moroccan samples, suggesting that zircon-bearing Hercynian granitic rocks of the Moroccan Meseta block were not yet outcropping at ca. 200 Ma. The only Moroccan samples that yield Paleozoic zircon ages are those interlayered within the CAMP lavas, suggesting an increased dismantling

Vitamin D Status and Early Age-Related Macular Degeneration in Postmenopausal Women

PubMed Central

Millen, Amy E.; Voland, Rick; Sondel, Sherie A.; Parekh, Niyati; Horst, Ronald L.; Wallace, Robert B.; Hageman, Gregory S.; Chappell, Rick; Blodi, Barbara A.; Klein, Michael L.; Gehrs, Karen M.; Sarto, Gloria E.; Mares, Julie A.

2010-01-01

Objective The relationship between serum 25-hydroxyvitamin D (25(OH)D) concentrations (nmol/L) and the prevalence of early age-related macular degeneration (AMD) was investigated among participants of the Carotenoids in Age-Related Eye Disease Study. Methods Stereoscopic fundus photographs, taken from 2001–2004, assessed AMD status. Baseline (1994–1998) serum samples were available for 25(OH)D assays in 1,313 women with complete ocular and risk factor data. Odds ratios (ORs) and 95% confidence intervals (CIs) for early AMD (n=241), among 1,287 without advanced disease, were estimated with logistic regression and adjusted for age, smoking, iris pigmentation, family history of AMD, cardiovascular disease, diabetes, and hormone therapy use. Results In multivariate models, no significant relationship was observed between early AMD and 25(OH)D (OR for quintile 5 vs. 1=0.79, 95% CI=0.50–1.24; p for trend=0.47). A significant age interaction (p=0.0025) suggested selective mortality bias in women ≥75 years: serum 25(OH)D was associated with decreased odds of early AMD in women <75 years (n=968) and increased odds in women ≥75 years (n=319) (OR for quintile 5 vs. 1=0.52, 95% CI=0.29–0.91; p for trend=0.02 and 1.76, 95% CI=0.77–4.13; p for trend=0.05, respectively). Further adjustment for body mass index and recreational physical activity, predictors of 25(OH)D, attenuated the observed association in women <75 years. Additionally, among women <75 years, intake of vitamin D from foods and supplements was related to decreased odds of early AMD in multivariate models; no relationship was observed with self-reported time spent in direct sunlight. Conclusions High serum 25(OH)D concentrations may protect against early AMD in women <75 years. PMID:21482873

Location of deeply buried, offshore Mesozoic transform fault along the western margin of the Gulf of Mexico inferred from gravity and magnetic data

NASA Astrophysics Data System (ADS)

Nguyen, L. C.; Mann, P.; Bird, D. E.

2013-12-01

Several workers have proposed that a Jurassic age, 500-km-long, right-lateral transform fault along the western margin of the Gulf of Mexico, possibly extending southward and onshore for another 500 km onto the isthmus area of southern Mexico, was formed as the ocean basin opened. This proposed transform fault plays a critical role in the most widely accepted tectonic model for the Mesozoic opening of the Gulf of Mexico by a ~40 degree, CCW rotation of the Yucatan block about a pole near southern Florida. Previously proposed names for the fault include the Tamaulipas-Chiapas transform fault and the Western Main transform fault for the offshore fault and the Orizaba transform fault for the southern, onland continuation of the fault into southern Mexico. There are few direct geologic or geophysical observations on the location or characteristics of the proposed offshore transform because it is buried beneath an over 10-km-thick sedimentary wedge along the continental margin of eastern Mexico. To better define this offshore fault, we identify a 500-km-long, 40-km-wide gravity anomaly, concentric with, and located about 60-70 km off the eastern coast of Mexico. Two east-west 200/1200-km-long gravity models constructed to cross the anomaly at right angles are parallel to existing multi-channel seismic lines with age-correlated stratigraphy. Both gravity models reveal an abrupt crustal thickness change beneath the gravity anomaly: from 27 km to 12 km over a distance of 65 km in the southern profile, and from 23 km to 16 km over a distance of 30 km in northern profile. The linearity of the anomaly in map view combined with the abrupt change in thickness inferred from gravity modeling is consistent with the tectonic origin of a right-lateral transform fault separating continental rocks of Mexico from Mesozoic seafloor produced by the opening of the Gulf of Mexico. Magnetic profiles were analyzed using a Werner depth-to-magnetic source technique, coincident with the gravity

Model Development and Trial of Early Detection Manual for the Special Needs Children at Early Age Education Level

ERIC Educational Resources Information Center

Anwar, Zainul; Ingarianti, Tri Muji; Suryaningrum, Cahyaning

2016-01-01

This research was aimed to produce the manual for early detection for ABK at the level of early age education (PAUD = "Pendidikan Anak Usia Dini"). Research was "action research" with stages as proposed by Buunk and Van Vugt. Metodology of research these stages were called as PATH ("Problem-Analysis-Test…

Evaluation of Early-Age Concrete Compressive Strength with Ultrasonic Sensors.

PubMed

Yoon, Hyejin; Kim, Young Jin; Kim, Hee Seok; Kang, Jun Won; Koh, Hyun-Moo

2017-08-07

Surface wave velocity measurement of concrete using ultrasonic sensors requires testing on only one side of a member. Thus, it is applicable to concrete cast inside a form and is often used to detect flaws and evaluate the compressive strength of hardened concrete. Predicting the in situ concrete strength at a very early stage inside the form helps with determining the appropriate form removal time and reducing construction time and costs. In this paper, the feasibility of using surface wave velocities to predict the strength of in situ concrete inside the form at a very early stage was evaluated. Ultrasonic sensors were used to measure a series of surface waves for concrete inside a form in the first 24 h after placement. A continuous wavelet transform was used to compute the travel time of the propagating surface waves. The cylindrical compressive strength and penetration resistance tests were also performed during the test period. Four mixtures and five curing temperatures were used for the specimens. The surface wave velocity was confirmed to be applicable to estimating the concrete strength at a very early age in wall-like elements. An empirical formula is proposed for evaluating the early-age compressive strength of concrete considering the 95% prediction intervals.

Evaluation of Early-Age Concrete Compressive Strength with Ultrasonic Sensors

PubMed Central

Yoon, Hyejin; Kim, Young Jin; Kim, Hee Seok; Kang, Jun Won; Koh, Hyun-Moo

2017-01-01

Surface wave velocity measurement of concrete using ultrasonic sensors requires testing on only one side of a member. Thus, it is applicable to concrete cast inside a form and is often used to detect flaws and evaluate the compressive strength of hardened concrete. Predicting the in situ concrete strength at a very early stage inside the form helps with determining the appropriate form removal time and reducing construction time and costs. In this paper, the feasibility of using surface wave velocities to predict the strength of in situ concrete inside the form at a very early stage was evaluated. Ultrasonic sensors were used to measure a series of surface waves for concrete inside a form in the first 24 h after placement. A continuous wavelet transform was used to compute the travel time of the propagating surface waves. The cylindrical compressive strength and penetration resistance tests were also performed during the test period. Four mixtures and five curing temperatures were used for the specimens. The surface wave velocity was confirmed to be applicable to estimating the concrete strength at a very early age in wall-like elements. An empirical formula is proposed for evaluating the early-age compressive strength of concrete considering the 95% prediction intervals. PMID:28783128

Evolution of mantis shrimps (Stomatopoda, Malacostraca) in the light of new Mesozoic fossils

PubMed Central

2010-01-01

Background We describe new specimens of Mesozoic mantis shrimps (Stomatopoda, Malacostraca) that exhibit morphological and developmental information previously unknown. Results Specimens assigned to the taxon Sculda exhibit preserved pleopods, thoracopods including all four raptorial limbs as well as details of antennae and antennulae. The pleopods and the antennulae resemble those of the modern mantis shrimps, but the raptorial limbs are not as differentiated as in the modern species. In some specimens, the first raptorial limb (second thoracopod) is not significantly larger than the similar-sized posterior three pairs (as in extant species), but instead these appendages become progressively smaller along the series. In this respect they resemble certain Palaeozoic stomatopods. Another specimen, most likely belonging to another species, has one pair of large anterior raptorial thoracopods, a median-sized pair and two more pairs of small-sized raptorial appendages and, thus, shows a new, previously unknown type of morphology. A single specimen of Pseudosculda laevis also exhibits the size of the raptorial limbs; they are differentiated as in modern species, one large pair and three small pairs. Furthermore, we report additional larval specimens and show also post-larval changes, e.g., of the tail fan. Conclusions These new data are used to reconsider the phylogeny of Stomatopoda. We still need a strict taxonomical revision of the Mesozoic mantis shrimps, but this first examination already demonstrates the importance of these fossils for understanding mantis shrimp evolution and the interpretation of evolutionary pathways of particular features. PMID:20858249

What can we tell from particle morphology in Mesozoic charcoal assemblages?

NASA Astrophysics Data System (ADS)

Crawford, Alastair; Belcher, Claire

2015-04-01

Sedimentary charcoal particles provide a valuable record of palaeofire activity on both human and geological timescales. Charcoal is both an unambiguous indicator of wildfire, and a means of preservation of plant material in an inert form; thus it records not only the occurrence and extent of wildfire, but also the species affected. While scanning electron microscopy can be usefully employed for precise taxonomic identification of charcoals, the time and cost associated with this limit the extent to which the technique is employed. Morphometric analysis of mesocharcoal particles (c. 125-1000 µm) potentially provides a simple method for obtaining useful information from optical microscopy images. Grass fires have been shown to produce mesocharcoal particles with a higher length-to-width ratio than woodland fuel sources. In Holocene archives, aspect ratio measurements are thus used to infer the broad taxonomic affinity of the burned vegetation. Since Mesozoic charcoals display similarly heterogeneous morphologies, we investigate whether there is a similar potential to infer the broad botanical affinities of Mesozoic charcoal assemblages from simple morphological metrics. We have used image analysis to analyse a range of Jurassic and Cretaceous sedimentary rocks representing different vegetation communities and depositional environments, and also to determine the range of charcoal particle morphologies which can be produced from different modern taxa under laboratory conditions. We find that modern charcoals break down into mesocharcoal particles of very variable aspect ratio, and this appears to be dependent on taxonomic position. Our analysis of fragmented laboratory-produced charcoals indicates that pteridophytes produce much more elongate particles than either conifers or non-grass angiosperms. We suggest that for charcoal assemblages that predate the evolution of grasses, high average aspect ratios may be a useful indicator of the burning of a pteridophyte

Association of early- and adult-life socioeconomic circumstances with muscle strength in older age.

PubMed

Cheval, Boris; Boisgontier, Matthieu P; Orsholits, Dan; Sieber, Stefan; Guessous, Idris; Gabriel, Rainer; Stringhini, Silvia; Blane, David; van der Linden, Bernadette W A; Kliegel, Matthias; Burton-Jeangros, Claudine; Courvoisier, Delphine S; Cullati, Stéphane

2018-05-01

socioeconomic circumstances (SEC) during a person's lifespan influence a wide range of health outcomes. However, solid evidence of the association of early- and adult-life SEC with health trajectories in ageing is still lacking. This study assessed whether early-life SEC are associated with muscle strength in later life-a biomarker of health-and whether this relationship is caused by adult-life SEC and health behaviours. we used data from the Survey of Health Ageing and Retirement in Europe, a 12-year population-based cohort study with repeated measurement in six waves (2004-15) and retrospective collection of life-course data. Participants' grip strength was assessed by using a handheld dynamometer. Confounder-adjusted logistic mixed-effect models were used to examine the associations of early- and adult-life SEC with the risk of low muscle strength (LMS) in older age. a total of 24,179 participants (96,375 observations) aged 50-96 living in 14 European countries were included in the analyses. Risk of LMS was increased with disadvantaged relative to advantaged early-life SEC. The association between risk of LMS and disadvantaged early-life SEC gradually decreased when adjusting for adult-life SEC for both sexes and with unhealthy behaviours for women. After adjusting for these factors, all associations between risk of LMS and early-life SEC remained significant for women. early-life SEC are associated with muscle strength after adjusting for adult-life SEC and behavioural lifestyle factors, especially in women, which suggests that early life may represent a sensitive period for future health.

Growth curve analyses of the relationship between early maternal age and children's mathematics and reading performance.

PubMed

Torres, D Diego

2015-03-01

Regarding the methods used to examine the early maternal age-child academic outcomes relationship, the extant literature has tended to examine change using statistical analyses that fail to appreciate that individuals vary in their rates of growth. Of the one study I have been able to find that employs a true growth model to estimate this relationship, the authors only controlled for characteristics of the maternal household after family formation; confounding background factors of mothers that might select them into early childbearing, a possible source of bias, were ignored. The authors' findings nonetheless suggested an inverse relationship between early maternal age, i.e., a first birth between the ages of 13 and 17, and Canadian adolescents' mean math performance at age 10. Early maternal age was not related to the linear slope of age. To elucidate whether the early maternal age-child academic outcomes association, treated in a growth context, is consistent with this finding, the present study built on it using US data and explored children's mathematics and reading trajectories from age 5 on. Its unique contribution is that it further explicitly controlled for maternal background factors and employed a three-level growth model with repeated measures of children nested within their mothers. Though the strength of the relationship varied between mean initial academic performance and mean academic growth, results confirmed that early maternal age was negatively related to children's mathematics and reading achievement, net of post-teen first birth child-specific and maternal household factors. Once maternal background factors were included, there was no statistically significant relationship between early maternal age and either children's mean initial mathematics and reading scores or their mean mathematics and reading growth. Copyright © 2014 Elsevier Inc. All rights reserved.

Problem Behaviour at Early Age--Basis for Prediction of Asocial Behaviour

ERIC Educational Resources Information Center

Krneta, Dragoljub; Ševic, Aleksandra

2015-01-01

This paper analyzes the results of the study of prevalence of problem behaviour of students in primary and secondary schools. The starting point is that it is methodologically and logically justified to look for early forms of problem behaviour of students, because it is likely that adult convicted offenders at an early school age manifested forms…

Sedimentation History and Provenance Analysis of a Late Mesozoic Rifting Event at Tavan Har, East Gobi, Mongolia

ERIC Educational Resources Information Center

Davidson, Sarah Cain

2005-01-01

The East Gobi Basin (EGB), which covers over 1.5 million square kilometers in southeastern Mongolia, is one of several basins in eastern China and Mongolia that was formed by extension and intracontinental rifting during the late Mesozoic. For reasons that are poorly understood, the continental lithosphere covering areas that are now known as…

Late Jurassic - Early Cretaceous convergent margins of Northeastern Asia with Northwestern Pacific and Proto-Arctic oceans

NASA Astrophysics Data System (ADS)

Sokolov, Sergey; Luchitskaya, Marina; Tuchkova, Marianna; Moiseev, Artem; Ledneva, Galina

2013-04-01

Continental margin of Northeastern Asia includes many island arc terranes that differ in age and tectonic position. Two convergent margins are reconstructed for Late Jurassic - Early Cretaceous time: Uda-Murgal and Alazeya - Oloy island arc systems. A long tectonic zone composed of Upper Jurassic to Lower Cretaceous volcanic and sedimentary rocks is recognized along the Asian continent margin from the Mongol-Okhotsk thrust-fold belt on the south to the Chukotka Peninsula on the north. This belt represents the Uda-Murgal arc, which was developed along the convergent margin between Northeastern Asia and Northwestern Meso-Pacific. Several segments are identified in this arc based upon the volcanic and sedimentary rock assemblages, their respective compositions and basement structures. The southern and central parts of the Uda-Murgal island arc system were a continental margin belt with heterogeneous basement represented by metamorphic rocks of the Siberian craton, the Verkhoyansk terrigenous complex of Siberian passive margin and the Koni-Taigonos late Paleozoic to early Mesozoic island arc with accreted oceanic terranes. At the present day latitude of the Pekulney and Chukotka segments there was an ensimatic island arc with relicts of the South Anyui oceanic basin in backarc basin. Alazeya-Oloy island arc systems consists of Paleozoic and Mesozoic complexes that belong to the convergent margin between Northeastern Asia and Proto-Artic Ocean. It separated structures of the North American and Siberian continents. The Siberian margin was active whereas the North American margin was passive. The Late Jurassic was characterized by termination of a spreading in the Proto-Arctic Ocean and transformation of the latter into the closing South Anyui turbidite basin. In the beginning the oceanic lithosphere and then the Chukotka microcontinent had been subducted beneath the Alazeya-Oloy volcanic belt

Lack of serotonin1B receptor expression leads to age-related motor dysfunction, early onset of brain molecular aging and reduced longevity.

PubMed

Sibille, E; Su, J; Leman, S; Le Guisquet, A M; Ibarguen-Vargas, Y; Joeyen-Waldorf, J; Glorioso, C; Tseng, G C; Pezzone, M; Hen, R; Belzung, C

2007-11-01

Normal aging of the brain differs from pathological conditions and is associated with increased risk for psychiatric and neurological disorders. In addition to its role in the etiology and treatment of mood disorders, altered serotonin (5-HT) signaling is considered a contributing factor to aging; however, no causative role has been identified in aging. We hypothesized that a deregulation of the 5-HT system would reveal its contribution to age-related processes and investigated behavioral and molecular changes throughout adult life in mice lacking the regulatory presynaptic 5-HT(1B) receptor (5-HT(1B)R), a candidate gene for 5-HT-mediated age-related functions. We show that the lack of 5-HT(1B)R (Htr1b(KO) mice) induced an early age-related motor decline and resulted in decreased longevity. Analysis of life-long transcriptome changes revealed an early and global shift of the gene expression signature of aging in the brain of Htr1b(KO) mice. Moreover, molecular changes reached an apparent maximum effect at 18-months in Htr1b(KO) mice, corresponding to the onset of early death in that group. A comparative analysis with our previous characterization of aging in the human brain revealed a phylogenetic conservation of age-effect from mice to humans, and confirmed the early onset of molecular aging in Htr1b(KO) mice. Potential mechanisms appear independent of known central mechanisms (Bdnf, inflammation), but may include interactions with previously identified age-related systems (IGF-1, sirtuins). In summary, our findings suggest that the onset of age-related events can be influenced by altered 5-HT function, thus identifying 5-HT as a modulator of brain aging, and suggesting age-related consequences to chronic manipulation of 5-HT.

Early childhood predictors of age of initiation to use of cannabis: a birth prospective study.

PubMed

Hayatbakhsh, Reza; Williams, Gail M; Bor, William; Najman, Jake M

2013-05-01

Early age of cannabis use predicts subsequent illicit drug abuse and other psychosocial problems. Identification of factors associated with early cannabis use may contribute to the development of preventive interventions. This study aimed to examine the early life predictors of age of initiation to cannabis. Data were from Mater Hospital and University of Queensland Study of Pregnancy, a population-based prospective birth cohort study. Participants were a cohort of 3488 young adults who self-reported frequency and age of onset of cannabis use at the 21 year follow up. Of 3488 young adults, 48.9% (51.8% men and 46.4% women) reported having ever used cannabis. For those who had ever used cannabis, age of onset had mean and median of 15.8 and 16.0 years, respectively. In multivariate analysis child's gender, change in maternal marital status, quality of marital relationship, maternal cigarette smoking and alcohol consumption and maternal depression when the child was 5 years statistically significantly predicted age of initiation to cannabis use. The present study explores the impact of early childhood factors associated with age of onset of cannabis use. It is suggested that the family environment within which children are reared, including factors such as parents' marital circumstances, has a major influence on initiation to cannabis use in adolescence. Research is needed to disentangle the pathways of association between these early life factors and early initiation to use of cannabis. © 2012 Australasian Professional Society on Alcohol and other Drugs.

Age effects on preattentive and early attentive auditory processing of redundant stimuli: is sensory gating affected by physiological aging?

PubMed

Gmehlin, Dennis; Kreisel, Stefan H; Bachmann, Silke; Weisbrod, Matthias; Thomas, Christine

2011-10-01

The frontal hypothesis of aging predicts an age-related decline in cognitive functions requiring inhibitory or attentional regulation. In Alzheimer's disease, preattentive gating out of redundant information is impaired. Our study aimed to examine changes associated with physiological aging in both pre- and early attentive inhibition of recurrent acoustic information. Using a passive double-click paradigm, we recorded mid-latency (P30-P50) and late-latency (N100 and P200) evoked potentials in healthy young (26 ± 5 years) and healthy elderly subjects (72 ± 5 years). Physiological aging did not affect auditory gating in amplitude measures. Both age groups exhibited clear inhibition in preattentive P50 and attention-modulated (N100) components, whereas P30 was not attenuated. Irrespective of age, the magnitude of inhibition differed significantly, being most pronounced for N100 gating. Inhibition of redundant information seems to be preserved with physiological aging. Early attentive N100 gating showed the maximum effect. Further studies are warranted to evaluate sensory gating as a suitable biomarker of underlying neurodegenerative disease.

Transformation and diversification in early mammal evolution.

PubMed

Luo, Zhe-Xi

2007-12-13

Evolution of the earliest mammals shows successive episodes of diversification. Lineage-splitting in Mesozoic mammals is coupled with many independent evolutionary experiments and ecological specializations. Classic scenarios of mammalian morphological evolution tend to posit an orderly acquisition of key evolutionary innovations leading to adaptive diversification, but newly discovered fossils show that evolution of such key characters as the middle ear and the tribosphenic teeth is far more labile among Mesozoic mammals. Successive diversifications of Mesozoic mammal groups multiplied the opportunities for many dead-end lineages to iteratively evolve developmental homoplasies and convergent ecological specializations, parallel to those in modern mammal groups.

Mayer Kangri metamorphic complexes in Central Qiangtang (Tibet, western China): implications for the Triassic-early Jurassic tectonics associated with the Paleo-Tethys Ocean

NASA Astrophysics Data System (ADS)

Wang, Yixuan; Liang, Xiao; Wang, Genhou; Yuan, Guoli; Bons, Paul D.

2018-03-01

The Mesozoic orogeny in Central Qiangtang Metamorphic Belt, northern Tibet, provides important insights into the geological evolution of the Paleo-Tethys Ocean. However, the Triassic-early Jurassic tectonics, particularly those associated with the continental collisionstage, remains poorly constrained. Here we present results from geological mapping, structural analysis, P-T data, and Ar-Ar geochronology of the Mayer Kangri metamorphic complex. Our data reveal an E-W-trending, 2 km wide dome-like structure associated with four successive tectonic events during the Middle Triassic and Early Jurassic. Field observations indicate that amphibolite and phengite schist complexes in this complex are separated from the overlying lower greenschist mélange by normal faulting with an evident dextral shearing component. Open antiform-like S2 foliation of the footwall phengite schist truncates the approximately north-dipping structures of the overlying mélange. Microtextures and mineral chemistry of amphibole reveal three stages of growth: Geothermobarometric estimates yield temperatures and pressures of 524 °C and 0.88 GPa for pargasite cores, 386 °C and 0.34 GPa for actinolite mantles, and 404 °C and 0.76 GPa for winchite rims. Peak blueschist metamorphism in the phengite schist occurred at 0.7-1.1 GPa and 400 °C. Our Ar-Ar dating of amphibole reveals rim-ward decreasing in age bands, including 242.4-241.2 Ma, ≥202.6-196.8, and 192.9-189.8 Ma. The results provide evidence for four distinct phases of Mesozoic tectonic evolution in Central Qiangtang: (1) northward oceanic subduction beneath North Qiangtang ( 244-220 Ma); (2) syn-collisional slab-break off (223-202 Ma); (3) early collisional extension driven by buoyant extrusion flow from depth ( 202.6-197 Ma); and (4) post-collision contraction and reburial (195.6-188.7 Ma).

Evolution of the stress field in the southern Scotia Arc from the late Mesozoic to the present-day

NASA Astrophysics Data System (ADS)

Maestro, Adolfo; López-Martínez, Jerónimo; Galindo-Zaldívar, Jesús; Bohoyo, Fernando; Mink, Sandra

2014-12-01

The geological evolution of the Scotia Arc, which developed between Antarctica and South America, has facilitated the connection between the Pacific and Atlantic oceans and, has important global implications. To improve the knowledge of the late Mesozoic evolution of the southern Scotia Arc, over 6000 brittle mesostructures were measured over the last 20 years at different outcrops from the northern Antarctic Peninsula and the South Shetland Islands as well as the James Ross and South Orkney archipelagos. This dataset covers a length of more than 1000 km of the arc. Fault data were analysed using the Etchecopar, y-R, Right Dihedra, Stress Inversion and Search Grid Inversion Palaeostress Determination methods. A total of 275 stress tensors were obtained. The results showed that the maximum horizontal stress was in the ENE-WSW and the NW-SE orientations and that the horizontal extension tensors were oriented NE-SW and NW-SE. In addition, seismic activity and focal mechanism solutions were analysed using the Gephart method to establish the present-day stress field and characterise the active tectonics. The results obtained suggest that there is a regional NE-SW compression and a NW-SE extension regime at the present day. The Southern Scotia Arc has a complex geological history due to the different tectonic settings (transform, convergent and divergent) that have affected this sector during its geological evolution from the late Mesozoic until the present day. Six stress fields were obtained from the brittle mesostructure population analysis in the region. The NW-SE and N-S maximum horizontal stresses were related to a combination of Mesozoic oceanic subduction of the former Phoenix Plate under the Pacific margin of the Antarctic Plate, Mesozoic-Cenozoic subduction of the northern Weddell Sea and the Oligocene to the Middle Miocene dextral strike-slip movement between the Scotia and Antarctic plates along the South Scotia Ridge. The NE-SW compression was related to

Evolutionary history of Otophysi (Teleostei), a major clade of the modern freshwater fishes: Pangaean origin and Mesozoic radiation

PubMed Central

2011-01-01

Background Freshwater harbors approximately 12,000 fish species accounting for 43% of the diversity of all modern fish. A single ancestral lineage evolved into about two-thirds of this enormous biodiversity (≈ 7900 spp.) and is currently distributed throughout the world's continents except Antarctica. Despite such remarkable species diversity and ubiquity, the evolutionary history of this major freshwater fish clade, Otophysi, remains largely unexplored. To gain insight into the history of otophysan diversification, we constructed a timetree based on whole mitogenome sequences across 110 species representing 55 of the 64 families. Results Partitioned maximum likelihood analysis based on unambiguously aligned sequences (9923 bp) confidently recovered the monophyly of Otophysi and the two constituent subgroups (Cypriniformes and Characiphysi). The latter clade comprised three orders (Gymnotiformes, Characiformes, Siluriformes), and Gymnotiformes was sister to the latter two groups. One of the two suborders in Characiformes (Characoidei) was more closely related to Siluriformes than to its own suborder (Citharinoidei), rendering the characiforms paraphyletic. Although this novel relationship did not receive strong statistical support, it was supported by analyzing independent nuclear markers. A relaxed molecular clock Bayesian analysis of the divergence times and reconstruction of ancestral habitats on the timetree suggest a Pangaean origin and Mesozoic radiation of otophysans. Conclusions The present timetree demonstrates that survival of the ancestral lineages through the two consecutive mass extinctions on Pangaea, and subsequent radiations during the Jurassic through early Cretaceous shaped the modern familial diversity of otophysans. This evolutionary scenario is consistent with recent arguments based on biogeographic inferences and molecular divergence time estimates. No fossil otophysan, however, has been recorded before the Albian, the early Cretaceous 100

Evolutionary history of Otophysi (Teleostei), a major clade of the modern freshwater fishes: Pangaean origin and Mesozoic radiation.

PubMed

Nakatani, Masanori; Miya, Masaki; Mabuchi, Kohji; Saitoh, Kenji; Nishida, Mutsumi

2011-06-22

Freshwater harbors approximately 12,000 fish species accounting for 43% of the diversity of all modern fish. A single ancestral lineage evolved into about two-thirds of this enormous biodiversity (≈ 7900 spp.) and is currently distributed throughout the world's continents except Antarctica. Despite such remarkable species diversity and ubiquity, the evolutionary history of this major freshwater fish clade, Otophysi, remains largely unexplored. To gain insight into the history of otophysan diversification, we constructed a timetree based on whole mitogenome sequences across 110 species representing 55 of the 64 families. Partitioned maximum likelihood analysis based on unambiguously aligned sequences (9923 bp) confidently recovered the monophyly of Otophysi and the two constituent subgroups (Cypriniformes and Characiphysi). The latter clade comprised three orders (Gymnotiformes, Characiformes, Siluriformes), and Gymnotiformes was sister to the latter two groups. One of the two suborders in Characiformes (Characoidei) was more closely related to Siluriformes than to its own suborder (Citharinoidei), rendering the characiforms paraphyletic. Although this novel relationship did not receive strong statistical support, it was supported by analyzing independent nuclear markers. A relaxed molecular clock Bayesian analysis of the divergence times and reconstruction of ancestral habitats on the timetree suggest a Pangaean origin and Mesozoic radiation of otophysans. The present timetree demonstrates that survival of the ancestral lineages through the two consecutive mass extinctions on Pangaea, and subsequent radiations during the Jurassic through early Cretaceous shaped the modern familial diversity of otophysans. This evolutionary scenario is consistent with recent arguments based on biogeographic inferences and molecular divergence time estimates. No fossil otophysan, however, has been recorded before the Albian, the early Cretaceous 100-112 Ma, creating an over 100

Risk Factors in Preschool Children for Predicting Asthma During the Preschool Age and the Early School Age: a Systematic Review and Meta-Analysis.

