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Sample records for miocene hawthorn group

  1. Natural Arsenic in the Miocene Hawthorn Group, Florida: Wide Ranging Implications for ASR, Phosphate Mining, Private Well

    NASA Astrophysics Data System (ADS)

    Lazareva, O. V.; Pichler, T.

    2004-12-01

    In order to understand the mineralogical association and distribution of arsenic (As) in the Hawthorn Group we examined in detail the chemical and mineralogical composition of 370 samples that were collected from 16 cores in central Florida. In our study area the Hawthorn group consists primarily of a basal carbonate unit (the Arcadia Formation) and an upper siliciclastic unit (The Peace River Formation). The Peace River Formation contains appreciable amounts of phosphate and is currently being exploited for phosphate ore. Samples were taken for each Formation at intervals of 25ft. In addition to the interval samples we also took samples that contained visible pyrite crystals, iron oxides, green clays, phosphatic and organic material. These additional samples were collected because of their potential of high As concentrations. Arsenic concentrations were determined by hydride generation - atomic fluorescence spectrometry (HG-AFS) after digestion with aqua regia (3:1 HCl and HNO3). The elements Fe, Na, Al, Si, Mg, Ca, S, P, and K were measured on the same solutions by inductively coupled plasma optical emission spectrometry (ICP-OES). The identification of discrete minerals was aided by scanning electron microscopy (SEM) and chemical compositions were obtained by electron-probe microanalyses (EMPA). Our study indicates that the average As concentrations significantly change from 9.0 ppm in the Peace River Formation to 3.0 ppm in the Tampa Member of the Arcadia Formation. As concentrations for all Hawthorn samples vary from 0.07 to 68.98 ppm ( μ = 5.6, σ = 7.1). Our detailed mineralogical and geochemical study demonstrates that: (1) The As in the Hawthorn group varies from the formation to formation and is mostly concentrated in trace minerals, such as pyrite; (2) Concentrations of the As in pyrite crystals can vary drastically from a minimum of 0 ppm to a maximum of 8260 ppm; (3) Pyrite is an unevenly distributed throughout the Hawthorn Group; (4) Phosphate and

  2. Origin of dolomite in the phosphatic Hawthorne Group of Florida

    SciTech Connect

    Compton, J.S.; Hall, D.L.; Mallinson, D.J. . Dept. of Marine Science); Hodell, D.A. . Dept. of Geology)

    1994-07-01

    In addition to large amounts of phosphorite, the Miocene Hawthorn Group of Florida contains abundant dolomite. Dolomite is present as disseminated silt-size rhombs, as friable dolosilt beds, and as pore-filling cement in dolostone beds and clasts. The dolomite formed during early burial diagenesis both in the sulfate-reduction zone, overlapping and extending below sediment depths of phosphorite formation, and in adjacent, nonphosphatic, shallow-water lagoonal environments. Much of the dolomite is closely associated with the fibrous, Mg-rich clay minerals palygorskite and sepiolite. The percent carbonate in the Hawthorn Group increases from north to south; the dominant carbonate mineral in north Florida is dolomite, whereas dolomite and calcite are both abundant in south Florida. The [delta][sup 13]C values of the dolomite, from +1.82 to [minus]6.21[per thousand] PDB, suggest that metastable biogenic carbonate (aragonite and high-Mg calcite) and seawater were the predominant sources of carbonate. However, negative [delta][sup 13]C values of dolomite from northeast Florida suggest that as much as 30--40% of the carbonate was derived from degradation of organic matter. Degradation of organic matter enhanced dolomitization by removing sulfate ion and increasing the carbonate alkalinity of the pore waters. The oxygen and strontium isotopic values along with moderate Na contents indicate a marine origin. Evaporation of seawater or mixing of seawater and meteoric water were apparently not major factors in dolomite formation. The presence of dolomite, along with phosphorite, in reworked sequences can indicate deposition of organic-rich sediments from which most of the organic matter has since been removed.

  3. The Phyllomedusa perinesos group (Anura: Hylidae) is derived from a Miocene Amazonian Lineage.

    PubMed

    Ron, Santiago R; Almendariz, Ana; Cannatella, David C

    2013-11-27

    The Phyllomedusa perinesos group is composed of four species that inhabit cloud forests in the eastern Andean slopes. We estimated the phylogenetic relationships among them and their closest relatives using mitochondrial DNA sequences. Our results confirm the monophyly of the group and a close relationship with the Amazonian species Phyllomedusa atelopoides and Phyllomedusa tomopterna. A chronogram indicates that the group originated during the Miocene and the contemporary species diverged from their closest relatives during the Miocene and early Pliocene. The timing of the group's origin suggests that its evolution was linked to the rise of the eastern Andes. Based on the phylogeny we expand the species content of the group to include P. atelopoides and P. tomopterna.

  4. The Miocene Topanga Group of Southern California - A 100-Year History of Changes in Stratigraphic Nomenclature

    USGS Publications Warehouse

    Campbell, Russell H.; McCulloh, Thane H.; Vedder, John G.

    2007-01-01

    A review of selected literature summarizes the origin and chronology of changes in usage of 'Topanga' in the Miocene stratigraphic nomenclature of the Los Angeles Basin and adjacent areas in southern California. The review was done to summarize and reconcile some differences in Miocene stratigraphic nomenclature as applied to geologic map compilations of the Santa Ana (Morton, 2004), San Bernardino (Morton and Miller, 2003), Long Beach (Saucedo and others, 2003) and Los Angeles (Yerkes and Campbell, 2005) 30' x 60' quadrangles, all of which are products of the cooperative (California Geological Survey-U.S. Geological Survey) Southern California Areal Mapping Project (SCAMP). The deposition of the Topanga Group spans about 6 my (from as old as about 18 ma to as young as about 12 ma), and the sequence of included strata records changes in provenance and depositional environments that are contemporaneous with part of a major Miocene tectonic episode in southern California -- the 'basin-inception phase' in the evolution of the Neogene Los Angeles basin (Yerkes and others, 1965). The area of Topanga deposition extends to the southern, eastern, northern, and northwestern sides of the Los Angeles basin, as well as the southern part of the eastern Ventura Basin. Topanga beds are inferred to underlie the thick upper Miocene and Pliocene deposits of the central Los Angeles Basin and the southern part of the eastern Ventura Basin; however, they have been reached by drilling only in marginal areas, where the overlying deposits are relatively thin. Post-Topanga strata were deposited in more-restricted areas of rapid subsidence. Selected papers are summarized as they relate to the Topanga nomenclature, and are presented in chronological order.

  5. Depositional environments and paleogeography of the Upper Miocene Wassuk Group, west-central Nevada

    USGS Publications Warehouse

    Golia, R.T.; Stewart, John H.

    1984-01-01

    Fluvial and lacustrine deposits of the Miocene Wassuk Group, exposed in Coal Valley, west-central Nevada, are divided into five lithofacies: (1) diatomite, claystone, siltstone, and carbonaceous siltstone deposited in a lake with paludal conditions at the margin; (2) upward-coarsening sequences of sandstone deposited on a delta and fan-delta; (3) channel-form sandstone deposited on a distal braided alluvial plain; (4) clast-supported conglomerate deposited on a proxial braided alluvial plain or distal alluvial fan; and (5) matrix-supported conglomerate deposited on a distal to middle alluvial fan. Petrographic analysis records an upsection change from a predominantly andesitic to a predominantly plutonic provenance. This change, combined with the overall upward-coarsening of the Wassuk Group and the great thickness (2400 m) of the sequence, suggests active uplift and rapid subsidence during deposition of the group. Facies relationships and paleocurrent directions indicate source areas to the south, southeast and west of Coal Valley. The Miocene Wassuk Group was deposited in an intra-arc basin with penecontemporaneous volcanism and tectonic activity. Syndepositional faulting at the southern margin of Coal Valley between 13 and 11 m.y. ago suggests an early episode of northeast-southwest extension prior to the onset of east-west basin and range extension. ?? 1984.

  6. Process Writing with Hawthorne.

    ERIC Educational Resources Information Center

    Edwards, Lita R.

    Teachers can use the process writing format for many assignments to teach and refine more skills than are often incorporated in older methods, and this is exemplified by a teaching unit comparing two short stories by Nathaniel Hawthorne. Peer conferences and peer editing in the revision stages, which are features of the process model, can lead to…

  7. Funalichnus bhubani isp. nov. from Bhuban Formation, Surma Group (Lower -Middle Miocene) of Aizawl, Mizoram, India.

    PubMed

    Tiwari, Raghavendra Prasad; Rajkonwar, Chinmoy; Patel, Satish Jaychandbhai

    2013-01-01

    A new ichnospecies of the ichnogenus Funalichnus Pokorný is described from the Middle Bhuban Unit, Bhuban Formation, Surma Group (Lower - Middle Miocene) of Aizawl, Mizoram, India. Funalichnus bhubani isp. Nov. Is a large burrow displaying cylindrical segments that are oriented nearly perpendicular to the bedding plane. The new ichnospecies can be identified on the basis of general form, size, unlined passive filling and twisted rod-like structure. The association of Funalichnus bhubani isp. Nov. With Arenicolites, Diplocraterion, Ophiomorpha Psilonichnus Skolithos and Thalassinoides points to its bathymetric restriction. The deep extension of the burrow in clastic sediments provides a favourable condition for preservation in the shoreface environment and occurrence in fine- to medium-grained clastic sediments may be a preservational preference.

  8. Funalichnus bhubani isp. nov. from Bhuban Formation, Surma Group (Lower -Middle Miocene) of Aizawl, Mizoram, India

    PubMed Central

    Tiwari, Raghavendra Prasad; Rajkonwar, Chinmoy; Patel, Satish Jaychandbhai

    2013-01-01

    A new ichnospecies of the ichnogenus Funalichnus Pokorný is described from the Middle Bhuban Unit, Bhuban Formation, Surma Group (Lower - Middle Miocene) of Aizawl, Mizoram, India. Funalichnus bhubani isp. Nov. Is a large burrow displaying cylindrical segments that are oriented nearly perpendicular to the bedding plane. The new ichnospecies can be identified on the basis of general form, size, unlined passive filling and twisted rod-like structure. The association of Funalichnus bhubani isp. Nov. With Arenicolites, Diplocraterion, Ophiomorpha Psilonichnus Skolithos and Thalassinoides points to its bathymetric restriction. The deep extension of the burrow in clastic sediments provides a favourable condition for preservation in the shoreface environment and occurrence in fine- to medium-grained clastic sediments may be a preservational preference. PMID:24204992

  9. What Caused the Hawthorne Effect?

    ERIC Educational Resources Information Center

    Parsons, H. McIlvaine

    1978-01-01

    Together, information feedback and differential reward could account for the gradually increasing productivity in the Hawthorne plant, especially in an explanatory framework of response shaping in operant conditioning. (Author/IRT)

  10. Calcareous nannofossil assemblages of the upper Miocene to Pliocene Shimajiri Group on Okinawa-jima, Ryukyu Islands, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Imai, Ryo; Sato, Tokiyuki; Iryu, Yasufumi

    2017-03-01

    We investigated the calcareous nannofossil biostratigraphy and paleoceanography of the Shimajiri Group in two exploratory wells (depths, 1243 and 1800 m) drilled on southern Okinawa-jima, Ryukyu Islands, southwestern Japan. Three late Miocene to Pliocene datum planes were identified: the first occurrence of Amaurolithus spp. (7.42 Ma), the last occurrence of Discoaster quinqueramus (5.59 Ma), and the first occurrence of Ceratolithus rugosus (5.12 Ma). These datum planes were also identified in two other deep wells on southern Okinawa-jima. Nutrient levels (reconstructed from the relative abundances of small Reticulofenestra spp., and the relative abundances of Discoaster spp. plus Sphenolithus abies) suggest that deposition of the Shimajiri Group (<8.29-3.50 Ma) occurred under conditions of increasing eutrophication. The eutrophication was likely caused by shallowing of the sedimentary basin, but a stepwise shift was associated with an abrupt eutrophication event that occurred in the northwestern Pacific Ocean at 5 Ma.