PubMed

Bao, Yixia; Chen, Zhimin; Liu, Enmei; Xiang, Li; Zhao, Deyu; Hong, Jianguo

2017-11-18

The aim of this study was to identify risk factors of asthma among children < 6 years old (preschool age) for predicting asthma during the preschool age and early school age (≤ 10 years of age). MEDLINE, Cochrane, EMBASE, and Google Scholar databases were searched until June 30, 2017. Prospective or retrospective cohort and case-control studies were included. Studies had to have evaluated risk factors or a predictive model for developing asthma in children ≤ 6 years of age or persistent asthma in early school age. A total of 17 studies were included in the analysis. Factors associated with developing asthma in children ≤ 10 years of age (both pre-school and early school age) included male gender (pooled OR = 1.70, P < 0.001), atopic dermatitis (pooled OR = 2.02, P < 0.001), a family history of asthma (pooled OR = 2.20, P < 0.001), and serum IgE levels ≥ 60 kU/l or having specific IgE (pooled OR = 2.36, P < 0.001). A history of exposure to smoke or wheezing was also associated with persistent asthma in early school age (pooled OR = 1.51, P = 0.030 and pooled OR = 2.59, P < 0.001, respectively). In general, asthma predictive models (e.g., API, PIAMA, PAPS) had relatively low sensitivity (range, 21% to 71.4%) but high specificity (range, 69% to 98%). The study found that male gender, exposure to smoke, atopic dermatitis, family history of asthma, history of wheezing, and serum IgE level ≥ 60 kU/l or having specific IgE were significantly associated with developing asthma by either preschool or early school age. Asthma predictive models can be developed by those risk factors.

Early Jurassic extensional inheritance in the Lurestan region of the Zagros fold-and-thrust belt, Iran.

NASA Astrophysics Data System (ADS)

Tavani, Stefano; Parente, Mariano; Vitale, Stefano; Puzone, Francesco; Erba, Elisabetta; Bottini, Cinzia; Morsalnejad, Davoud; Mazzoli, Stefano

2017-04-01

It has long been recognized that the tectonic architecture of the Zagros mountain belt was strongly controlled by inherited structures previously formed within the Arabian plate. These preexisting features span in age from the pre-Cambrian to the Mesozoic, showing different trends and deformation styles. Yet, these structures are currently not fully understood. This uncertainty is partly related with the paucity of exposures, which rarely allows a direct observation of these important deformation features. The Lurestan Province of Iran provides a remarkable exception, since it is one of the few places of the Zagros mountain belt where exposures of Triassic and Jurassic rocks are widespread. In this area we carried out structural observations on Mesozoic extensional structures developed at the southern margin of the Neo-Tethyan basin. Syn-sedimentary extensional faults are hosted within the Triassic-Cretaceous succession, being particularly abundant in the Jurassic portion of the stratigraphy. Early to Middle Jurassic syn-sedimentary faults are observed in different paleogeographic domains of the area, and their occurrence is coherent with the subsequent transition from shallow-water to deep-sea basin environments, observed in a wide portion of the area. Most of the thrusts exposed in the area may indeed be interpreted as reactivated Jurassic extensional faults, or as reverse faults whose nucleation was controlled by the location of preexisting normal faults, as a result of positive inversion during crustal shortening and mountain building.

A compilation of K-Ar-ages for southern California

USGS Publications Warehouse

Miller, Fred K.; Morton, Douglas M.; Morton, Janet L.; Miller, David M.

2014-01-01

The purpose of this report is to make available a large body of conventional K-Ar ages for granitic, volcanic, and metamorphic rocks collected in southern California. Although one interpretive map is included, the report consists primarily of a systematic listing, without discussion or interpretation, of published and unpublished ages that may be of value in future regional and other geologic studies. From 1973 to 1979, 468 rock samples from southern California were collected for conventional K-Ar dating under a regional geologic mapping project of Southern California (predecessor of the Southern California Areal Mapping Project). Most samples were collected and dated between 1974 and 1977. For 61 samples (13 percent of those collected), either they were discarded for varying reasons, or the original collection data were lost. For the remaining samples, 518 conventional K-Ar ages are reported here; coexisting mineral pairs were dated from many samples. Of these K-Ar ages, 225 are previously unpublished, and identified as such in table 1. All K-Ar ages are by conventional K-Ar analysis; no 40Ar/39Ar dating was done. Subsequent to the rock samples collected in the 1970s and reported here, 33 samples were collected and 38 conventional K-Ar ages determined under projects directed at (1) characterization of the Mesozoic and Cenozoic igneous rocks in and on both sides of the Transverse Ranges and (2) clarifying the Mesozoic and Cenozoic tectonics of the eastern Mojave Desert. Although previously published (Beckerman et al., 1982), another eight samples and 11 conventional K-Ar ages are included here, because they augment those completed under the previous two projects.

Geochronology and geochemistry of deep-seated crustal xenoliths in the northern North China Craton: Implications for the evolution and structure of the lower crust

NASA Astrophysics Data System (ADS)

Su, Yuping; Zheng, Jianping; Griffin, William L.; Huang, Yan; Wei, Ying; Ping, Xianquan

2017-11-01

The age and composition of the lower crust are critical in understanding the processes of continental formation and evolution, and deep-seated granulite xenoliths can offer direct information on the lower crust. Here, we report mineral chemistry, whole-rock major and trace elements, Sr-Nd isotopes and zircon U-Pb-Hf results for a suite of deep-seated crustal xenoliths, recently discovered in the Cenozoic basalts of the Nangaoya area in the northern part of the North China Craton (NCC). Based on the P-T estimates, these xenoliths including mafic, intermediate and felsic granulites and hornblendites were sampled from different levels of the lower crust. While a hornblendite has a flat REE pattern, all other xenoliths display LREE enrichment and depletion of Nb, Ta, Th and Ti. The mafic granulite xenolith has relatively high whole-rock εNd(t) value of - 13.37, and yields Mesozoic (188-59 Ma) zircons ages with high εHf(t) values from - 15.3 to - 9.2. The garnet-bearing intermediate granulite-facies rocks show low εNd(t) values from - 16.92 to - 17.48, and reveal both Paleoproterozoic (1948 Ma) and Mesozoic (222-63 Ma) zircon U-Pb ages. Their Mesozoic zircons have lower εHf(t) values (from - 18.4 to - 13.8) than those from the mafic xenolith. The remaining intermediate to felsic xenoliths show Paleoproterozoic zircon ages, and the lowest εNd(t) values (from - 20.78 to - 24.03). The mafic-intermediate granulites with Mesozoic zircons originated from the interaction of lower crust-derived magmas with mantle melts, with higher proportions of mantle magmas involved in the generation of mafic granulite, whereas intermediate to felsic xenoliths without Mesozoic zircons represent ancient Paleoproterozoic to Neoarchean deep crust. These deep-seated xenoliths reveal complicated crustal evolution processes, including crustal growth during Neoarchean (2.5-2.7 Ga), middle Paleoproterozoic (2.2-2.1 Ga) and Mesozoic, and reworking during early Paleoproterozoic, late

Coercive Family Process and Early-Onset Conduct Problems From Age 2 to School Entry

PubMed Central

Smith, Justin D.; Dishion, Thomas J.; Shaw, Daniel S.; Wilson, Melvin N.; Winter, Charlotte C.; Patterson, Gerald R.

2013-01-01

The emergence and persistence of conduct problems during early childhood is a robust predictor of behavior problems in school and future maladaptation. In this study we examined the reciprocal influences between observed coercive interactions between children and caregivers, oppositional and aggressive behavior, and growth in parent report of early childhood (ages 2–5) and school-age conduct problems (age 7.5 and 8.5). Participants were drawn from the Early Steps multisite randomized prevention trial that includes an ethnically diverse sample of male and female children and their families (N = 731). A parallel process growth model combining latent trajectory and cross-lagged approaches revealed the amplifying effect of observed coercive caregiver–child interactions on children's noncompliance, whereas child oppositional and aggressive behaviors did not consistently predict increased coercion. The slope and initial levels of child oppositional and aggressive behaviors and the stability of caregiver–child coercion were predictive of teacher-reported oppositional behavior at school age. Families assigned to the Family Check-Up condition had significantly steeper declines in child oppositional and aggressive behavior and moderate reductions in oppositional behavior in school and in coercion at age 3. Results were not moderated by child gender, race/ethnicity, or assignment to the intervention condition. The implications of these findings are discussed with respect to understanding the early development of conduct problems and to designing optimal strategies for reducing problem behavior in early childhood with families most in need. PMID:24690305

Coercive family process and early-onset conduct problems from age 2 to school entry.

PubMed

Smith, Justin D; Dishion, Thomas J; Shaw, Daniel S; Wilson, Melvin N; Winter, Charlotte C; Patterson, Gerald R

2014-11-01

The emergence and persistence of conduct problems (CPs) during early childhood is a robust predictor of behavior problems in school and of future maladaptation. In this study we examined the reciprocal influences between observed coercive interactions between children and caregivers, oppositional and aggressive behavior, and growth in parent report of early childhood (ages 2-5) and school-age CPs (ages 7.5 and 8.5). Participants were drawn from the Early Steps multisite randomized prevention trial that includes an ethnically diverse sample of male and female children and their families (N = 731). A parallel-process growth model combining latent trajectory and cross-lagged approaches revealed the amplifying effect of observed coercive caregiver-child interactions on children's noncompliance, whereas child oppositional and aggressive behaviors did not consistently predict increased coercion. The slope and initial levels of child oppositional and aggressive behaviors and the stability of caregiver-child coercion were predictive of teacher-reported oppositional behavior at school age. Families assigned to the Family Check-Up condition had significantly steeper declines in child oppositional and aggressive behavior and moderate reductions in oppositional behavior in school and in coercion at age 3. Results were not moderated by child gender, race/ethnicity, or assignment to the intervention condition. The implications of these findings are discussed with respect to understanding the early development of CPs and to designing optimal strategies for reducing problem behavior in early childhood with families most in need.

Structural framework and Mesozoic Cenozoic evolution of Ponta Grossa Arch, Paraná Basin, southern Brazil

NASA Astrophysics Data System (ADS)

Strugale, Michael; Rostirolla, Sidnei Pires; Mancini, Fernando; Portela Filho, Carlos Vieira; Ferreira, Francisco José Fonseca; de Freitas, Rafael Corrêa

2007-09-01

The integration of structural analyses of outcrops, aerial photographs, satellite images, aeromagnetometric data, and digital terrain models can establish the structural framework and paleostress trends related to the evolution of Ponta Grossa Arch, one of the most important structures of the Paraná Basin in southern Brazil. In the study area, the central-northern region of Paraná State, Brazil, the arch crosses outcropping areas of the Pirambóia, Botucatu, and Serra Geral Formations (São Bento Group, Mesozoic). The Pirambóia and Botucatu Formations are composed of quartz sandstones and subordinated siltstones. The Serra Geral Formation comprises tholeiitic basalt lava flows and associated intrusive rocks. Descriptive and kinematic structural analyses reveal the imprint of two brittle deformation phases: D1, controlled by the activation of an extensional system of regional faults that represent a progressive deformation that generated discontinuous brittle structures and dike swarm emplacement along a NW-SE trend, and D2, which was controlled by a strike-slip (transtensional) deformation system, probably of Late Cretaceous-Tertiary age, responsible for important fault reactivation along dykes and deformation bands in sandstones.

Early Enrollees and Peer Age Effect: First Evidence from INVALSI Data

ERIC Educational Resources Information Center

Ordine, Patrizia; Rose, Giuseppe; Sposato, Daniela

2015-01-01

This paper estimates peer age effect on educational outcomes of Italian pupils attending primary school by exploiting changes in enrollment rules over the last few years. The empirical procedure allows to understand if there is selection in classroom formation, arguing that in the absence of pupils sorting by early age at school entry, it is…

Mixed-Age Grouping in Early Childhood--Creating the Outdoor Learning Environment

ERIC Educational Resources Information Center

Rouse, Elizabeth

2015-01-01

Children attending centre-based early childhood care and education programmes across Australia are most likely to be grouped according to age and development. While multi- or mixed-age grouping has been seen to have positive benefits on young children's learning and pro-social behaviours, this approach is not usually adopted in the organisation of…

K/T age for the popigai impact event

NASA Technical Reports Server (NTRS)

Deino, A. L.; Garvin, J. B.; Montanari, S.

1991-01-01

The multi-ringed POPIGAI structure, with an outer ring diameter of over 100 km, is the largest impact feature currently recognized on Earth with an Phanerozoic age. The target rocks in this relatively unglaciated region consist of upper Proterozoic through Mesozoic platform sediments and igneous rocks overlying Precambrian crystalline basement. The reported absolute age of the Popigai impact event ranges from 30.5 to 39 Ma. With the intent of refining this age estimate, a melt-breccia (suevite) sample from the inner regions of the Popigai structure was prepared for total fusion and step-wise heating Ar-40/Ar-39 analysis. Although the total fusion and step-heating experiments suggest some degree of age heterogeneity, the recurring theme is an age of around 64 to 66 Ma.

Synchronization of the astronomical time scales in the Early Toarcian: A link between anoxia, carbon-cycle perturbation, mass extinction and volcanism

NASA Astrophysics Data System (ADS)

Ait-Itto, Fatima-Zahra; Martinez, Mathieu; Price, Gregory D.; Ait Addi, Abdellah

2018-07-01

The Late Pliensbachian-Early Toarcian is a pivotal time in the Mesozoic era, marked by pronounced carbon-isotope excursions, biotic crises and major climatic and oceanographic changes. Here we present new high-resolution carbon-isotope and magnetic-susceptibility measurements from an expanded hemipelagic Late Pliensbachian-Early Toarcian section from the Middle Atlas Basin (Morocco). Our new astronomical calibration allows the construction of an orbital time scale based on the 100-kyr eccentricity cycle. The Early Toarcian Polymorphum Zone contains 10 to 10.5 repetitions of the 100-kyr eccentricity both in the carbon-isotope and the magnetic-susceptibility data, leading to an average duration of 1.00 ± 0.08 myr. We also show that the Late Pliensbachian-Early Toarcian global carbon-cycle perturbation has an average duration of 0.24 ± 0.02 myr. These durations are comparable to previous astrochronological time scales provided for this time interval in the most complete sections of the Tethyan area, and longer than what has been provided in condensed sections. Anchoring this framework on published radiometric ages and astrochronological time scales, we estimate that the carbon-cycle perturbation of the Late Pliensbachian-Early Toarcian corresponds with the early phase of the Karoo and Chonke Aike large igneous provinces. Likewise, our new age constraints confirm that the Toarcian oceanic anoxic event is synchronous to the main phase of the Ferrar volcanic activity. Thus, these successive and short phases of the volcanic activity may have been at the origin of the successive phases of the mass extinctions observed in marine biotas in the Pliensbachian and Toarcian times.

Mesozoic tectonic history and geochronology of the Kular Dome, Russia and Bendeleben Mountains, Seward Peninsula, Alaska

NASA Astrophysics Data System (ADS)

Harris, Daniel B.

sandstones and Jurassic greywackes near the Kular Dome and compared to results from previously studied surrounding regions in Russia and the Arctic Alaska-Chukotka microplate in order to better define the relationship between the Arctic Alaska-Chukotka microplate and northern Russia during the Mesozoic. Results suggest that though the Chukotkan portion of the Arctic Alaska-Chukotka microplate was separated from the Kular Dome area during the Triassic, by the Tithonian it shared similar source regions for detrital zircon populations. Based on detrital zircon data from Chukotka, the Kular Dome, and the In’Yali Debin area, a new tectonic model for the formation of the Amerasian Basin and structures within is proposed. In this new model, Chukotka separated from and moved independently of the North Slope of Alaska during the Late Triassic-Early Jurassic, experiencing strike-slip emplacement along the northern coast of paleo-Russia and closed the South Anyui Ocean via transpression to form the South Anyui suture. Geochronologic and geochemical results from the Bendeleben and Windy Creek plutons of the southeastern Seward Peninsula were also studied to better describe Arctic tectonic conditions during the Late Mesozoic. In this area, six samples were collected from the multiple lithologies seen within the Bendeleben and Windy Creek plutons and were also dated by zircon U-Pb geochronology and analyzed for their major and trace element geochemistry. Results suggest that the Bendeleben and Windy Creek plutons were emplaced during multiple extensionally driven pulses of magmatism above a southward-retreating, northward-subducting slab causing extension in the overlying crust from about 104 Ma to 83 Ma. The magma chamber at depth was experiencing continuous replenishment and liquid segregation causing stratification of the Bendeleben pluton. Magmas of the felsic cap, which now form the outer region of the Bendeleben pluton, were emplaced first, followed by subsequent intrusion of

Early Histories of School-Aged Children with Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Loe, Irene M.; Balestrino, Maria D.; Phelps, Randall A.; Kurs-Lasky, Marcia; Chaves-Gnecco, Diego; Paradise, Jack L.; Feldman, Heidi M.

2008-01-01

In a prospective study of developmental outcomes in relation to early-life otitis media, behavioral, cognitive, and language measures were administered to a large, diverse sample of children at 2, 3, 4, 6, and 9-11 years of age (N = 741). At 9-11 years of age, 9% of the children were categorized as having attention-deficit/hyperactivity disorder…

Mitigation strategies for early-age shrinkage cracking in bridge decks.

DOT National Transportation Integrated Search

2010-04-01

Early-age shrinkage cracking has been observed in many concrete bridge decks in Washington State and elsewhere around the U.S. The cracking increases the effects of freeze-thaw damage, spalling, and corrosion of steel reinforcement, thus resulting in...

The influence of living conditions in early life on life satisfaction in old age.

PubMed

Deindl, Christian

2013-03-01

This article examines the influence of living conditions in early life on life satisfaction in old age in eleven Western European countries. It combines the influence of individual conditions, for example housing and family background, with country characteristics in the decade of birth. Using pooled data from the second and third wave of the Survey of Health, Ageing and Retirement in Europe, multilevel models show that early life living conditions have an influence on life satisfaction in old age. Furthermore, interaction effects between current and past living conditions show that adverse living conditions strengthen the effect of early life on life satisfaction in later life and therefore are an indication of cumulative inequality over the life course. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reduction in the retinotopic early visual cortex with normal aging and magnitude of perceptual learning.

PubMed

Chang, Li-Hung; Yotsumoto, Yuko; Salat, David H; Andersen, George J; Watanabe, Takeo; Sasaki, Yuka

2015-01-01

Although normal aging is known to reduce cortical structures globally, the effects of aging on local structures and functions of early visual cortex are less understood. Here, using standard retinotopic mapping and magnetic resonance imaging morphologic analyses, we investigated whether aging affects areal size of the early visual cortex, which were retinotopically localized, and whether those morphologic measures were associated with individual performance on visual perceptual learning. First, significant age-associated reduction was found in the areal size of V1, V2, and V3. Second, individual ability of visual perceptual learning was significantly correlated with areal size of V3 in older adults. These results demonstrate that aging changes local structures of the early visual cortex, and the degree of change may be associated with individual visual plasticity. Copyright © 2015 Elsevier Inc. All rights reserved.

Early-age monitoring of cement structures using FBG sensors

NASA Astrophysics Data System (ADS)

Wang, Chuan; Zhou, Zhi; Zhang, Zhichun; Ou, Jinping

2006-03-01

With more and more broad applications of the cement-based structures such as neat cement paste, cement mortar and concrete in civil engineering, people hope to find out what their performances should like. The in-service performances of cement-based structures are highly affected by their hardening process during the early-age. But it is still a big problem for traditional sensors to be used to monitor the early curing of cement-based structures due to such disadvantages as difficulties to install sensors inside the concrete, limited measuring points, poor durability and interference of electromagnetic wave and so on. In this paper, according to the sensing properties of the Fiber Bragg Grating sensors and self-characters of the cement-based structures, we have successfully finished measuring and monitoring the early-age inner-strain and temperature changes of the neat cement paste, concrete with and without restrictions, mass concrete structures and negative concrete, respectively. Three types of FBG-based sensors have been developed to monitor the cement-based structures. Besides, the installation techniques and the embedding requirements of FBG sensors in cement-based structures are also discussed. Moreover, such kind of technique has been used in practical structure, 3rd Nanjing Yangtze Bridge, and the results show that FBG sensors are well proper for measuring and monitoring the temperature and strain changes including self-shrinkage, dry shrinkage, plastic shrinkage, temperature expansion, frost heaving and so on inside different cement-based structures. This technique provides us a new useful measuring method on early curing monitoring of cement-based structures and greater understanding of details of their hardening process.

Normal aging delays and compromises early multifocal visual attention during object tracking.

PubMed

Störmer, Viola S; Li, Shu-Chen; Heekeren, Hauke R; Lindenberger, Ulman

2013-02-01

Declines in selective attention are one of the sources contributing to age-related impairments in a broad range of cognitive functions. Most previous research on mechanisms underlying older adults' selection deficits has studied the deployment of visual attention to static objects and features. Here we investigate neural correlates of age-related differences in spatial attention to multiple objects as they move. We used a multiple object tracking task, in which younger and older adults were asked to keep track of moving target objects that moved randomly in the visual field among irrelevant distractor objects. By recording the brain's electrophysiological responses during the tracking period, we were able to delineate neural processing for targets and distractors at early stages of visual processing (~100-300 msec). Older adults showed less selective attentional modulation in the early phase of the visual P1 component (100-125 msec) than younger adults, indicating that early selection is compromised in old age. However, with a 25-msec delay relative to younger adults, older adults showed distinct processing of targets (125-150 msec), that is, a delayed yet intact attentional modulation. The magnitude of this delayed attentional modulation was related to tracking performance in older adults. The amplitude of the N1 component (175-210 msec) was smaller in older adults than in younger adults, and the target amplification effect of this component was also smaller in older relative to younger adults. Overall, these results indicate that normal aging affects the efficiency and timing of early visual processing during multiple object tracking.

Hydrocarbon provinces and productive trends in Libya and adjacent areas

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

Missallati, A.A.

1988-08-01

According to the age of major reservoirs, hydrocarbon occurrences in Libya and adjacent areas can be grouped into six major systems which, according to their geographic locations, can be classified into two major hydrocarbon provinces: (1) Sirte-Pelagian basins province, with major reservoirs ranging from middle-late Mesozoic to early Tertiary, and (2) Murzog-Ghadames basins province, with major reservoirs ranging from early Paleozoic to early Mesozoic. In the Sirte-Pelagian basins province, hydrocarbons have been trapped in structural highs or in stratigraphic wedge-out against structural highs and in carbonate buildups. Here, hydrocarbon generation is characterized by the combined effect of abundant structural reliefmore » and reservoir development in the same hydrocarbon systems of the same age, providing an excellent example of hydrocarbon traps in sedimentary basins that have undergone extensive tensional fracturing in a shallow marine environment. In the Murzog-Ghadames basins province, hydrocarbons have been trapped mainly in structural highs controlled by paleostructural trends as basement arches which acted as focal points for oil migration and accumulation.« less

Controls of late Palaeozoic and Mesozoic extension in the British Isles: evidence from seismic reflection data in the Central North Sea

NASA Astrophysics Data System (ADS)

Smith, K.; Cameron, T. D. J.

2009-04-01

Controls of late Palaeozoic and Mesozoic extension in the British Isles: evidence from seismic reflection data in the Central North Sea. Kevin Smith (1) and Don Cameron (2) (1) British Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9 3LA. (ksm@bgs.ac.uk). (2) British Geological Survey, 376 Gilmerton Road, Edinburgh, EH17 7QS. In the area of the British Isles during the late Devonian and early Carboniferous, the oblique convergence of Laurentia and Gondwana imposed a torque on the adjoining terranes of Baltica and Avalonia. Their resulting clockwise rotation was accommodated by widely distributed N-S extension in the intervening zones previously formed by Caledonian and Acadian convergence. South of Laurentia and Baltica, late Palaeozoic extension was focused (1) at terrane margins, (2) in areas of limited Caledonian-Acadian plutonism, and (3) in places where the western (Iapetus) and eastern (Tornquist) convergence zones intersect at a high angle. One of these latter areas lies in Central England immediately north of the Midland Microcraton (part of Eastern Avalonia), where thermal subsidence associated with early Carboniferous extension gave rise to the late Carboniferous Pennine Basin. Interpretation of an extensive set of 3D and 2D long-offset seismic reflection data suggests that a similar area of enhanced extension at a fold belt intersection lies to north of the Mid North Sea High in the middle of the Central North Sea. Variscan uplift and inversion of the late Palaeozoic basins began to predominate in mid-Carboniferous times as final amalgamation of all the different terranes to form Pangaea curtailed the initial episode of extension and thermal subsidence. This change in the tectonic regime was associated with the onset of tholeiitic volcanism within the convergence zones, and was followed by localised extension during the earliest Permian. Evidence obtained from seismic interpretation of the deep structure of the UK sector of the Central

Tracking development from early speech-language acquisition to reading skills at age 13.

PubMed

Bartl-Pokorny, Katrin D; Marschik, Peter B; Sachse, Steffi; Green, Vanessa A; Zhang, Dajie; Van Der Meer, Larah; Wolin, Thomas; Einspieler, Christa

2013-06-01

Previous studies have indicated a link between speech-language and literacy development. To add to this body of knowledge, we investigated whether lexical and grammatical skills from toddler to early school age are related to reading competence in adolescence. Twenty-three typically developing children were followed from age 1;6 to 13;6 (years;months). Parental checklists and standardized tests were used to assess the development of mental lexicon, grammatical and reading capacities of the children. Direct assessment of early speech-language functions positively correlated with later reading competence, whereas lexical skills reported by parents were not associated with this capacity. At (pre-) school age, larger vocabulary and better grammatical abilities predicted advanced reading abilities in adolescence. Our study contributes to the understanding of typical speech-language development and its relation to later reading outcome, extending the body of knowledge on these developmental domains for future early identification of children at risk for reading difficulties.

Mesozoic to Eocene ductile deformation of western Central Iran: From Cimmerian collisional orogeny to Eocene exhumation

NASA Astrophysics Data System (ADS)

Kargaranbafghi, Fariba; Neubauer, Franz; Genser, Johann; Faghih, Ali; Kusky, Timothy

2012-09-01

To advance our understanding of the Mesozoic to Eocene tectonics and kinematics of basement units exposed in the south-western Central Iran plateau, this paper presents new structural and thermochronological data from the Chapedony metamorphic core complex and hangingwall units, particularly from the Posht-e-Badam complex. The overall Paleogene structural characteristics of the area are related to an oblique convergent zone. The Saghand area represents part of a deformation zone between the Arabian and Eurasian plates, and can be interpreted to result from the Central Iran intracontinental deformation acting as a weak zone during Mesozoic to Paleogene times. Field and microstructural evidence reveal that the metamorphic and igneous rocks suffered a ductile shear deformation including mylonitization at the hangingwall boundary of the Eocene Chapedony metamorphic core complex. Comparison of deformation features in the mylonites and other structural features within the footwall unit leads to the conclusion that the mylonites were formed in a subhorizontal shear zone by NE-SW stretching during Middle to Late Eocene extensional tectonics. The Chapedony metamorphic core complex is characterized by amphibolite-facies metamorphism and development of S and S-L tectonic fabrics. The Posht-e-Badam complex was deformed by two stages during Cimmerian tectonic processes forming the Paleo-Tethyan suture.

Early language mediates the relations between preschool inattention and school-age reading achievement.

PubMed

O'Neill, Sarah; Thornton, Veronica; Marks, David J; Rajendran, Khushmand; Halperin, Jeffrey M

2016-05-01

Early inattention is associated with later reading problems in children, but the mechanism by which this occurs is unclear. We investigated whether the negative relation between preschoolers' ADHD symptoms and 8-year-old reading achievement is directly related to the severity of inattention or is mediated by early language skills. Children (n = 150; 76% boys) were evaluated at 3 time points: preschool (T1), mean (SD) age = 4.24 (.49) years; 1 year later (T2), mean (SD) age = 5.28 (.50) years; and during school age (T3), mean (SD) age = 8.61 (.31) years. At T1, parents' Kiddie-SADS responses were dimensionalized to reflect ADHD severity. Children completed the Language domain of the NEPSY (i.e., A Developmental Neuropsychological Assessment) at T1 and again at T2. At T3, children completed the Wechsler Individual Achievement Test, Second Edition Word Reading, Pseudoword Decoding, Reading Comprehension, and Spelling subtests, and their teachers completed ratings of Reading and Written Expression performance in school. The mediating effect of T2 Language on the relation between preschool Inattention and age 8 Reading was examined using the nonparametric bootstrapping procedure, while controlling for T1 Language. Language ability at T2 mediated the path from preschool inattention (but not hyperactivity/impulsivity) to 8-year-old reading achievement (both test scores and ratings) after controlling for preschoolers' language ability. Early attentional deficits may negatively impact school-age reading outcomes by compromising the development of language skills, which in turn imperils later reading achievement. Screening children with attentional problems for language impairment, as well as implementing early intervention for both attentional and language problems may be critical to promote reading achievement during school years. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Age 26 Cost-Benefit Analysis of the Child-Parent Center Early Education Program

ERIC Educational Resources Information Center

Reynolds, Arthur J.; Temple, Judy A.; White, Barry A. B.; Ou, Suh-Ruu; Robertson, Dylan L.

2011-01-01

Using data collected up to age 26 in the Chicago Longitudinal Study, this cost-benefit analysis of the Child-Parent Centers (CPC) is the first for a sustained publicly funded early intervention. The program provides services for low-income families beginning at age 3 in 20 school sites. Kindergarten and school-age services are provided up to age 9…

Detrital zircons from the Tananao metamorphic complex of Taiwan: Implications for sediment provenance and Mesozoic tectonics

NASA Astrophysics Data System (ADS)

Yui, T. F.; Maki, K.; Lan, C. Y.; Hirata, T.; Chu, H. T.; Kon, Y.; Yokoyama, T. D.; Jahn, B. M.; Ernst, W. G.

2012-05-01

Taiwan formed during the Plio-Pleistocene collision of Eurasia with the outboard Luzon arc. Its pre-Tertiary basement, the Tananao metamorphic complex, consists of the western Tailuko belt and the eastern Yuli belt. These circum-Pacific belts have been correlated with the high-temperature/low-pressure (HT/LP) Ryoke belt and the high-pressure/low-temperature (HP/LT) Sanbagawa belt of Japan, respectively. To test this correlation and to reveal the architecture and plate-tectonic history of the Tananao metamorphic basement, detrital zircons were separated from 7 metasedimentary rock samples for U-Pb dating by LA-ICPMS techniques. Results of the present study, coupled with previous data, show that (1) the Tailuko belt consists of a Late Jurassic to earliest Cretaceous accretionary complex sutured against a Permian-Early Jurassic marble ± metabasaltic terrane, invaded in the north by scattered Late Cretaceous granitic plutons; the latter as well as minor Upper Cretaceous cover strata probably formed in a circum-Pacific forearc; (2) the Yuli belt is a mid- to Late Cretaceous accretionary complex containing HP thrust sheets that were emplaced attending the Late Cenozoic Eurasian plate-Luzon arc collision; (3) these two Late Mesozoic belts are not coeval, and in part were overprinted by low-grade metamorphism during the Plio-Pleistocene collision; (4) accreted clastic sediments of the Tailuko belt contain mainly Phanerozoic detrital zircons, indicating that terrigenous sediments were mainly sourced from western Cathaysia, whereas in contrast, clastic rocks of the Yuli accretionary complex contain a significant amount of Paleoproterozoic and distinctive Neoproterozoic zircons, probably derived from the North China craton and the Yangtze block ± eastern Cathaysia, as a result of continent uplift/exhumation after the Permo-Triassic South China-North China collision; and (5) the Late Jurassic-Late Cretaceous formation of the Tananao basement complex precludes the possibility

Prevalence of Early and Late Age-Related Macular Degeneration in India: The INDEYE Study

PubMed Central

Krishnan, Tiruvengada; Ravindran, Ravilla D.; Murthy, Gudlavalleti V. S.; Vashist, Praveen; Fitzpatrick, Kathryn E.; Thulasiraj, R. Duraisami; John, Neena; Maraini, Giovanni; Camparini, Monica; Chakravarthy, Usha

2010-01-01

Purpose. To estimate the prevalence of early and late age-related macular degeneration (AMD) in India. Methods. Of 7518 people aged 60 years and older identified from randomly sampled villages in North and South India, 5853 (78%) attended an eye examination including fundus photography. Fundus images were graded according to the Wisconsin Age-Related Maculopathy Grading System. Results. Fundus images were ungradable in 1587 people, mainly because of cataract. People 80 years of age and older were less likely to attend the eye examination and more likely to have ungradable images. For ages 60 to 79 years, the percent prevalence (95% confidence interval [CI]) were late AMD 1.2 (0.8–1.5); and early AMD: grade 1 (soft distinct drusen or pigmentary irregularities), 39.3 (37.2–41.5); grade 2 (soft distinct drusen with pigmentary irregularities or soft indistinct or reticular drusen), 6.7 (5.8–7.6); and grade 3 (soft indistinct or reticular drusen with pigmentary irregularities), 0.2 (0.1–0.4). For ages 80 and older, the respective percent prevalence was: late AMD, 2.5 (0.4–4.7); and early AMD: grade 1, 43.1(35.7–50.6); grade 2, 8.1 (4.3–12.0); and grade 3, 0.5 (0–1.5). Conclusions. The prevalence of early AMD (grades 1 and 2) is similar to that observed in Western populations, but grade 3 appears to be lower. The prevalence of late AMD is comparable to that in Western populations in the age group 60 to 79 years. It is likely that the prevalence in the 80 and older age group is underestimated. PMID:19696177

Anatexis, hybridization and the modification of ancient crust: Mesozoic plutonism in the Old Woman Mountains area, California

USGS Publications Warehouse

Miller, C.F.; Wooden, J.L.

1994-01-01

A compositionally expanded array of granitic (s.l.) magmas intruded the > 2 Ga crust of the Old Woman Mountains area between 160 and 70 Ma. These magmas were emplaced near the eastern (inland) edge of the Jurassic/Cretaceous arcs of western North America, in an area where magma flux, especially during the Jurassic, was considerably lower than to the west. The Jurassic intrusives and over half of the Cretaceous intrusives are predominantly metaluminous and variable in composition; a major Cretaceous suite comprises only peraluminous monzogranite. Only the Jurassic intrusions show clear evidence for the presence of mafic liquids. All units, including the most mafic rocks, reveal isotopic evidence for a significant crustal component. However, none of the Mesozoic intrusives matches in isotopic composition either average pre-intrusion crust or any major unit of the exposed crust. Elemental inconsistencies also preclude closed system derivation from exposed crust. Emplacement of these magmas, which doubled the volume of the mid- to upper crust, did not dramatically change its elemental composition. It did, however, affect its Nd and especially Sr isotopic composition and modify some of the distinctive aspects of the elemental chemistry. We propose that Jurassic magmatism was open-system, with a major influx of mantle-derived mafic magma interacting strongly with the ancient crust. Mesozoic crustal thickening may have led to closed-system crustal melting by the Late Cretaceous, but the deep crust had been profoundly modified by earlier Mesozoic hybridization so that crustal melts did not simply reflect the original crustal composition. The clear evidence for a crustal component in magmas of the Old Woman Mountains area may not indicate any fundamental differences from the processes at work elsewhere in this or other magmatic arcs where the role of pre-existing crust is less certain. Rather, a compositionally distinctive, very old crust may simply have yielded a more

Donor age is a predictor of early low output after heart transplantation.

PubMed

Fujino, Takeo; Kinugawa, Koichiro; Nitta, Daisuke; Imamura, Teruhiko; Maki, Hisataka; Amiya, Eisuke; Hatano, Masaru; Kimura, Mitsutoshi; Kinoshita, Osamu; Nawata, Kan; Komuro, Issei; Ono, Minoru

2016-05-01

Using hearts from marginal donors could be related to increased risk of primary graft dysfunction and poor long-term survival. However, factors associated with delayed myocardial recovery after heart transplantation (HTx) remain unknown. We sought to clarify risk factors that predict early low output after HTx, and investigated whether early low output affects mid-term graft dysfunction. We retrospectively analyzed patients who had undergone HTx at The University of Tokyo Hospital. We defined early low output patients as those whose cardiac index (CI) was <2.2 L/min/m(2) despite the use of intravenous inotrope at 1 week after HTx. We included 45 consecutive HTx recipients, and classified 11 patients into early low output group, and the others into early preserved output group. We performed univariable logistic analysis and found that donor age was the only significant factor that predicted early low output (odds ratio 1.107, 95% confidence interval 1.034-1.210, p=0.002). CI of early low output patients gradually increased and it caught up with that of early preserved output patients at 2 weeks after HTx (2.4±0.6 L/min/m(2) in early low output group vs 2.5±0.5 L/min/m(2) in early preserved output group, p=0.684). Plasma B-type natriuretic peptide concentration of early low output patients was higher (1118.5±1250.2 pg/ml vs 526.4±399.5 pg/ml; p=0.033) at 1 week, 703.6±518.4 pg/ml vs 464.6±509.0 pg/ml (p=0.033) at 2 weeks, and 387.7±231.9 pg/ml vs 249.4±209.5 pg/ml (p=0.010) at 4 weeks after HTx, and it came down to that of early preserved output patients at 12 weeks after HTx. Donor age was a predictor of early low output after HTx. We should be careful after HTx from old donors. However, hemodynamic parameters of early low output patients gradually caught up with those of early preserved output patients. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

School Age Outcomes of Children with Autism Spectrum Disorder Who Received Community-Based Early Interventions.

PubMed

Vinen, Zoe; Clark, Megan; Paynter, Jessica; Dissanayake, Cheryl

2018-05-01

This study followed children with Autism Spectrum Disorder (ASD) from early intervention into their early schooling years, when they were aged between 6 and 9 years, on autism symptom severity and cognitive functioning. The children, matched at pre-intervention, were compared on type of community provided service: 31 were in receipt of community-based group Early Start Denver Model and 28 had received other community provisions for ASD. Irrespective of groups, cognitive functioning was found to have significantly improved by school age compared to pre-intervention. Autism symptom severity increased during the same developmental period, seemingly driven by an increase in restricted and repetitive behaviours over time. In contrast, both groups displayed improved social affect by school age.

Petrologic Aspects of Seamount and Guyot Volcanism on the Ancestral Mesozoic Pacific Plate: a Review

NASA Astrophysics Data System (ADS)

Natland, J. H.

2007-12-01

Hundreds of large seamounts and guyots are widely scattered almost in a "shotgun-blast" arrangement in an area about the size of the United States west of the Mississippi River on the Mesozoic Pacific plate between the Mariana Trench and the Gilbert Islands. Most of these formed between ~160-100 Ma while the Pacific plate was surrounded by spreading ridges and growing outward in all directions. There is little to no indication that the seamounts and guyots formed along linear seamount chains; existing radiometric-age data show no age progressions. The volcanoes appear to have formed in response to a uniform stress configuration across the plate, which was either not moving or moving very slowly at the time (1, 2), much like the modern Antarctic plate. When the growing plate started to encounter subduction systems in the western Pacific at ~90 Ma, consistent stress patterns began to develop, and the broad linear Gilbert and Line volcanic ridge systems began to form. Even then, however, considerable overlapping of volcanism occurred, and only the most general age progressions are evident in existing data. Petrologic data from samples obtained from dozens of volcanic summits by dredging and beneath several carbonate platforms by drilling reveal considerable diversity in development of differentiated alkalic magmatic lineages rooted in diverse parental basaltic rocks. These include transitional, alkalic and basanitic compositions, with differentiates of hawaiite, mugearite, trachyte and one phonolite. Many of the basaltic rocks are partly to significantly transformed by alteration under oxidative conditions (dredged rocks) and both oxidative and non-oxidative conditions (drilled rocks). This can make estimations of mantle geochemical provenance difficult. Nevertheless, the province has been linked by backtracking techniques to the modern SOPITA region of the South Pacific (3), and its rocks show enrichments in trace elements and isotopic characteristics similar to

Effect of early age woody and herbaceous competition control on wood properties of loblolly pine

Treesearch

F. Antony; L. R. Schimleck; L. Jordan; Alexander Clark; R. F. Daniels

2011-01-01

Early age competition control has been reported to significantly improve the growth and yield of plantation grown loblolly pine. The objective of this paper is to understand the changes in wood properties: basal area weighted whole disk SG, earlywood SG (EWSG), latewood SG (LWSG) and latewood percent (LWP) of 14 year-old trees which received early age herbaceous and...

A low-angle normal fault and basement structures within the Enping Sag, Pearl River Mouth Basin: Insights into late Mesozoic to early Cenozoic tectonic evolution of the South China Sea area

NASA Astrophysics Data System (ADS)

Ye, Qing; Mei, Lianfu; Shi, Hesheng; Shu, Yu; Camanni, Giovanni; Wu, Jing

2018-04-01

The basement structure of the Cenozoic Enping Sag, within the Pearl River Mouth Basin on the northern margin of South China Sea, is revealed by borehole-constrained high-quality 3D seismic reflection data. Such data suggest that the Enping Sag is bounded in the north by a low-angle normal fault. We interpret this low-angle normal fault to have developed as the result of the reactivation of a pre-existing thrust fault part of a pre-Cenozoic thrust system. This is demonstrated by the selective reactivation of the pre-existing thrust and by diffuse contractional deformation recognized from the accurate analysis of basement reflections. Another significant result of this study is the finding of some residual rift basins within the basement of the Enping Sag. Both the thrust system and the residual basins are interpreted to have developed after the emplacement of continental margin arc-related granitoids (J3-K1) that define the basement within the study area. Furthermore, seismic sections show that the pre-existing residual rift basins are offset by the main thrust fault and they are both truncated by the Tg unconformity. These structural relationships, interpreted in the frame of previous studies, help us to reconstruct a six-event structural evolution model for the Enping Sag from the late Mesozoic to the early Cenozoic. In particular, we interpret the residual rift basins to have formed as the result of back-arc extension due to the slab roll-back of the Paleo-Pacific Plate subduction in the early K2. The thrust system has recorded a compressional event in the late K2 that followed the back-arc extension in the SCS area. The mechanism of this compressional event is still to be clarified, and might be related to continuous subduction of the Paleo-Pacific Plate or to the continent-continent collision between a micro-continental block and the South China margin.

Petrogenesis of early Jurassic basalts in southern Jiangxi Province, South China: Implications for the thermal state of the Mesozoic mantle beneath South China

NASA Astrophysics Data System (ADS)

Cen, Tao; Li, Wu-xian; Wang, Xuan-ce; Pang, Chong-jin; Li, Zheng-xiang; Xing, Guang-fu; Zhao, Xi-lin; Tao, Jihua

2016-07-01

Early Jurassic bimodal volcanic and intrusive rocks in southern South China show distinct associations and distribution patterns in comparison with those of the Middle Jurassic and Cretaceous rocks in the area. It is widely accepted that these rocks formed in an extensional setting, although the timing of the onset and the tectonic driver for extension are debated. Here, we present systematic LA-ICP-MS zircon U-Pb ages, whole-rock geochemistry and Sr-Nd isotope data for bimodal volcanic rocks from the Changpu Formation in the Changpu-Baimianshi and Dongkeng-Linjiang basins in southern Jiangxi Province, South China. Zircon U-Pb ages indicate that the bimodal volcanic rocks erupted at ca. 190 Ma, contemporaneous with the Fankeng basalts ( 183 Ma). A compilation of geochronological results demonstrates that basin-scale basaltic eruptions occurred during the Early Jurassic within a relatively short interval (< 5 Ma). These Early Jurassic basalts have tholeiitic compositions and OIB-like trace element distribution patterns. Geochemical analyses show that the basalts were derived from depleted asthenospheric mantle, dominated by a volatile-free peridotite source. The calculated primary melt compositions suggest that the basalts formed at 1.9-2.1 GPa, with melting temperatures of 1378 °C-1405 °C and a mantle potential temperature (TP) ranging from 1383 °C to 1407 °C. The temperature range is somewhat hotter than normal mid-ocean-basalt (MORB) mantle but similar to an intra-plate continental mantle setting, such as the Basin and Range Province in western North America. This study provides an important constraint on the Early Jurassic mantle thermal state beneath South China. Reference: Raczek, I., Stoll, B., Hofmann, A.W., Jochum, K.P. 2001. High-precision trace element data for the USGS reference materials BCR-1, BCR-2, BHVO-1, BHVO-2, AGV-1, AGV-2, DTS-1, DTS-2, GSP-1 and GSP-2 by ID-TIMS and MIC-SSMS. Geostandards Newsletter 25(1), 77-86.

INEQUITY ISSUES AND MOTHERS' PREGNANCY, DELIVERY AND EARLY-AGE SURVIVAL EXPERIENCES IN ENDE DISTRICT, INDONESIA.

PubMed

Pardosi, Jerico Franciscus; Parr, Nick; Muhidin, Salut

2015-11-01

Indonesia's infant mortality rates are among the highest in South-East Asia, and there are substantial variations between its sub-national regions. This qualitative study aims to explore early mortality-related health service provision and gender inequity issues based on mothers' pregnancy, delivery and early-age survival experience in Ende district, Nusa Tenggara Timur province. Thirty-two mothers aged 18-45 years with at least one birth in the previous five years were interviewed in depth in May 2013. The results show most mothers have little knowledge about the danger signs for a child's illness. Mothers with early-age deaths generally did not know the cause of death. Very few mothers had received adequate information on maternal and child health during their antenatal and postnatal visits to the health facility. Some mothers expressed a preference for using a traditional birth attendant, because of their ready availability and the more extensive range of support services they provide, compared with local midwives. Unprofessional attitudes displayed by midwives were reported by several mothers. As elsewhere in Indonesia, the power of health decision-making lies with the husband. Policies aimed at elevating mothers' roles in health care decision-making are discussed as measures that would help to improve early-age survival outcomes. Widening the public health insurance distribution, especially among poorer mothers, and equalizing the geographical distribution of midwives and health facilities are recommended to tackle geographical inequities and to increase early-age survival in Ende district.

Early developmental milestones and age of independent walking in orphans compared with typical home-raised infants.

PubMed

Chaibal, Supattra; Bennett, Surussawadi; Rattanathanthong, Korrawan; Siritaratiwat, Wantana

2016-10-01

Early gross motor development is a major indicator of global milestones in the first year of life, affecting the walking ability of a child. There has been limited research reporting on early motor development and the age of independent walking of orphaned infants compared to typical home-raised infants. The purpose of this study was to compare the mean scores of early gross motor movement at 4, 6 and 8months of age and at the age of walking attainment of typically raised infants and orphaned infants. In addition, we looked to compare the walking age between these same infants. This cross-sectional study recruited 59 typical home-raised infants and 62 orphans. Their gross motor development was assessed using the Alberta Infant Motor Scale (AIMS). The age of walking attainment was also prospectively monitored and ascertained. The Student's independent t-test was used to analyse the differences of the AIMS scores at 4, 6 and 8months of age and at the age of independent walking between the two groups. The orphans showed significantly lower AIMS scores at 4, 6 and 8months of age and the age of independent walking (P-value<0.05). The orphan group had a 5-month older mean age of walking attainment (15.0±4.2months) compared with typical home-raised infants (9.9±1.4months). Orphans have delays in early gross motor development and walk independently at an older age, compared with home-raised infants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Loss of Nfkb1 leads to early onset aging.

PubMed

Bernal, Giovanna M; Wahlstrom, Joshua S; Crawley, Clayton D; Cahill, Kirk E; Pytel, Peter; Liang, Hua; Kang, Shijun; Weichselbaum, Ralph R; Yamini, Bakhtiar

2014-11-01

NF-κB is a major regulator of age-dependent gene expression and the p50/NF-κB1 subunit is an integral modulator of NF-κB signaling. Here, we examined Nfkb1-/- mice to investigate the relationship between this subunit and aging. Although Nfkb1-/- mice appear similar to littermates at six months of age, by 12 months they have a higher incidence of several observable age-related phenotypes. In addition, aged Nfkb1-/- animals have increased kyphosis, decreased cortical bone, increased brain GFAP staining and a decrease in overall lifespan compared to Nfkb1+/+. In vitro, serially passaged primary Nfkb1-/- MEFs have more senescent cells than comparable Nfkb1+/+ MEFs. Also, Nfkb1-/- MEFs have greater amounts of phospho-H2AX foci and lower levels of spontaneous apoptosis than Nfkb1+/+, findings that are mirrored in the brains of Nfkb1-/- animals compared to Nfkb1+/+. Finally, in wildtype animals a substantial decrease in p50 DNA binding is seen in aged tissue compared to young. Together, these data show that loss of Nfkb1 leads to early animal aging that is associated with reduced apoptosis and increased cellular senescence. Moreover, loss of p50 DNA binding is a prominent feature of aged mice relative to young. These findings support the strong link between the NF-κB pathway and mammalian aging.

GhNAC12, a neutral candidate gene, leads to early aging in cotton (Gossypium hirsutum L).

PubMed

Zhao, Fengli; Ma, Jianhui; Li, Libei; Fan, Shuli; Guo, Yaning; Song, Meizhen; Wei, Hengling; Pang, Chaoyou; Yu, Shuxun

2016-01-15

NAC (NAM, ATAF, and CUC) is one of the largest transcription factor families in plants, and its members play various roles in plant growth, development, and the response to biotic and abiotic stresses. Currently, 77 NAC genes have been reported in cotton (Gossypium hirsutum L.). And GhNAC12 showed up-regulation during leaf senescence, but its role in this process is poorly understood. In the present study, a preliminary function analysis of GhNAC12 was performed during leaf senescence. qRT-PCR analysis indicated that GhNAC12 expression increased during the early-aging process and the aging of cotyledons. Additionally, we observed that overexpression of GhNAC12 in Arabidopsis led to early senescence (early aging). Our findings suggest that GhNAC12 is a candidate gene for early aging in upland cotton cultivars. Neutrality tests suggested that there was no selection pressure imposed on GhNAC12 during the domestication of upland cotton. Copyright © 2015 Elsevier B.V. All rights reserved.

Early and intermediate age-related macular degeneration: update and clinical review.

PubMed

García-Layana, Alfredo; Cabrera-López, Francisco; García-Arumí, José; Arias-Barquet, Lluís; Ruiz-Moreno, José M

2017-01-01

Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in developed countries. With the aging of population, AMD will become globally an increasingly important and prevalent disease worldwide. It is a complex disease whose etiology is associated with both genetic and environmental risk factors. An extensive decline in the quality of life and progressive need of daily living assistance resulting from AMD among those most severely affected highlights the essential role of preventive strategies, particularly advising patients to quit smoking. In addition, maintaining a healthy diet, controlling other risk factors (such as hypertension, obesity, and atherosclerosis), and the use of nutritional supplements (antioxidants) are recommendable. Genetic testing may be especially important in patients with a family history of AMD. Recently, unifying criteria for the clinical classification of AMD, defining no apparent aging changes; normal aging changes; and early, intermediate, and late AMD stages, are of value in predicting AMD risk of progression and in establishing recommendations for the diagnosis, therapeutic approach, and follow-up of patients. The present review is focused on early and intermediate AMD and presents a description of the clinical characteristics and ophthalmological findings for these stages, together with algorithms for the diagnosis and management of patients, which are easily applicable in daily clinical practice.

Early and intermediate age-related macular degeneration: update and clinical review

PubMed Central

García-Layana, Alfredo; Cabrera-López, Francisco; García-Arumí, José; Arias-Barquet, Lluís; Ruiz-Moreno, José M

2017-01-01

Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in developed countries. With the aging of population, AMD will become globally an increasingly important and prevalent disease worldwide. It is a complex disease whose etiology is associated with both genetic and environmental risk factors. An extensive decline in the quality of life and progressive need of daily living assistance resulting from AMD among those most severely affected highlights the essential role of preventive strategies, particularly advising patients to quit smoking. In addition, maintaining a healthy diet, controlling other risk factors (such as hypertension, obesity, and atherosclerosis), and the use of nutritional supplements (antioxidants) are recommendable. Genetic testing may be especially important in patients with a family history of AMD. Recently, unifying criteria for the clinical classification of AMD, defining no apparent aging changes; normal aging changes; and early, intermediate, and late AMD stages, are of value in predicting AMD risk of progression and in establishing recommendations for the diagnosis, therapeutic approach, and follow-up of patients. The present review is focused on early and intermediate AMD and presents a description of the clinical characteristics and ophthalmological findings for these stages, together with algorithms for the diagnosis and management of patients, which are easily applicable in daily clinical practice. PMID:29042759

Early Cretaceous bimodal volcanic rocks in the southern Lhasa terrane, south Tibet: Age, petrogenesis and tectonic implications

NASA Astrophysics Data System (ADS)

Wang, Chao; Ding, Lin; Liu, Zhi-Chao; Zhang, Li-Yun; Yue, Ya-Hui

2017-01-01

Limited geochronological and geochemical data from Early Cretaceous igneous rocks of the Gangdese Belt have resulted in a dispute regarding the subduction history of Neo-Tethyan Ocean. To approach this issue, we performed detailed in-situ zircon U-Pb and Hf isotopic, whole-rock elemental and Sr-Nd isotopic analyses on Late Mesozoic volcanic rocks exposed in the Liqiongda area, southern Lhasa terrane. These volcanic rocks are calc-alkaline series, dominated by basalts, basaltic andesites, and subordinate rhyolites, with a bimodal suite. The LA-ICPMS zircon U-Pb dating results of the basaltic andesites and rhyolites indicate that these volcanic rocks erupted during the Early Cretaceous (137-130 Ma). The basaltic rocks are high-alumina (average > 17 wt.%), enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs), showing subduction-related characteristics. They display highly positive zircon εHf(t) values (+ 10.0 to + 16.3) and whole-rock εNd(t) values (+ 5.38 to + 7.47). The silicic suite is characterized by low Al2O3 (< 15.4 wt.%), Mg# (< 40), and TiO2 (< 0.3 wt.%) abundances; enriched and variable concentrations of LILEs and REEs; and strongly negative Eu anomalies (Eu/Eu* = 0.08-0.19), as well as depleted Hf isotopic compositions (εHf(t) = + 4.9 to + 16.4) and Nd isotopic compositions (εNd(t) = + 5.26 to + 6.71). Consequently, we envision a process of basaltic magmas similar to that of MORB extracted from a source metasomatized by slab-derived components for the petrogenesis of mafic rocks, whereas the subsequent mafic magma underplating triggered partial melting of the juvenile crust to generate acidic magma. Our results confirm the presence of Early Cretaceous volcanism in the southern Lhasa terrane. Combined with the distribution of the contemporary magmatism, deformation style, and sedimentary characteristics in the Lhasa terrane, we favor the suggestion that the Neo

Education and Learning in the Early Middle Ages: New Perspectives and Old Problems.

ERIC Educational Resources Information Center

Contreni, John J.

1989-01-01

Discusses various scholarly views of education and learning in the early middle ages and identifies some problems confronting scholars investigating this period. Points out new perspectives relative to the role of education during this time. Asserts that future study of early medieval education will benefit from focusing on the minds of masters…

Meteoritic trace element toxification and the terminal Mesozoic mass extinction

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

Dickson, S.M.; Erickson, D.J. III

1985-01-01

Calculations of trace element fluxes to the earth associated with 5 and 10 kilometer diameter Cl chondrites and iron meteorites are presented. The data indicate that the masses of certain trace elements contained in the bolide, such as Fe, Co, Ni, Cr, Pb, and Cu, are as large as or larger than the world ocean burden. The authors believe that this pulse of trace elements was of sufficient magnitude to perturb the biogeochemical cycles operative 65 million years ago, a probably time of meteorite impact. Geochemical anomalies in Cretaceous-Tertiary boundary sediments suggest that elevated concentrations of trace elements may havemore » persisted for thousands of years in the ocean. Through direct exposure and bioaccumulation, many trophic levels of the global food chain, including that of the dinosaurs, would have been adversely affected by these meteoritic trace elements. The trace element toxification hypothesis may account for the selective extinction of both marine and terrestrial species in the enigmatic terminal Mesozoic event.« less

New uppermost Cambrian U-Pb date from Avalonian Wales and age of the Cambrian-Ordovician boundary

USGS Publications Warehouse

Davidek, K.; Landing, E.; Bowring, S.A.; Westrop, S.R.; Rushton, A.W.A.; Fortey, R.A.; Adrain, J.M.

1998-01-01

A crystal-rich volcaniclastic sandatone in the lower Peltura scarabaeoides Zone at Ogof-odi near Criccieth, North Wales, yields a U-Pb zircon age of 491 ?? 1 Ma. This late Late Cambrian date indicates a remarkably young age for the Cambrian-Ordovician boundary whose age must be less than 491 Ma. Hence the revised duration of the post-Placentian (trilobite-bearing) Cambrian indicates that local trilobite zonations allow a biostratigraphic resolution comparble to that provided by Ordovician graptolites and Mesozoic ammonites.

Viking and Early Middle Ages Northern Scandinavian Textiles Proven to be made with Hemp

NASA Astrophysics Data System (ADS)

Skoglund, G.; Nockert, M.; Holst, B.

2013-10-01

Nowadays most plant textiles used for clothing and household are made of cotton and viscose. Before the 19th century however, plant textiles were mainly made from locally available raw materials, in Scandinavia these were: nettle, hemp and flax. It is generally believed that in Viking and early Middle Ages Scandinavia hemp was used only for coarse textiles (i.e. rope and sailcloth). Here we present an investigation of 10 Scandinavian plant fibre textiles from the Viking and Early Middle Ages, believed to be locally produced. Up till now they were all believed to be made of flax. We show that 4 textiles, including two pieces of the famous Överhogdal Viking wall-hanging are in fact made with hemp (in three cases hemp and flax are mixed). This indicates that hemp was important, not only for coarse but also for fine textile production in Viking and Early Middle Ages in Scandinavia.

Viking and early Middle Ages northern Scandinavian textiles proven to be made with hemp.

PubMed

Skoglund, G; Nockert, M; Holst, B

2013-10-18

Nowadays most plant textiles used for clothing and household are made of cotton and viscose. Before the 19th century however, plant textiles were mainly made from locally available raw materials, in Scandinavia these were: nettle, hemp and flax. It is generally believed that in Viking and early Middle Ages Scandinavia hemp was used only for coarse textiles (i.e. rope and sailcloth). Here we present an investigation of 10 Scandinavian plant fibre textiles from the Viking and Early Middle Ages, believed to be locally produced. Up till now they were all believed to be made of flax. We show that 4 textiles, including two pieces of the famous Överhogdal Viking wall-hanging are in fact made with hemp (in three cases hemp and flax are mixed). This indicates that hemp was important, not only for coarse but also for fine textile production in Viking and Early Middle Ages in Scandinavia.