  11. Hawthorn Fruit Extract Elevates Expression of Nrf2/HO-1 and Improves Lipid Profiles in Ovariectomized Rats

    PubMed Central

    Yoo, Jeong-Hyun; Liu, Yanan; Kim, Hyun-Sook

    2016-01-01

    The purpose of this study was to investigate the effects of hawthorn (Crataegus pinnatifida Bunge) extract on the lipid profiles and antioxidant properties in ovariectomized (OVX) rats. After ovariectomy, the rats were randomly divided into four groups: the non-OVX control (Sham), the OVX-control (OVX), the OVX + 100 mg/kg b.w. of hawthorn extract (OL), and the OVX + 200 mg/kg b.w. of hawthorn extract (OH). The final body weights of the OVX group were significantly increased, but the increment was significantly decreased in hawthorn groups (p < 0.05). The serum total and low-density lipoprotein (LDL) cholesterol levels were significantly elevated in the OVX group, whereas the hawthorn groups showed a significant decrease in these levels (p < 0.05). The hepatic triglyceride (TG) and malondialdehyde (MDA) levels were significantly reduced in the hawthorn groups compared with the OVX group (p < 0.05). The mRNA expression of nuclear factor erythroid 2–related factor (Nrf2), heme oxygenase-1 (HO-1), and glutathione peroxidase (GPx) were significantly decreased in the OVX group, whereas the hawthorn groups exhibited a significant increase in expression (p < 0.05). The protein expressions of Nrf2, HO-1, and GPx were lower in the OVX group than the Sham group (p < 0.05). The oral administration of hawthorn extract reversed the suppression of protein levels. These results suggest that hawthorn extract could have protective effects in OVX rats by improving lipid profiles, decreasing oxidative stress, and improving the antioxidant defense system. PMID:27187458

  12. Hawthorn Fruit Extract Elevates Expression of Nrf2/HO-1 and Improves Lipid Profiles in Ovariectomized Rats.

    PubMed

    Yoo, Jeong-Hyun; Liu, Yanan; Kim, Hyun-Sook

    2016-05-13

    The purpose of this study was to investigate the effects of hawthorn (Crataegus pinnatifida Bunge) extract on the lipid profiles and antioxidant properties in ovariectomized (OVX) rats. After ovariectomy, the rats were randomly divided into four groups: the non-OVX control (Sham), the OVX-control (OVX), the OVX + 100 mg/kg b.w. of hawthorn extract (OL), and the OVX + 200 mg/kg b.w. of hawthorn extract (OH). The final body weights of the OVX group were significantly increased, but the increment was significantly decreased in hawthorn groups (p < 0.05). The serum total and low-density lipoprotein (LDL) cholesterol levels were significantly elevated in the OVX group, whereas the hawthorn groups showed a significant decrease in these levels (p < 0.05). The hepatic triglyceride (TG) and malondialdehyde (MDA) levels were significantly reduced in the hawthorn groups compared with the OVX group (p < 0.05). The mRNA expression of nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase-1 (HO-1), and glutathione peroxidase (GPx) were significantly decreased in the OVX group, whereas the hawthorn groups exhibited a significant increase in expression (p < 0.05). The protein expressions of Nrf2, HO-1, and GPx were lower in the OVX group than the Sham group (p < 0.05). The oral administration of hawthorn extract reversed the suppression of protein levels. These results suggest that hawthorn extract could have protective effects in OVX rats by improving lipid profiles, decreasing oxidative stress, and improving the antioxidant defense system.

  13. The Hawthorne Effect: a randomised, controlled trial

    PubMed Central

    McCarney, Rob; Warner, James; Iliffe, Steve; van Haselen, Robbert; Griffin, Mark; Fisher, Peter

    2007-01-01

    Background The 'Hawthorne Effect' may be an important factor affecting the generalisability of clinical research to routine practice, but has been little studied. Hawthorne Effects have been reported in previous clinical trials in dementia but to our knowledge, no attempt has been made to quantify them. Our aim was to compare minimal follow-up to intensive follow-up in participants in a placebo controlled trial of Ginkgo biloba for treating mild-moderate dementia. Methods Participants in a dementia trial were randomised to intensive follow-up (with comprehensive assessment visits at baseline and two, four and six months post randomisation) or minimal follow-up (with an abbreviated assessment at baseline and a full assessment at six months). Our primary outcomes were cognitive functioning (ADAS-Cog) and participant and carer-rated quality of life (QOL-AD). Results We recruited 176 participants, mainly through general practices. The main analysis was based on Intention to treat (ITT), with available data. In the ANCOVA model with baseline score as a co-variate, follow-up group had a significant effect on outcome at six months on the ADAS-Cog score (n = 140; mean difference = -2.018; 95%CI -3.914, -0.121; p = 0.037 favouring the intensive follow-up group), and on participant-rated quality of life score (n = 142; mean difference = -1.382; 95%CI -2.642, -0.122; p = 0.032 favouring minimal follow-up group). There was no significant difference on carer quality of life. Conclusion We found that more intensive follow-up of individuals in a placebo-controlled clinical trial of Ginkgo biloba for treating mild-moderate dementia resulted in a better outcome than minimal follow-up, as measured by their cognitive functioning. Trial registration Current controlled trials: ISRCTN45577048 PMID:17608932

  14. Vertebrate-bearing eolian unit from the Ogallala Group (Miocene) in northwestern Texas

    SciTech Connect

    Winkler, D.A.

    1987-08-01

    The upper Couch Formation is part of the lower of two formations composing the Ogallala Group in Blanco and Yellowhouse canyons in northwestern Texas. An eolian origin for the upper Couch Formation is indicated by its mean grain size, pedogenic carbonate nodules, massive bedding, and blanketlike morphology. The unit conforms poorly to the usual eolian depositional models; it resulted from a combination of the processes involved in loess and sand-sheet formation. Grassland or savanna vegetation probably existed over the area and aided in sediment trapping. Vertebrates are unusual in eolian units, but the adaptations and mode of preservation of those in the upper Couch Formation also support an eolian interpretation. This and other widespread silty sand sheets in the Ogallala indicate major fluctuations in depositional style, possibly climatically controlled. Lateral continuity and preservation of vertebrates give silty sand sheets great potential as correlation tools.

  15. Genetic relationships among some hawthorn (Crataegus spp.) species and genotypes.

    PubMed

    Yilmaz, Kadir Ugurtan; Yanar, Makbule; Ercisli, Sezai; Sahiner, Hatice; Taskin, Tuncer; Zengin, Yasar

    2010-10-01

    The genus Crataegus is well distributed in Turkey as a wild plant, with numerous, inherently variable species and genotypes. RAPD markers were used to study 17 hawthorn genotypes belonging to Crataegus monogyna ssp. monogyna Jacq (2 genotypes), C. monogyna ssp. azarella Jacq (1), Crataegus pontica K.Koch (3), Crataegus orientalis var. orientalis Pallas Ex Bieb (3), Crataegus pseudoheterophylla Pojark (1), Crataegus aronia var. dentata Browicz (1), C. aronia var. aronia Browicz (4), and Crateagus x bornmuelleri Zabel (2). The 10 RAPD primers produced 72 polymorphic bands (88% polymorphism). A dendrogram based on Jaccard's index included four major groups and one outgroup according to taxa. The lowest genetic variability was observed within C. aronia var. aronia genotypes. The study demonstrated that RAPD analysis is efficient for genotyping wild-grown hawthorns.

  16. Correlation and analysis of Miocene paleochannels in the central Sierra Nevada, California, as displayed by the Stanislaus Group

    NASA Astrophysics Data System (ADS)

    Jones, S.; Pluhar, C. J.; Farner, M. J.; Deino, A. L.

    2013-12-01

    The proposed Neogene uplift of the Sierra Nevada has been debated for several decades. Although multiple lines of evidence indicate substantial uplift of the Sierran crest over the last ten million years, recent isotopic and paleobotanical methods have called the validity of these calculations into question. Our study focuses on the discontinuous units of the Miocene Stanislaus Group: Table Mountain Formation lavas, Dardenelles Formation lavas, and Eureka Valley Tuff (EVT) lava and tuffs. These units are significant because they have been used as a tilt indicator to calculate the uplift of the Sierra Nevada crest since their emplacement, 9.0-10.2 million years ago. Our research increased the quantity of primary data, which will be used to develop and verify a digitally-derived model of the paleodrainage systems of the ancient Sierra Nevada. The localities, Dorrington, Pikes Peak, Rancheria Mountain, Three Chimneys, and Sonora Pass are significant because they may represent the few remaining Table Mountain Formation (trachyandesite) outcrops of previously unmapped paleodrainage channels. To test this hypothesis, geochemical and paleomagnetic data were used to correlate the localities and thereby reconstruct the paleochannels. Outcrops near Dorrington, California contain biotite, display eutaxitic textures and are characterized by a reverse polarity indistinguishable from the Tollhouse Flat Member of the EVT. Previously mapped as Table Mountain Latite, we reclassify these units as Tollhouse Flat Member and eliminate the hypothesis that the units were once part of a potentially lava-back-flooded tributary of the paleo-Stanislaus River. The high potassium, columnar jointed lava at Pikes Peak, exhibits normal polarity; it is plausibly part of the Stanislaus Group and may be correlated to flows along the main 'cataract channel' of the Stanislaus Group. Results from Rancheria Mountain verify the presence of Stanislaus Group lavas and the EVT, previously mapped by Huber et

  17. Interaction study between digoxin and a preparation of hawthorn (Crataegus oxyacantha).

    PubMed

    Tankanow, Roberta; Tamer, Helen R; Streetman, Daniel S; Smith, Scott G; Welton, Janice L; Annesley, Thomas; Aaronson, Keith D; Bleske, Barry E

    2003-06-01

    Hawthorn, an herbal supplement, is currently being evaluated for the treatment of heart failure. The flavonoid components of hawthorn may be responsible for hawthorn's beneficial effects in the treatment of heart failure. However, these components may also affect P-glycoprotein function and cause interactions with drugs that are P-glycoprotein substrates, such as digoxin, which is also used to treat heart failure. Therefore, the purpose of this study was to determine the effect of hawthorn on digoxin pharmacokinetic parameters. A randomized, crossover trial with 8 healthy volunteers was performed evaluating digoxin 0.25 mg alone (D) for 10 days and digoxin 0.25 mg with Crataegus special extract WS 1442 (hawthorn leaves with flowers; Dr. Willmar Schwabe Pharmaceuticals) 450 mg twice daily (D + H) for 21 days. Pharmacokinetic studies were performed for 72 hours. There were no statistically significant differences in any measured pharmacokinetic parameters. The AUC0-infinity, Cmax-Cmin, Cmin, and renal clearance for the D group were 79 +/- 26 mcg.h/L, 1.4 +/- 0.7 mcg/L, 0.84 +/- 0.2 mcg/L, and 74 +/- 10 mL/min versus 73 +/- 20 mcg.h/L, 1.1 +/- 0.1 mcg/L, 0.65 +/- 0.2 mcg/L, and 81 +/- 22 mL/min for the D + H group, respectively (p > 0.05). Following 3 weeks of concomitant therapy, hawthorn did not significantly alter the pharmacokinetic parameters for digoxin. This suggests that both hawthorn and digoxin, in the doses and dosage form studied, may be coadministered safely.

  18. Composition and health effects of phenolic compounds in hawthorn (Crataegus spp.) of different origins.

    PubMed

    Yang, Baoru; Liu, Pengzhan

    2012-06-01

    Epicatechin, aglycons and glycosides of B-type oligomeric procyanidins and flavonols, phenolic acids and C-glycosyl flavones are the major groups of phenolic compounds in hawthorn (Crataegus spp). The total content of phenolic compounds is higher in the leaves and flowers than in the fruits. Procyanidins dominate in the fruits, whereas flavonol glycosides and C-glycosyl flavones are most abundant in the leaves. Genotype and developmental/ripening stage have strong impacts. Procyanidin glycosides and C-glycosyl flavones may be chemotaxonomic markers differentiating species and varieties of hawthorn. Future research shall improve the separation, identification and quantification of procyanidins with degree of polymerisation (DP) ≥ 6, procyanidin glycosides, C-glycosyl flavones and some flavonol glycosides. In vitro and animal studies have shown cardioprotective, hypolipidaemic, hypotensive, antioxidant, radical-scavenging and anti-inflammatory potentials of hawthorn extracts, suggesting different phenolic compounds as the major bioactive components. However, the varying and insufficiently defined composition of the extracts investigated, as a result of different raw materials and extraction methods, makes comparison of the studies very difficult. Clinical evidence indicates that some hawthorn extracts may increase the exercise tolerance of patients with congestive heart failure. More clinical studies are needed to establish the effects of hawthorn, especially in healthy humans.

  19. A "H--ll-Fired Story": Hawthorne's Rhetoric of Rumor.

    ERIC Educational Resources Information Center

    Harshbarger, Scott

    1994-01-01

    Considers Nathaniel Hawthorne's literary technique of providing various, often conflicting, accounts of a narrative scene or event. Analyzes Hawthorne's rhetoric of rumor as featured in "The Scarlet Letter." Shows how Hawthorne tried to translate the dynamics of interpersonal communication into print in this novel. (HB)

  20. The Hawthorne effect and energy awareness

    PubMed Central

    Schwartz, Daniel; Fischhoff, Baruch; Krishnamurti, Tamar; Sowell, Fallaw

    2013-01-01

    The feeling of being observed or merely participating in an experiment can affect individuals’ behavior. Referred to as the Hawthorne effect, this inconsistently observed phenomenon can both provide insight into individuals' behavior and confound the interpretation of experimental manipulations. Here, we pursue both topics in examining how the Hawthorne effect emerges in a large field experiment focused on residential consumers’ electricity use. These consumers received five postcards notifying, and then reminding, them of their participation in a study of household electricity use. We found evidence for a Hawthorne (study participation) effect, seen in a reduction of their electricity use—even though they received no information, instruction, or incentives to change. Responses to a follow-up survey suggested that the effect reflected heightened awareness of energy consumption. Consistent with that interpretation, the treatment effect vanished when the intervention ended. PMID:24003110

  1. 77 FR 64889 - Amendment of Class D and Class E Airspace; Hawthorne, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-24

    ... Administration 14 CFR Part 71 Amendment of Class D and Class E Airspace; Hawthorne, CA AGENCY: Federal Aviation... description for Class D and Class E airspace at Jack Northrop Field/Hawthorne Municipal Airport, Hawthorne, CA... Class D and E airspace at Jack Northrop Field/Hawthorne Municipal Airport, Hawthorne, CA. The...