Early Onset Ageing and Service Preparation in People with Intellectual Disabilities: Institutional Managers' Perspective

ERIC Educational Resources Information Center

Lin, Jin-Ding; Wu, Chia-Ling; Lin, Pei-Ying; Lin, Lan-Ping; Chu, Cordia M.

2011-01-01

Although longevity among older adults with intellectual disabilities is increasing, there is limited information on their premature aging related health characteristics and how it may change with increasing age. The present paper provides information of the institutional manager's perception on early onset aging and service preparation for this…

Automatic segmentation of the hippocampus for preterm neonates from early-in-life to term-equivalent age.

PubMed

Guo, Ting; Winterburn, Julie L; Pipitone, Jon; Duerden, Emma G; Park, Min Tae M; Chau, Vann; Poskitt, Kenneth J; Grunau, Ruth E; Synnes, Anne; Miller, Steven P; Mallar Chakravarty, M

2015-01-01

The hippocampus, a medial temporal lobe structure central to learning and memory, is particularly vulnerable in preterm-born neonates. To date, segmentation of the hippocampus for preterm-born neonates has not yet been performed early-in-life (shortly after birth when clinically stable). The present study focuses on the development and validation of an automatic segmentation protocol that is based on the MAGeT-Brain (Multiple Automatically Generated Templates) algorithm to delineate the hippocampi of preterm neonates on their brain MRIs acquired at not only term-equivalent age but also early-in-life. First, we present a three-step manual segmentation protocol to delineate the hippocampus for preterm neonates and apply this protocol on 22 early-in-life and 22 term images. These manual segmentations are considered the gold standard in assessing the automatic segmentations. MAGeT-Brain, automatic hippocampal segmentation pipeline, requires only a small number of input atlases and reduces the registration and resampling errors by employing an intermediate template library. We assess the segmentation accuracy of MAGeT-Brain in three validation studies, evaluate the hippocampal growth from early-in-life to term-equivalent age, and study the effect of preterm birth on the hippocampal volume. The first experiment thoroughly validates MAGeT-Brain segmentation in three sets of 10-fold Monte Carlo cross-validation (MCCV) analyses with 187 different groups of input atlases and templates. The second experiment segments the neonatal hippocampi on 168 early-in-life and 154 term images and evaluates the hippocampal growth rate of 125 infants from early-in-life to term-equivalent age. The third experiment analyzes the effect of gestational age (GA) at birth on the average hippocampal volume at early-in-life and term-equivalent age using linear regression. The final segmentations demonstrate that MAGeT-Brain consistently provides accurate segmentations in comparison to manually

Automatic segmentation of the hippocampus for preterm neonates from early-in-life to term-equivalent age

PubMed Central

Guo, Ting; Winterburn, Julie L.; Pipitone, Jon; Duerden, Emma G.; Park, Min Tae M.; Chau, Vann; Poskitt, Kenneth J.; Grunau, Ruth E.; Synnes, Anne; Miller, Steven P.; Mallar Chakravarty, M.

2015-01-01

Introduction The hippocampus, a medial temporal lobe structure central to learning and memory, is particularly vulnerable in preterm-born neonates. To date, segmentation of the hippocampus for preterm-born neonates has not yet been performed early-in-life (shortly after birth when clinically stable). The present study focuses on the development and validation of an automatic segmentation protocol that is based on the MAGeT-Brain (Multiple Automatically Generated Templates) algorithm to delineate the hippocampi of preterm neonates on their brain MRIs acquired at not only term-equivalent age but also early-in-life. Methods First, we present a three-step manual segmentation protocol to delineate the hippocampus for preterm neonates and apply this protocol on 22 early-in-life and 22 term images. These manual segmentations are considered the gold standard in assessing the automatic segmentations. MAGeT-Brain, automatic hippocampal segmentation pipeline, requires only a small number of input atlases and reduces the registration and resampling errors by employing an intermediate template library. We assess the segmentation accuracy of MAGeT-Brain in three validation studies, evaluate the hippocampal growth from early-in-life to term-equivalent age, and study the effect of preterm birth on the hippocampal volume. The first experiment thoroughly validates MAGeT-Brain segmentation in three sets of 10-fold Monte Carlo cross-validation (MCCV) analyses with 187 different groups of input atlases and templates. The second experiment segments the neonatal hippocampi on 168 early-in-life and 154 term images and evaluates the hippocampal growth rate of 125 infants from early-in-life to term-equivalent age. The third experiment analyzes the effect of gestational age (GA) at birth on the average hippocampal volume at early-in-life and term-equivalent age using linear regression. Results The final segmentations demonstrate that MAGeT-Brain consistently provides accurate segmentations

Early Math Trajectories: Low-Income Children's Mathematics Knowledge from Age 4 to 11

ERIC Educational Resources Information Center

Rittle-Johnson, Bethany; Fyfe, Emily R.; Hofer, Kerry G.; Farran, Dale C.

2016-01-01

Early mathematics knowledge is a strong predictor of later academic achievement, but children from low-income families enter school with weak mathematics knowledge. An Early Math Trajectories model is proposed and evaluated within a longitudinal study of 517 low-income American children from age 4 to 11. This model includes a broad range of math…

Executive Function in Very Preterm Children at Early School Age

ERIC Educational Resources Information Center

Aarnoudse-Moens, Cornelieke S. H.; Smidts, Diana P.; Oosterlaan, Jaap; Duivenvoorden, Hugo J.; Weisglas-Kuperus, Nynke

2009-01-01

We examined whether very preterm ([less than or equal to] 30 weeks gestation) children at early school age have impairments in executive function (EF) independent of IQ and processing speed, and whether demographic and neonatal risk factors were associated with EF impairments. A consecutive sample of 50 children (27 boys and 23 girls) born very…

Age and tectonic implications of some low-grade metamorphic rocks from the Yucatan Channel

USGS Publications Warehouse

Vedder, J.G.; MacLeod, N.S.; Lanphere, M.A.; Dillon, William P.

1973-01-01

Phyllite and marble dredged from the lower part of the continental slope between Cuba and the Yucatan Peninsula seem to support the contention that a pre-early Tertiary metamorphic belt extends from the western Greater Antilles into northern Central America. The minimum K-Ar ages derived from the samples suggest that the metamorphic event was pre-Late Cretaceous, and evaluation of the K-Ar data implies that this metamorphic event is not older than Late Jurassic. Greater antiquity, however, is inferred from structural and stratigraphic relations in British Honduras, where the latest regional metamorphic event was post-Early Permian and pre-Middle Jurassic.  Rifting and extension related to plate motions along the British Honduras Quintana Roo margin through Mesozoic and earliest Cenozoic time presumably would preclude extensive regional metamorphism, permitting only limited development of schistose rocks there during that interval. The timing of metamorphic events in western Cuba is uncertain, but a pre-Middle Jurassic episode possibly is reflected in the phyllite and marble terranes of Isla de Pinos and Sierra de Trinidad. Local incipient metamorphism of Early and Middle Jurassic strata in the Sierra de los Organos may have resulted from severe tectonism that began in Late Cretaceous time and diminished in the Eocene.

Age Validation in the Long Life Family Study Through a Linkage to Early-Life Census Records

PubMed Central

2013-01-01

Objectives. Studies of health and longevity require accurate age reporting. Age misreporting among older adults in the United States is common. Methods. Participants in the Long Life Family Study (LLFS) were matched to early-life census records. Age recorded in the census was used to evaluate age reporting in the LLFS. The study population was 99% non-Hispanic white. Results. About 88% of the participants were matched to 1910, 1920, or 1930 U.S. censuses. Match success depended on the participant’s education, place of birth, and the number of censuses available to be searched. Age at the time of the interview based on the reported date of birth and early-life census age were consistent for about 89% of the participants, and age consistency within 1 year was found for about 99% of the participants. Discussion. It is possible to match a high fraction of older study participants to their early-life census records when detailed information is available on participants’ family of origin. Such record linkage can provide an important source of information for evaluating age reporting among the oldest old participants. Our results are consistent with recent studies suggesting that age reporting among older whites in the United States appears to be quite good. PMID:23704206

Comparison of unitary associations and probabilistic ranking and scaling as applied to mesozoic radiolarians

NASA Astrophysics Data System (ADS)

Baumgartner, Peter O.

A database on Middle Jurassic-Early Cretaceous radiolarians consisting of first and final occurrences of 110 species in 226 samples from 43 localities was used to compute Unitary Associations and probabilistic ranking and scaling (RASC), in order to test deterministic versus probabilistic quantitative biostratigraphic methods. Because the Mesozoic radiolarian fossil record is mainly dissolution-controlled, the sequence of events differs greatly from section to section. The scatter of local first and final appearances along a time scale is large compared to the species range; it is asymmetrical, with a maximum near the ends of the range and it is non-random. Thus, these data do not satisfy the statistical assumptions made in ranking and scaling. Unitary Associations produce maximum ranges of the species relative to each other by stacking cooccurrence data from all sections and therefore compensate for the local dissolution effects. Ranking and scaling, based on the assumption of a normal random distribution of the events, produces average ranges which are for most species much shorter than the maximum UA-ranges. There are, however, a number of species with similar ranges in both solutions. These species are believed to be the most dissolution-resistant and, therefore, the most reliable ones for the definition of biochronozones. The comparison of maximum and average ranges may be a powerful tool to test reliability of species for biochronology. Dissolution-controlled fossil data yield high crossover frequencies and therefore small, statistically insignificant interfossil distances. Scaling has not produced a useful sequence for this type of data.

Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania

NASA Astrophysics Data System (ADS)

Kędzior, Artur; Popa, Mihai E.

2013-06-01

Kędzior, A. and Popa, E.M. 2013. Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania. Acta Geologica Polonica, 63 (2), 175-199. Warszawa. The continental, coal bearing Steierdorf Formation, Hettangian - Sinemurian in age, is included in the Mesozoic cover of the Reşiţa Basin, Getic Nappe, South Carpathians, Romania. The Steierdorf Formation can be studied in Anina, a coal mining center and an exceptional locality for Early Jurassic flora and fauna, occurring in the middle of the Reşiţa Basin. This paper presents the results of sedimentological, stratigraphical and paleobotanical researches undertaken in Colonia Cehă open cast mine in Anina, where the Steierdorf Formation outcrops widely. Several sedimentary facies associations have been described, these associations permitting the reconstruction of various depositional systems such as alluvial fans, braided and meandering river systems, as well as lacustrine and coal generating marsh systems of the Steierdorf Formation. The sedimentary associations recorded within the Steierdorf Formation show a gradual fining upward trend, pointing to a rising marine water table and a decreasing relief within the source area.

Early determinants of vagal activity at preschool age - With potential dependence on sex.

PubMed

Kühne, Britta; Genser, Bernd; De Bock, Freia

2016-12-01

In children, autonomic nervous function is related to various highly prevalent health problems and might therefore represent an early indicator of ill health. We aimed to investigate the role of early-life exposures and physical activity (PA) as potential determinants of autonomic function at preschool age. We used an existing longitudinal data set of repeated vagal tone measurements (assessed via heart rate recovery (HRR)) and retrospectively assessed early-life exposures in 1052 children (mean age: 59.4months, 47.5% girls) from 52 preschools in Germany recruited from 2008 to 2010. HRR 1min after submaximal exercise served as primary outcome. Through multilevel linear regression analysis adjusted for demographic and socioeconomic factors, we assessed the association between repeatedly measured HRR and pregnancy smoking status, breastfeeding and objectively measured PA. Besides significant regression coefficients for previously described correlates of HRR (sex, age), we could show positive associations of HRR with breastfeeding (six versus zero months: +4.2 beats per minute (BPM), p=0.004) and PA (+1.0BPM for 10min increase of moderate-to-vigorous PA/day, p<0.001). Smoking before and during pregnancy showed no significant association with HRR in the total sample. However, we found interactions between sex and smoking before and during pregnancy as well as between sex and breastfeeding, suggesting significant associations with HRR only in girls. Besides PA, early pre- and postnatal exposures seem to have long-lasting effects on children's autonomic function, still recordable at preschool age. Our data suggest that these effects might be sex-dependent. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates.

PubMed

Motani, Ryosuke; Jiang, Da-Yong; Tintori, Andrea; Ji, Cheng; Huang, Jian-Dong

2017-05-17

The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates. © 2017 The Author(s).

Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates

PubMed Central

Ji, Cheng; Huang, Jian-dong

2017-01-01

The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates. PMID:28515201

Artificial Neural Network-Based Early-Age Concrete Strength Monitoring Using Dynamic Response Signals.

PubMed

Kim, Junkyeong; Lee, Chaggil; Park, Seunghee

2017-06-07

Concrete is one of the most common materials used to construct a variety of civil infrastructures. However, since concrete might be susceptible to brittle fracture, it is essential to confirm the strength of concrete at the early-age stage of the curing process to prevent unexpected collapse. To address this issue, this study proposes a novel method to estimate the early-age strength of concrete, by integrating an artificial neural network algorithm with a dynamic response measurement of the concrete material. The dynamic response signals of the concrete, including both electromechanical impedances and guided ultrasonic waves, are obtained from an embedded piezoelectric sensor module. The cross-correlation coefficient of the electromechanical impedance signals and the amplitude of the guided ultrasonic wave signals are selected to quantify the variation in dynamic responses according to the strength of the concrete. Furthermore, an artificial neural network algorithm is used to verify a relationship between the variation in dynamic response signals and concrete strength. The results of an experimental study confirm that the proposed approach can be effectively applied to estimate the strength of concrete material from the early-age stage of the curing process.

Artificial Neural Network-Based Early-Age Concrete Strength Monitoring Using Dynamic Response Signals

PubMed Central

Kim, Junkyeong; Lee, Chaggil; Park, Seunghee

2017-01-01

Concrete is one of the most common materials used to construct a variety of civil infrastructures. However, since concrete might be susceptible to brittle fracture, it is essential to confirm the strength of concrete at the early-age stage of the curing process to prevent unexpected collapse. To address this issue, this study proposes a novel method to estimate the early-age strength of concrete, by integrating an artificial neural network algorithm with a dynamic response measurement of the concrete material. The dynamic response signals of the concrete, including both electromechanical impedances and guided ultrasonic waves, are obtained from an embedded piezoelectric sensor module. The cross-correlation coefficient of the electromechanical impedance signals and the amplitude of the guided ultrasonic wave signals are selected to quantify the variation in dynamic responses according to the strength of the concrete. Furthermore, an artificial neural network algorithm is used to verify a relationship between the variation in dynamic response signals and concrete strength. The results of an experimental study confirm that the proposed approach can be effectively applied to estimate the strength of concrete material from the early-age stage of the curing process. PMID:28590456

Latitudinal diversity gradients in Mesozoic non-marine turtles

NASA Astrophysics Data System (ADS)

Nicholson, David B.; Holroyd, Patricia A.; Valdes, Paul; Barrett, Paul M.

2016-11-01

The latitudinal biodiversity gradient (LBG)-the pattern of increasing taxonomic richness with decreasing latitude-is prevalent in the structure of the modern biota. However, some freshwater taxa show peak richness at mid-latitudes; for example, extant Testudines (turtles, terrapins and tortoises) exhibit their greatest diversity at 25° N, a pattern sometimes attributed to recent bursts of climatically mediated species diversification. Here, we test whether this pattern also characterizes the Mesozoic distribution of turtles, to determine whether it was established during either their initial diversification or as a more modern phenomenon. Using global occurrence data for non-marine testudinate genera, we find that subsampled richness peaks at palaeolatitudes of 15-30° N in the Jurassic, 30-45° N through the Cretaceous to the Campanian, and from 30° to 60° N in the Maastrichtian. The absence of a significant diversity peak in southern latitudes is consistent with results from climatic models and turtle niche modelling that demonstrate a dearth of suitable turtle habitat in Gondwana during the Jurassic and Late Cretaceous. Our analyses confirm that the modern testudinate LBG has a deep-time origin and further demonstrate that LBGs are not always expressed as a smooth, equator-to-pole distribution.

Aspirin use and early age-related macular degeneration: a meta-analysis.

PubMed

Kahawita, Shyalle K; Casson, Robert J

2014-02-01

The aim of this review was to evaluate the evidence for an association between Aspirin use and early age-related macular degeneration (ARMD). A literature search was performed in 5 databases with no restrictions on language or date of publication. Four studies involving 10292 individuals examining the association between aspirin and ARMD met the inclusion criteria. Meta-analysis was carried out by Cochrane Collaboration Review Manager 5.2 software (Cochrane Collaboration, Copenhagen, Denmark). The pooled odd ratios showed that Aspirin use was associated with early ARMD (pooled odds ratio 1.43, 95% CI 1.09-1.88). There is a small but statistically significant association between Aspirin use and early ARMD, which may warrant further investigation. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Telomere biology in aging and cancer: early history and perspectives.

PubMed

Hayashi, Makoto T

2018-01-20

The ends of eukaryotic linear chromosomes are protected from undesired enzymatic activities by a nucleoprotein complex called the telomere. Expanding evidence indicates that telomeres have central functions in human aging and tumorigenesis. While it is undoubtedly important to follow current advances in telomere biology, it is also fruitful to be well informed in seminal historical studies for a comprehensive understanding of telomere biology, and for the anticipation of future directions. With this in mind, I here summarize the early history of telomere biology and current advances in the field, mostly focusing on mammalian studies relevant to aging and cancer.

Early Impacts on the Moon: Crystallization Ages of Apollo 16 Melt Breccias

NASA Technical Reports Server (NTRS)

Norman, M. D.; Shih, C.-Y.; Nyquist, L. E.; Bogard, D. D.; Taylor, L. A.

2007-01-01

A better understanding of the early impact history of the terrestrial planets has been identified one of the highest priority science goals for solar system exploration. Crystallization ages of impact melt breccias from the Apollo 16 site in the central nearside lunar highlands show a pronounced clustering of ages from 3.75-3.95 Ga, with several impact events being recognized by the association of textural groups and distinct ages. Here we present new geochemical and petrologic data for Apollo 16 crystalline breccia 67955 that document a much older impact event with an age of 4.2 Ga.

U-Pb zircon geochronology of the Paleogene - Neogene volcanism in the NW Anatolia: Its implications for the Late Mesozoic-Cenozoic geodynamic evolution of the Aegean

NASA Astrophysics Data System (ADS)

Ersoy, E. Yalçın; Akal, Cüneyt; Genç, Ş. Can; Candan, Osman; Palmer, Martin R.; Prelević, Dejan; Uysal, İbrahim; Mertz-Kraus, Regina

2017-10-01

The northern Aegean region was shaped by subduction, obduction, collision, and post-collisional extension processes. Two areas in this region, the Rhodope-Thrace-Biga Peninsula to the west and Armutlu-Almacık-Nallıhan (the Central Sakarya) to the east, are characterized by extensive Eocene to Miocene post-collisional magmatic associations. We suggest that comparison of the Cenozoic magmatic events of these two regions may provide insights into the Late Mesozoic to Cenozoic tectonic evolution of the Aegean. With this aim, we present an improved Cenozoic stratigraphy of the Biga Peninsula derived from a new comprehensive set of U-Pb zircon age data obtained from the Eocene to Miocene volcanic units in the region. The compiled radiometric age data show that calc-alkaline volcanic activity occurred at 43-15 Ma in the Biga Peninsula, 43-17 Ma in the Rhodope and Thrace regions, and 53-38 Ma in the Armutlu-Almacık-Nallıhan region, which are slightly overlapping. We discuss the possible cause for the distinct Cenozoic geodynamic evolution of the eastern and western parts of the region, and propose that the Rhodope, Thrace and Biga regions in the north Aegean share the same Late Mesozoic to Cenozoic geodynamic evolution, which is consistent with continuous subduction, crustal accretion, southwestward trench migration and accompanying extension; all preceded by the Late Cretaceous - Paleocene collision along the Vardar suture zone. In contrast, the Armutlu-Almacık-Nallıhan region was shaped by slab break-off and related processes following the Late Cretaceous - Paleocene collision along the İzmir-Ankara suture zone. The eastern and western parts of the region are presently separated by a northeast-southwest trending transfer zone that was likely originally present as a transform fault in the subducted Tethys oceanic crust, and demonstrates that the regional geodynamic evolution can be strongly influenced by the geographical distribution of geologic features on the

Isotopic constraints on the age and early differentiation of the Earth.

PubMed

McCulloch, M T

1996-03-01

The Earth's age and early differentiation history are re-evaluated using updated isotopic constraints. From the most primitive terrestrial Pb isotopic compositions found at Isua Greenland, and the Pilbara of Western Australia, combined with precise geochronology of these localities, an age 4.49 +/- 0.02 Ga is obtained. This is interpreted as the mean age of core formation as U/Pb is fractionated due to sequestering of Pb into the Earth's core. The long-lived Rb-Sr isotopic system provides constraints on the time interval for the accretion of the Earth as Rb underwent significant depletion by volatile loss during accretion of the Earth or its precursor planetesimals. A primitive measured 87Sr/86Sr initial ratio of 0.700502 +/- 10 has been obtained for an early Archean (3.46 Ga) barite from the Pilbara Block of Western Australia. Using conservative models for the evolution of Rb/Sr in the early Archean mantle allows an estimate to be placed on the Earth's initial Sr ratio at approximately 4.50 Ga, of 0.69940 +/- 10. This is significantly higher than that measured for the Moon (0.69900 +/- 2) or in the achondrite, Angra dos Reis (0.69894 +/- 2) and for a Rb/Sr ratio of approximately 1/2 of chondrites corresponds to a mean age for accretion of the Earth of 4.48 + /- 0.04 Ga. The now extinct 146Sm-142Nd (T1/2(146)=103 l0(6)yrs) combined with the long-lived 147Sm-143Nd isotopic systematics can also be used to provide limits on the time of early differentiation of the Earth. High precision analyses of the oldest (3.8-3.9 Ga) Archean gneisses from Greenland (Amitsoq and Akilia gneisses), and Canada (Acasta gneiss) do not show measurable (> +/- l0ppm) variations of 142Nd, in contrast to the 33 ppm 142Nd excess reported for an Archean sample. The general lack of 142Nd variations, combined with the presence of highly positive epsilon 143 values (+4.0) at 3.9 Ga, indicates that the record of large-scale Sm/Nd fractionation events was not preserved in the early-Earth from 4

The curvilinear relationship of early-life adversity and successful aging: the mediating role of mental health.

PubMed

Höltge, Jan; Mc Gee, Shauna L; Thoma, Myriam V

2018-02-15

The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health. Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (M age = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted. Significant inverse U-shaped associations were found between ELA and iQoL (β = -.59, p = .005) and between ELA and mental health (β = -.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = -.84, BCa CI [-1.66, -.27]). Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity.

Mesozoic non-marine petroleum source rocks determined by palynomorphs in the Tarim Basin, Xinjiang, northwestern China

USGS Publications Warehouse

Jiang, D.-X.; Wang, Y.-D.; Robbins, E.I.; Wei, J.; Tian, N.

2008-01-01

The Tarim Basin in Northwest China hosts petroleum reservoirs of Cambrian, Ordovician, Carboniferous, Triassic, Jurassic, Cretaceous and Tertiary ages. The sedimentary thickness in the basin reaches about 15 km and with an area of 560000 km2, the basin is expected to contain giant oil and gas fields. It is therefore important to determine the ages and depositional environments of the petroleum source rocks. For prospective evaluation and exploration of petroleum, palynological investigations were carried out on 38 crude oil samples collected from 22 petroleum reservoirs in the Tarim Basin and on additionally 56 potential source rock samples from the same basin. In total, 173 species of spores and pollen referred to 80 genera, and 27 species of algae and fungi referred to 16 genera were identified from the non-marine Mesozoic sources. By correlating the palynormorph assemblages in the crude oil samples with those in the potential source rocks, the Triassic and Jurassic petroleum source rocks were identified. Furthermore, the palynofloras in the petroleum provide evidence for interpretation of the depositional environments of the petroleum source rocks. The affinity of the miospores indicates that the petroleum source rocks were formed in swamps in brackish to lacustrine depositional environments under warm and humid climatic conditions. The palynomorphs in the crude oils provide further information about passage and route of petroleum migration, which is significant for interpreting petroleum migration mechanisms. Additionally, the thermal alternation index (TAI) based on miospores indicates that the Triassic and Jurassic deposits in the Tarim Basin are mature petroleum source rocks. ?? Cambridge University Press 2008.

Fetal environment and early age at natural menopause in a British birth cohort study

PubMed Central

Tom, Sarah E.; Cooper, Rachel; Kuh, Diana; Guralnik, Jack M.; Hardy, Rebecca; Power, Chris

2010-01-01

BACKGROUND Early life development may influence the timing of natural menopause through association with size of the initial follicle pool or early follicular loss. This study examines the relationships of birthweight, gestational age and birthweight standardized by gestational age with early menopause in the 1958 British birth cohort study. METHODS Study participants were over 2900 women with data on birthweight, gestational age (obtained at birth), menopausal status at age 44–45 years and potential confounding factors. Logistic regression was used to study relationships of birthweight, gestational age and birthweight standardized by gestational age with post-menopausal status by 44–45 years, with and without adjustments for confounding factors. RESULTS There was a U-shaped association between birthweight and menopausal status at 44–45 years: women at either extremes of birthweight (<2.5 and ≥4.0 kg) had increased odds of post-menopausal status compared with those weighing 3.0–3.49 kg [odds ratio (OR) = 1.91, 95% confidence interval (CI) 1.08, 3.38; 1.81, 95% CI 1.11, 2.97, respectively]. Women with higher birthweight standardized by gestational age (which indicates faster fetal growth rate) also had increased odds of being post-menopausal by 44–45 years (OR for fastest quarter versus second fastest quarter = 1.80; 95% CI 1.16, 2.81). These associations persisted after adjustment for socioeconomic position at birth, adult smoking status and use of oral contraceptives. CONCLUSIONS These findings suggest that variations in fetal environment may be associated with the timing of menopause. Given that extremes of birthweight and higher birthweight standardized by gestational age were associated with earlier age at menopause, mechanisms related to these characteristics that also regulate ovarian function should be investigated further. PMID:20047935

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.

Mesozoic (Upper Jurassic-Lower Cretaceous) deep gas reservoir play, central and eastern Gulf coastal plain

USGS Publications Warehouse

Mancini, E.A.; Li, P.; Goddard, D.A.; Ramirez, V.O.; Talukdar, S.C.

2008-01-01

The Mesozoic (Upper Jurassic-Lower Cretaceous) deeply buried gas reservoir play in the central and eastern Gulf coastal plain of the United States has high potential for significant gas resources. Sequence-stratigraphic study, petroleum system analysis, and resource assessment were used to characterize this developing play and to identify areas in the North Louisiana and Mississippi Interior salt basins with potential for deeply buried gas reservoirs. These reservoir facies accumulated in Upper Jurassic to Lower Cretaceous Norphlet, Haynesville, Cotton Valley, and Hosston continental, coastal, and marine siliciclastic environments and Smackover and Sligo nearshore marine shelf, ramp, and reef carbonate environments. These Mesozoic strata are associated with transgressive and regressive systems tracts. In the North Louisiana salt basin, the estimate of secondary, nonassociated thermogenic gas generated from thermal cracking of oil to gas in the Upper Jurassic Smackover source rocks from depths below 3658 m (12,000 ft) is 4800 tcf of gas as determined using software applications. Assuming a gas expulsion, migration, and trapping efficiency of 2-3%, 96-144 tcf of gas is potentially available in this basin. With some 29 tcf of gas being produced from the North Louisiana salt basin, 67-115 tcf of in-place gas remains. Assuming a gas recovery factor of 65%, 44-75 tcf of gas is potentially recoverable. The expelled thermogenic gas migrated laterally and vertically from the southern part of this basin to the updip northern part into shallower reservoirs to depths of up to 610 m (2000 ft). Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

Premature brain aging in humans exposed to maternal nutrient restriction during early gestation.

PubMed

Franke, Katja; Gaser, Christian; Roseboom, Tessa J; Schwab, Matthias; de Rooij, Susanne R

2018-06-01

Prenatal exposure to undernutrition is widespread in both developing and industrialized countries, causing irreversible damage to the developing brain, resulting in altered brain structure and decreased cognitive function during adulthood. The Dutch famine in 1944/45 was a humanitarian disaster, now enabling studies of the effects of prenatal undernutrition during gestation on brain aging in late adulthood. We hypothesized that study participants prenatally exposed to maternal nutrient restriction (MNR) would demonstrate altered brain structure resembling premature brain aging in late adulthood, expecting the effect being stronger in men. Utilizing the Dutch famine birth cohort (n = 118; mean age: 67.5 ± 0.9 years), this study implements an innovative biomarker for individual brain aging, using structural neuroimaging. BrainAGE was calculated using state-of-the-art pattern recognition methods, trained on an independent healthy reference sample, then applied to the Dutch famine MRI sample, to evaluate the effects of prenatal undernutrition during early gestation on individual brain aging in late adulthood. Exposure to famine in early gestation was associated with BrainAGE scores indicative of an older-appearing brain in the male sample (mean difference to subjects born before famine: 4.3 years, p < 0.05). Furthermore, in explaining the observed variance in individual BrainAGE scores in the male sample, maternal age at birth, head circumference at birth, medical treatment of hypertension, history of cerebral incidences, actual heart rate, and current alcohol intake emerged to be the most influential variables (adjusted R 2  = 0.63, p < 0.01). The findings of our study on exposure to prenatal undernutrition being associated with a status of premature brain aging during late adulthood, as well as individual brain structure being shaped by birth- and late-life health characteristics, are strongly supporting the critical importance of sufficient nutrient

Age at adoption from institutional care as a window into the lasting effects of early experiences

PubMed Central

Julian, Megan M.

2013-01-01

One of the major questions of human development is how early experience impacts the course of development years later. Children adopted from institutional care experience varying levels of deprivation in their early life followed by qualitatively better care in an adoptive home, providing a unique opportunity to study the lasting effects of early deprivation and its timing. The effects of age at adoption from institutional care are discussed for multiple domains of social and behavioral development within the context of several prominent developmental hypotheses about the effects of early deprivation (cumulative effects, experience-expectant developmental programming, and experience-adaptive developmental programming). Age at adoption effects are detected in a majority of studies, particularly when children experienced global deprivation and were assessed in adolescence. For most outcomes, institutionalization beyond a certain age is associated with a step-like increase in risk for lasting social and behavioral problems, with the step occurring at an earlier age for children who experienced more severe levels of deprivation. Findings are discussed in terms of their concordance and discordance with our current hypotheses, and speculative explanations for the findings are offered. PMID:23576122

Adverse Childhood Experiences and Alcohol Consumption in Midlife and Early Old-Age

PubMed Central

Leung, Jessica Pui Kei; Britton, Annie; Bell, Steven

2016-01-01

Aims To examine the individual and cumulative effects of adverse childhood experiences (ACEs) on alcohol consumption in midlife and early old-age, and the role of ACEs in 10-year drinking trajectories across midlife. Methods Data were from the Whitehall II study, a longitudinal British civil service-based cohort study (N = 7870, 69.5% male). Multinomial logistic regression was used to examine the individual and cumulative effects of ACEs on weekly alcohol consumption. Mixed-effect multilevel modelling was used to explore the relationship between ACEs and change in alcohol consumption longitudinally. Results Participants who were exposed to parental arguments/fights in childhood were 1.24 (95% CI 1.06, 1.45) times more likely to drink at hazardous levels in midlife (mean age 56 years) after controlling for covariates and other ACEs. For each additional exposure to an ACE, the risk of hazardous drinking versus moderate drinking was increased by 1.12 (95% CI 1.03, 1.21) after adjusting for sex, age, adult socio-economic status, ethnicity and marital status. No associations between ACEs and increased risk of hazardous drinking in early old-age (mean age 66 years) were found. In longitudinal analyses, ACEs did not significantly influence 10-year drinking trajectories across midlife. Conclusion The effect of exposure to parental arguments on hazardous drinking persists into midlife. PMID:26553290

Canadian Sedentary Behaviour Guidelines for the Early Years (aged 0-4 years).

PubMed

Tremblay, Mark S; Leblanc, Allana G; Carson, Valerie; Choquette, Louise; Connor Gorber, Sarah; Dillman, Carrie; Duggan, Mary; Gordon, Mary Jane; Hicks, Audrey; Janssen, Ian; Kho, Michelle E; Latimer-Cheung, Amy E; Leblanc, Claire; Murumets, Kelly; Okely, Anthony D; Reilly, John J; Stearns, Jodie A; Timmons, Brian W; Spence, John C

2012-04-01

The Canadian Society for Exercise Physiology (CSEP), with assistance from multiple partners, stakeholders, and researchers, developed the first Canadian Sedentary Behaviour Guidelines for the Early Years (aged 0-4 years). These national guidelines are in response to a call from health and health care professionals, child care providers, and fitness practitioners for guidance on sedentary behaviour in the early years. The guideline development process followed the Appraisal of Guidelines for Research Evaluation (AGREE) II framework. The recommendations are informed by evidence from a systematic review that examined the relationships between sedentary behaviour (predominantly screen time) and health indicators (healthy body weight, bone and skeletal health, motor skill development, psychosocial health, cognitive development, and cardio-metabolic disease risk factors) for three age groups (infants aged <1 year; toddlers aged 1-2 years; preschoolers aged 3-4 years). Evidence from the review was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The new guidelines include a preamble to provide context, followed by the specific recommendations. The final guidelines benefitted from extensive on-line consultations with input from >900 domestic and international stakeholders, end-users, and key informants. The final guidelines state: for healthy growth and development, caregivers should minimize the time infants (aged <1 year), toddlers (aged 1-2 years), and preschoolers (aged 3-4 years) spend being sedentary during waking hours. This includes prolonged sitting or being restrained (e.g., stroller, high chair) for more than 1 h at a time. For those under 2 years, screen time (e.g., TV, computer, electronic games) is not recommended. For children 2-4 years, screen time should be limited to under 1 h per day; less is better.

Removing obstacles for pavement cost reduction by examining early age opening requirements : material properties.

DOT National Transportation Integrated Search

2015-08-01

The risk of cracking in a concrete pavement that is opened to traffic at early ages is related to the maximum tensile stress, , that : develops in the pavement and its relationship to the measured, age dependent, flexural strength of a beam, fr . T...

Effects of early age at natural menopause on coronary heart disease and stroke in Chinese women.

PubMed

Shen, Lijun; Song, Lulu; Liu, Bingqing; Li, Hui; Zheng, Xiaoxuan; Zhang, Lina; Yuan, Jing; Liang, Yuan; Wang, Youjie

2017-08-15

Menopause is identified as a risk factor for cardiovascular disease because of the change of estrogen. The objective of the study was to explore the associations between early age at natural menopause (menopause at an age≤45years) and the presence of CHD and stroke. The study subjects were from the first follow-up survey of the Dongfeng-Tongji cohort study. A total of 16,515 postmenopausal women were included for the analysis. Logistic regression models were used to examine the associations between age at natural menopause (≤45, 45-52, >52years) and the presence of CHD and stroke adjusted for sociodemographic characteristics, lifestyle, reproductive history and metabolic factors. In the fully adjusted model, for each 1-year delay in menopausal age, the prevalence of CHD and stroke was reduced by 3% (OR, 0.97; 95% CI, 0.95-0.98) and 5% (OR, 0.95; 95% CI, 0.92-0.98), respectively. Women with early menopause (≤45years) had a higher prevalence of CHD (OR, 1.33; 95% CI, 1.13-1.57) compared with those with menopause at ages 45-52years. Similarly, women with early menopause (≤45years) was associated with higher prevalence of stroke (OR, 1.69; 95% CI, 1.25-2.30) compared with those with menopause at ages 45-52years. Early age at natural menopause is significantly associated with the presence of CHD and stroke among Chinese women. Copyright © 2017. Published by Elsevier B.V.

A source-depleted Early Jurassic granitic pluton from South China: Implication to the Mesozoic juvenile accretion of the South China crust

NASA Astrophysics Data System (ADS)

Zhou, Zuo-Min; Ma, Chang-Qian; Wang, Lian-Xun; Chen, Shu-Guang; Xie, Cai-Fu; Li, Yong; Liu, Wei

2018-02-01

Source-depleted granites were rarely reported in South China. Hereby we identified such a granitic pluton, the Tiandong pluton, at Northeastern Guangdong province in Southeastern (SE) China. Whole-rock Sr-Nd and zircon Hf isotopes of the Tiandong granites both revealed obviously depleted source signatures, with initial isotopic values of initial 87Sr/86Sr = 0.7032-0.7040, εNd(t) = 1.1-1.5, and εHf(t) = 6-13, respectively. Zircon U-Pb dating implied the granite was intruded in Early Jurassic (188 Ma). The dominant minerals of the Tiandong granite consist of K-feldspar, plagioclase, quartz and biotite, with accessory mineral assemblage of apatite + zircon + magnetite. Based on the mineralogy and the depleted isotopic signature, the granites chemically show I-type affinity such as low Zr + Nb + Ce + Y (131.6 to 212.2), 104 × Ga/Al (2.12-2.27), A/CNK values < 1.1 (0.97-1.03), corundum molecule < 1 (0-0.55) and extremely low P2O5 contents (0.05 wt%). The one-stage and two-stage depleted mantle Nd model ages (TDM = 0.89 to 0.84 Ga, T2DM = 0.88 to 0.85 Ga) are consistent. TDM(Hf) values of 0.31-0.63 Ga are also indistinguishable from T2DM(Hf) values of 0.35-0.75 Ga. The Nd and Hf isotopic compositions confirm that the Tiandong granites are juvenile crustal accretion but decoupled Nd-Hf isotopic systems. The juvenile crust is likely to originate from a mixed source of the primary asthenospheric mantle and the subordinate EMII. Combined with early studies of adjacent rocks, we propose that the early Jurassic ( 200-175 Ma) magmatism as evidenced by the Tiandong granites might be driven by upwelling of asthenosphere and subsequent underplating of mafic melts in an intra-plate extensional setting as a response to far-field stress during early stage subduction of the paleo-pacific plate.

[Obesity associated metabolic impairment is evident at early ages: Spanish collaborative study].

PubMed

Martos-Moreno, Gabriel Á; Gil-Campos, Mercedes; Bueno, Gloria; Bahillo, Pilar; Bernal, Susana; Feliu, Albert; Lechuga-Sancho, Alfonso M; Palomo, Enrique; Ruiz, Rafael; Vela, Amaia

2014-10-01

The objectives of this study are to provide a description of the demographic, anthropometric characteristics and metabolic abnormalities in children with early-onset (< 10 years) and of very-early-onset obesity (< 5 years). We also evaluate the diagnostic ability using the definition of metabolic syndrome (MS) according to different criteria. It is a retrospective, case-control, cross-sectional, multicenter study. A total of 10 Pediatric Endocrinology Units in different Spanish hospitals were involved. A group of 469 children with early-onset obesity and another group of 30 children with very early-onset obesity were studied. The control group consisted of 224 healthy children younger than 10 years. Anthropometric and analytical determination of carbohydrates metabolism parameters and the lipid profile were performed. The presence of metabolic alterations associated with obesity in children and adolescents in Spain is remarkable, either on their own, or encompassed within the definition of MS. This prevalence increases substantially when considering the peripheral resistance to insulin action as a diagnostic criterion. It also shows how children who could not be diagnosed with MS according to the definition provided by the International Diabetes Federation (IDF) due to age below 10 years, these alterations are already present in a remarkable percentage. In fact, metabolic abnormalities are already present in the very-early-onset obese children ( <5 years). In Spanish children there are metabolic alterations associated with obesity in the infant-juvenile stages alone or encompassed within the definition of MS,and are already present at earlier ages. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Age and Origin of Eclogite Xenoliths from Navajo Diatremes on the Colorado Plateau

NASA Astrophysics Data System (ADS)

Schulze, D. J.; Malik, L.; Davis, D. W.; Helmstaedt, H. H.

2017-12-01

Six eclogite xenoliths from the Moses Rock and Mule Ear diatremes of the Navajo Volcanic Field on the Colorado Plateau were studied to determine their age(s) and shed light on their origin. Laser ablation inductively-coupled plasma mass spectrometry was used to date zircons in situ by the U-Pb method. In all samples, most of the zircons have low Th/U ratios (<0.1) characteristic of metamorphic zircon and plot on or very near concordia with ages between 27 and 40 Ma, with a few outliers as old as 80 Ma. Some grains with higher Th/U, typically characteristic of magmatic zircon, yield older ages, as old as 1717 ± 25 Ma. In two samples, five zircon yielded data that fall on a discordia between 40 ± 20 and 1717 ± 25 Ma. This suggests that simple derivation from metamorphosed Mesozoic oceanic crust of the shallowly subducted Farallon Plate is not a viable hypothesis for the origin of these eclogites. Instead, the Proterozoic component may indicate that the Farallon Plate also transported material scraped from the overlying Proterozoic mantle during late Mesozoic to Cenozoic subduction. The relationship between the causes of zircon growth in Cenozoic time and the growth of monazite at 28-30 Ma in eclogites of the same suite is unclear, but both may be related to fluxing by water derived from dehydration of serpentinites of the Farallon Plate.

Early Selection versus Late Correction: Age-Related Differences in Controlling Working Memory Contents

PubMed Central

Schwarzkopp, Tina; Mayr, Ulrich; Jost, Kerstin

2016-01-01

We examined whether a reduced ability to ignore irrelevant information is responsible for the age-related decline of working-memory (WM) functions. By means of event-related brain potentials we will show that filtering is not out of service in older adults but shifted to a later processing stage. Participants performed a visual short-term memory task (change-detection task) in which targets were presented along with distractors. To allow early selection, a cue was presented in advance of each display, indicating where the targets were to appear. Despite this relatively easy selection criterion, older adults’ filtering was delayed as indicated by the amplitude pattern of the contralateral delay activity. Importantly, WM-equated younger adults did not show a delay indicating that the delay is specific to older adults and not a general phenomenon that comes with low WM capacity. Moreover, the analysis of early visual potentials revealed qualitatively different perceptual/attentional processing between the age groups. Young adults exhibited stronger distractor sensitivity that in turn facilitated filtering. Older adults, in contrast, seemed to initially store distractors and to suppress them after the fact. These early-selection versus late-correction modes suggest an age-related shift in the strategy to control the contents of WM. PMID:27253867

LA-ICP-MS zircon U-Pb and muscovite K-Ar ages of basement rocks from the south arm of Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Jaya, Asri; Nishikawa, Osamu; Hayasaka, Yasutaka

2017-11-01

The zircon U-Pb and muscovite K-Ar age from the Bantimala, Barru and Biru basement complexes in the South Arm of Sulawesi, Indonesia provide new information regarding the timing of magmatism, metamorphism and sedimentation in this region and have implications for the origin and evolution of the study area. The study area is at the juncture between the southeast margin of Sundaland and Bird's Head-Australia. The age of both the zircon U-Pb of detrital materials in the Bantimala Complex and the muscovite K-Ar of amphibolite in the Biru Complex fall in the Late Early Cretaceous (between 109 and 115 Ma), which is a similar age range to previous data for both the sedimentary and metamorphic rocks. The youngest detrital zircon in the schist samples from the Barru Complex fall into the Triassic in age (between 243 and 247 Ma). These age data indicate that the protolith of all three basement complexes were involved in the subduction system and metamorphosed in the late Early Cretaceous, but there are several differences in their deposition environment under and out of the influence of the late Early Cretaceous magmatism in the Bantimala and Barru Complexes, respectively. Felsic igneous activities are confirmed in the Late Cretaceous and the Eocene by the zircon U-Pb age of igneous rocks intruding or included as detrital fragments in three basement complexes. These dates are similar to those reported from the Meratus Complex of South Kalimantan. The detrital zircon age distributions of the basement rocks in the South Arm of Sulawesi display predominant Mesozoic (Cretaceous and Triassic) and Paleozoic populations with a small population of Proterozoic ages supporting the hypothesis that the West Sulawesi block originated from the region of the circum Bird's Head-Australian, namely the Inner Banda block. The absence of Jurassic zircon age population in the South Arm of Sulawesi suggests the division of the South Arm of Sulawesi from the Inner Banda block in early stage of

Criteria for the recognition and correlation of sandstone units in the Precambrian and Paleozoic-Mesozoic clastic sequence in the near east

NASA Astrophysics Data System (ADS)

Weissbrod, T.; Perath, I.

units. Clay minerals, though subordinate, characterize certain units. Illite is usually the dominant clay mineral in the Precambrain-Paleozoic sediments, showing different degress of crystallization in different units. Kaolinite is the main, often the only clay mineral in Mesozoic units. Heavy minerals, whose species spectra reflect on parent rock and provenance terrain and whose differential response to degradation points to the sedimentary history of the deposit, show certain vertical regularities, such as the abrupt disappearance of species or whole assemblages at certain levels, indicating unconformities. Trace metals, which in places reach ore concentrations (e.g. copper), are often extensive, though of well-defined vertical distribution. They express adsorptive capacity of specific widespread lithologies, enabling the discrimination of units. Even though each of these criteria is not always by itself diagnostic, they may in conjuction with one or more other criteria amount to a petrographic fingerprint that enables fairly accurate identification of the age interval of the unit, and its relation both to the regional and the local stratigraphic sequence.

Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia).

PubMed

O'Keefe, F R; Chiappe, L M

2011-08-12

Viviparity is known in several clades of Mesozoic aquatic reptiles, but evidence for it is lacking in the Plesiosauria. Here, we report a Late Cretaceous plesiosaur fossil consisting of a fetus preserved within an adult of the same taxon. We interpret this occurrence as a gravid female and unborn young and hence as definitive evidence for plesiosaur viviparity. Quantitative analysis indicates that plesiosaurs gave birth to large, probably single progeny. The combination of viviparity, large offspring size, and small brood number differs markedly from the pattern seen in other marine reptiles but does resemble the K-selected strategy of all extant marine mammals and a few extant lizards. Plesiosaurs may have shared other life history traits with these clades, such as sociality and maternal care.

Early childhood malnutrition predicts depressive symptoms at ages 11-17.

PubMed

Galler, J R; Bryce, C P; Waber, D; Hock, R S; Exner, N; Eaglesfield, D; Fitzmaurice, G; Harrison, R

2010-07-01

We examined the prevalence of depressive symptoms in Barbadian youth with histories of infantile malnutrition and in a healthy comparison group and the extent to which the effect of malnutrition was mediated/moderated by maternal depression. Depressive symptoms were assessed using a 20-item scale administered to youths (11-17 years of age) who had experienced an episode of protein-energy malnutrition (marasmus or kwashiorkor) during the first year of life and in a comparison group of healthy youths without a history of malnutrition. Their mothers completed the same questionnaire on the same test on three occasions when their children were 5-17 years of age at 2-5-year intervals. The prevalence of depressive symptoms was elevated among previously malnourished youth relative to healthy comparison children (p < .001). When youth depression scores were subjected to a longitudinal multiple regression analysis, adjusting for the effect of maternal depressive symptoms, significant effects due to the history of early childhood malnutrition remained and were not discernibly attenuated from an unadjusted analysis. We also found significant independent effects of maternal depressive symptoms on youth depressive symptoms. Early childhood malnutrition contributed independently to depressive symptoms in youths who experienced a significant episode of malnutrition in the first year of life. This relationship was not mediated or moderated by the effects of maternal depression. Whether the later vulnerability to depression is a direct effect of the episode of malnutrition and related conditions early in life or whether it is mediated by the more proximal neurobehavioral effects of the malnutrition remains to be determined.

Independent Deficits of Visual Word and Motion Processing in Aging and Early Alzheimer's Disease

PubMed Central

Velarde, Carla; Perelstein, Elizabeth; Ressmann, Wendy; Duffy, Charles J.

2013-01-01

We tested whether visual processing impairments in aging and Alzheimer's disease (AD) reflect uniform posterior cortical decline, or independent disorders of visual processing for reading and navigation. Young and older normal controls were compared to early AD patients using psychophysical measures of visual word and motion processing. We find elevated perceptual thresholds for letters and word discrimination from young normal controls, to older normal controls, to early AD patients. Across subject groups, visual motion processing showed a similar pattern of increasing thresholds, with the greatest impact on radial pattern motion perception. Combined analyses show that letter, word, and motion processing impairments are independent of each other. Aging and AD may be accompanied by independent impairments of visual processing for reading and navigation. This suggests separate underlying disorders and highlights the need for comprehensive evaluations to detect early deficits. PMID:22647256

Attitudes of Veterinary Teaching Staff and Exposure of Veterinary Students to Early-Age Desexing, with Review of Current Early-Age Desexing Literature

PubMed Central

Jupe, Alannah; Rand, Jacquie; Morton, John; Fleming, Sophie

2017-01-01

Simple Summary A substantial proportion of cats and a smaller proportion of dogs entering animal shelters are juveniles. Cats are prolific breeders and can be pregnant by 4 months of age, although the traditional desexing age in veterinary practice is 6 months for dogs and cats. Understanding what veterinary students across Australia and New Zealand are being taught in regards to early age desexing (EAD) is necessary to determine the reasons why EAD is not utilized in client-owned cats and dogs more frequently. There are no current studies documenting the exposure of new veterinary graduates to EAD, nor the opinions to EAD of the academics teaching these students. Of staff teaching veterinary students in Australia and New Zealand in 2015, a majority (64%) did not advocate EAD in their teaching of students. Only three out of eight universities provided a majority of students with exposure to EAD procedures before graduation, and only two of these allowed most students to perform EAD. Abstract Approximately 50% of cats admitted to Australian shelters are kittens, and 26% of dogs are puppies, and, particularly for cats, euthanasia rates are often high. Cats can be pregnant by 4 months of age, yet the traditional desexing age is 5–6 months, and studies in Australasia and Nth America reveal that only a minority of veterinarians routinely perform early age desexing (EAD) of cats or dogs, suggesting they are not graduating with these skills. This study aimed to describe the attitudes of veterinary teaching staff in Australian and New Zealand universities towards EAD, and to determine if these changed from 2008 to 2015. It also aimed to identify students’ practical exposure to EAD. Most (64%) of the 25 participants in 2015 did not advocate EAD in their teaching and, in their personal opinion, only 32% advocated it for cats. Concerns related to EAD cited by staff included anesthetic risk, orthopedic problems, hypoglycemia, and, in female dogs, urinary incontinence

Inversion of the Erlian Basin (NE China) in the early Late Cretaceous: Implications for the collision of the Okhotomorsk Block with East Asia

NASA Astrophysics Data System (ADS)

Guo, Zhi-Xin; Shi, Yuan-Peng; Yang, Yong-Tai; Jiang, Shuan-Qi; Li, Lin-Bo; Zhao, Zhi-Gang

2018-04-01

A significant transition in tectonic regime from extension to compression occurred throughout East Asia during the mid-Cretaceous and has stimulated much attention. However, the timing and driving mechanisms of the transition remain disputed. The Erlian Basin, a giant late Mesozoic intracontinental petroliferous basin located in the Inner Mongolia, Northeast China, contains important sedimentary and structural records related to the mid-Cretaceous compressional event. The stratigraphical, sedimentological and structural analyses reveal that a NW-SE compressional inversion occurred in the Erlian Basin between the depositions of the Lower Cretaceous Saihan and Upper Cretaceous Erlian formations, causing intense folding of the Saihan Formation and underlying strata, and the northwestward migration of the depocenters of the Erlian Formation. Based on the newly obtained detrital zircon U-Pb data and previously published paleomagnetism- and fossil-based ages, the Saihan and Erlian formations are suggested as latest Aptian-Albian and post-early Cenomanian in age, respectively, implying that the inversion in the Erlian Basin occurred in the early Late Cretaceous (Cenomanian time). Apatite fission-track thermochronological data record an early Late Cretaceous cooling/exhuming event in the basin, corresponding well with the aforementioned sedimentary, structural and chronological analyses. Combining with the tectono-sedimentary evolutions of the neighboring basins of the Erlian Basin, we suggest that the early Late Cretaceous inversional event in the Erlian Basin and the large scale tectonic transition in East Asia shared the common driving mechanism, probably resulting from the Okhotomorsk Block-East Asia collisional event at about 100-89 Ma.

Age of Izu-Bonin-Mariana arc basement

NASA Astrophysics Data System (ADS)

Ishizuka, Osamu; Hickey-Vargas, Rosemary; Arculus, Richard J.; Yogodzinski, Gene M.; Savov, Ivan P.; Kusano, Yuki; McCarthy, Anders; Brandl, Philipp A.; Sudo, Masafumi

2018-01-01

Documenting the early tectonic and magmatic evolution of the Izu-Bonin-Mariana (IBM) arc system in the Western Pacific is critical for understanding the process and cause of subduction initiation along the current convergent margin between the Pacific and Philippine Sea plates. Forearc igneous sections provide firm evidence for seafloor spreading at the time of subduction initiation (52 Ma) and production of "forearc basalt". Ocean floor drilling (International Ocean Discovery Program Expedition 351) recovered basement-forming, low-Ti tholeiitic basalt crust formed shortly after subduction initiation but distal from the convergent margin (nominally reararc) of the future IBM arc (Amami Sankaku Basin: ASB). Radiometric dating of this basement gives an age range (49.3-46.8 Ma with a weighted average of 48.7 Ma) that overlaps that of basalt in the present-day IBM forearc, but up to 3.3 m.y. younger than the onset of forearc basalt activity. Similarity in age range and geochemical character between the reararc and forearc basalts implies that the ocean crust newly formed by seafloor spreading during subduction initiation extends from fore- to reararc of the present-day IBM arc. Given the age difference between the oldest forearc basalt and the ASB crust, asymmetric spreading caused by ridge migration might have taken place. This scenario for the formation of the ASB implies that the Mesozoic remnant arc terrane of the Daito Ridges comprised the overriding plate at subduction initiation. The juxtaposition of a relatively buoyant remnant arc terrane adjacent to an oceanic plate was more favourable for subduction initiation than would have been the case if both downgoing and overriding plates had been oceanic.

The power of personality in discriminating between healthy aging and early-stage Alzheimer's disease.

PubMed

Duchek, Janet M; Balota, David A; Storandt, Martha; Larsen, Randy

2007-11-01

This study examined differences in personality in the earliest stages of dementia of the Alzheimer type (DAT) relative to healthy aging, and the power of personality in discriminating healthy aging from early-stage DAT. Four groups of participants (middle-aged controls, older controls, persons with very mild DAT, and persons with mild DAT) and their families were administered Costa and McCrae's NEO Five-Factor Inventory. On the basis of both self-report and informant report, there was an increase in neuroticism and a decrease in conscientiousness in persons with very mild DAT relative to healthy individuals without it, and in persons with mild DAT relative to those with very mild DAT. Moreover, informant reports of neuroticism and conscientiousness capture substantial unique variance in discriminating healthy aging and very mild DAT, above and beyond standard neuropsychological tests. Discussion focuses on the importance of personality traits as a noncognitive indicator of early-stage DAT.

Up, Not Down: The Age Curve in Happiness from Early Adulthood to Midlife in Two Longitudinal Studies

ERIC Educational Resources Information Center

Galambos, Nancy L.; Fang, Shichen; Krahn, Harvey J.; Johnson, Matthew D.; Lachman, Margie E.

2015-01-01

Happiness is an important indicator of well-being, and little is known about how it changes in the early adult years. We examined trajectories of happiness from early adulthood to midlife in 2 Canadian longitudinal samples: high school seniors followed from ages 18-43 and university seniors followed from ages 23-37. Happiness increased into the…

Early vs late age at onset frontotemporal dementia and frontotemporal lobar degeneration.

PubMed

Seo, Sang Won; Thibodeau, Marie-Pierre; Perry, David C; Hua, Alice; Sidhu, Manu; Sible, Isabel; Vargas, Jose Norberto S; Gaus, Stephanie E; Rabinovici, Gil D; Rankin, Katherine D; Boxer, Adam L; Kramer, Joel H; Rosen, Howard J; Gorno-Tempini, Maria Luisa; Grinberg, Lea T; Huang, Eric J; DeArmond, Stephen J; Trojanowski, John Q; Miller, Bruce L; Seeley, William W

2018-03-20

To examine clinicopathologic correlations in early vs late age at onset frontotemporal dementia (FTD) and frontotemporal lobar degeneration (FTLD). All patients were clinically evaluated and prospectively diagnosed at the UCSF Memory and Aging Center. Two consecutive series were included: (1) patients with a clinically diagnosed FTD syndrome who underwent autopsy (cohort 1) and (2) patients with a primary pathologic diagnosis of FTLD, regardless of the clinical syndrome (cohort 2). These series were divided by age at symptom onset (cutoff 65 years). In cohort 1, 48 (25.3%) were 65 years or older at symptom onset. Pathologic causes of behavioral variant FTD (bvFTD) were similar in the early age at onset (EO) and late age at onset (LO) bvFTD groups. In corticobasal syndrome (CBS), however, the most common pathologic substrate differed according to age at onset: progressive supranuclear palsy (42.9%) in LO-CBS and Alzheimer disease (AD; 40.7%) in EO-CBS. In cohort 2, 57 (28.4%) were classified as LO-FTLD. Regarding FTLD major molecular classes, FTLD with transactive response DNA-binding protein of 43 kDa was most common in EO-FTLD (44.4%), whereas FTLD-tau (58.3%) was most common in LO-FTLD. Antemortem diagnosis of a non-FTD syndrome, usually AD-type dementia, was more frequent in LO-FTLD than EO-FTLD (19.3% vs 7.7%, p = 0.017). LO-FTLD was also associated with more prevalent comorbid pathologic changes. Of these, moderate to severe AD neuropathologic change and argyrophilic grain disease were overrepresented among patients who received an antemortem diagnosis of AD-type dementia. Patients with FTD and FTLD often develop symptoms after age 65, and age at onset represents an important consideration when making antemortem neuropathologic predictions. © 2018 American Academy of Neurology.

Growth in early life and the development of obesity by age 9 years: are there critical periods and a role for an early life stressor?