  2. Genetic diversity analysis of fruit characteristics of hawthorn germplasm.

    PubMed

    Su, K; Guo, Y S; Wang, G; Zhao, Y H; Dong, W X

    2015-12-07

    One hundred and six accessions of hawthorn intraspecific resources, from the National Germplasm Repository at Shenyang, were subjected to genetic diversity and principal component analysis based on evaluation data of 15 fruit traits. Results showed that the genetic diversity of hawthorn fruit traits varied. Among the 15 traits, the fruit shape variable coefficient had the most obvious evaluation, followed by fruit surface state, dot color, taste, weight of single fruit, sepal posture, peduncle form, and metula traits. These are the primary traits by which hawthorn could be classified in the future. The principal component demonstrated that these traits are the most influential factors of hawthorn fruit characteristics.

  3. 75 FR 17406 - Hawthorn Oil Transportation; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hawthorn Oil Transportation; Notice of Filing March 31, 2010. Take notice that on February 12, 2010, Hawthorn Oil Transportation submitted a request for the waiver of...

  4. Secular variation of the middle and late Miocene geomagnetic field recorded by the Columbia River Basalt Group in Oregon, Idaho and Washington, USA

    NASA Astrophysics Data System (ADS)

    Dominguez, Ada R.; Van der Voo, Rob

    2014-06-01

    This study of 118 discrete volcanic flows from the Columbia River Basalt Group is aimed to determine their distribution of geomagnetic field directions and virtual geomagnetic poles (VGPs) and to compare the inherent secular variation parameters with those from other studies. The magnetic signature of these rocks is uniformly carried by primary titanomagnetite, indicating that magnetic changes are due to variations in the magnetic field. Although most flows are flat lying, those that are tilted pass the Tauxe and Watson tilt test. Sequential flows with statistically similar site means were grouped, and directions that were considered outliers were evaluated and removed using the Vandamme cut-off method. Three normal-polarity (N-polarity) and three reversed-polarity (R-polarity) intervals are revealed by the stratigraphically ordered flows and have mean directions of N polarity (dec/inc = 6.6°/+61.2°, k = 29.3, α95 = 4.2°), and R polarity (dec/inc = 178.2°/-59.2°, k = 16, α95 = 5.5°). Regression analysis indicates that the secular variation analysis has not been affected by regional rotation, and that apparent polar wander is negligible. The VGP distribution is almost perfectly circular and supports the preference of VGP positions for the dispersion analysis. Dispersion parameters with corrections for within-site scatter (Sb) show a range of 14.3°-25.5°, including error limits, and were consistently higher for R-polarity results than for those of N polarity. Published dispersion parameters for extrusives <5 Ma show Sb values slightly lower than ours, yielding values of 16°-19°, although the difference is not statistically significant. In contrast, published dispersion parameters from high quality data from the Cretaceous Normal Superchron are lower than those for the Neogene, which suggests that the noisiness of the magnetic field correlates with the frequency of reversals. Our new results allow us to extend the Plio-Pleistocene palaeosecular variation

  5. 77 FR 7525 - Revision of Class D and Class E Airspace; Hawthorne, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ... Class D and Class E airspace at Jack Northrop Field/Hawthorne Municipal Airport, Hawthorne, CA... Field/Hawthorne Municipal Airport airspace area that further enhances the safety and management of... designated as an extension to Class D surface area at Jack Northrop Field/Hawthorne Municipal...

  6. 76 FR 67103 - Proposed Revision of Class D and Class E Airspace; Hawthorne, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... (NPRM). SUMMARY: This action proposes to revise Class D and E airspace at Jack Northrop Field/Hawthorne... with a study of the Jack Northrop Field/Hawthorne Municipal Airport airspace area that would further... D surface area at Jack Northrop Field/Hawthorne Municipal Airport, Hawthorne, CA,...

  7. Tissue distribution comparison between healthy and fatty liver rats after oral administration of hawthorn leaf extract.

    PubMed

    Yin, Jingjing; Qu, Jianguo; Zhang, Wenjie; Lu, Dongrui; Gao, Yucong; Ying, Xixiang; Kang, Tingguo

    2014-05-01

    Hawthorn leaves, a well-known traditional Chinese medicine, have been widely used for treating cardiovascular and fatty liver diseases. The present study aimed to investigate the therapeutic basis treating fatty liver disease by comparing the tissue distribution of six compounds of hawthorn leaf extract (HLE) in fatty liver rats and healthy rats after oral administration at first day, half month and one month, separately. Therefore, a sensitive and specific HPLC method with internal standard was developed and validated to determine chlorogenic acid, vitexin-4''-O-glucoside, vitexin-2''-O-rhamnoside, vitexin, rutin and hyperoside in the tissues including heart, liver, spleen, kidney, stomach and intestine. The results indicated that the six compounds in HLE presented some bioactivity in treating rat fatty liver as the concentrations of the six compounds varied significantly in inter- and intragroup comparisons (healthy and/or fatty liver group).

  8. Effects of pretreatments on anthocyanin composition, phenolics contents and antioxidant capacities during fermentation of hawthorn (Crataegus pinnatifida) drink.

    PubMed

    Liu, Suwen; Chang, Xuedong; Liu, Xiufeng; Shen, Zhanwei

    2016-12-01

    The effect of microwave and heat pretreatment on the content and composition of anthocyanins, phenolics, and the antioxidant capacity of hawthorn drink were studied. Nine anthocyanins were isolated by chromatographic separation from the Zirou hawthorn source and their structure identified using HPLC-DAD-ESI/MS analysis. Heat and microwave pretreatments had a significant impact on the relative contents of hawthorn anthocyanins, such as cyanidin-3-galactoside (82.9% and 76.9%, respectively) and cyanidin-3-glucoside (9.2% and 11.5%, respectively). Pretreatment had no significant effect on pH, total soluble solid or total acid. More anthocyanins remained after heat treatment than after microwaving (0.745mg/100mL), and were 52.4% higher than the control group after storage for 7days. The colour density of the heat treated group was higher than the control group (24.5%) after 12days of fermentation. The main antioxidant capacities of the hawthorn drinks came from total polyphenolics rather than total anthocyanins or total flavonoids.

  9. Marine mammals from the Miocene of Panama

    NASA Astrophysics Data System (ADS)

    Uhen, Mark D.; Coates, Anthony G.; Jaramillo, Carlos A.; Montes, Camilo; Pimiento, Catalina; Rincon, Aldo; Strong, Nikki; Velez-Juarbe, Jorge

    2010-12-01

    Panama has produced an abundance of Neogene marine fossils both invertebrate (mollusks, corals, microfossils etc.) and vertebrate (fish, land mammals etc.), but marine mammals have not been previously reported. Here we describe a cetacean thoracic vertebra from the late Miocene Tobabe Formation, a partial cetacean rib from the late Miocene Gatun Formation, and a sirenian caudal vertebra and rib fragments from the early Miocene Culebra Formation. These finds suggest that Central America may yet provide additional fossil marine mammal specimens that will help us to understand the evolution, and particularly the biogeography of these groups.

  10. [Determination of amygdalin in hawthorn by high performance liquid chromatography].

    PubMed

    Lü, Weifeng; Ding, Mingyu

    2005-09-01

    A suitable method for extraction of amygdalin from hawthorn has been established. At first, the lipophilic components were removed with petroleum ether by ultrasonic extraction. The amygdalin was then extracted by methanol in a Soxhlet's apparatus. For quantitation, a high performance liquid chromatographic method was developed by using a reversed-phase C18 column, mobile phase of methanol-water (15:85, v/v) and a detection wavelengh of 215 nm. It can be concluded that the content of amygdalin is higher in the seeds than that in the hawthorn powder without the seeds and the yield of amygdalin is higher in the hawthorn pieces than that in the hawthorn powder.

  11. Acids, sugars, and sugar alcohols in Chinese hawthorn (Crataegus spp.) fruits.

    PubMed

    Liu, Pengzhan; Kallio, Heikki; Lü, Deguo; Zhou, Chuansheng; Ou, Shiyi; Yang, Baoru

    2010-01-27

    Acids, sugars, and sugar alcohols in the fruits of 22 cultivars/origins of three species of hawthorn (Crataegus spp.) were analyzed by gas chromatography and mass spectrometry. Citric acid (2.0-8.4 g/100 g dry mass [DM]), quinic acid (0.5-5.6 g/100 g DM), malic acid (0.3-1.1 g/100 g DM), fructose (5.5-18.4 g/100 g DM), glucose (5.3-16.6 g/100 g DM), sorbitol (3.0-15.7 g/100 g DM), and myo-inositol (0.1-0.3 g/100 g DM) were found in all the samples. Sucrose was present only in C. scabrifolia and three cultivars of C. pinnatifida var. major. C. scabrifolia differed from other species by its high content of quinic acid. The cultivars of C. pinnatifida var. major and C. brettschneideri had a higher content of total sugars and a higher sugar/acid ratio than the natural origins of C. pinnatifida and C. scabrifolia (P < 0.05). The hawthorn samples analyzed fell into two groups rich in sugars and acids respectively. This is the first report of the profiles of sugars and sugar alcohols and the occurrence of quinic acid in hawthorn fruits.

  12. Hawthorn (Crataegus spp.) in the treatment of cardiovascular disease.

    PubMed

    Tassell, Mary C; Kingston, Rosari; Gilroy, Deirdre; Lehane, Mary; Furey, Ambrose

    2010-01-01

    The medicinal properties of hawthorn (Crataegus spp., a genus comprising approximately 300 species) have been utilized by many cultures for a variety of therapeutic purposes for many centuries. In the Western world cardiovascular disease (CVD) has become one of the single most significant causes of premature death. Echoing this situation, more recent research into the therapeutic benefits of hawthorn preparations has focused primarily upon its cardiovascular effects. This review covers research into the various mechanisms of action proposed for Crataegus preparations, clinical trials involving Crataegus preparations, and the herb's safety profile.Clinical trials reviewed have been inconsistent in terms of criteria used (sample size, preparation, dosage, etc) but have been largely consistent with regard to positive outcomes. An investigation into data available to date regarding hawthorn preparations and herb/drug interactions reveals that theoretical adverse interactions have not been experienced in practice. Further, adverse reactions relating to the use of hawthorn preparations are infrequent and mild, even at higher dosage ranges. A recent retrospective study by Zick et al. has suggested a negative outcome for the long-term use of hawthorn in the prognosis of heart failure. These findings are examined in this paper.Although further research is needed in certain areas, current research to date suggests that hawthorn may potentially represent a safe, effective, nontoxic agent in the treatment of CVD and ischemic heart disease (IHD).

  13. The Effectiveness of Crataegus orientalis M Bieber. (Hawthorn) Extract Administration in Preventing Alveolar Bone Loss in Rats with Experimental Periodontitis.

    PubMed

    Hatipoğlu, Mükerrem; Sağlam, Mehmet; Köseoğlu, Serhat; Köksal, Ekrem; Keleş, Ali; Esen, Hacı Hasan

    2015-01-01

    The purpose of this animal study was to evaluate the effects of hawthorn (Crataeus orientalis M Bieber.) extract on serum oxidative status and alveolar bone loss in experimental periodontitis. Twenty-seven Wistar rats were assigned to one of the following groups: non- ligated+placebo (saline) (NL, n = 9), ligature only+placebo (saline) (LO, n = 9), and ligature and treated with hawthorn extract in saline (H, n = 9) (100 mg/kg orogastrically, once a day for 11 days). Periodontitis was induced by submerging a 4/0 silk ligature in the sulcus of the mandibular right first molars of rats, and the animals were sacrificed after 11 days. Micro-CT examinations were performed for linear and volumetric parameter assessment of alveolar bone. Periodontal tissues were histopathologically examined to assess the differences among the study groups. Levels of serum total antioxidant status (TAS)/total oxidant status (TOS), and oxidative stress index (OSI) were also analyzed. Alveolar bone loss was significantly reduced by hawthorn administration compared to LO group (p<0.05). The number of inflammatory cells and osteoclasts in the LO group was significantly higher than that of the NL and H groups (p< 0.05). The number of osteoblasts in the LO and H groups was significantly higher than that of the NL group (p<0.05). TOS and OSI levels were significantly reduced in H group compared to LO group (P <0.05) and TAS levels were similar in H and NL group (p< 0.05). Hawthorn extract showed inhibitory effect on periodontal inflammation and alveolar bone loss by regulating TAS, TOS and OSI levels in periodontal disease in rats when administered systemically.

  14. Hawthorn (Crataegus monogyna Jacq.) extract exhibits atropine-sensitive activity in a cultured cardiomyocyte assay.

    PubMed

    Salehi, Satin; Long, Shannon R; Proteau, Philip J; Filtz, Theresa M

    2009-01-01

    Hawthorn (Crataegus spp.) plant extract is used as a herbal alternative medicine for the prevention and treatment of various cardiovascular diseases. Recently, it was shown that hawthorn extract preparations caused negative chronotropic effects in a cultured neonatal murine cardiomyocyte assay, independent of beta-adrenergic receptor blockade. The aim of this study was to further characterize the effect of hawthorn extract to decrease the contraction rate of cultured cardiomyocytes. To test the hypothesis that hawthorn is acting via muscarinic receptors, the effect of hawthorn extract on atrial versus ventricular cardiomyocytes in culture was evaluated. As would be expected for activation of muscarinic receptors, hawthorn extract had a greater effect in atrial cells. Atrial and/or ventricular cardiomyocytes were then treated with hawthorn extract in the presence of atropine or himbacine. Changes in the contraction rate of cultured cardiomyocytes revealed that both muscarinic antagonists significantly attenuated the negative chronotropic activity of hawthorn extract. Using quinuclidinyl benzilate, L-[benzylic-4,4'-(3)H] ([(3)H]-QNB) as a radioligand antagonist, the effect of a partially purified hawthorn extract fraction to inhibit muscarinic receptor binding was quantified. Hawthorn extract fraction 3 dose-dependently inhibited [(3)H]-QNB binding to mouse heart membranes. Taken together, these findings suggest that decreased contraction frequency by hawthorn extracts in neonatal murine cardiomyocytes may be mediated via muscarinic receptor activation.