PubMed

Giles, L C; Whitrow, M J; Rumbold, A R; Davies, C E; de Stavola, B; Pitcher, J B; Davies, M J; Moore, V M

2013-04-01

Rapid growth, possibly occurring in critical periods in early life, may be important for the development of obesity. It is unknown whether this is influenced by postnatal exposures such as age-relevant sources of stress. Frequent house moves may be one such stressor. We aimed to examine if there is a period of growth in early life critical for the development of child obesity by age 9 years and assess the role of house moves in modifying any relationships between early life growth and obesity at age 9 years. Prospective Australian birth cohort study. In all, 392 children with serial body size measurements from birth to age 9 years. Standardized body mass index (z-BMI) was available for six time points (spanning birth to 3½ years), and the total number of house moves between birth and 3½ years. The outcomes considered were z-BMI and % body fat (%BF) at age 9 years. Linear regression models were used to estimate the effects of serial measurements of z-BMI and number of house moves on the outcomes. Life-course plots showed that z-BMI at 3½ years was a statistically significant predictor of z-BMI at 9 years (β=0.80; standard error (s.e.), 0.04), whereas z-BMI at 9 months (β=-1.13; s.e., 0.40) and 3½ years (β=4.82; s.e., 0.42) were significant predictors of %BF at age 9 years. There were statistically significant interactions between the number of house moves and change in z-BMI between 9 and 12 months, such that ≥ 3 house moves in early life amplified the detrimental effects of earlier rapid growth on both body size and composition at age 9 years. In the absence of evidence for a single critical period, efforts to prevent overweight and obesity are required throughout childhood. In addition, modifiable postnatal stressors may exacerbate effects of early growth on obesity in later childhood.

Exploring Work and Development Options to Reduce Early Labour Force Exit of Mature Aged Australians

ERIC Educational Resources Information Center

Pillay, Hitendra; Kelly, Kathy; Tones, Megan

2008-01-01

Early labour force exit is a significant challenge associated with the ageing workforce in Australia and many other developed countries. A reduction and increased flexibility of work hours has been suggested to improve labour force participation of the mature aged cohort. However, little is known about mature aged workers' aspirations for…

Geophysical survey within the Mesozoic magnetic anomaly sequence south of Bermuda

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

Purdy, G.M.; Rohr, K.

1979-09-10

This geophysical survey of an approximate 1/sup 0/ square covers Mesozoic magnetic anomalies M0, M2, and M4 south of Bermuda. Bathymetry, magnetics seismic reflection profiling, and seismic refraction data are presented. The isochron trend within the survey area at magnetic anomaly M4 times is 025/sup 0/. Two left lateral fracture zones exist: the southern fracture zone has an offset of <10 km at M4 time and 33 km at M0 time. The northern fracture zone has an offset of 37 km at M4 time and 26 km at M0 time. These changes in ofsett are accounted for by asymmetric spreading,more » an 11/sup 0/ change in trend of anomaly M0 relative to M4, and by M0 time, growth of a small right lateral fracture zone. Seismic refraction data provide poor control on the shallow crustal structure but suggest the presence of significant lateral inhomogeneities with layer 2.« less

Age at onset of DSM-IV pathological gambling in a non-treatment sample: Early- versus later-onset.

PubMed

Black, Donald W; Shaw, Martha; Coryell, William; Crowe, Raymond; McCormick, Brett; Allen, Jeff

2015-07-01

Pathological gambling (PG) is a prevalent and impairing public health problem. In this study we assessed age at onset in men and women with PG and compared the demographic and clinical picture of early- vs. later-onset individuals. We also compared age at onset in PG subjects and their first-degree relatives with PG. Subjects with DSM-IV PG were recruited during the conduct of two non-treatment clinical studies. Subjects were evaluated with structured interviews and validated questionnaires. Early-onset was defined as PG starting prior to age 33years. Age at onset of PG in the 255 subjects ranged from 8 to 80years with a mean (SD) of 34.0 (15.3) years. Men had an earlier onset than women. 84% of all subjects with PG had developed the disorder by age 50years. Early-onset subjects were more likely to be male, to prefer action games, and to have substance use disorders, antisocial personality disorder, attention deficit/hyperactivity disorder, trait impulsiveness, and social anxiety disorder. Later-onset was more common in women and was associated with a preference for slots and a history of sexual abuse. Age at onset of PG is bimodal and differs for men and women. Early-onset PG and later-onset PG have important demographic and clinical differences. The implications of the findings are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Emotional and behavioral problems in late preterm and early term births: outcomes at child age 36 months.

PubMed

Stene-Larsen, Kim; Lang, Astri M; Landolt, Markus A; Latal, Beatrice; Vollrath, Margarete E

2016-12-01

Recent findings has shown that late preterm births (gestational weeks 34-36) and early term births (gestational weeks 37-38) is associated with an increased risk of several psychological and developmental morbidities. In this article we investigate whether late preterm and early term births is associated with an increased risk of emotional and behavioral problems at 36 months of age and whether there are gender differences in risk of these outcomes. Forty-three thousand, two hundred ninety-seven children and their mothers participating in the Norwegian Mother and Child Cohort Study (MoBa). One thousand, eight hundred fifty-three (4.3%) of the children in the sample were born late preterm and 7,835 (18.1%) were born early term. Information on gestational age and on prenatal and postnatal risk factors was retrieved from the Medical Birth Registry of Norway. Information on emotional and behavioral problems was assessed by standardized questionnaires (CBCL/ITSEA) filled out by the mothers. Gender-stratified logistic regression analyses were used to explore the association between late preterm / early term and emotional and behavioral problems at 36 months of age. We found a gender-specific increased risk of emotional problems in girls born late preterm (OR 1.47 95%CI 1.11-1.95) and in girls born early term (OR 1.21 95%CI 1.04-1.42). We did not find an increased risk of emotional problems in boys born late preterm (OR 1.09 95%CI 0.82-1.45) or early term (OR 0.93 95%CI 0.79-1.10). Behavioral problems were not increased in children born late preterm or early term. Girls born late preterm and early term show an increased risk of emotional problems at 36 months of age. This finding suggests that gender should be taken into account when evaluating children born at these gestational ages.

Deletion of Ku80 causes early aging independent of chronic inflammation and Rag-1-induced DSBs.

PubMed

Holcomb, Valerie B; Vogel, Hannes; Hasty, Paul

2007-01-01

Animal models of premature aging are often defective for DNA repair. Ku80-mutant mice are disabled for nonhomologous end joining; a pathway that repairs both spontaneous DNA double-strand breaks (DSBs) and induced DNA DSBs generated by the action of a complex composed of Rag-1 and Rag-2 (Rag). Rag is essential for inducing DSBs important for assembling V(D)J segments of antigen receptor genes that are required for lymphocyte development. Thus, deletion of either Rag-1 or Ku80 causes severe combined immunodeficiency (scid) leading to chronic inflammation. In addition, Rag-1 induces breaks at non-B DNA structures. Previously we reported Ku80-mutant mice undergo premature aging, yet we do not know the root cause of this phenotype. Early aging may be caused by either defective repair of spontaneous DNA damage, defective repair of Rag-1-induced breaks or chronic inflammation caused by scid. To address this issue, we analyzed aging in control and Ku80-mutant mice deleted for Rag-1 such that both cohorts are scid and suffer from chronic inflammation. We make two observations: (1) chronic inflammation does not cause premature aging in these mice and (2) Ku80-mutant mice exhibit early aging independent of Rag-1. Therefore, this study supports defective repair of spontaneous DNA damage as the root cause of early aging in Ku80-mutant mice.

Computational Thermomechanical Modelling of Early-Age Silicate Composites

NASA Astrophysics Data System (ADS)

Vala, J.; Št'astník, S.; Kozák, V.

2009-09-01

Strains and stresses in early-age silicate composites, widely used in civil engineering, especially in fresh concrete mixtures, in addition to those caused by exterior mechanical loads, are results of complicated non-deterministic physical and chemical processes. Their numerical prediction at the macro-scale level requires the non-trivial physical analysis based on the thermodynamic principles, making use of micro-structural information from both theoretical and experimental research. The paper introduces a computational model, based on a nonlinear system of macroscopic equations of evolution, supplied with certain effective material characteristics, coming from the micro-scale analysis, and sketches the algorithm for its numerical analysis.

Larval cases of caddisfly (Insecta: Trichoptera) affinity in Early Permian marine environments of Gondwana

NASA Astrophysics Data System (ADS)

Mouro, Lucas D.; Zatoń, Michał; Fernandes, Antonio C. S.; Waichel, Breno L.

2016-01-01

Caddisflies (Trichoptera) are small, cosmopolitan insects closely related to the Lepidoptera (moths and butterflies). Most caddisflies construct protective cases during their larval development. Although the earliest recognisable caddisflies date back to the early Mesozoic (Early and Middle Triassic), being particularly numerous and diverse during the Late Jurassic and Early Cretaceous, the first records of their larval case constructions are known exclusively from much younger, Early to Middle Jurassic non-marine deposits in the northern hemisphere. Here we present fossils from the Early Permian (Asselian-Sakmarian) marine deposits of Brazil which have strong morphological and compositional similarity to larval cases of caddisflies. If they are, which is very probable, these finds not only push back the fossil record of true caddisflies, but also indicate that their larvae constructed cases at the very beginning of their evolution in marine environments. Since modern caddisflies that construct larval cases in marine environments are only known from eastern Australia and New Zealand, we suggest that this marine ecology may have first evolved in western Gondwana during the Early Permian and later spread across southern Pangea.

Larval cases of caddisfly (Insecta: Trichoptera) affinity in Early Permian marine environments of Gondwana

PubMed Central

Mouro, Lucas D.; Zatoń, Michał; Fernandes, Antonio C.S.; Waichel, Breno L.

2016-01-01

Caddisflies (Trichoptera) are small, cosmopolitan insects closely related to the Lepidoptera (moths and butterflies). Most caddisflies construct protective cases during their larval development. Although the earliest recognisable caddisflies date back to the early Mesozoic (Early and Middle Triassic), being particularly numerous and diverse during the Late Jurassic and Early Cretaceous, the first records of their larval case constructions are known exclusively from much younger, Early to Middle Jurassic non-marine deposits in the northern hemisphere. Here we present fossils from the Early Permian (Asselian–Sakmarian) marine deposits of Brazil which have strong morphological and compositional similarity to larval cases of caddisflies. If they are, which is very probable, these finds not only push back the fossil record of true caddisflies, but also indicate that their larvae constructed cases at the very beginning of their evolution in marine environments. Since modern caddisflies that construct larval cases in marine environments are only known from eastern Australia and New Zealand, we suggest that this marine ecology may have first evolved in western Gondwana during the Early Permian and later spread across southern Pangea. PMID:26765261

Larval cases of caddisfly (Insecta: Trichoptera) affinity in Early Permian marine environments of Gondwana.

PubMed

Mouro, Lucas D; Zatoń, Michał; Fernandes, Antonio C S; Waichel, Breno L

2016-01-14

Caddisflies (Trichoptera) are small, cosmopolitan insects closely related to the Lepidoptera (moths and butterflies). Most caddisflies construct protective cases during their larval development. Although the earliest recognisable caddisflies date back to the early Mesozoic (Early and Middle Triassic), being particularly numerous and diverse during the Late Jurassic and Early Cretaceous, the first records of their larval case constructions are known exclusively from much younger, Early to Middle Jurassic non-marine deposits in the northern hemisphere. Here we present fossils from the Early Permian (Asselian-Sakmarian) marine deposits of Brazil which have strong morphological and compositional similarity to larval cases of caddisflies. If they are, which is very probable, these finds not only push back the fossil record of true caddisflies, but also indicate that their larvae constructed cases at the very beginning of their evolution in marine environments. Since modern caddisflies that construct larval cases in marine environments are only known from eastern Australia and New Zealand, we suggest that this marine ecology may have first evolved in western Gondwana during the Early Permian and later spread across southern Pangea.

Form, function and environments of the early angiosperms: merging extant phylogeny and ecophysiology with fossils.

PubMed

Feild, Taylor S; Arens, Nan Crystal

2005-05-01

The flowering plants--angiosperms--appeared during the Early Cretaceous period and within 10-30 Myr dominated the species composition of many floras worldwide. Emerging insights into the phylogenetics of development and discoveries of early angiosperm fossils are shedding increased light on the patterns and processes of early angiosperm evolution. However, we also need to integrate ecology, in particular how early angiosperms established a roothold in pre-existing Mesozoic plant communities. These events were critical in guiding subsequent waves of angiosperm diversification during the Aptian-Albian. Previous pictures of the early flowering plant ecology have been diverse, ranging from large tropical rainforest trees, weedy drought-adapted and colonizing shrubs, disturbance- and sun-loving rhizomatous herbs, and, more recently, aquatic herbs; however, none of these images were tethered to a robust hypothesis of angiosperm phylogeny. Here, we synthesize our current understanding of early angiosperm ecology, focusing on patterns of functional ecology, by merging recent molecular phylogenetic studies and functional studies on extant 'basal angiosperms' with the picture of early angiosperm evolution drawn by the fossil record.

The Border Ranges fault system in Glacier Bay National Park, Alaska: Evidence for major early Cenozoic dextral strike-slip motion

USGS Publications Warehouse

Smart, K.J.; Pavlis, T.L.; Sisson, V.B.; Roeske, S.M.; Snee, L.W.

1996-01-01

The Border Ranges fault system of southern Alaska, the fundamental break between the arc basement and the forearc accretionary complex, is the boundary between the Peninsular-Alexander-Wrangellia terrane and the Chugach terrane. The fault system separates crystalline rocks of the Alexander terrane from metamorphic rocks of the Chugach terrane in Glacier Bay National Park. Mylonitic rocks in the zone record abundant evidence for dextral strike-slip motion along north-northwest-striking subvertical surfaces. Geochronologic data together with regional correlations of Chugach terrane rocks involved in the deformation constrain this movement between latest Cretaceous and Early Eocene (???50 Ma). These findings are in agreement with studies to the northwest and southeast along the Border Ranges fault system which show dextral strike-slip motion occurring between 58 and 50 Ma. Correlations between Glacier Bay plutons and rocks of similar ages elsewhere along the Border Ranges fault system suggest that as much as 700 km of dextral motion may have been accommodated by this structure. These observations are consistent with oblique convergence of the Kula plate during early Cenozoic and forearc slivering above an ancient subduction zone following late Mesozoic accretion of the Peninsular-Alexander-Wrangellia terrane to North America.

Early age at start of antiretroviral therapy associated with better virologic control after initial suppression in HIV-infected infants.

PubMed

Shiau, Stephanie; Strehlau, Renate; Technau, Karl-Günter; Patel, Faeezah; Arpadi, Stephen M; Coovadia, Ashraf; Abrams, Elaine J; Kuhn, Louise

2017-01-28

The report of the 'Mississippi baby' who was initiated on antiretroviral therapy (ART) within 30 h of birth and maintained viral suppression off ART for 27 months has increased interest in the timing of ART initiation early in life. We examined associations between age at ART initiation and virologic outcomes in five cohorts of HIV-infected infants and young children who initiated ART before 2 years of age in Johannesburg, South Africa. We compared those who initiated ART early (<6 months of age) and those who started ART late (6-24 months of age). Two primary outcomes were examined: initial response to ART in three cohorts and later sustained virologic control after achieving suppression on ART in two cohorts. We did not observe consistent differences in initial viral suppression rates by age at ART initiation. Overall, initial viral suppression rates were low. Only 31, 40.1, and 26.5% of early-treated infants (<6 months of age) in the three cohorts, respectively, were suppressed less than 50 copies/ml of HIV RNA 6 months after starting ART. We did observe better sustained virologic control after achieving suppression on ART among infants starting ART early compared with late. Children who started ART early were less likely to experience viral rebound (>50 copies/ml or >1000 copies/ml) than children who started late in both cohorts. These findings provide additional support for early initiation of ART in HIV-infected infants.

Neuromotor outcomes at school age after extremely low birth weight: early detection of subtle signs.

PubMed

Gidley Larson, Jennifer C; Baron, Ida Sue; Erickson, Kristine; Ahronovich, Margot D; Baker, Robin; Litman, Fern R

2011-01-01

Motor impairments are prevalent in children born at extremely low birth weight (ELBW; <1,000 g). Rarely studied are subtle motor deficits that indicate dysfunction or delay in neural systems critical for optimal cognitive, academic, and behavioral function. We aimed to examine quantifiable signs of subtle neuromotor dysfunction in an early school-aged ELBW cohort that coincidentally had age-appropriate cognition and design copying. We studied 97 participants born between 1998 and 2001; 74 ELBW (6.7 years ± 0.75) compared with 23 term-born (6.6 years ± 0.29). Neuromotor outcomes were assessed using the Physical and Neurological Examination of Subtle Signs-Revised, and measures of dexterity/coordination and visual-motor integration. ELBW participants performed worse than term-born on design-copying and dexterity, were age-appropriate compared to normative data, and had slower timed movements and more subtle overflow movements. Those ELBW born <26 weeks performed most poorly compared with those born 26-34 weeks and term-born. Subtle motor dysfunctions are detectable and quantifiable in ELBW children by school age, even in the presence of average cognition. Early age assessment of incoordination, motor speed, and overflow movements should aid initiation of timely therapies to prepare at-risk ELBW children for subsequent school entry and facilitate design of optimal early treatment strategies. (c) 2010 APA, all rights reserved.

Language development of internationally adopted children: Adverse early experiences outweigh the age of acquisition effect.

PubMed

Rakhlin, Natalia; Hein, Sascha; Doyle, Niamh; Hart, Lesley; Macomber, Donna; Ruchkin, Vladislav; Tan, Mei; Grigorenko, Elena L

2015-01-01

We compared English language and cognitive skills between internationally adopted children (IA; mean age at adoption=2.24, SD=1.8) and their non-adopted peers from the US reared in biological families (BF) at two time points. We also examined the relationships between outcome measures and age at initial institutionalization, length of institutionalization, and age at adoption. On measures of general language, early literacy, and non-verbal IQ, the IA group performed significantly below their age-peers reared in biological families at both time points, but the group differences disappeared on receptive vocabulary and kindergarten concept knowledge at the second time point. Furthermore, the majority of children reached normative age expectations between 1 and 2 years post-adoption on all standardized measures. Although the age at adoption, age of institutionalization, length of institutionalization, and time in the adoptive family all demonstrated significant correlations with one or more outcome measures, the negative relationship between length of institutionalization and child outcomes remained most robust after controlling for the other variables. Results point to much flexibility and resilience in children's capacity for language acquisition as well as the potential primacy of length of institutionalization in explaining individual variation in IA children's outcomes. (1) Readers will be able to understand the importance of pre-adoption environment on language and early literacy development in internationally adopted children. (2) Readers will be able to compare the strength of the association between the length of institutionalization and language outcomes with the strength of the association between the latter and the age at adoption. (3) Readers will be able to understand that internationally adopted children are able to reach age expectations on expressive and receptive language measures despite adverse early experiences and a replacement of their first

[Relationship between body weight status in early adulthood and body weight change to middle age and high-density lipoprotein cholesterol level in middle aged Chinese people].

PubMed

Zhao, L C; Zhou, L; Li, Y; Guo, M; Wu, Y F

2016-08-24

To explore the relationship between early adulthood weight status and body weight changes from early adulthood to middle age and high-density lipoprotein cholesterol (HDL-C) level. Data were obtained from China Multicenter Collaborative Study of Cardiovascular Epidemiology Study, which was conducted in 1998, 15 participants population samples aged from 35-59 years old from 12 provinces were selected by random cluster sampling. Approximately 1 000 men and women in each sample population were surveyed for cardiovascular disease risk factors, body weight at age 25 from all participants were also obtained. Body mass index (BMI) at the age of 25 years was calculated with the weight at 25 years and the height measured during the survey, participants were divided into underweight (BMI<18.5 kg/m(2), n=1 331), normal-weight (18.5 kg/m(2)≤BMI <24 kg/m(2), n=10 400), overweight (24 kg/m(2)≤BMI<28 kg/m(2), n=2 019) and obesity (BMI≥28 kg/m(2), n=133) groups. Weight change was defined as the difference between the body weight at the age of 25 and at the survey and was grouped into<-7.5 kg (n=903), -7.5--2.6 kg (n=1 883), -2.5-2.5 kg (n=2 573), 2.6-7.5 kg (n=2 786), 7.6-12.5 kg (n=2 674) and>12.5 kg (n=3 064). The association of body weight status in early adulthood and body weight change from early adulthood to middle age with HDL-C level was examined by logistic regression model. The prevalence of low HDL-C in underweight, normal weight, overweight and obesity groups at age of 25 years were 10.7%(143/1 331), 15.5%(1 612/10 400), 16.3%(330/2 019) and 24.8%(33/133), respectively(P for trend <0.01). The prevalence of low HDL-C for adult weight change were 8.8%(79/903), 8.0%(151/1 883), 10.5%(269/2 573), 13.4%(373/2 786), 19.1%(511/2 674), and 24.0%(735/3 064)(P for trend <0.01)for weight change of <-7.5 kg, -7.5--2.6 kg, -2.5-2.5 kg, 2.6-7.5 kg, 7.6-12.5 kg and>12.5 kg, respectively. Multivariate logistic regression showed that overweight and obesity at age of 25 years and

Petrology and K-Ar ages of rift-related basaltic rocks, offshore northern Brazil, 3/sup 0/N

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

Fodor, R.V.; McKee, E.H.

1986-07-01

Tholeiitic basaltic rock in three cores from Petrobras drill site APS-21, 1960-2480 m depths, Amapa basin, offshore Brazil is compositionally similar to rift-related basaltic rock associated with the opening of both the North and South Atlantic Oceans (SiO/sub 2/ 52-54 wt %; K/sub 2/O 0.7-1.3%; TiO/sub 2/ 1.3-2%). Whole-rock K-Ar ages are 185.4, 183.2, and 126.5 m.y. If these represent crystallization ages, then the older samples correspond to North Atlantic tectonism (as represented by the Liberian dike system) and the younger correlates with South Atlantic rift-related magmatism (of which Serra Geral flood basalts are the best example). Trace- and REE-elementsmore » identify T-type mantle source-areas (La/Sm/sub (n)/ approx. 2; Zr/Nb 8-11) that feasibly were mixes of N-type and P-type components (metasomatized or veined upper mantle). These Amapa basin mafic rocks document the southernmost magmatism related to North Atlantic rifting, as well as early Mesozoic mantle source-areas and processes beneath Gondwanaland such as those identified with basalts in the South Atlantic basin.« less

Early crop-tree release in even-aged stands of Appalachian hardwoods

Treesearch

George R., Jr. Trimble; George R. Trimble

1971-01-01

Now that even-aged silviculture is well established as a successful method of growing Appalachian hardwoods, a pressing need exists for guidelines for precommercial operations. We started research several years ago on the Fernow Experimental Forest near Parsons, West Virginia, to learn more about the cost and methodology of early crop-tree release in mountain hardwood...

Caloric restriction preserves memory and reduces anxiety of aging mice with early enhancement of neurovascular functions.

PubMed

Parikh, Ishita; Guo, Janet; Chuang, Kai-Hsiang; Zhong, Yu; Rempe, Ralf G; Hoffman, Jared D; Armstrong, Rachel; Bauer, Björn; Hartz, Anika M S; Lin, Ai-Ling

2016-11-08

Neurovascular integrity plays an important role in protecting cognitive and mental health in aging. Lifestyle interventions that sustain neurovascular integrity may thus be critical on preserving brain functions in aging and reducing the risk for age-related neurodegenerative disorders. Here we show that caloric restriction (CR) had an early effect on neurovascular enhancements, and played a critical role in preserving vascular, cognitive and mental health in aging. In particular, we found that CR significantly enhanced cerebral blood flow (CBF) and blood-brain barrier function in young mice at 5-6 months of age. The neurovascular enhancements were associated with reduced mammalian target of rapamycin expression, elevated endothelial nitric oxide synthase signaling, and increased ketone bodies utilization. With age, CR decelerated the rate of decline in CBF. The preserved CBF in hippocampus and frontal cortex were highly correlated with preserved memory and learning, and reduced anxiety, of the aging mice treated with CR (18-20 months of age). Our results suggest that dietary intervention started in the early stage (e.g., young adults) may benefit cognitive and mental reserve in aging. Understanding nutritional effects on neurovascular functions may have profound implications in human brain aging and age-related neurodegenerative disorders.

The Little Six Personality Dimensions From Early Childhood to Early Adulthood: Mean-Level Age and Gender Differences in Parents' Reports.

PubMed

Soto, Christopher J

2016-08-01

The present research pursues three major goals. First, we develop scales to measure the Little Six youth personality dimensions: Extraversion, Agreeableness, Conscientiousness, Neuroticism, Openness to Experience, and Activity. Second, we examine mean-level age and gender differences in the Little Six from early childhood into early adulthood. Third, we examine the development of more specific nuance traits. We analyze parent reports, made using the common-language California Child Q-Set (CCQ), for a cross-sectional sample of 16,000 target children ranging from 3 to 20 years old. We construct CCQ-Little Six scales that reliably measure each Little Six dimension. Using these scales, we find (a) curvilinear, U-shaped age trends for Agreeableness, Conscientiousness, and Openness, with declines followed by subsequent inclines; (b) monotonic, negative age trends for Extraversion and Activity; (c) higher levels of Conscientiousness and Agreeableness among girls than boys, as well as higher levels of Activity among boys than girls; and (d) gender-specific age trends for Neuroticism, with girls scoring higher than boys by mid-adolescence. Finally, we find that several nuance traits show distinctive developmental trends that differ from their superordinate Little Six dimension. These results highlight childhood and adolescence as key periods of personality development. © 2015 Wiley Periodicals, Inc.

The post-Paleozoic chronology and mechanism of 13C depletion in primary marine organic matter

NASA Technical Reports Server (NTRS)

Popp, B. N.; Takigiku, R.; Hayes, J. M.; Louda, J. W.; Baker, E. W.

1989-01-01

Carbon-isotopic compositions of geoporphyrins have been measured from marine sediments of Mesozoic and Cenozoic age in order to elucidate the timing and extent of depletion of 13C in marine primary producers. These results indicate that the difference in isotopic composition of coeval marine carbonates and marine primary photosynthate was approximately 5 to 7 permil greater during the Mesozoic and early Cenozoic than at present. In contrast to the isotopic record of marine primary producers, isotopic compositions of terrestrial organic materials have remained approximately constant for this same interval of time. This difference in the isotopic records of marine and terrestrial organic matter is considered in terms of the mechanisms controlling the isotopic fractionation associated with photosynthetic fixation of carbon. We show that the decreased isotopic fractionation between marine carbonates and organic matter from the Early to mid-Cenozoic may record variations in the abundance of atmospheric CO2.

ASSOCIATION BETWEEN VISUAL FUNCTION AND SUBRETINAL DRUSENOID DEPOSITS IN NORMAL AND EARLY AGE-RELATED MACULAR DEGENERATION EYES.

PubMed

Neely, David; Zarubina, Anna V; Clark, Mark E; Huisingh, Carrie E; Jackson, Gregory R; Zhang, Yuhua; McGwin, Gerald; Curcio, Christine A; Owsley, Cynthia

2017-07-01

To examine the association between subretinal drusenoid deposits (SDDs) identified by multimodal retinal imaging and visual function in older eyes with normal macular health or in the earliest phases of age-related macular degeneration (AMD). Age-related macular degeneration status for each eye was defined according to the Age-Related Eye Disease Study (AREDS) 9-step classification system (normal = Step 1, early AMD = Steps 2-4) based on color fundus photographs. Visual functions measured were best-corrected photopic visual acuity, contrast and light sensitivity, mesopic visual acuity, low-luminance deficit, and rod-mediated dark adaptation. Subretinal drusenoid deposits were identified through multimodal imaging (color fundus photographs, infrared reflectance and fundus autofluorescence images, and spectral domain optical coherence tomography). The sample included 1,202 eyes (958 eyes with normal health and 244 eyes with early AMD). In normal eyes, SDDs were not associated with any visual function evaluated. In eyes with early AMD, dark adaptation was markedly delayed in eyes with SDDs versus no SDD (a 4-minute delay on average), P = 0.0213. However, this association diminished after age adjustment, P = 0.2645. Other visual functions in early AMD eyes were not associated with SDDs. In a study specifically focused on eyes in normal macular health and in the earliest phases of AMD, early AMD eyes with SDDs have slower dark adaptation, largely attributable to the older ages of eyes with SDD; they did not exhibit deficits in other visual functions. Subretinal drusenoid deposits in older eyes in normal macular health are not associated with any visual functions evaluated.

Early primary repair of tetralogy of fallot in neonates and infants less than four months of age.

PubMed

Tamesberger, Melanie I; Lechner, Evelyn; Mair, Rudolf; Hofer, Anna; Sames-Dolzer, Eva; Tulzer, Gerald

2008-12-01

The ideal age for correction of tetralogy of Fallot is still under discussion. The aim of this study was to analyze morbidity and mortality in patients who underwent early primary repair of tetralogy of Fallot at the age of less than 4 months and to assess whether neonates, who needed early repair within the first 4 weeks of life, faced an increased risk. From 1995 to 2006, 90 consecutive patients with tetralogy of Fallot and pulmonary stenosis underwent early primary repair. Patient charts were analyzed retrospectively for two groups: group A, 25 neonates younger than 28 days who needed early operation owing to duct-dependent pulmonary circulation or severe hypoxemia; and group B, 65 infants younger than 4 months of age who underwent elective early repair. There was no 30-day mortality; late mortality was 2% after a median follow-up time of 4.7 years. Seven of 88 patients (8%) needed reoperation and twelve of 88 patients (14%) needed reintervention. Groups A and B did not differ significantly in terms of intensive care unit stay, days of mechanical ventilation, overall hospital stay, major or minor complications, or reoperation. Significant differences were found in a more frequent use of a transannular patch (p = 0.045) and more reinterventions (p = 0.046) in group A. Early primary repair of tetralogy of Fallot can be performed safely and effectively in infants younger than 4 months of age and even in neonates younger than 28 days with duct-dependent pulmonary circulation or severe hypoxemia.

My Entirely Plausible Fantasy: Early Mathematics Education in the Age of the Touchscreen Computer

ERIC Educational Resources Information Center

Ginsburg, Herbert P.

2014-01-01

This paper offers an account of what early mathematics education could look like in an age of young digital natives. Each "Tubby," as the tablets are called, presents Nicole (our generic little child) with stimulating mathematics microworlds, from which, beginning at age 3, she can learn basic math concepts, as well as methods of…

Sex differences in episodic memory in early midlife: impact of reproductive aging.

PubMed

Rentz, Dorene M; Weiss, Blair K; Jacobs, Emily G; Cherkerzian, Sara; Klibanski, Anne; Remington, Anne; Aizley, Harlyn; Goldstein, Jill M

2017-04-01

Few have characterized cognitive changes with age as a function of menopausal stage relative to men, or sex differences in components of memory in early midlife. The study aim was to investigate variation in memory function in early midlife as a function of sex, sex steroid hormones, and reproductive status. A total of 212 men and women aged 45 to 55 were selected for this cross-sectional study from a prenatal cohort of pregnancies whose mothers were originally recruited in 1959 to 1966. They underwent clinical and cognitive testing and hormonal assessments of menopause status. Multivariate general linear models for multiple memory outcomes were used to test hypotheses controlling for potential confounders. Episodic memory, executive function, semantic processing, and estimated verbal intelligence were assessed. Associative memory and episodic verbal memory were assessed using Face-Name Associative Memory Exam (FNAME) and Selective Reminding Test (SRT), given increased sensitivity to detecting early cognitive decline. Impacts of sex and reproductive stage on performance were tested. Women outperformed men on all memory measures including FNAME (β = -0.30, P < 0.0001) and SRT (β = -0.29, P < 0.0001). Furthermore, premenopausal and perimenopausal women outperformed postmenopausal women on FNAME (initial learning, β= 0.32, P = 0.01) and SRT (recall, β= 2.39, P = 0.02). Across all women, higher estradiol was associated with better SRT performance (recall, β = 1.96, P = 0.01) and marginally associated with FNAME (initial learning, β = 0.19, P = 0.06). This study demonstrated that, in early midlife, women outperformed age-matched men across all memory measures, but sex differences were attenuated for postmenopausal women. Initial learning and memory retrieval were particularly vulnerable, whereas memory consolidation and storage were preserved. Findings underscore the significance of the decline in ovarian estradiol production in

Mind the gap: the distributional effects of raising the early eligibility age and full retirement age.

PubMed

Olsen, Anya

2012-01-01

Policymakers have proposed increases to the early eligibility age (EEA) and/or full retirement age (FRA) to address increasing life expectancy and Social Security solvency issues. This analysis uses the Social Security Administration's Modeling Income in the Near Term, version 6 (MINT6) model to compare three retirement-age increases suggested by the Social Security Advisory Board: increase the gap between the EEA and FRA by raising only the FRA, increase both the EEA and FRA to maintain a 4-year gap between them, and increase both the EEA and FRA to maintain a 5-year gap between them. Although all three options would improve system solvency by similar proportions, their effect on individual beneficiaries in the future would vary. Benefit reductions are greater under the proposals with more months between the EEA and FRA, while the option that maintains a 4-year gap results in benefit increases for some beneficiaries compared with current law.

School Age Outcomes of Children with Autism Spectrum Disorder Who Received Community-Based Early Interventions

ERIC Educational Resources Information Center

Vinen, Zoe; Clark, Megan; Paynter, Jessica; Dissanayake, Cheryl

2018-01-01

This study followed children with Autism Spectrum Disorder (ASD) from early intervention into their early schooling years, when they were aged between 6 and 9 years, on autism symptom severity and cognitive functioning. The children, matched at pre-intervention, were compared on type of community provided service: 31 were in receipt of…

Structures in the transition zone of the northeast South China Sea: serpentinite dome vs mantle exhumation, or evidence of Mesozoic active subduction transferring to Cenozoic passive extension?

NASA Astrophysics Data System (ADS)

Sun, Z.; Zhou, D.

2013-12-01

Complete sedimentary sequences and weak erosion make the transition zone of the South China Sea the optimal place to study the entire evolution history of marginal sea basins, as well as the transition mechanism from active subduction to passive extension. 2D long cable seismic profiles revealed that both Baiyun and Liwan sag in the northeast South China Sea margin were lack of large controlling faults, especially in Liwan sag, syn-rift sequences waved above the basement. Dome-like uplifts(serpetinite uplifts?) or diapirs(?) came from below the basement, caused the syn-rift sequences pushed up around 36Ma(T80). Gravity inversion based on seismic reflection indicated that the dome has a lower density and a lower layer velocity than normal crust. Also around the Continent-Ocean Boundary (COB), a small segment similar to the lower crust was exposed. Between this exposed segment and the Cenozoic oceanic crust, mantle seems to be exhumed along the breakup point. Between the COB and roughly the shelf break, high velocity lower crust was discriminated in the northeast continental margin. Structures in northeast South China Sea seems having many similarities with Newfoundland-Iberia margin, by serpentinite(?) dome and exhumed mantle, although spreading rate here is intermediate. In fact, regional background suggests that there might be another interpretation: transition from Mesozoic subduction to Cenozoic extension occurred through paleo oceanic crust breakup in the northeast, which in turn retained Mesozoic subduction system beneath the northeast continental margin. Confined with magnetic anomaly, Bouguer gravity gradient anomaly, and well drilling lithological evidences, Cenozoic Baiyun sag developed upon Mesozoic fore-arc, while Cenozoic Liwan sag developed upon Mesozoic accretionary prism. The high velocity lower crust was caused by both remnant subducted slab and by Oceanic-Continent interaction due to subduction. There might also be serpentinite dome and exhumed

Early age exposure to moisture damage and systemic inflammation at the age of 6 years.

PubMed

Karvonen, A M; Tischer, C; Kirjavainen, P V; Roponen, M; Hyvärinen, A; Illi, S; Mustonen, K; Pfefferle, P I; Renz, H; Remes, S; Schaub, B; von Mutius, E; Pekkanen, J

2018-05-01

Cross-sectional studies have shown that exposure to indoor moisture damage and mold may be associated with subclinical inflammation. Our aim was to determine whether early age exposure to moisture damage or mold is prospectively associated with subclinical systemic inflammation or with immune responsiveness in later childhood. Home inspections were performed in children's homes in the first year of life. At age 6 years, subclinical systemic inflammation was measured by serum C-reactive protein (CRP) and blood leukocytes and immune responsiveness by ex vivo production of interleukin 1-beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) in whole blood cultures without stimulation or after 24 hours stimulation with phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG) in 251-270 children. Moisture damage in child's main living areas in infancy was not significantly associated with elevated levels of CRP or leukocytes at 6 years. In contrast, there was some suggestion for an effect on immune responsiveness, as moisture damage with visible mold was positively associated with LPS-stimulated production of TNF-α and minor moisture damage was inversely associated with PI-stimulated IL-1β. While early life exposure to mold damage may have some influence on later immune responsiveness, it does not seem to increase subclinical systemic inflammation in later life. © 2018 National Institute for Health and Welfare, Finland Indoor Air published by John Wiley & Sons Ltd.

Foot pad dermatitis develops at an early age in commercial turkeys.

PubMed

Mayne, R K; Hocking, P M; Else, R W

2006-02-01

1. A field experiment was conducted to identify the macroscopic and histological changes associated with the development of foot pad dermatitis (FPD) in growing turkeys. Two affected and two unaffected turkeys were sampled weekly from 1 to 8 and at 10 and 21 weeks of age. 2. At one week old, birds with external signs of FPD (surface skin discolouration) showed abnormal cellular changes of the foot pad integument. As the flock aged the reactions intensified, with one sample exhibiting a fully developed macroscopic lesion at 3 weeks. 3. Major pathological changes had occurred by 6 weeks and all turkeys with external signs of lesions had fully developed microscopic inflammatory cellular lesions. From 6 weeks of age onwards lesions were increasingly numerous and became more overtly necrotic. 4. Externally normal foot pads showed microscopic evidence of lesions after the turkeys reached 4 weeks. 5. We conclude that FPD lesions become severe over a short period of time and at a very early age.

Tok-Algoma magmatic complex of the Selenga-Stanovoi Superterrain in the Central Asian fold belt: Age and tectonic setting

NASA Astrophysics Data System (ADS)

Kotov, A. B.; Larin, A. M.; Salnikova, E. B.; Velikoslavinskii, S. D.; Sorokin, A. A.; Sorokin, A. P.; Yakovleva, S. Z.; Anisimova, I. V.; Tolmacheva, E. V.

2012-05-01

According to the results of U-Pb geochronological investigations, the hornblende subalkali diorite rocks making up the Tok-Algoma Complex in the eastern part of the Selenga-Stanovoi Superterrain of the Central Asian fold belt were formed in the Middle Jurassic rather than in the Middle Archean as was suggested previously. Thus, the age of the regional amphibolite facies metamorphism manifested itself in the Ust'-Gilyui rock sequence of the Stanovoi Complex and that superimposed on granitoids of the Tok-Algoma Complex is Mesozoic rather than Early Precambrian. The geochemical features of the Tok-Algoma granitoids are indicative of the fact that they were formed in the geodynamic setting of the active continental margin or a mature island arc. Hence, it is possible to suggest that the subduction processes along the southern boundary between the Selenga-Stanovoi Superterrain and the Mongolian-Okhotsk ocean basin in the Middle Jurassic resulted in the formation of a magmatic belt of over 500 km in length.

Time Outdoors at Specific Ages During Early Childhood and the Risk of Incident Myopia.

PubMed

Shah, Rupal L; Huang, Yu; Guggenheim, Jeremy A; Williams, Cathy

2017-02-01

Time outdoors during childhood is negatively associated with incident myopia. Consequently, additional time outdoors has been suggested as a public health intervention to reduce the prevalence of myopia. We investigated whether there were specific ages during early childhood when the time outdoors versus incident myopia association was strongest. Children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) were studied from age 2 to 15 years. Parentally reported time outdoors and time spent reading were assessed longitudinally in early childhood (ages 2, 3, 4, 5, 7, and 9 years). Noncycloplegic autorefraction was carried out longitudinally in later childhood (ages 10, 11, 12, and 15 years). Information was available for 2833 participants. Cox proportional hazards regression was used to test for association between time outdoors and incident myopia. From 3 years of age onward, greater time outdoors was associated with a reduced risk of incident myopia. The hazard ratio for myopia changed progressively from 0.90 (95% CI 0.83-0.98, P = 0.012) at age 3 years, to 0.86 (95% CI 0.78-0.93, P = 0.001) at age 9 years, for each additional SD of time spent outdoors per day. These associations were independent of two major risk factors for myopia: time reading and number of myopic parents. Additional time spent outdoors across the 3 to 9 years age range was associated with a reduced incidence of myopia between ages 10 and 15 years. There was a trend for the association to increase toward the older end of the 3 to 9 years range.

Early Math Trajectories: Low-Income Children's Mathematics Knowledge from Ages 4 to 11

ERIC Educational Resources Information Center

Rittle-Johnson, Bethany; Fyfe, Emily R.; Hofer, Kerry G.; Farran, Dale C.

2017-01-01

Early mathematics knowledge is a strong predictor of later academic achievement, but children from low-income families enter school with weak mathematics knowledge. An early math trajectories model is proposed and evaluated within a longitudinal study of 517 low-income American children from ages 4 to 11. This model includes a broad range of math…

Caloric restriction preserves memory and reduces anxiety of aging mice with early enhancement of neurovascular functions

PubMed Central

Parikh, Ishita; Guo, Janet; Chuang, Kai-Hsiang; Zhong, Yu; Rempe, Ralf G.; Hoffman, Jared D.; Armstrong, Rachel; Bauer, Björn; Hartz, Anika M.S.; Lin, Ai-Ling

2016-01-01

Neurovascular integrity plays an important role in protecting cognitive and mental health in aging. Lifestyle interventions that sustain neurovascular integrity may thus be critical on preserving brain functions in aging and reducing the risk for age-related neurodegenerative disorders. Here we show that caloric restriction (CR) had an early effect on neurovascular enhancements, and played a critical role in preserving vascular, cognitive and mental health in aging. In particular, we found that CR significantly enhanced cerebral blood flow (CBF) and blood-brain barrier function in young mice at 5-6 months of age. The neurovascular enhancements were associated with reduced mammalian target of rapamycin expression, elevated endothelial nitric oxide synthase signaling, and increased ketone bodies utilization. With age, CR decelerated the rate of decline in CBF. The preserved CBF in hippocampus and frontal cortex were highly correlated with preserved memory and learning, and reduced anxiety, of the aging mice treated with CR (18-20 months of age). Our results suggest that dietary intervention started in the early stage (e.g., young adults) may benefit cognitive and mental reserve in aging. Understanding nutritional effects on neurovascular functions may have profound implications in human brain aging and age-related neurodegenerative disorders. PMID:27829242

Mental health functioning (SF-36) and intentions to retire early among ageing municipal employees: the Helsinki Health Study.

PubMed

Harkonmäki, Karoliina; Lahelma, Eero; Martikainen, Pekka; Rahkonen, Ossi; Silventoinen, Karri

2006-01-01

To examine the associations of mental health functioning with intentions to retire early among ageing municipal employees. Cross-sectional survey data (n = 7,765) from the Helsinki Health Study in 2000, 2001, and 2002 were used. Intentions to retire early were sought with a question: "Have you considered retiring before normal retirement age?" The dependent variable was divided into three categories: 1 = no intentions to retire early; 2 = weak intentions; 3 = strong intentions. Mental health functioning was measured by the Short Form 36 (SF-36) mental component summary (MCS). Other variables included age, sex, physical health functioning (SF-36), limiting longstanding illness, socioeconomic status, and spouse's employment status. Multinomial regression analysis was used to examine the association of mental health functioning with intentions to retire early. Employees with the poorest mental health functioning were much more likely to report strong intentions to retire early (OR 6.09, 95% CI 4.97-7.47) than those with the best mental health functioning. Adjustments for physical health, socioeconomic status, and spouse's employment status did not substantially affect this association. The findings highlight the importance of mental health for intentions to retire early. Strategies aimed at keeping people at work for longer should emphasize the importance of mental well-being and the prevention of poor mental health. More evidence is needed on why mental problems among ageing baby-boomer employees are giving rise to increasing social consequences, although the overall prevalence of mental problems has not increased.

Early Family System Types Predict Children's Emotional Attention Biases at School Age

ERIC Educational Resources Information Center

Lindblom, Jallu; Peltola, Mikko J.; Vänskä, Mervi; Hietanen, Jari K.; Laakso, Anu; Tiitinen, Aila; Tulppala, Maija; Punamäki, Raija-Leena

2017-01-01

The family environment shapes children's social information processing and emotion regulation. Yet, the long-term effects of early family systems have rarely been studied. This study investigated how family system types predict children's attentional biases toward facial expressions at the age of 10 years. The participants were 79 children from…

Stratigraphy of Slick Rock district and vicinity, San Miguel and Dolores Counties, Colorado

USGS Publications Warehouse

Shawe, Daniel R.; Simmons, George C.; Archbold, Norbert L.

1968-01-01

The Slick Rock district covers about 570 square miles in western San Miguel and Dolores Counties, in southwestern Colorado. It is at the south edge of the salt-anticline region of southwestern Colorado and southeastern Utah and of the Uravan mineral belt.Deposition of Paleozoic sedimentary rocks in the district and vicinity was principally controlled by development of the Paradox Basin, and of Mesozoic rocks by development of a depositional basin farther west. The Paleozoic rocks generally are thickest at the northeast side of the Paradox Basin in a northwest- trending trough which seems to be a wide graben in Precambrian igneous and metamorphic basement rocks; Mesozoic rocks generally thicken westward and southwestward from the district.Sedimentary rocks rest on a Precambrian basement consisting of a variety of rocks, including granite and amphibolite. The surface of the Precambrian rocks is irregular and generally more than 2,000 feet below sea level and 7,000-11,000 feet below the ground surface. In the northern part of the district the Precambrian surface plunges abruptly northeastward into the trough occupying the northeast side of the Paradox Basin, and in the southern part it sags in a narrow northeasterly oriented trough. Deepening of both troughs, or crustal deformation in their vicinity, influenced sedimentation during much of late Paleozoic and Mesozoic time.The maximum total thickness of sedimentary rocks underlying the district is 13,000 feet, and prior to extensive erosion in the late Tertiary and the Quaternary it may have been as much as about 18,000 feet. The lower 5,000 feet or more of the sequence of sedimentary rocks consists of arenaceous strata of early Paleozoic age overlain by dominantly marine carbonate rocks and evaporite beds interbedded with lesser amounts of clastic sediments of late Paleozoic age. Overlying these rocks is about 4,500 feet of terrestrial clastic sediments, dominantly sandstone with lesser amounts of shale, mudstone

Porphyry deposits of the Canadian Cordillera

USGS Publications Warehouse

McMillan, W.J.; Thompson, J.F.H.; Hart, C.J.R.; Johnston, S.T.

1996-01-01

Porphyry deposits are intrusion-related, large tonnage low grade mineral deposits with metal assemblages that may include all or some of copper, molybdenum, gold and silver. The genesis of these deposits is related to the emplacement of intermediate to felsic, hypabyssal, generally porphyritic intrusions that are commonly formed at convergent plate margins. Porphyry deposits of the Canadian Cordillera occur in association with two distinctive intrusive suites: calc-alkalic and alkalic. In the Canadian Cordillera, these deposits formed during two separate time periods: Late Triassic to Middle Jurassic (early Mesozoic), and Late Cretaceous to Eocene (Mesozoic-Cenozoic). Deposits of the early Mesozoic period occur in at least three different arc terranes (Wrangellia, Stikinia and Quesnellia) with a single deposit occurring in the oceanic assemblage of the Cache Creek terrane. These terranes were located outboard from continental North America during formation of most of their contained early Mesozoic porphyry deposits. Some of the deposits of this early period may have been emplaced during terrane collisions. Metal assemblages in deposits of the calc-alkalic suite include Mo-Cu (Brenda), Cu-Mo (Highland Valley, Gibraltar), Cu-Mo-Au-Ag (Island Copper, Schaft Creek) and Cu-Au (Kemess, Kerr).The alkalic suite deposits are characterized by a Cu-Au assemblage (Copper Mountain, Afton-Ajax, Mt. Milligan, Mount Polley, Galore Creek). Although silver is recovered from calc-alkalic and alkalic porphyry copper mining operations, silver data are seldom included in the published reserve figures. Those available are in the range of 1-2 grams per tonne (g??t-1). Alkalic suite deposits are restricted to the early Mesozoic and display distinctive petrology, alteration and mineralization that suggest a similar tectonic setting for both Quesnellia and Stikinia in Early Jurassic time. The younger deposits, late Mesozoic to Cenozoic in age, formed in an intracontinental setting, after the

Confirmation of a late Oligocene-early Miocene age of the Deseadan Salla Beds of Bolivia.

USGS Publications Warehouse

Naeser, C.W.; McKee, E.H.; Johnson, N.M.; Macfadden, B.J.

1987-01-01

Three new fission-track (zircon) and four new K-Ar (biotite) dates corroborate a late Oligocene-early Miocene age (22-28 Ma) for the Salla Beds of Bolivia. These ages contrast markedly with the previously accepted age of about 35 Ma for these strata and their contained faunas, and recasts of order and chronology of interchange between New World and Old World mammals. -Authors

Early childhood growth patterns and school-age respiratory resistance, fractional exhaled nitric oxide and asthma.

PubMed

Casas, Maribel; den Dekker, Herman T; Kruithof, Claudia J; Reiss, Irwin K; Vrijheid, Martine; de Jongste, Johan C; Jaddoe, Vincent W V; Duijts, Liesbeth

2016-12-01

Greater infant weight gain is associated with lower lung function and increased risk of childhood asthma. The role of early childhood peak growth patterns is unclear. We assessed the associations of individually derived early childhood peak growth patterns with respiratory resistance, fractional exhaled nitric oxide, wheezing patterns, and asthma until school-age. We performed a population-based prospective cohort study among 5364 children. Repeated growth measurements between 0 and 3 years of age were used to derive standard deviation scores (s.d.s) of peak height and weight velocities (PHV and PWV, respectively), and body mass index (BMI) and age at adiposity peak. Respiratory resistance and fractional exhaled nitric oxide were measured at 6 years of age. Wheezing patterns and asthma were prospectively assessed by annual questionnaires. We also assessed whether any association was explained by childhood weight status. Greater PHV was associated with lower respiratory resistance [Z-score (95% CI): -0.03 (-0.04, -0.01) per s.d.s increase] (n = 3382). Greater PWV and BMI at adiposity peak were associated with increased risks of early wheezing [relative risk ratio (95% CI): 1.11 (1.06, 1.16), 1.26 (1.11, 1.43), respectively] and persistent wheezing [relative risk ratio (95% CI): 1.09 (1.03, 1.16), 1.37 (1.17, 1.60), respectively] (n = 3189 and n = 3005, respectively). Childhood weight status partly explained these associations. No other associations were observed. PWV and BMI at adiposity peak are critical for lung developmental and risk of school-age wheezing. Follow-up studies at older ages are needed to elucidate whether these effects persist at later ages. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tectonics and hydrocarbon potential of the Barents Megatrough

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

Baturin, D.; Vinogradov, A.; Yunov, A.

1991-08-01

Interpretation of geophysical data shows that the geological structure of the Eastern Barents Shelf, named Barents Megatrough (BM), extends sublongitudinally almost from the Baltic shield to the Franz Josef Land archipelago. The earth crust within the axis part of the BM is attenuated up to 28-30 km, whereas in adjacent areas its thickness exceeds 35 km. The depression is filled with of more than 15 km of Upper Paleozoic, Mesozoic, and Cenozoic sediments overlying a folded basement of probable Caledonian age. Paleozoic sediments, with exception of the Upper Permian, are composed mainly of carbonates and evaporites. Mesozoic-Cenozoic sediments are mostlymore » terrigenous. The major force in the development of the BM was due to extensional tectonics. Three rifting phases are recognizable: Late Devonian-Early Carboniferous, Early Triassic, and Jurassic-Early Cretaceous. The principal features of the geologic structure and evolution of the BM during the late Paleozoic-Mesozoic correlate well with those of the Sverdup basin, Canadian Arctic. Significant quantity of Late Jurassic-Early Cretaceous basaltic dikes and sills were intruded within Triassic sequence during the third rifting phase. This was probably the main reason for trap disruption and hydrocarbon loss from Triassic structures. Lower Jurassic and Lower Cretaceous reservoir sandstones are most probably the main future objects for oil and gas discoveries within the BM. Upper Jurassic black shales are probably the main source rocks of the BM basin, as well as excellent structural traps for hydrocarbon fluids from the underlying sediments.« less

Association of Intrauterine and Early-Life Exposures With Age at Menopause in the Sister Study

PubMed Central

Steiner, Anne Z.; D'Aloisio, Aimee A.; DeRoo, Lisa A.; Sandler, Dale P.; Baird, Donna D.

2010-01-01

Oocytes are formed in utero; menopause occurs when the oocyte pool is depleted. The authors hypothesized that early-life events could affect the number of a woman's oocytes and determine age at menopause. To test their hypothesis, the authors conducted a secondary analysis of baseline data from 22,165 participants in the Sister Study (2003–2007) who were aged 35–59 years at enrollment. To estimate the association between early-life events and age at natural menopause, the authors used Cox proportional hazards models to estimate hazard ratios with 95% confidence intervals, adjusting for current age, race/ethnicity, education, childhood family income, and smoking history. Earlier menopause was associated with in-utero diethylstilbestrol exposure (hazard ratio (HR) = 1.45, 95% confidence interval (CI): 1.27, 1.65). Suggestive associations included maternal prepregnancy diabetes (HR = 1.33, 95% CI: 0.89, 1.98) and low birth weight (HR = 1.09, 95% CI: 0.99, 1.20). Having a mother aged 35 years or older at birth appeared to be associated with a later age at menopause (HR = 0.95, 95% CI: 0.89, 1.01). Birth order, in-utero smoke exposure, and having been breastfed were not related to age at menopause. In-utero and perinatal events may subsequently influence age at menopause. PMID:20534821

Birdshot Retinochoroidopathy: Differences in Clinical Characteristics between Patients with Early and Late Age of Onset.

PubMed

Silpa-Archa, Sukhum; Cao, Jennifer H; Boonsopon, Sutasinee; Lee, Joan; Preble, Janine M; Foster, C Stephen

2017-10-01

To describe differences in the clinical characteristics of birdshot retinochoroidopathy (BSRC) patients diagnosed early and later in life. This is a retrospective cohort study. Age was primarily analyzed and 50 years of age at diagnosis was selected as a cut-off point. A total of 144 patients (288 eyes) were included; 68 with early-onset and 76 with late-onset BSRC. The younger group had a statistically significant higher rate of more severe iritis (p = 0.04); an average number of non-steroidal immunosuppressants and biologic agents (NSIB) (p = 0.04); and a prolonged time to initiation of NSIB (p = 0.01). There were only four patients (3%) who had >0.5+ cells in the anterior chamber. Patients with early-onset BSRC carried a higher risk for anterior segment inflammation, had a more prolonged delay to initiation of treatment with NSIB, and required a greater number of NSIBs to achieve remission.

The first horse herders and the impact of early Bronze Age steppe expansions into Asia.

PubMed

de Barros Damgaard, Peter; Martiniano, Rui; Kamm, Jack; Moreno-Mayar, J Víctor; Kroonen, Guus; Peyrot, Michaël; Barjamovic, Gojko; Rasmussen, Simon; Zacho, Claus; Baimukhanov, Nurbol; Zaibert, Victor; Merz, Victor; Biddanda, Arjun; Merz, Ilja; Loman, Valeriy; Evdokimov, Valeriy; Usmanova, Emma; Hemphill, Brian; Seguin-Orlando, Andaine; Yediay, Fulya Eylem; Ullah, Inam; Sjögren, Karl-Göran; Iversen, Katrine Højholt; Choin, Jeremy; de la Fuente, Constanza; Ilardo, Melissa; Schroeder, Hannes; Moiseyev, Vyacheslav; Gromov, Andrey; Polyakov, Andrei; Omura, Sachihiro; Senyurt, Süleyman Yücel; Ahmad, Habib; McKenzie, Catriona; Margaryan, Ashot; Hameed, Abdul; Samad, Abdul; Gul, Nazish; Khokhar, Muhammad Hassan; Goriunova, O I; Bazaliiskii, Vladimir I; Novembre, John; Weber, Andrzej W; Orlando, Ludovic; Allentoft, Morten E; Nielsen, Rasmus; Kristiansen, Kristian; Sikora, Martin; Outram, Alan K; Durbin, Richard; Willerslev, Eske

2018-05-09

The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (~3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyze 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after but not at the time of Yamnaya culture. We find no evidence of steppe ancestry in Bronze Age Anatolia from when Indo-European languages are attested there. Thus, in contrast to Europe, Early Bronze Age Yamnaya-related migrations had limited direct genetic impact in Asia. Copyright © 2018, American Association for the Advancement of Science.

Early-life conditions and health at older ages: The mediating role of educational attainment, family and employment trajectories.

PubMed

Arpino, Bruno; Gumà, Jordi; Julià, Albert

2018-01-01

We examine to what extent the effect of early-life conditions (health and socioeconomic status) on health in later life is mediated by educational attainment and life-course trajectories (fertility, partnership, employment). Using data from the Survey of Health, Ageing and Retirement in Europe (N = 12,034), we apply, separately by gender, multichannel sequence analysis and cluster analysis to obtain groups of similar family and employment histories. The KHB method is used to disentangle direct and indirect effects of early-life conditions on health. Early-life-conditions indirectly impact on health in later life as result of their influence on education and family and employment trajectories. For example, between 22% and 42% of the effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Even higher percentages are found for men (35% - 57%). On the contrary, the positive effect of poor health at childhood on poor health at older ages is not significantly mediated by education and life-course trajectories. Education captures most of the mediating effect of parental socio-economic status. More specifically, between 66% and 75% of the indirect effect of low parental socio-economic status at childhood on the three considered health outcomes at older age is explained by educational attainment for women. Again, higher percentages are found for men (86% - 93%). Early-life conditions, especially socioeconomic status, influence family and employment trajectories indirectly through their impact on education. We also find a persistent direct impact of early-life conditions on health at older ages. Our findings demonstrate that early-life experiences influence education and life-course trajectories and health in later life, suggesting that public investments in children are expected to produce long lasting effects on people's lives throughout the different phases of their

Age and Early Revision After Primary Total Hip Arthroplasty for Osteoarthritis.