  15. Nathaniel Hawthorne's Garden of Eden Story: "Rappaccini's Daughter."

    ERIC Educational Resources Information Center

    Meixner, Linda L.

    1990-01-01

    Presents a four-day lesson plan for secondary U.S. literature or Bible-and-literature classes, using the Garden of Eden story and Nathaniel Hawthorne's "Rappaccini's Daughter." Identifies objectives, materials, procedure, and evaluation measures. Develops students' ability to discover analogies and irony in literary texts. Lists teacher…

  16. Mozart, Hawthorne, and Mario Savio: Aesthetic Power and Political Complicity.

    ERIC Educational Resources Information Center

    Herbert, T. Walter

    1995-01-01

    Discusses the false dichotomy pitting aesthetic power against political complicity in literary criticism. Considers the sexual politics of the household of Nathaniel Hawthorne in light of this opposition. Suggests how literary works keep warring voices and inner conflicts alive and at odds. (HB)

  17. Nathaniel Hawthorne and Herman Melville: A Research Guide.

    ERIC Educational Resources Information Center

    Van Noate, Judith, Comp.

    This handout is a guide to library resources in the J. Murrey Atkins Library at the University of North Carolina-Charlotte for the study of the 19th-century American authors Nathaniel Hawthorne and Herman Melville. The guide details resources in Atkins library for biographical and critical material on the two authors. The guide is in four…

  18. Is the Hawthorne Effect in Educational Experiments a Chimera?

    ERIC Educational Resources Information Center

    Bauernfeind, Robert H.; Olson, Carl J.

    1973-01-01

    Reports on an experimental study designed to investigate the relationship between two factors commonly regarded as components of the Hawthorne Effect on pupil performance and on intellectual task. These factors are (1) direct cue, or awareness of experimentation, as represented by an announcement that pupils were the subjects of an experiment; and…

  19. Energy Engineering Analysis Program, limited energy study of steam distribution systems, Hawthorne Army Ammunition Depot, Hawthorne, Nevada. Programming documents

    SciTech Connect

    1995-09-01

    The project is a significant part of Hawthorne Army Ammunition Depot`s effort to achieve a 20-percent reduction in energy consumption by FY2000 versus FY1985 baseline levels. The project will also assure that heating services are provided to Industrial Area facilities on a continuing basis, supporting mission requirements.

  20. Triterpenic Acids Present in Hawthorn Lower Plasma Cholesterol by Inhibiting Intestinal ACAT Activity in Hamsters.

    PubMed

    Lin, Yuguang; Vermeer, Mario A; Trautwein, Elke A

    2011-01-01

    Hawthorn (Crataegus pinnatifida) is an edible fruit used in traditional Chinese medicine to lower plasma lipids. This study explored lipid-lowering compounds and underlying mechanisms of action of hawthorn. Hawthorn powder extracts inhibited acylCoA:cholesterol acyltransferase (ACAT) activity in Caco-2 cells. The inhibitory activity was positively associated with triterpenic acid (i.e., oleanolic acid (OA) and ursolic acid (UA)) contents in the extracts. Cholesterol lowering effects of hawthorn and its potential additive effect in combination with plant sterol esters (PSE) were further studied in hamsters. Animals were fed a semi-synthetic diet containing 0.08% (w/w) cholesterol (control) or the same diet supplemented with (i) 0.37% hawthorn dichloromethane extract, (ii) 0.24% PSE, (iii) hawthorn dichloromethane extract (0.37%) plus PSE (0.24%) or (iv) OA/UA mixture (0.01%) for 4 weeks. Compared to the control diet, hawthorn, PSE, hawthorn plus PSE and OA/UA significantly lowered plasma non-HDL (VLDL + LDL) cholesterol concentrations by 8%, 9%, 21% and 6% and decreased hepatic cholesterol ester content by 9%, 23%, 46% and 22%, respectively. The cholesterol lowering effects of these ingredients were conversely associated with their capacities in increasing fecal neutral sterol excretion. In conclusion, OA and UA are responsible for the cholesterol lowering effect of hawthorn by inhibiting intestinal ACAT activity. In addition, hawthorn and particularly its bioactive compounds (OA and UA) enhanced the cholesterol lowering effect of plant sterols.

  1. Screening low fire blight susceptible Crataegus species for host suitability to hawthorn leaf-curling aphids (Dysaphis spp.).

    PubMed

    Bribosia, E; Bylemans, D; Van Impe, G; Migon, M

    2002-01-01

    The group of hawthorn leaf-curling aphids (Dysaphis spp.) hosted by the common hawthorn Crataegus monogyna Jacq. may play an important role in the biological control of the rosy apple aphid, Dysaphis plantaginea (Passerini), by increasing reproduction opportunities for the indigenous hymenopteran parasitoid Ephedrus persicae Froggatt. Unfortunately, most fruitgrowers hesitate to introduce the common hawthorn in their orchards because they fear fire blight infections which may be transmitted by this highly susceptible hawthron species. This potential hazard led us to investigate the suitability to leaf-curling aphids of alternative Crataegus species. As representative for these closely-related aphids, the species Dysaphis apiifolia petroselini (Börner) was used in the trials. Ten Crataegus species characterized by their very low susceptibility to fire blight were examined from two angles. Firstly, aphid sexuals were introduced in autumn onto the different species to verify whether egg laying could take place. Secondly, the development of fundatrices and gall formation were followed the next spring. Although eggs and mature fundatrices could be obtained on almost all species, no fundatrice-hosting galls were recorded in spring. The possible causes of these negative results with respect to the geographical origin of the particular Crataegus species involved in this work are discussed.

  2. [Detection of Hawthorn Fruit Defects Using Hyperspectral Imaging].

    PubMed

    Liu, De-hua; Zhang, Shu-juan; Wang, Bin; Yu, Ke-qiang; Zhao, Yan-ru; He, Yong

    2015-11-01

    Hyperspectral imaging technology covered the range of 380-1000 nm was employed to detect defects (bruise and insect damage) of hawthorn fruit. A total of 134 samples were collected, which included damage fruit of 46, pest fruit of 30, injure and pest fruit of 10 and intact fruit of 48. Because calyx · s⁻¹ tem-end and bruise/insect damage regions offered a similar appearance characteristic in RGB images, which could produce easily confusion between them. Hence, five types of defects including bruise, insect damage, sound, calyx, and stem-end were collected from 230 hawthorn fruits. After acquiring hyperspectral images of hawthorn fruits, the spectral data were extracted from region of interest (ROI). Then, several pretreatment methods of standard normalized variate (SNV), savitzky golay (SG), median filter (MF) and multiplicative scatter correction (MSC) were used and partial least squares method(PLS) model was carried out to obtain the better performance. Accordingly to their results, SNV pretreatment methods assessed by PLS was viewed as best pretreatment method. Lastly, SNV was chosen as the pretreatment method. Spectral features of five different regions were combined with Regression coefficients(RCs) of partial least squares-discriminant analysis (PLS-DA) model was used to identify the important wavelengths and ten wavebands at 483, 563, 645, 671, 686, 722, 777, 819, 837 and 942 nm were selected from all of the wavebands. Using Kennard-Stone algorithm, all kinds of samples were randomly divided into training set (173) and test set (57) according to the proportion of 3:1. And then, least squares-support vector machine (LS-SVM) discriminate model was established by using the selected wavebands. The results showed that the discriminate accuracy of the method was 91.23%. In the other hand, images at ten important wavebands were executed to Principal component analysis (PCA). Using "Sobel" operator and region growing algrorithm "Regiongrow", the edge and defect

  3. Capillary electrophoretic analysis of flavonoids in single-styled hawthorn (Crataegus monogyna Jacq.) ethanolic extracts.

    PubMed

    Urbonaviciūte, A; Jakstas, V; Kornysova, O; Janulis, V; Maruska, A

    2006-04-21

    Flavonoids are an important group of natural compounds, which can prevent coronary heart disease and have antioxidant properties. Hawthorn is a well known and widely used medicinal plant due to its cardiotonic activity. Previous studies refer mostly to the HPLC analysis of the flavonoids: vitexin, quercetin, hyperoside, oligomeric procyanidins, which appear to be primarily responsible for the cardiac action of the plant. Aqueous ethanolic extracts of single-styled hawthorn (Crataegus monogyna Jacq., f.: Rosaceae Juss.) leaves and sprouts were analyzed by means of capillary zone electrophoresis (CZE). Influence of vegetation period on the extract qualitative composition and flavonoids quantities was evaluated. Sample preparation by extraction using different concentration of aqueous ethanol (40-96%, v/v) and the influence of extractant composition on the recovery of flavonoids are discussed in detail. The results obtained using CZE are compared to the results of spectrophotometric and HPLC analysis of the extracts. The effect of storage conditions of extracts (solar irradiation, temperature and duration) on degradation of flavonoids was investigated.

  4. Miocene Coralline algae

    SciTech Connect

    Bosence, D.W.J.

    1988-01-01

    The coralline algae (Order Corallinales) were sedimentologically and ecologically important during the Miocene, a period when they were particularly abundant. The many poorly described and illustrated species and the lack of quantitative data in coralline thalli make specific determinations particularly difficult, but some species are well known and widespread in the Tethyan area. The sedimentologic importance of the Miocene coralline algae is reflected in the abundance of in-situ coralline buildups, rhodoliths, and coralline debris facies at Malta and Spain; similar sequences are known throughout the Tethyan Miocene. In-situ buildups vary from leafy crustose biostromes to walled reefs with dense coralline crusts and branches. Growth forms are apparently related to hydraulic energy. Rhodoliths vary from leafy, crustose, and open-branched forms in muddy sediments to dense, crustose, and radial-branching forms in coarse grainstones. Rhodolith form and internal structure correlate closely with hydraulic energy. Coralline genera are conservative and, as such, are useful in paleoenvironmental analysis. Of particular interest are the restricted depth ranges of recent coralline genera. More research is needed on the sedimentology, paleoecology, and systematics of the Cenozoic corallines, as they have particular value in paleoenvironmental analysis.

  5. Antarctic Miocene Climate

    NASA Astrophysics Data System (ADS)

    Ashworth, A. C.; Lewis, A. R.

    2013-12-01

    Fossils from Antarctic Miocene terrestrial deposits, coupled with stratigraphic, geochemical and paleontological data from marine boreholes, provide new insights into the climatic history of the continent. During the Miocene, ice caps coalesced to form ice sheets and vegetated surfaces gave way to barren expanses. The cryospheric changes especially have global climatic implications. The fossil data consists of diatoms, pollen and spores, and macroscopic remains of plants, ostracods, insects, molluscs and a fish. Plant fossils include wood and leaves of Nothofagus (southern beech), seeds of several vascular plants, including Ranunculus (buttercup), Hippuris (mare's-tail) and Myriophyllum (watermilfoil), megaspores of Isoetes (quillwort), and moss species. The insect chitin consists of larval head capsules of Chironomidae (midges) and exoskeletal parts of Coleoptera (beetles). The molluscs include freshwater gastropods and bivalves. The majority of these taxa are likely descendants of taxa that had survived on the continent from the Paleogene or earlier. Even though early Miocene glaciations may have been large, the climate was never cold enough to cause the extinction of the biota, which probably survived in coastal refugia. Early Miocene (c. 20 Ma) macrofossils from the McMurdo Dry Valleys (77°S) support palynological interpretations from the Cape Roberts and ANDRILL marine records that the upland vegetation was a shrub tundra. Mean summer temperature (MST) in the uplands was c. 6°C and possibly higher at the coast. The climate was wet, supporting mires and lakes. By the mid-Miocene, even though the climate continued to be wet. MST was c. 4°C which was too cold to support Nothofagus and most vascular plant species. Stratigraphic evidence indicates that the time between the Early and Mid-Miocene was a time of repeated ice advances and retreats of small glaciers originating from ice caps. At c. 14 Ma there appears to have been a modal shift in climate to

  6. Preparative isolation of oligomeric procyanidins from Hawthorn (Crataegus spp.).

    PubMed

    Zumdick, S; Petereit, F; Luftmann, H; Hensel, A

    2009-04-01

    The oligomeric procyanidins (OPC) from Hawthorn leaves and flowers (Crataegi folium cum flore) are considered to be in part responsible for the cardiotonic clinical activity of the herbal material. Effective methods for rapid isolation of these heterogenous oligomeric clusters with defined molecular weight as reference compounds are not published until now. Therefore the water soluble fraction of an acetone/water (7 + 3) extract of Hawthorn leaves and flowers was fractionated by a combination of MPLC on RP-18 material and preparative HPLC using a diol stationary phase. This procedure resulted in the effective isolation of procyanidins with a distinct degree of polymerization (DP) from dimers DP2 up to tridecamers DP13. Exact mass measurements with negative ESI-TOF/MS were employed to confirm the respective structures of the isolated procyanidins.

  7. Metal characterization of white hawthorn organs and infusions.

    PubMed

    Juranović Cindrić, Iva; Zeiner, Michaela; Konanov, Darija Mihajlov; Stingeder, Gerhard

    2015-02-18

    Hawthorn is one of the most commonly used European and North American phytopharmaceuticals. Because there is no information on metals in seeds, and only rare data for leaves and flowers, the aim of the present study was elemental analysis of the white hawthorn (Crataegus monogyna) by inductively coupled plasma emission spectrometry (ICP-AES) or inductively coupled plasma mass spectrometry (ICP-MS) after digestion in a microwave-assisted system. The limits of detection are below 2 μg/g for ICP-AES and 0.5 μg/g for ICP-MS. Hawthorn leaves and flowers contain essential elements at concentrations (mean values, RSD 2-8%) in mg/g of Ca, 1-4; K, 4-5; Mg, 1-2; and Na, <0.2); and at μg/g levels of Ba, 1-10; Co, <0.16; Cr, <1.4; Cu, 0.6-7; Fe, 1-37; Li, <0.5; Mn, 1-13; Mo, <0.17; Ni, <0.6; Sr, 0.2-2; and Zn, 1-31. Toxic elements were found in low quantities: As (<0.04), Cd (0.04-0.1), and Pb (0.1-2). Up to 10% of the metals is extracted into the infusions. The analyzed plant parts and infusions contain essential elements justifying its use as a medicinal plant, whereas the low quantities of harmful elements will not pose any risk to humans when consumed.

  8. Review of Miocene larger foraminifera

    SciTech Connect

    Glenn, E.C.

    1988-01-01

    Miocene larger foraminifera were generally restricted to shallow (<100m), warm, clear, normal marine environments and were primarily dependent on brief drifting of juveniles and rafting on vegetation for dispersal. These factors are reflected in both regional and local occurrences. Regional occurrences of Miocene larger foraminifera vary with bio-province and time. Three main foraminiferal provinces (Central American, Mediterranean, and Indo-West Pacific) developed through a combination of tectonics, eustasy, climate, and faunal evolution and migration. Important effects of Miocene tectonics included widening of the Atlantic, early Miocene occlusion of the western neo-Tethys, and northern movement of the Australian plate into the tropics. Changes in climate primarily expanded or constricted latitudinal provincial boundaries. Eustatic sea level variations caused by the destruction of the late Miocene Mediterranean fauna. Globally, Miocene faunas underwent a progressive loss of taxa. This is particularly noticeable in post-early Miocene faunas of the Mediterranean and Central American provinces. Although post-early Miocene taxa evolved in all three areas, faunal migration was prevented by environmental barriers. For a given time and province, the occurrence of larger foraminifera in well-preserved Miocene reef facies is related to paleoenvironmental factors of water depth, turbidity, water energy, and substrate and to post-mortem processes of transport and selective test destruction. Environmentally related changes in test morphology, together with the relative abundances of planktonic species and small benthic taxa, allow an estimation of the magnitude of the various environmental factors, even without detailed foraminiferal taxonomy.

  9. Identification of host fruit volatiles from hawthorn (Crataegus spp.) attractive to hawthorn-origin Rhagoletis pomonella flies.

    PubMed

    Nojima, Satoshi; Linn, Charles; Morris, Bruce; Zhang, Aijun; Roelofs, Wendell

    2003-02-01

    Solid-phase microextraction (SPME) and gas chromatography coupled with electroantennographic detection (GC-EAD) were used to identify volatile compounds from hawthorn fruit (Crataegus spp.) acting as behavioral attractants for hawthorn-infesting Rhagoletis pomonella flies. Consistent EAD activity was obtained for six chemicals: ethyl acetate (94.3%), 3-methylbutan-1-ol (4.0%), isoamyl acetate (1.5%), 4,8-dimethyl-1,3(E),7-nonatriene (0.07%), butyl hexanoate (0.01%), and dihydro-beta-ionone (0.10%). In a flight-tunnel bioassay, there was a dose-related increase in the percentage of flies flying upwind to the six-component mixture. Hawthorn-origin flies also made equivalent levels of upwind flight with the synthetic blend and an adsorbent extract of volatiles collected from whole fruit, each containing the same amount of the 3-methylbutan-1-ol compound. Significantly lower levels of upwind flight occurred to a previously identified volatile blend of ester compounds that attracts R. pomonella flies infesting domestic apples, compared with the hawthorn volatile mix. Selected subtraction assays showed further that the four-component mixture of 3-methylbutan-1-ol, 4,8-dimethyl-1,3(E),7-nonatriene, butyl hexanoate, and dihydro-beta-ionone also elicited levels of upwind flight equivalent to the six-component mix. Removal of 3-methylbutan-1-ol from the four-component blend resulted in complete loss of upwind flight behavior. Removal of dihydro-beta-ionone, 4,8-dimethyl-1,3(E),7-nonatriene, or butyl hexanoate from the four-component mixture resulted in significant decreases in the mean number of upwind flights compared to the four- or six-component mixtures.

  10. 76 FR 25320 - Hawthorn Water LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hawthorn Water LLC; Notice of Preliminary Permit Application Accepted for..., Hawthorn Water LLC filed an application, pursuant to section 4(f) of the Federal Power Act, proposing...

  11. The 2011 Hawthorne, Nevada, Earthquake Sequence; Shallow Normal Faulting

    NASA Astrophysics Data System (ADS)

    Smith, K. D.; Johnson, C.; Davies, J. A.; Agbaje, T.; Knezevic Antonijevic, S.; Kent, G.

    2011-12-01

    An energetic sequence of shallow earthquakes that began in early March 2011 in western Nevada, near the community of Hawthorne, has slowly decreased in intensity through mid-2011. To date about 1300 reviewed earthquake locations have been compiled; we have computed moment tensors for the larger earthquakes and have developed a set of high-precision locations for all reviewed events. The sequence to date has included over 50 earthquakes ML 3 and larger with the largest at Mw 4.6. Three 6-channel portable stations configured with broadband sensors and accelerometers were installed by April 20. Data from the portable instruments is telemetered through NSL's microwave backbone to Reno where it is integrated with regional network data for real-time notifications, ShakeMaps, and routine event analysis. The data is provided in real-time to NEIC, CISN and the IRIS DMC. The sequence is located in a remote area about 15-20 km southwest of Hawthorne in the footwall block of the Wassuk Range fault system. An initial concern was that the sequence might be associated with volcanic processes due to the proximity of late Quaternary volcanic flows; there have been no volcanic signatures observed in near source seismograms. An additional concern, as the sequence has proceeded, was a clear progression eastward toward the Wassuk Range front fault. The east dipping range bounding fault is capable of M 7+ events, and poses a significant hazard to the community of Hawthorne and local military facilities. The Hawthorne Army Depot is an ordinance storage facility and the nation's storage site for surplus mercury. The sequence is within what has been termed the 'Mina Deflection' of the Central Walker Lane Belt. Faulting along the Whiskey Flat section of the Wassuk front fault would be primarily down-to-the-east, with an E-W extension direction; moment tensors for the 2011 earthquake show a range of extension directions from E-W to NW-SE, suggesting a possible dextral component to the Wassuk

  12. Miocene Antarctic Terrestrial Realm

    NASA Astrophysics Data System (ADS)

    Ashworth, A. C.; Lewis, A.; Marchant, D. R.

    2009-12-01

    The discovery of several locations in the Transantarctic Mountains that contain macrofossils and pollen is transforming our understanding of late Cenozoic Antarctica. The most southerly location is on the Beardmore Glacier (85.1°S) about 500 km from the South Pole. The environment was an active glacial margin in which plants, insects and freshwater mollusks inhabited the sand and gravel bars and small lakes on an outwash plain. In addition to leaves and wood of dwarf Nothofagus (Southern Beech) shrubs, achenes of Ranunculus (Buttercup), in situ cushion growth forms of mosses and a vascular plant, the assemblages contains various exoskeletal parts of carabid and curculionid beetles and a cyclorrhaphan fly, the shells of freshwater bivalve and gastropod species and a fish tooth. Initially the deposits were assigned a Pliocene age (3.5 Ma) but a mid- to early Miocene age is more probable (c. 14 - 25 Ma) based on correlation of fossil pollen from the deposits with 39Ar/40Ar dated pollen assemblages from the McMurdo Dry Valleys locations. The oldest location within the Dry Valleys also involved an active ice margin but was part of a valley system that was completely deglaciated for intervals long enough for thick paleosols to develop. The Friis Hills fossil deposits of the Taylor Valley region (77.8°S) are at least 19.76 Ma based on the 39Ar/40Ar age of a volcanic ash bed. The valley floor during the non-glacial phases had poorly-drained soils and the extensive development of mossy mires. Wood and leaves of Nothofagus are abundant in lacustrine deposits. The silts of shallow fluvial channels contain abundant megaspores and spiky leaves of the aquatic lycopod Isoetes (Quillwort). Fossils of beetles are also present in these deposits. During the glacial phases, proglacial lakes were surrounded by dwarfed, deciduous Nothofagus shrubs. The youngest fossils recovered from the Dry Valleys are from the Olympus Range (77.5°S) with an age of 14.07 Ma. The environment was an

  13. Miocene reef corals: A review

    SciTech Connect

    Frost, S.H.

    1988-01-01

    Tectonic blockage in the Middle East of westward-flowing Tethys surface circulation during the latest Oligocene led to creation in the earliest Miocene of endemic Mediterranean, Western Atlantic-Caribbean, and Indo-Pacific realms. A great reduction in reef coral diversity from 60-80 Oligocene species to 25-35 early Miocene species occurred in the Western Atlantic-Caribbean and Mediterranean areas accompanied by a decrease in reef growth. A slower and less drastic change apparently occurred in the Indo-Pacific area. Early Miocene reef corals of the Western Atlantic-Caribbean comprise a transition between the cosmopolitan Oligocene fauna and its endemic mid-Miocene to modern counterpart. Although early Miocene reefs were dominated by a Porites-Montastrea assemblage, eastward flow of Pacific circulation brought with it ''exotic'' corals such as Coscinaraea and Pseudocolumnastrea. Also, many cosmopolitan genera persisted from the Oligocene. During the middle to late Miocene, most of the species still living on Holocene reefs evolved. As the Mediterranean basin became more restricted, there was a slow decline in reef corals from 20 - 25 species in the Aquitainian to less than five species in the Messinian. Eustatic lowstand led to the extinction of reef-building corals in the late Messinian. In the Indo-Pacific, Neogene evolution of reef corals was conservative. Excluding the Acroporidae and Seriatoporidae, most Holocene framework species had evolved by the middle Miocene. Interplay between regional tectonics and eustatic sea level changes led to extensive development of middle to late Miocene pinnacle reefs over the southwestern Pacific.

  14. [Study on self-microemulsifying membrane controlled-release drop pill of hawthorn leaves flavonoids].

    PubMed

    Wang, Jin-Xuan; Huang, Hong-Zhang; Li, Ning; Gao, Chong-Kai

    2014-03-01

    To prepare the hawthorn leaves flavonoids self-microemulsifying membrane controlled-release coated drop pill, and to study its release rate in vitro and pharmacokinetics study in vivo. In order to improve the dissolution of hawthorn leaves flavonoids, self-microemulsifying technology was used to prepare the hawthorn leaves flavonoids self-microemulsion. Hawthorn leaves flavonoids self-microemulsifying drop pill was prepared with the PEG 6000. Studies were made on the in vitro release of flavonoids from hawthorn leaves self-micro-emulsifying membrane-moderated coated drop pills and the in vivo pharmacokinetic in rats. The prescription of flavonoids from hawthorn leaves self-micro-emulsifying drop pills was 0.25 g of flavonoids from hawthorn leaves, 0.25 g of iodophenyl maleimide, 0.375 g of polyethylene glycol 400, 0.375 g of cremophor RH 40 and 2 g of polyethylene glycol 6000. The optimized prescription was 4 g of ethyl cellulose 20, 0.64 g of polyethylene glycol 400, 1.8 g of diethyl phthalate, and the weight of coating materials increased by 3.5%. Flavonoids from hawthorn leaves self-micro-emulsifying membrane-moderated coated drop pills complied with the design of sustained-release in 12 h in terms of in vitro release and in vivo pharmacokinetic parameters in rats, and its bioavailability was 2.47 times of quick-release drop pills. Slightly soluble flavonoids from hawthorn leaves could be made into sustained-release preparations by the self-micro-emulsifying and coating technology.

  15. Study on antibacterial effect of medlar and hawthorn compound extract in vitro.

    PubMed

    Niu, Yang; Nan, Yi; Yuan, Ling; Wang, Rong

    2013-01-01

    This paper evaluated the antibacterial effect of medlar and hawthorn compound extract in vitro. Water extract method and ethanol extraction method was adopted to prepare the compound extracts, and disc diffusion method and improved test tube doubling dilution method were used to conduct the antibacterial test on the two common pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumonia, in vitro. The results showed that medlar and hawthorn compound extract was moderately sensitive to Staphylococcus aureus, while its inhibiting effect on Klebsiella pneumoniae was particularly significant, moreover, the antibacterial effect of ethanol extract was better than water extract. Medlar and hawthorn compounds had good antibacterial effect on the two pathogenic bacteria.