PubMed

Meyer, Zachary; Baca, Geneva; Rames, Richard; Barrack, Robert; Clohisy, John; Nam, Denis

2017-11-01

Prior reports have noted an increased risk of early revision among younger patients undergoing total hip arthroplasty (THA) but have been confounded by the inclusion of various diagnoses. The purpose of this study was to assess the revision rate and the time to revision for patients undergoing THA for osteoarthritis based on age. Patients with a diagnosis of osteoarthritis who underwent both primary and revision THA at the same institution were identified. The time between primary and revision surgery and the indication for revision were collected. Patients were stratified into 2 groups based on age at the time of primary THA: 64 years or younger (group 1) or 65 years or older (group 2). Between 1996 and 2016, a total of 4662 patients (5543 hips) underwent primary THA for a diagnosis of osteoarthritis. Of these, 100 patients (104 hips) received a revision THA (62 in group 1 and 42 in group 2). Mean age was 52.7±8.4 years in group 1 vs 73.4±6.3 years in group 2 (P<.001). There was no significant difference in mean body mass index (29.7±7.3 kg/m 2 vs 28.4±4.6 kg/m 2 , P=.30). Rate of revision was not significantly different between the groups (1.8% vs 2.0%, P=.7). Average time from primary to revision surgery was 3.0±3.2 years for group 1 and 1.1±2.1 years for group 2 (P=.001). Among patients undergoing primary THA for a diagnosis of osteoarthritis, younger age is not associated with an increased rate of early failure or revision. [Orthopedics. 2017; 40(6):e1069-e1073.]. Copyright 2017, SLACK Incorporated.

Time Outdoors at Specific Ages During Early Childhood and the Risk of Incident Myopia

PubMed Central

Shah, Rupal L.; Huang, Yu; Guggenheim, Jeremy A.; Williams, Cathy

2017-01-01

Purpose Time outdoors during childhood is negatively associated with incident myopia. Consequently, additional time outdoors has been suggested as a public health intervention to reduce the prevalence of myopia. We investigated whether there were specific ages during early childhood when the time outdoors versus incident myopia association was strongest. Methods Children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) were studied from age 2 to 15 years. Parentally reported time outdoors and time spent reading were assessed longitudinally in early childhood (ages 2, 3, 4, 5, 7, and 9 years). Noncycloplegic autorefraction was carried out longitudinally in later childhood (ages 10, 11, 12, and 15 years). Information was available for 2833 participants. Cox proportional hazards regression was used to test for association between time outdoors and incident myopia. Results From 3 years of age onward, greater time outdoors was associated with a reduced risk of incident myopia. The hazard ratio for myopia changed progressively from 0.90 (95% CI 0.83–0.98, P = 0.012) at age 3 years, to 0.86 (95% CI 0.78–0.93, P = 0.001) at age 9 years, for each additional SD of time spent outdoors per day. These associations were independent of two major risk factors for myopia: time reading and number of myopic parents. Conclusions Additional time spent outdoors across the 3 to 9 years age range was associated with a reduced incidence of myopia between ages 10 and 15 years. There was a trend for the association to increase toward the older end of the 3 to 9 years range. PMID:28245296

How Persistent is a Diagnosis of Mathematical Disorder at an Early Age? A Longitudinal Study

ERIC Educational Resources Information Center

Desoete, Annemmie; De Weerd, Frauke; Vanderswalmen, Ruth; De Bond, Annemie

2014-01-01

The study was conducted to look at differences between children who outgrew and did not outgrow an early diagnosis of mathematical learning disorder (MD; n=13), and peers without MD (n=13). Children were tested at 5, 6, 7 and 10 years of age. About 54% of the children with an early diagnosis of MD still experienced mathematical difficulties at the…

The first Mesozoic microwhip scorpion (Palpigradi): a new genus and species in mid-Cretaceous amber from Myanmar

NASA Astrophysics Data System (ADS)

Engel, Michael S.; Breitkreuz, Laura C. V.; Cai, Chenyang; Alvarado, Mabel; Azar, Dany; Huang, Diying

2016-04-01

A fossil palpigrade is described and figured from mid-Cretaceous (Cenomanian) amber from northern Myanmar. Electrokoenenia yaksha Engel and Huang, gen. n. et sp. n., is the first Mesozoic fossil of its order and the only one known as an inclusion in amber, the only other fossil being a series of individuals encased in Pliocene onyx marble and 94-97 million years younger than E. yaksha. The genus is distinguished from other members of the order but is remarkably consistent in observable morphological details when compared to extant relatives, likely reflecting a consistent microhabitat and biological preferences over the last 100 million years.

Reprint of: Aspirin use and early age-related macular degeneration: a meta-analysis.

PubMed

Kahawita, Shyalle K; Casson, Robert J

2015-06-01

The aim of this review was to evaluate the evidence for an association between Aspirin use and early age-related macular degeneration (ARMD). A literature search was performed in 5 databases with no restrictions on language or date of publication. Four studies involving 10292 individuals examining the association between aspirin and ARMD met the inclusion criteria. Meta-analysis was carried out by Cochrane Collaboration Review Manager 5.2 software (Cochrane Collaboration, Copenhagen, Denmark). The pooled odd ratios showed that Aspirin use was associated with early ARMD (pooled odds ratio 1.43, 95% CI 1.09-1.88). There is a small but statistically significant association between Aspirin use and early ARMD, which may warrant further investigation. Copyright © 2015. Published by Elsevier Inc.

Macro-level age norms for the timing of sexual initiation and adolescents' early sexual initiation in 17 European countries.

PubMed

Madkour, Aubrey Spriggs; de Looze, Margaretha; Ma, Ping; Halpern, Carolyn Tucker; Farhat, Tilda; Ter Bogt, Tom F M; Ehlinger, Virginie; Nic Gabhainn, Saoirse; Currie, Candace; Godeau, Emmanuelle

2014-07-01

To examine the relationship between country-level age norms for sexual initiation timing and early sexual initiation (ESI) among adolescent boys and girls. Nationally representative data from 17 countries that participated in the 2006/2007 European Social Survey (ESS-3, n = 33,092) and the 2005/2006 Health Behaviour in School-Aged Children Study (HBSC, n = 27,702) were analyzed. Age norms were measured as the average country-level response to an item asking the age at which ESS respondents believed someone is too young to have sexual intercourse. HBSC respondents (aged 14-16 years) self-reported age at sexual initiation, which we defined as early (<15 years) or not early (≥15 years or no initiation). Control variables included age, family affluence, perceived socioeconomic status, family living arrangement, substance use, school attachment, and country-level legal age of consent. Multivariable three-level logistic models with random intercepts were run separately by sex. In multivariable analyses, higher overall age norms were associated with reduced likelihood of ESI among girls (AOR .60, 95% CI .45-.79); associations with ESI were stronger for parent cohort (ages 31-65 years) norms (AOR .37, 95% CI .23-.58) than for peer cohort (ages 15-20 years) norms (AOR .60, 95% CI .49-.74). For boys, overall norms were also significantly negatively associated with ESI (AOR .68, 95% CI .46-.99), as were parent cohort norms (AOR .66, 95% CI .45-.96). Peer cohort norms were not significantly related to boys' ESI. Macrolevel cultural norms may impact adolescents' sexual initiation timing. Research exploring the sexual health outcomes of early initiators in countries with contrasting age norms is warranted. Copyright © 2014 Society for Adolescent Health and Medicine. All rights reserved.

Association of postural balance and isometric muscle strength in early- and middle-school-age boys.

PubMed

Ibrahim, Alaa I; Muaidi, Qassim I; Abdelsalam, Mohammed S; Hawamdeh, Ziad M; Alhusaini, Adel A

2013-01-01

The purpose of this study was to evaluate the isometric muscle strength (IMS) and dynamic balance in early- and middle-school-age boys and to assess the strength of association between the dynamic balance scores and 6 different IMS indexes. This is a cross-sectional study of a convenience sample of 94 boys who were 6 to 10 years of age and classified into an early school age (6-8 years) group (n = 50) and a middle school age (8-10 years) group (n = 44). Balance was tested using a Biodex Balance System. Anteroposterior Stability Index, Mediolateral Stability Index, and Overall Stability Index were recorded. IMS of 11 muscle groups was measured with a handheld dynamometer and categorized into 6 different muscle strength indices. The mean (SD) values of anteroposterior, mediolateral, and overall stability indexes observed for all study boys were 1.9 ± 1.0, 1.2 ± 0.7, and 2.5 ± 1.2 respectively. In the middle school age group, strong positive relationships were detected between the overall stability index and trunk, lower limb, anti-gravity, pro-gravity, and total strength indexes (r = -0.86/P < .001, r = -0.91/P < .001, r = -0.88/P < .001, r = -0.83/P < .001, and r = -0.84/P < .001 respectively), while no significant relationship was detected with the upper limb strength index (r = 0.159/P = .303). In the early school age group, moderate positive relationships were detected between the overall stability index and anti-gravity, lower limb, and total strength indexes (r = -0.404/P = .004, r = -0.356/P = .011, and r = -0.350/P = .013 respectively). Dynamic balance did not appear to be mature by the age of 10 years. Better balance skills were recorded in the mediolateral direction than in the anteroposterior direction. In the middle school age group, the overall stability index had positive relationships with almost all examined muscle strength indexes excepting the upper limb strength index. © 2013. Published by National University of Health Sciences All rights

Early Childhood Risk Factors for Decreased FEV1 at Age Six to Seven Years in Young Children with Cystic Fibrosis.

PubMed

Sanders, Don B; Emerson, Julia; Ren, Clement L; Schechter, Michael S; Gibson, Ronald L; Morgan, Wayne; Rosenfeld, Margaret

2015-08-01

There are limited objective measures of the severity of lung disease before children are able to routinely perform spirometry, generally at age 6 years. Identifying risk factors for reduced lung function at age 6 provides opportunities to intervene and slow the progression of cystic fibrosis (CF) lung disease. To evaluate early childhood predictors of lung function at age 6-7 in a large U.S. CF cohort in the current era of widespread early eradication therapy for Pseudomonas aeruginosa (P. aeruginosa). Participants were children with CF enrolled before age 4 in the Early Pseudomonas Infection Control (EPIC) Observational Study, a multicenter, longitudinal study that enrolled P. aeruginosa-negative children not exceeding 12 years of age. Linear regression was used to estimate the association between potential early childhood risk factors and the best FEV1% predicted at age 6-7 years. Four hundred and eighty-four children (of 1,797 enrolled in the EPIC Observational Study) met the eligibility criteria for this analysis. Mean (SD) age at enrollment was 2.0 (1.3) years. In a multivariable model adjusted for age at enrollment, the following risk factors were significantly associated with lower mean (95% confidence interval) FEV1% predicted at age 6-7: weight percentile less than 10% during the year of enrollment (-5.3 [-9.1, -1.5]), P. aeruginosa positive during the year of enrollment (-2.8 [-5.7, 0.0]), crackles or wheeze during the year of enrollment (-5.7 [-9.4, -1.9]), mother's education of high school or less (-4.2 [-7.3, -1.2]), and mother smoked during pregnancy (-4.4 [-8.8, 0.1]). In this large U.S. cohort, we identified several early childhood risk factors for lower FEV1 at age 6-7 years, most of which are modifiable. Clinical trial registered with www.clinicaltrials.gov (NCT00097773).

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.

Identification of morphological markers of sarcopenia at early stage of aging in skeletal muscle of mice.

PubMed

Sayed, Ramy K A; de Leonardis, Erika Chacin; Guerrero-Martínez, José A; Rahim, Ibtissem; Mokhtar, Doaa M; Saleh, Abdelmohaimen M; Abdalla, Kamal E H; Pozo, María J; Escames, Germaine; López, Luis C; Acuña-Castroviejo, Darío

2016-10-01

The gastrocnemius muscle (GM) of young (3months) and aged (12months) female wild-type C57/BL6 mice was examined by light and electron microscopy, looking for the presence of structural changes at early stage of the aging process. Morphometrical parameters including body and gastrocnemius weights, number and type of muscle fibers, cross section area (CSA), perimeter, and Feret's diameter of single muscle fiber, were measured. Moreover, lengths of the sarcomere, A-band, I-band, H-zone, and number and CSA of intermyofibrillar mitochondria (IFM), were also determined. The results provide evidence that 12month-old mice had significant changes on skeletal muscle structure, beginning with the reduction of gastrocnemius weight to body weight ratio, compatible with an early loss of skeletal muscle function and strength. Moreover, light microscopy revealed increased muscle fibers size, with a significant increase on their CSA, perimeter, and diameter of both type I and type II muscle fibers, and a reduction in the percentage of muscle area occupied by type II fibers. Enhanced connective tissue infiltrations, and the presence of centrally nucleated muscle fibers, were also found in aged mice. These changes may underlie an attempt to compensate the loss of muscle mass and muscle fibers number. Furthermore, electron microscopy discovered a significant age-dependent increase in the length of sarcomeres, I and H bands, and reduction on the overlapped actin/myosin length, supporting contractile force loss with age. Electron microscopy also showed an increased number and CSA of IFM with age, which may reveal more endurance at 12months of age. Together, mice at early stage of aging already show significant changes in gastrocnemius muscle morphology and ultrastructure that are suggestive of the onset of sarcopenia. Copyright © 2016 Elsevier Inc. All rights reserved.

Prospective associations between adolescent mental health problems and positive mental wellbeing in early old age.

PubMed

Nishida, Atsushi; Richards, Marcus; Stafford, Mai

2016-01-01

Mental health problems in adolescence are predictive of future mental distress and psychopathology; however, few studies investigated adolescent mental health problems in relation to future mental wellbeing and none with follow-up to older age. To test prospective associations between adolescent mental health problems and mental wellbeing and life satisfaction in early old age. A total of 1561 men and women were drawn from the Medical Research Council National Survey of Health and Development (the British 1946 birth cohort). Teachers had previously completed rating scales to assess emotional adjustment and behaviours, which allowed us to extract factors of mental health problems measuring self-organisation, behavioural problems, and emotional problems during adolescence. Between the ages of 60-64 years, mental wellbeing was assessed using the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) and life satisfaction was self-reported using the Satisfaction with Life Scale (SWLS). After controlling for gender, social class of origin, childhood cognitive ability, and educational attainment, adolescent emotional problems were independently inversely associated with mental wellbeing and with life satisfaction. Symptoms of anxiety/depression at 60-64 years explained the association with life satisfaction but not with mental wellbeing. Associations between adolescent self-organisation and conduct problems and mental wellbeing and life satisfaction were of negligible magnitude, but higher childhood cognitive ability significantly predicted poor life satisfaction in early old age. Adolescent self-organisation and conduct problems may not be predictive of future mental wellbeing and life satisfaction. Adolescent emotional problems may be inversely associated with future wellbeing, and may be associated with lower levels of future life satisfaction through symptoms of anxiety/depression in early old age. Initiatives to prevent and treat emotional problems in adolescence may

Early psychomotor development of low-risk preterm infants: Influence of gestational age and gender.

PubMed

Romeo, Domenico M; Brogna, Claudia; Sini, Francesca; Romeo, Mario G; Cota, Francesco; Ricci, Daniela

2016-07-01

The influence of gestational age and gender in the neurodevelopment of infants during the first year of age is not yet fully elucidated. The purpose of this study was to identify the early occurrence of neurodevelopmental differences, between very preterm, late preterm and term born infants and the possible influence of the gender on the neurodevelopment in early infancy. A total of 188 low-risk infants, 69 very preterms, 71 late-preterms, and 48 term infants were assessed at 3, 6, 9, 12 months corrected age using the Hammersmith Infant Neurological Examination (HINE). At two years of age infants performed the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development. The main results indicate that both very preterms and late-preterms showed significant lower global scores than term born infants at each evaluation (p < 0.001) at HINE and namely, at 3 months for the subsections "cranial nerve" and "posture" and at every age for "tone"; no gender differences has been evidenced in neurological performances. At the MDI, very preterms showed significant lower scores (p < 0.01) than both late-preterm and term born infants; gender differences were observed for preterms only (very and late), with best performances for females. Our results point out the presence of gestational age and gender-dependent differences in the development of infants assessed during the first 2 years of life. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Stress in childhood, adolescence and early adulthood, and cortisol levels in older age.

PubMed

Harris, Mathew A; Cox, Simon R; Brett, Caroline E; Deary, Ian J; MacLullich, Alasdair M J

2017-03-01

The glucocorticoid hypothesis suggests that overexposure to stress may cause permanent upregulation of cortisol. Stress in youth may therefore influence cortisol levels even in older age. Using data from the 6-Day Sample, we investigated the effects of high stress in childhood, adolescence and early adulthood - as well as individual variables contributing to these measures; parental loss, social deprivation, school and home moves, illness, divorce and job instability - upon cortisol levels at age 77 years. Waking, waking +45 min (peak) and evening salivary cortisol samples were collected from 159 participants, and the 150 who were not using steroid medications were included in this study. After correcting for multiple comparisons, the only significant association was between early-adulthood job instability and later-life peak cortisol levels. After excluding participants with dementia or possible mild cognitive impairment, early-adulthood high stress showed significant associations with lower evening and mean cortisol levels, suggesting downregulation by stress, but these results did not survive correction for multiple comparisons. Overall, our results do not provide strong evidence of a relationship between stress in youth and later-life cortisol levels, but do suggest that some more long-term stressors, such as job instability, may indeed produce lasting upregulation of cortisol, persisting into the mid-to-late seventies.

Stress in childhood, adolescence and early adulthood, and cortisol levels in older age

PubMed Central

Harris, Mathew A.; Cox, Simon R.; Brett, Caroline E.; Deary, Ian J.; MacLullich, Alasdair M. J.

2017-01-01

Abstract The glucocorticoid hypothesis suggests that overexposure to stress may cause permanent upregulation of cortisol. Stress in youth may therefore influence cortisol levels even in older age. Using data from the 6-Day Sample, we investigated the effects of high stress in childhood, adolescence and early adulthood – as well as individual variables contributing to these measures; parental loss, social deprivation, school and home moves, illness, divorce and job instability – upon cortisol levels at age 77 years. Waking, waking +45 min (peak) and evening salivary cortisol samples were collected from 159 participants, and the 150 who were not using steroid medications were included in this study. After correcting for multiple comparisons, the only significant association was between early-adulthood job instability and later-life peak cortisol levels. After excluding participants with dementia or possible mild cognitive impairment, early-adulthood high stress showed significant associations with lower evening and mean cortisol levels, suggesting downregulation by stress, but these results did not survive correction for multiple comparisons. Overall, our results do not provide strong evidence of a relationship between stress in youth and later-life cortisol levels, but do suggest that some more long-term stressors, such as job instability, may indeed produce lasting upregulation of cortisol, persisting into the mid-to-late seventies. PMID:28140738

Xenohormesis in early life: New avenues of research to explore anti-aging strategies through the maternal diet.

PubMed

de Medina, Philippe

2017-11-01

Aging is a progressive internal physiological deterioration of the organism, leading to the occurrence of age-related lethal diseases. It has become a major societal challenge to understand the processes that drive aging and to develop rational pharmacological agents and dietary approaches to fight against age-related deterioration and diseases. Interestingly, several lines of evidence highlight an influence of the developmental period on the risk of age-related diseases later in life. This field is known as the developmental origins of health and disease. Following this logic, studying the modification of maternal diet during early life may provide innovative new anti-aging approaches. Nutritional and psychological stresses during gestation are associated with poorer offspring health conditions in late life, and must be avoided during pregnancy. Besides these recommendations, very little has been published about the possible use of maternal diet to program offspring for healthy aging and an extended lifespan. Such health benefits may be provided by different foreign molecules, and particularly the phytochemicals produced by stressed plants, or xenohormetins. The xenohormesis hypothesis proposes that xenohormetins are signals of environmental change and trigger a beneficial adaptive response in individuals who consume them. No studies to date have investigated whether the consumption of stressed plants during pregnancy and lactation could provide chemical cues that impact early life programming and thus influence the future health and lifespan of offspring. Investigating the effect of xenohormesis in early life will involve adding edible plants exposed to different stressors (i.e. UV light, heat, ozone, etc.) to maternal diet and the exposure of offspring to this xenohormetin-enriched maternal diet at different periods of their prenatal life. The hypothesis proposed in this article is a potential tool to decipher the possible impact of xenohormesis during early

Community factors shaping early age at first sex among adolescents in Burkina Faso, Ghana, Malawi, and Uganda.

PubMed

Stephenson, Rob; Simon, Calleen; Finneran, Catherine

2014-06-01

Using data from the National Survey of Adolescents (2004), we examine the community-level factors associated with early age at first sex among adolescents 14-19 years old in four African countries. Regression models are fitted separately by sex for each country for an outcome measuring early age at first sex, with a focus on community-level factors as potential influences of age on sexual debut. The community-level factors associated with adolescents' sexual debut vary widely by both country and gender. Community influences that emerge as risk or protective factors of early sexual debut include community levels of adolescent marriage, wealth, religious group affiliation, sex education, parental monitoring, reproductive health knowledge, media exposure, membership in adolescent social group, and use of alcohol. Results indicate the importance of context-specific understanding of adolescents' sexual behaviour and suggest how elements of place should be harnessed in the development of effective HIV and sexual health interventions.

Effects of comorbidity and early age of onset in young people with Bipolar Disorder on self harming behaviour and suicide attempts.

PubMed

Moor, Stephanie; Crowe, Marie; Luty, Sue; Carter, Janet; Joyce, Peter R

2012-02-01

The age of the first episode of illness in Bipolar Disorder has been shown to be an important predictor of outcome with early onset, particularly onset before puberty, associated with greater comorbidity, a poorer quality of life and greatest impairment in functioning. Baseline data from a psychotherapy study was used to examine the prevalence of other comorbid psychiatric conditions and the impact of onset at an early age on both self harming behaviour and suicide attempts in young people with Bipolar Disorder. This study of 100 adolescents and young adults (aged 15-36 years) with Bipolar Disorder showed that comorbid conditions were very common, even at the start of their bipolar illness. Comorbidity increased as the age of onset decreased with very early onset (<13 years) patients bearing the greatest burden of disease. Greater comorbidity also significantly increased the risk of having self harmed and attempted suicide with high lethal intent. Self harming behaviour was predicted by having a lifetime diagnoses of Borderline Personality Disorder and Panic Disorder along with an early age of onset of Bipolar Disorder. In contrast, previous suicide attempts were predicted by greater comorbidity and not by very early (<13 years) age of onset. Copyright © 2011 Elsevier B.V. All rights reserved.

Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

NASA Astrophysics Data System (ADS)

Chaunsali, Piyush

Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement

Lithospheric mantle structure beneath Northern Scotland: Pre-plume remnant or syn-plume signature?

NASA Astrophysics Data System (ADS)

Knapp, J.

2003-04-01

Upper mantle reflectors (Flannan and W) beneath the northwestern British Isles are some of the best-known and most-studied examples of preserved structure within the continental mantle lithosphere, and are spatially coincident with the surface location of early Iceland plume volcanism in the British Tertiary Province. First observed on BIRPS (British Institutions Reflection Profiling Syndicate) marine deep seismic reflection profiles in the early 1980's, these reflectors have subsequently been imaged and correlated on additional reflection and refraction profiles in the offshore area of northern and western Scotland. The age and tectonic significance of these reflectors remains a subject of wide debate, due in part to the absence of robust characterization of the upper mantle velocity structure in this tectonically complex area. Interpretations advanced over the past two decades for the dipping Flannan reflector range from fossilized subduction complex to large-scale extensional shear zone, and span ages from Proterozoic to early Mesozoic. Crustal geology of the region records early Paleozoic continental collision and late Paleozoic to Mesozoic extension. Significant modification of the British lithosphere in early Tertiary time, including dramatic thinning and extensive basaltic intrusion associated with initiation and development of the Iceland plume, suggests either (1) an early Tertiary age for the Flannan reflector or (2) preservation of ancient features within the mantle lithosphere despite such pervasive modification. Exisitng constraints are consistent with a model for early Tertiary origin of the Flannan reflector as the downdip continuation of the Rockall Trough extensional system of latest Cretaceous to earliest Tertiary age during opening of the northern Atlantic Ocean and initiation of the Iceland plume. Lithopsheric thinning beneath present-day northern Scotland could have served to focus the early expression of plume volcanism (British Tertiary

Early Parental Abuse and Daily Assistance to Aging Parents With Disability: Associations With the Middle-Aged Adults' Daily Well-being.

PubMed

Liu, Yin; Kong, Jooyoung; Bangerter, Lauren R; Zarit, Steven H; Almeida, David M

2018-01-09

The current study examined the within-person association between providing daily assistance to aging parents with disability and adult children's daily mood in the context of early relationship with parents. We used data from 782 participants and 5,758 daily interviews from the Midlife in the United States (MIDUS) Refresher, with 248 people self-reported providing daily assistance ranging from 1 to 8 days out of the entire daily-interview period. Multilevel models were fit to examine the moderating effect of physical and emotional abuse from parents in early life on the associations between daily assistance to parents today and yesterday and daily mood. Additional analyses were conducted to examine whether the moderating effect of parental abuse remained when the assistance was provided for other family members and friends. Providing assistance today and yesterday to parents had immediate and lagged associations with higher negative affect when adult children experienced childhood emotional abuse from parents. No significant findings were found for daily positive affect. The moderating effect of parental abuse became nonsignificant when the assistance was provided to other family members or friends. Daily assistance to parents with disability needs to be examined in the context of the relationship history with parents. The impact of childhood abuse can linger long after the actual incident. Frequent early emotional abuse from parents was associated with greater distress when the middle-aged provided daily assistance to their aging parents. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Three-Dimensional Seismic Imaging of Eastern Russia

DTIC Science & Technology

2008-09-01

small blocks or microplates within the ancient suture and present-day plate boundary zones. We assembled catalog picks from ~13,000 events and ~100... oceanic fragments that have been disrupted, deformed, and juxtaposed. The Kolyma-Omolon superterrane consists of a number of cratonal (Omolon...Prikolyma), continental margin (Omulevka), island arc (Alazeya, Khetachan), and oceanic terranes of diverse ages that amalgamated in the Early Mesozoic

Mesozoic Crustal Thickening of the Longmenshan Belt (NE Tibet, China) by Imbrication of Basement Slices: Insights From Structural Analysis, Petrofabric and Magnetic Fabric Studies, and Gravity Modeling

NASA Astrophysics Data System (ADS)

Xue, Zhenhua; Martelet, Guillaume; Lin, Wei; Faure, Michel; Chen, Yan; Wei, Wei; Li, Shuangjian; Wang, Qingchen

2017-12-01

This work first presents field structural analysis, anisotropy of magnetic susceptibility (AMS) measurements, and kinematic and microstructural studies on the Neoproterozoic Pengguan complex located in the middle segment of the Longmenshan thrust belt (LMTB), NE Tibet. These investigations indicate that the Pengguan complex is a heterogeneous unit with a ductilely deformed NW domain and an undeformed SE domain, rather than a single homogeneous body as previously thought. The NW part of the Pengguan complex is constrained by top-to-the-NW shearing along its NW boundary and top-to-the-SE shearing along its SE boundary, where it imbricates and overrides the SE domain. Two orogen-perpendicular gravity models not only support the imbricated shape of the Pengguan complex but also reveal an imbrication of high-density material hidden below the Paleozoic rocks on the west of the LMTB. Regionally, this suggests a basement-slice-imbricated structure that developed along the margin of the Yangtze Block, as shown by the regional gravity anomaly map, together with the published nearby seismic profile and the distribution of orogen-parallel Neoproterozoic complexes. Integrating the previously published ages of the NW normal faulting and of the SE directed thrusting, the locally fast exhumation rate, and the lithological characteristics of the sediments in the LMTB front, we interpret the basement-slice-imbricated structure as the result of southeastward thrusting of the basement slices during the Late Jurassic-Early Cretaceous. This architecture makes a significant contribution to the crustal thickening of the LMTB during the Mesozoic, and therefore, the Cenozoic thickening of the Longmenshan belt might be less important than often suggested.

Self-healing of early age cracks in cement-based materials by mineralization of carbonic anhydrase microorganism

PubMed Central

Qian, Chunxiang; Chen, Huaicheng; Ren, Lifu; Luo, Mian

2015-01-01

This research investigated the self-healing potential of early age cracks in cement-based materials incorporating the bacteria which can produce carbonic anhydrase. Cement-based materials specimens were pre-cracked at the age of 7, 14, 28, 60 days to study the repair ability influenced by cracking time, the width of cracks were between 0.1 and 1.0 mm to study the healing rate influenced by width of cracks. The experimental results indicated that the bacteria showed excellent repairing ability to small cracks formed at early age of 7 days, cracks below 0.4 mm was almost completely closed. The repair effect reduced with the increasing of cracking age. Cracks width influenced self-healing effectiveness significantly. The transportation of CO2and Ca2+ controlled the self-healing process. The computer simulation analyses revealed the self-healing process and mechanism of microbiologically precipitation induced by bacteria and the depth of precipitated CaCO3 could be predicted base on valid Ca2+. PMID:26583014

Evaluation of Standardized Instruments for Use in Universal Screening of Very Early School-Age Children: Suitability, Technical Adequacy, and Usability

ERIC Educational Resources Information Center