  16. Miocene reefs of Dominican Republic

    SciTech Connect

    Evans, C.C.

    1988-01-01

    The reefs are overlain by conglomeratic strata. The stratigraphic setting of these reefs suggests that they have developed along the stalled portions of rapidly prograding fan deltas. Thickets and layers of coral debris are found seaward and stratigraphically above the well-developed reef. The matrix sediments are exclusively fine-grained sand to mud, and the fauna are suggestive of more open shelf conditions. In thickets, branched (porites spp., Pocillopora spp.), small massive (Montastrea spp., Siderastrea spp.), and foliose or plate like (Agaricia spp.) corals are found upright in the muddy sediment. Similarities in coral species and areal proximity suggest that thickets are the source of most layers of coralline debris. The association of coral debris with graded bedding and cross-bedding suggests that coral debris has been reworked by storms. The growth of corals and development of coral reefs in the Miocene-Pliocene Yaque Group is limited only by opportunities created by the slowing of siliciclastic sedimentation. Soft, muddy, terrigenous substrates and a continuing supply of terrigenous mud exert only a limited, indirect effect on reef growth.

  17. Calcareous Nannofossil Evolution Vs. Climatic Evolution In The Miocene

    NASA Astrophysics Data System (ADS)

    Raffi, I.; Backman, J.; Ciummelli, M.

    2013-12-01

    Miocene times were characterized by major changes in ocean circulation and global climate that were driven by a complex set of factors operating on tectonic, orbital and suborbital timescales (Zachos et al., 2001). This time dependent development of Miocene paleo-environmental conditions is reflected in the distribution and evolutionary patterns, often expressed in terms of biostratigraphic resolution, among the dominant sediment-forming oceanic plankton groups (Kennett & Srinivasan, 1983; Baldauf & Barron, 1990; Perch-Nielsen, 1985) including calcareous nannofossils. In the Miocene through Pleistocene interval, calcareous nannofossil evolutionary appearances or extinctions provide eight biostratigraphically useful biohorizons between 23 Ma and 14 Ma, giving an average rate of 1.5 biohorizon per million years. In the next following eight million years (14-5 Ma), the number of biohorizons are 29 (3.6 biohorizons/million years), representing well over a doubling of the rate of taxonomic evolution among open ocean calcareous nannofossils compared with that of the early half of the Miocene. This observation demonstrates that a distinct evolutionary response to climatic evolution throughout the Miocene, specifically to changing conditions in the photic zone of the middle and late Miocene oceans. This assumption is supported by the behavior of some nannofossil groups, in particular by the representatives of the genus Discoaster, a key group that gives nearly half (14 of 29) of biohorizons in the younger half of the Miocene. The Discoaster's environmental distribution and abundance may provide some information about the complex interaction between climatic evolution and biotic evolution in the plankton realm.

  18. An overview of Miocene reefs

    SciTech Connect

    Jordan, C.F. Jr. ); Colgan, M.W. ); Frost, S.H. ); Glenn, E.C. ); Bosence, D. ); Esteban, M. )

    1990-05-01

    Miocene reefs lived approximately within the latitudes of 27{degree}S to 48{degree}N compared with 25{degree}S and 32{degree}N for Holocene reefs. This expansion of reef-growing environments was the result of warm Miocene climates, aided by a eustatic sea level rise and tectonic styles that provided numerous foundations for reef development. The majority of Miocene reefs are found in three main areas: (1) Southeast Asia and the western Pacific, (2) the Mediterranean-Middle East, and (3) Middle America and the Caribbean. These regions, with their distinctive suites of coral and foramineral species, formed three biological provinces; respectively, they are the Indo-Pacific, Tethyan, and Western Atlantic provinces. Miocene reefs in Southeast Asia occur in several foreland basins as patch reef complexes on paleohighs and as barrier reefs in back-arc basins. Those reefs in the Mediterranean occur as fringing reefs, middle-shelf patch reefs, or as barrier reefs on the edges of tectonic blocks associated with Alpine thrust belts. Most reefs in the Caribbean grew on isolated open-ocean highs of volcanic origin. Miocene reefs display a diversity of framework types: (1) coral-encrusting, red algal boundstones with diverse coral faunas, (2) branching coral-encrusting, red algal boundstones with a limited Poritid fauna, (3) encrusting red algal boundstones. Barrier reef systems are especially rich in encrusting red algae and robust corals; grainstones are common as interbedded sediment. Patch reef complexes, however, display muddy carbonate textures, may have less diverse coral faunas, and commonly have larger foraminifera. The global distribution of Miocene reefs is important because (1) it provides insight into a paleoclimatic view of the earth during a major greenhouse stage and (2) Miocene buildups, such as the Arun (EUR of 14 tcf) and Bima fields (EUR of about 100 MMBO), are exploration targets.

  19. The Hawthorne experiments and the introduction of Jean Piaget in American industrial psychology, 1929-1932.

    PubMed

    Hsueh, Yeh

    2002-05-01

    The Hawthorne interview program between 1929 and 1932 was one of the most significant industrial studies in the United States. The Hawthorne researchers applied Jean Piaget's clinical method in their extensive interviews with tens of thousands of workers. Chiefly responsible for the program's methodology was Elton Mayo, an Australian who saw interviewing as a means to promote social cooperation. Previous discussions of the Hawthorne experiments have ignored the influence of Piaget in the social sciences. This article provides an account of Mayo's and the Hawthorne researchers' efforts to fuse Piaget's innovation with burgeoning American industrial psychology. The endeavor was not an isolated event but rather drew on the theories and practice of Janet-Piaget psychology, on the support of the Laura Spelman Rockefeller Memorial Foundation, and on the discourse among social scientists about Piaget's work.

  20. Protective effect of hawthorn extract against genotoxicity induced by methyl methanesulfonate in human lymphocytes.

    PubMed

    Hosseinimehr, Seyed Jalal; Azadbakht, Mohammad; Tanha, Mohammad; Mahmodzadeh, Aziz; Mohammadifar, Sohila

    2011-05-01

    The preventive effect of hawthorn (Crataegus microphylla) fruit extract against genotoxicity induced by methyl methanesulfonate (MMS) has been investigated in human cultured blood lymphocytes. Peripheral blood samples were collected from human volunteers at 0 (10 minutes before), and at 1 and 2 hours after a single oral ingestion of 1 g hawthorn powder extract. At each time point, the whole blood was treated in vitro with MMS (200 µmol) at 24 hours after cell culture, and then the lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis-blocked binucleated cells. The lymphocytes treated with hawthorn and MMS to exhibit a significant decreasing in the incidence of micronucleated binucleated cells, as compared with similarly MMS-treated lymphocytes from blood samples collected at 0 hour. The maximum protection and decreasing in frequency of micronuclei (36%) was observed at 1 hour after ingestion of hawthorn extract. The high performance liquid chromatography (HPLC) analysis showed that hawthorn contained chlorogenic acid, epicatechin and hyperoside. It is obvious that hawthorn, particularly flavonoids constituents with antioxidative activity, reduced the oxidative stress and genotoxicity induced by toxic compounds. This set of data may have an important application for the protection of human lymphocyte from the genetic damage and side effects induced by chemicals hazardous in people.

  1. A macroecological glance at the structure of late Miocene rodent assemblages from Southwest Europe

    PubMed Central

    Cano, Ana Rosa Gómez; Cantalapiedra, Juan L.; Álvarez-Sierra, M. Ángeles; Fernández, Manuel Hernández

    2014-01-01

    Deep-time perspectives in macroecology are essential with regard to understanding the impact of climate forcing on faunal communities. Using late Miocene rodent faunas (12 to 5 Ma) from two different biogeographical provinces from southwestern Europe, we asked whether the waxing and waning of faunas with dissimilar ecological affinities tracked climate in different ways. The latest middle Miocene featured a fauna dominated by dormice with forest and mixed-habitat affinities. This group declined towards the Upper Miocene. Rodent taxa with the highest values of richness at the beginning of the Upper Miocene are generalists in the southern province and specialists of forested habitats in the northern province. Finally, we identified a third, increasingly significant group of rodents linked to open landscapes towards the end of the Miocene. These three broad ecological groups showed differential responses to a complex set of interconnected circumstances, including the biogeographic structure of the study area and climatic changes throughout time. PMID:25297009

  2. A macroecological glance at the structure of late Miocene rodent assemblages from Southwest Europe

    NASA Astrophysics Data System (ADS)

    Cano, Ana Rosa Gómez; Cantalapiedra, Juan L.; Álvarez-Sierra, M. Ángeles; Fernández, Manuel Hernández

    2014-10-01

    Deep-time perspectives in macroecology are essential with regard to understanding the impact of climate forcing on faunal communities. Using late Miocene rodent faunas (12 to 5 Ma) from two different biogeographical provinces from southwestern Europe, we asked whether the waxing and waning of faunas with dissimilar ecological affinities tracked climate in different ways. The latest middle Miocene featured a fauna dominated by dormice with forest and mixed-habitat affinities. This group declined towards the Upper Miocene. Rodent taxa with the highest values of richness at the beginning of the Upper Miocene are generalists in the southern province and specialists of forested habitats in the northern province. Finally, we identified a third, increasingly significant group of rodents linked to open landscapes towards the end of the Miocene. These three broad ecological groups showed differential responses to a complex set of interconnected circumstances, including the biogeographic structure of the study area and climatic changes throughout time.

  3. Middle Miocene dispersals of apes.

    PubMed

    Andrews, Peter; Kelley, Jay

    2007-01-01

    The earliest record of fossil apes outside Africa is in the latest early Miocene of Turkey and eastern Europe. There were at least 2, and perhaps 4, species of ape, which were found associated with subtropical mixed environments of forest and more open woodland. Postcranial morphology is similar to that of early Miocene primates and indicates mainly generalized arboreal quadrupedal behaviours similar to those of less specialized New World monkeys such as Cebus. Robust jaws and thick enamelled teeth indicate a hard fruit diet. The 2 best known species of fossil ape are known from the site of Paşalar in Turkey. They have almost identical molar and jaw morphology. Molar morphology is also similar to that of specimens from Germany and Slovakia, but there are significant differences in the anterior teeth of the 2 Paşalar species. The more common species, Griphopithecus alpani, shares mainly primitive characters with early and middle Miocene apes in Africa, and it is most similar phenetically to Equatorius africanus from Maboko Island and Kipsaramon. The second species is assigned to a new species of Kenyapithecus, an African genus from Fort Ternan in Kenya, on the basis of a number of shared derived characters of the anterior dentition, and it is considered likely that there is a phylogenetic link between them. The African sites all date from the middle Miocene, similar in age to the Turkish and European ones, and the earliest emigration of apes from Africa coincides with the closure of the Tethys Sea preceding the Langhian transgression. Environments indicated for the African sites are mixtures of seasonal woodlands with some forest vegetation. The postcrania of both African taxa again indicate generalized arboreal adaptation but lacking specialized arboreal function. This middle Miocene radiation of both African and non-African apes was preceded by a radiation of arboreal catarrhine primates in the early Miocene, among which were the earliest apes. The earliest

  4. Apatite (U-Th)/He Thermochronometry as an innovative Geothermal Exploration Tool - A case study from the Wassuk Range, Hawthorne, Nevada

    NASA Astrophysics Data System (ADS)

    Gorynski, K. E.; Stockli, D. F.; Walker, J. D.

    2010-12-01

    A utility-grade geothermal system requires increased, near-surface temperatures (>120°C), water to transfer heat, and structural or sedimentological fluid conduits. In extensional tectonic settings, geothermal anomalies often occur in areas with recent, high strain accumulation and complex faulting (i.e., cross-faults, accommodation zones) where exhumation and uplift of footwall rocks transfer heat, via advection, to the near-surface which is further carried by water through structural fluid conduits. Apatite helium (AHe) thermochronometric footwall age mapping can be used in conjunction with these genetic occurrence models to further focus regional-scale geothermal exploration efforts to areas of probabilistic increased fracture permeability and most recent, rapid footwall exhumation. Furthermore, partially reset apatites resulting from interaction with hydrothermal fluids (>40°C) will show which areas have been hottest most recently. This case study in the Wassuk Range, Hawthrone, NV confirms the utility of AHe thermochronometry as a geothermal exploration tool. A dense grid of footwall samples were collected adjacent to the Hawthorne geothermal anomaly (>85°C BHT) located in the hanging wall of the Wassuk Range block. Our data show that the location of the present-day geothermal anomaly correlates with the location of 1) the most recent episode of rapid footwall exhumation at 3.5-4 Ma, 2) km scale accommodation zones between differentially tilted Wassuk Range blocks, and 3) an elevated Miocene geothermal gradient. Furthermore, anomalously young AHe ages (<3.5 Ma) mimic the lateral extent of the Hawthorne geothermal anomaly and likely resulted from interaction with a deep-seated geothermal cell or hot hydrothermal fluids.

  5. Identification of host fruit volatiles from domestic apple (Malus domestica), native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (C. monogyna) attractive to R. pomonella flies from the western U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apple maggot fly, Rhagoletis pomonella, infests apple (Malus domestica) and hawthorn species (most notably the downy hawthorn, Crataegus mollis) in the eastern USA. Evidence suggests that the fly was introduced into the western USA sometime in the last 60 years. In addition to apple, R. pomonel...

  6. Antitumoral, antioxidant, and antimelanogenesis potencies of Hawthorn, a potential natural agent in the treatment of melanoma.

    PubMed

    Mustapha, Nadia; Mokdad-Bzéouich, Imèn; Maatouk, Mouna; Ghedira, Kamel; Hennebelle, Thierry; Chekir-Ghedira, Leila

    2016-06-01

    The lack of an efficient agent that does not have the disadvantage of low activity (kojic acid), high cytotoxicity, and mutagenicity (hydroquinone), poor skin penetration (arbutin), or low stability in formulation (glabridin) led us to continue our research on new antipigmentation/skin-lightening agents. Therefore, research of natural products that can modulate the metabolism of pigmentation is of great interest. Otherwise, malignant melanoma is one of the most aggressive forms of skin cancer, with high metastatic potential, and currently, there is no effective chemotherapy against invasive melanoma. Therefore, it is necessary to develop new drugs with potent activity and weak side effects against melanoma. The in-vitro anticancer effect of hawthorn was analyzed against B16F10 melanoma cells using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effect of isolated compounds from hawthorn on melanogenesis in B16F10 melanoma cells was investigated by measuring the amounts of melanin and tyrosinase spectrophotometrically at 475 nm. Balb/c mice models inoculated with B16F10 mouse tumor cells were used to evaluate the in-vivo antitumoral potential of hawthorn by assessing its effect on the growth of transplanted tumors. The antioxidant potential of tested samples was evaluated in B16F10 and primary human keratinocyte cells using a cellular antioxidant activity assay. Hawthorn tested samples inhibited effectively the growth of melanoma cells in vitro. Furthermore, it appears that tested samples from hawthorn reduced melanogenesis by inhibiting the tyrosinase activity of B16F10 cells in a dose-dependent manner. In-vivo studies showed that hawthorn total oligomer flavonoids extract treatment at a dose of 150 mg/kg body weight for 21 days in implanted tumor mice resulted in significant inhibition of the tumor growth volume and weight. In addition, tested samples showed significant cellular antioxidant capacity against the reactive oxygen species

  7. Phytochemical and pharmacological activity profile of Crataegus oxyacantha L. (hawthorn) - A cardiotonic herb.

    PubMed

    Orhan, Ilkay Erdogan

    2016-09-18

    Crataegus oxyacantha L. (syn. C. rhipidophylla Gand.) (Rosaceae) is one of two medicinally recognized hawthorn species in European Pharmacopeia. Standardization of the extract prepared from the berry and flowers of the plant is required according to its oligomeric procyanidins. C. oxyacantha is well-known for its use in the treatment of various heart problems particularly, including heart failure in cases of declining cardiac performance equivalent to stages I and II of the New York Heart Association classification, angina pectoris, hypertension with myocardial insufficiency, mild alterations of cardiac rhythm, and atherosclerosis. C. oxyacantha has been reported to exert several other pharmacological activities such as hypotensive, antihyperlipidemic, antihyperglycemic, anxiolytic, immunomodulatory, and antimutagenic. Oligomeric procyanidins and flavone/flavonol types of flavonoids, which are considered to be the chief groups of active substances, phenolic acids, triterpenes, fatty acids, and sterols are present in the plant. The present review aims mainly to outline cardiotonic effect of C. oxyacantha as well as its brief phytochemistry. Numerous experiments and clinical studies have underlined cardiovascular efficacy of the plant through various mechanisms including positive inotropic and negative chronotropic effects, escalation in coronary blood flow and exercise tolerance, inhibition of the enzymes such as angiotensin-converting enzyme (ACE) and phosphodiesterase, anti-inflammatory and antihyperlipidemic effects, improving status of antioxidant enzymes, etc., which support its cardioactive efficacy. The plant possesses several other bioactivities for human health usually concomitant to its rich polyphenolic content.

  8. Abundances of apple maggot, Rhagoletis pomonella, across different areas in central Washington, with special reference to black-fruited hawthorns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apple maggot fly, Rhagoletis pomonella (Walsh), has infested native black-fruited hawthorn (mostly Crataegus douglasii Lindl.) in central Washington since at least 2003, but little is known about the fly’s ecology in hawthorns there. The main objective here was to determine adult and larval abu...

  9. Identification of host fruit volatiles from domestic apple (Malus domestica), native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (C. monogyna) attractive to Rhagoletis pomonella flies from the western United States.

    PubMed

    Cha, Dong H; Yee, Wee L; Goughnour, Robert B; Sim, Sheina B; Powell, Thomas H Q; Feder, Jeffrey L; Linn, Charles E

    2012-03-01

    The apple maggot fly, Rhagoletis pomonella, infests apple (Malus domestica) and hawthorn species (most notably the downy hawthorn, Crataegus mollis) in the eastern USA. Evidence suggests that the fly was introduced into the western USA sometime in the last 60 years. In addition to apple, R. pomonella also infests two species of hawthorns in the western USA as major hosts: the native black hawthorn (C. douglasii) and the introduced ornamental English hawthorn, C. monogyna. Apple and downy hawthorn-origin flies in the eastern USA use volatile blends emitted from the surface of their respective ripening fruit to find and discriminate among host trees. To test whether the same is true for western flies, we used coupled gas chromatography and electroantennographic detection (GC-EAD) and developed a 7-component apple fruit blend for western apple-origin flies, an 8-component black hawthorn fruit blend for flies infesting C. douglasii, and a 9-component ornamental hawthorn blend for flies from C. monogyna. Crataegus douglasii and C. monogyna-origin flies showed similar levels of upwind directed flight to their respective natal synthetic fruit blends in flight tunnel assays compared to whole fruit adsorbent extracts, indicating that the blends contain all the behaviorally relevant fruit volatiles to induce maximal response levels. The black and ornamental hawthorn blends shared four compounds in common including 3-methylbutan-1-ol, which appears to be a key volatile for R. pomonella populations in the eastern, southern, and western USA that show a preference for fruit from different Crataegus species. However, the blends also differed from one another and from domesticated apple in several respects that make it possible that western R. pomonella flies behaviorally discriminate among fruit volatiles and form ecologically differentiated host races, as is the case for eastern apple and hawthorn flies.

  10. Changes in physicochemical characteristics and free amino acids of hawthorn (Crataegus pinnatifida) fruits during maturation.

    PubMed

    Li, Wei-Qin; Hu, Qing-Ping; Xu, Jian-Guo

    2015-05-15

    In this study, changes in physicochemical characteristics associated with fruit quality and free amino acids were investigated during maturation of hawthorn fruits. Significant differences in these parameters were found during maturation. The color turned progressively from mature green to semi-red, to reach bright red; the shape changed gradually from oval to round or approached round; the size, weight, and edible part (flesh/core ratio) of hawthorns increased while the density of intact fruits did not change. The content of moisture, total soluble sugars, soluble pectin, reduced ascorbic acid, total ascorbic acid, fructose, and sucrose increased while crude protein content decreased significantly. The levels of starch, sucrose, titratable acidity, protopectin, pectin, total free amino acids, and total essential amino acids initially increased and then decreased gradually during maturation. The outcomes of this study provide additional and useful information for fresh consumption and processing as well as utilization of dropped unripe hawthorn fruits.

  11. Polyphenolic profile and biological activity of Chinese hawthorn (Crataegus pinnatifida BUNGE) fruits.

    PubMed

    Jurikova, Tunde; Sochor, Jiri; Rop, Otakar; Mlcek, Jiri; Balla, Stefan; Szekeres, Ladislav; Adam, Vojtech; Kizek, Rene

    2012-12-06

    Chinese hawthorn (Crataegus pinnatifida Bge.) fruits are rich in polyphenols (e.g., epicatechin, procyanidin B2, procyanidin B5, procyanidin C1, hyperoside, isoquercitrin and chlorogenic acid)--active compounds that exert beneficial effects. This review summarizes all information available on polyphenolic content and methods for their quantification in Chinese hawthorn berries and the relationships between individual polyphenolic compounds as well. The influence of species or cultivars, the locality of cultivation, the stage of maturity, and extract preparation conditions on the polyphenolic content were discussed as well. Currently, only fruits of C. pinnatifida and C. pinnatifida var. major are included in the Chinese Pharmacopoeia. Recent trials have demonstrated the efficacy of Chinese hawthorn fruit in lowering blood cholesterol and the risk of cardiovascular diseases. The fruit has also demonstrated anti-inflammatory and anti-tumour activities. This review deals mainly with the biological activity of the fruit related to its antioxidant properties.

  12. Comparative Protective Effect of Hawthorn Berry Hydroalcoholic Extract, Atorvastatin, and Mesalamine on Experimentally Induced Colitis in Rats

    PubMed Central

    Shafie-Irannejad, Vahid; Hobbenaghi, Rahim; Tabatabaie, Seyed Hamed; Moshtaghion, Seyed-Mehdi

    2013-01-01

    Abstract The protective effect of hydroalcoholic extract of hawthorn berries (HBE) on acetic acid (AA)–induced colitis in rats was investigated. Forty-two Wistar rats were divided into seven groups, including control and test groups (n=6). The control animals received saline, and the test animals were treated with saline (sham group), mesalamine (50 mg/kg; M group), atorvastatin (20 mg/kg; A group), HBE (100 mg/kg; H group), mesalamine and HBE (HM group), or atorvastatin plus HBE (HA group), 3 days before and a week after colitis induction. Colitis was induced by administration of 1 mL AA (4%) via a polyethylene catheter intrarectally. High-performance liquid chromatography analyses showed that HBE contained 0.13% and 0.5% oleanolic acid and ursolic acid, respectively. Elevated myeloperoxidase activity and lipid peroxidation were attenuated in the HA group. The H and HM groups showed marked reductions in colitis-induced decreases in total thiol molecules and body weight. The histopathological studies revealed that HBE decreased colitis-induced edema and infiltration of neutrophils. Our data suggest the anti-inflammatory and antioxidant effects of HBE and atorvastatin protect against AA-induced colitis. The anti-inflammatory effect of HBE may be attributable to its ability to decrease myeloperoxidase activity as a biomarker of neutrophil infiltration. PMID:23875899

  13. Gall production on hawthorns caused by Gymnosporangium spp.in Hatay province, Turkey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three hawthorn and related rust diseases caused by Gymnosporangium confusum on Crataegus monogyna, G. clavariiforme on C. orientalis, and G. sabinae on Pyrus communis were detected in Hatay province, Turkey. Gymnosporangium confusum was also found causing telial galls on Juniperus communis. Gymnospo...

  14. The Repressive Nature of the Past: Hawthorne's "House of the Seven Gables."

    ERIC Educational Resources Information Center

    Loges, Max L.

    "The House of the Seven Gables" describes the problems that emerge when a family allows itself to become so locked into the traditions and sins of the past that each new generation becomes a slightly degenerated facsimile of the previous generation. Nathaniel Hawthorne manages this task by comparing Clifford, a descendent of a long line…

  15. The investigation of some bioactive compounds and antioxidant properties of hawthorn (Crataegus monogyna subsp. monogyna Jacq)

    PubMed Central

    Keser, Serhat; Celik, Sait; Turkoglu, Semra; Yilmaz, Ökkes; Turkoglu, Ismail

    2014-01-01

    Aim: The antioxidant and pharmacological effects of hawthorn have mainly been attributed to the polyphenolic contents. The aim of this research is to determine some bioactive compounds and antioxidant properties of hawthorn aqueous and ethanol extracts of leaves, flowers, and ripened fruits. Materials and Methods: For this purpose, antioxidant activities of extracts were assessed on DPPH•, ABTS•+, superoxide scavenging, reducing power and ferrous metal chelating activity assays and phenolic content of extracts was determined by Folin—Cioacalteu’s reagent. Results: The flavonoids including rutin, apigenin, myricetin, quercetin, naringenin and kaempferol, were identified by high-performance liquid chromatography in the hawthorn extract. Conclusion: It was observed the aqueous and ethanol extracts of Crataegus monogyna subsp. monogyna fruits showed the highest activity in reducing power and metal chelating activity assays. In addition, it was determined that the aqueous flower extract showed higher flavonoid content than aqueous leaves extract. The antioxidant and pharmacological effects of hawthorn have mainly been attributed to the polyphenolic contents. PMID:26401347

  16. Singing and Companionship in the Hawthorn University of the Third-Age Choir, Australia

    ERIC Educational Resources Information Center

    Joseph, Dawn; Southcott, Jane

    2015-01-01

    The international University of the Third Age (U3A) embodies the principles of lifelong learning and personal fulfilment amongst members. The research reported in this article focused on the Choir of the U3A Hawthorn, Melbourne, Australia and the benefits perceived by members undertaking this active music engagement in non-competitive choral…

  17. Miocene reefs in western Mediterranean

    SciTech Connect

    Esteban, M.

    1988-01-01

    Coral reefs were particularly abundant and well developed during the late Tortonian and Messinian in southeastern Spain, the Balearic Islands, Italy, Sicily, Algeria, and Morocco. These reefs occurred just before and during the deposition of the thick Messinian evaporite units in the basinal areas and disappeared completely from Mediteranean during the early Pliocene. Most of the coral reefs are fringing terrigenous coastal fan complexes with very small lagoons and show progradation of less than 2 km. Some of the reefs occur on, or are intercalated with, Neogene volcanics or Messinian evaporites. Barrier-reef complexes are less common, have extensive lagoons behind them, and show complex progradational geometries more than 10 km wide. Excellent outcrops allow detailed reconstruction of paleogeography and sea level changes. Progradation predominated during phases of relative sea level drops and stillsands, while significant retrogradation occurred during sea level rises. The coral reef wall framework is commonly less than 20 m thick and is dominated by Porites and, locally, Tarbellastrae. Older Miocene reefs are less well developed, but show greater diversity of corals and reef organisms. Younger Miocene reef complexes occurring in open ocean settings are formed by only one branching coral genus (Porites or, locally, Tarbellastraea) with branching colonies up to 7 m high. Halimeda sands are particularly abundant in the upper reef slopes with occasional intercalations of red algae pavements that most likely coincide with episodes of terrigenous influx.

  18. Assessment of phenolic acid content and in vitro antiradical characteristics of hawthorn.

    PubMed

    Öztürk, Nilgün; Tunçel, Muzaffer

    2011-06-01

    The infusions and extracts obtained from leaves with flowers, fruit peel, and seed from hawthorn (Crataegus monogyna Jacq., Family Rosaceae) were subjected to evaluation as potential sources of antioxidant phytochemicals on the basis of their total content of phenolics, levels of phenolic acids, and in vitro antiradical activity. Total phenolic content of extracts was determined using the modified Folin-Ciocalteau method. Antioxidant activity was determined for phenolic extracts by a method involving the use of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Phenolic acids containing extracts and infusions from hawthorn leaves, fruit peel, and seeds were obtained using different polarity solvents and separated by reverse-phase high-performance liquid chromatography, which enabled improved separation by the use of a C(18) column, an acidic mobile phase, and gradient elusion. The highest total phenolic content (343.54 mg of gallic acid equivalents/g) and the highest DPPH radical scavenging activity as the inhibition percentage (60.36%) were obtained in ethyl acetate extract from hawthorn leaves with flower. Also, the highest phenolic acid content was measured in the extracts of hawthorn leaves with flowers: protocathechuic (108-128 mg/100 g), p-hydroxy benzoic (141-468 mg/100 g), caffeic (137-3,580 mg/100 g), chlorogenic (925-4,637 mg/100 g), ferulic (3,363-3,462 mg/100 g), vanillic (214 mg/100 g), and syringic (126 mg/100 g) acids. The results indicate that hawthorn is a promising plant because of its high antioxidant activity.

  19. New primate genus from the Miocene of Argentina

    PubMed Central

    Tejedor, Marcelo F.; Tauber, Adán A.; Rosenberger, Alfred L.; Swisher, Carl C.; Palacios, María E.

    2006-01-01

    Killikaike blakei is a new genus and species of anthropoid from the late Early Miocene of southeastern Argentina based on the most pristine fossil platyrrhine skull and dentition known so far. It is part of the New World platyrrhine clade (Family Cebidae; Subfamily Cebinae) including modern squirrel (Saimiri) and capuchin monkeys (Cebus) and their fossil relatives known from Early to Middle Miocene and subrecent periods. Living cebines are relatively large-brained, adroit predatory foragers and live within complex social groups, and wild capuchins exhibit a wide range of behaviors associated with enhanced intelligence. We show that K. blakei lacks diagnostic derived characteristics of the lower face and premolar dentition that are shared by modern cebines, but its strongly vaulted frontal bone and capacious anterior cranial fossa indicate the early evolution of an enlarged forebrain. PMID:16567649

  20. Effect of hawthorn (Crataegus oxycantha) crude extract and chromatographic fractions on multiple activities in a cultured cardiomyocyte assay.

    PubMed

    Long, S R; Carey, R A; Crofoot, K M; Proteau, P J; Filtz, T M

    2006-11-01

    Extracts of hawthorn (Crataegus oxycantha) have become popular herbal supplements for their well-recognized cardiotonic effects. Many commercial preparations have been used successfully in the treatment of congestive heart failure, although the active principles within these extracts have yet to be conclusively identified. Several hawthorn preparations were studied and found to have negative chronotropic effects in a cultured neonatal murine cardiomyocyte assay using unpaced cells. As compared to conventional cardiac drugs (i.e., epinephrine, milrinone, ouabain, or propranolol), hawthorn extract has a unique activity profile. Hawthorn extract appears to be anti-arrhythmic and capable of inducing rhythmicity in quiescent cardiomyocytes. Hawthorn extract does not cause beta-adrenergic receptor blockade at concentrations which cause negative chronotropic effects. Commercial hawthorn preparations, extracts prepared from dried leaves and those made from dried berries have similar chronotropic activities. When crude extracts are separated using size-exclusion chromatography, several fractions retain multiple cardiac activities. Assays with chromatographic fractions reveal that multiple dissimilar cardioactive components may exist within the extract, making the identification of individual active constituents more challenging.

  1. Ammonium carbonate is more attractive than apple and hawthorn fruit volatile lures to Rhagoletis pomonella (Diptera: Tephritidae) in Washington State.

    PubMed

    Yee, Wee L; Nash, Meralee J; Goughnour, Robert B; Cha, Dong H; Linn, Charles E; Feder, Jeffrey L

    2014-08-01

    The apple maggot fly, Rhagoletis pomonella (Walsh), is an introduced, quarantine pest of apple (Malus domestica Borkhausen) in the Pacific Northwest of the United States. In the eastern United States where the fly is native, fruit volatiles have been reported to be more attractive than ammonia compounds to R. pomonella. However, the opposite may be true in the western United States. Here, we determined whether newly identified western apple and western hawthorn fruit volatiles are more attractive than ammonium carbonate (AC) to R. pomonella in apple, black hawthorn, and ornamental hawthorn trees in western Washington State. In all three host trees, sticky red sphere or yellow panel traps baited with AC generally caught more flies than traps baited with lures containing the four newly developed fruit blends (modified eastern apple, western apple, western ornamental hawthorn, and western black hawthorn) or two older blends (eastern apple and eastern downy hawthorn). Fruit volatiles also displayed more variation among trapping studies conducted at different sites, in different host trees, and across years than AC. The results imply that traps baited with AC represent the best approach to monitoring R. pomonella in Washington State.

  2. Panafrican distribution of Lower Miocene Hominoidea

    NASA Astrophysics Data System (ADS)

    Senut, Brigitte; Pickford, Martin; Wessels, Dudley

    1997-11-01

    Palaeontological survey of the Neogene littoral deposits of the Namaqualand coastal strip, Northern Cape Province, South Africa, has resulted in the collection of the first Lower Miocene faunas from South Africa. Among the mammals from Ryskop and Hondeklip Bay is a gorilla-sized hominoid. This discovery greatly increases the geographic range of early Miocene hominoids and suggests that even at this remote epoch, the superfamily had a Panafrican distribution.

  3. B. F. Skinner and T. N. Whitehead: a brief encounter, research similarities, hawthorne revisited, what next?

    PubMed

    Claus, Calvin K

    2007-01-01

    B. F. Skinner and T. N. Whitehead recalled a personal interaction in 1934, with differing memories of the event. No evidence of other subsequent interactions or mutual citations has been found. Although they went their separate ways, three similarities in their research strategies have been found and are discussed. Elements of Whitehead's Hawthorne study and Skinner's concurrent, parallel work reveal that they both (a) introduced the cumulative curve to report data, (b) used a small number of subjects studied over time, and (c) used highly accurate recording devices. A few "afterwords" are offered on their lives and writings, and again, on the Hawthorne effect. A suggestion is made that a Skinner-Whitehead research approach might be useful in studying gambling behavior.

  4. Phenylpropanoid-substituted procyanidins and tentatively identified procyanidin glycosides from hawthorn (Crataegus spp.).

    PubMed

    Sendker, Jandirk; Petereit, Frank; Lautenschläger, Marcus; Hellenbrand, Nils; Hensel, Andreas

    2013-01-01

    The rational use of hawthorn leafs and flowers from Crataegus spp. for declining cardiac performance is mainly due to flavon-C-glycosides and oligomeric procyanidins (OPC). From OPC-enriched extracts from different batches, a dimeric phenylpropanoid-substituted procyanidin (cinchonain II b, 1) was isolated and characterized by MS, CD, and NMR. Also the presence of higher oligomeric cinchonains (degree of polymerization 3 to 8) in hawthorn extracts was shown by a specific ultrahigh-pressure liquid chromatography-ESI-qTOF-MS method. Interestingly, strong evidence for the occurrence of oligomeric procyanidin hexosides was found by ultrahigh-pressure liquid chromatography-ESI-qTOF-MS analysis which additionally revealed the presence of peaks indicative of dimeric procyanidin hexosides by their exact mass, which were clearly distinguishable from the cinchonain II type peaks.

  5. B. F. Skinner and T. N. Whitehead: A Brief Encounter, Research Similarities, Hawthorne Revisited, What Next?

    PubMed Central

    Claus, Calvin K

    2007-01-01

    B. F. Skinner and T. N. Whitehead recalled a personal interaction in 1934, with differing memories of the event. No evidence of other subsequent interactions or mutual citations has been found. Although they went their separate ways, three similarities in their research strategies have been found and are discussed. Elements of Whitehead's Hawthorne study and Skinner's concurrent, parallel work reveal that they both (a) introduced the cumulative curve to report data, (b) used a small number of subjects studied over time, and (c) used highly accurate recording devices. A few “afterwords” are offered on their lives and writings, and again, on the Hawthorne effect. A suggestion is made that a Skinner–Whitehead research approach might be useful in studying gambling behavior. PMID:22478490

  6. Updated chronology for the Miocene hominoid radiation in Western Eurasia

    PubMed Central

    Casanovas-Vilar, Isaac; Alba, David M.; Garcés, Miguel; Robles, Josep M.; Moyà-Solà, Salvador

    2011-01-01

    Extant apes (Primates: Hominoidea) are the relics of a group that was much more diverse in the past. They originated in Africa around the Oligocene/Miocene boundary, but by the beginning of the Middle Miocene they expanded their range into Eurasia, where they experienced a far-reaching evolutionary radiation. A Eurasian origin of the great ape and human clade (Hominidae) has been favored by several authors, but the assessment of this hypothesis has been hampered by the lack of accurate datings for many Western Eurasian hominoids. Here we provide an updated chronology that incorporates recently discovered Iberian taxa and further reevaluates the age of many previously known sites on the basis of local biostratigraphic scales and magnetostratigraphic data. Our results show that identifiable Eurasian kenyapithecins (Griphopithecus and Kenyapithecus) are much younger than previously thought (ca. 14 Ma instead of 16 Ma), which casts serious doubts on the attribution of the hominoid tooth from Engelswies (16.3–16.5 Ma) to cf. Griphopithecus. This evidence is further consistent with an alternative scenario, according to which the Eurasian pongines and African hominines might have independently evolved in their respective continents from similar kenyapithecin ancestors, resulting from an early Middle Miocene intercontinental range extension followed by vicariance. This hypothesis, which would imply an independent origin of orthogrady in pongines and hominines, deserves further testing by accurately inferring the phylogenetic position of European dryopithecins, which might be stem pongines rather than stem hominines. PMID:21436034

  7. Miocene reef carbonates of Mariana Islands

    SciTech Connect

    Siegrist, H.G. Jr.

    1988-02-01

    Miocene carbonates in the southern Mariana Islands are impressive for their lithologic diversity, thicknesses (over 250 m), and geographic extent (> 20% combined outcrop coverage over four major high islands: Guam, Rota, Tinian and Saipan). Sections are dominated either by lagoonal algal-foraminiferal wackestones and mudstones with locally abundant high-energy shelly-skeletal facies, or by rubbly to muddy, fore-reef-to-bank deposits of packstones and grainstones with highly diverse and variable biogenic clasts. Fresh to deeply weathered volcaniclastic material may comprise at least 80% of some high-energy fore-reef facies, whereas lagoonal and bank deposits usually contain less than 0.5% terrigenous material. Surprisingly, the Miocene in the Marianas lacks almost completely any reef-core facies. Several poorly developed coral-rich mounds on Saipan and localized laminated red algal buildups on Guam appear to constitute the extant reef-wall facies in the Miocene. The lack of buildups may be a matter of differential survival; it may result from headland erosion and benching associated with emergence of narrow reef tracts as has been postulated by others for south Guam. Alternatively, the authors are proposing that Miocene bathymetry and the volume of terrigenous influx militated against significant reef core formation. Radiometric age dating of these reef carbonates has proven unsuccessful because pervasive diagenesis has transformed the entire Miocene section into low-magnesium calcite with minor and occasional dolomite. Freshwater phreatic diagenesis accounts for the principal porosity variation and trace element distribution.

  8. Additional material of the enigmatic Early Miocene mammal Kelba and its relationship to the order Ptolemaiida

    PubMed Central

    Cote, Susanne; Werdelin, Lars; Seiffert, Erik R.; Barry, John C.

    2007-01-01

    Kelba quadeemae, a fossil mammal from the Early Miocene of East Africa, was originally named on the basis of three isolated upper molars. Kelba has previously been interpreted as a creodont, a pantolestid, an insectivoran, and a hemigaline viverrid. The true affinities of this taxon have remained unclear because of the limited material and its unique morphology relative to other Miocene African mammals. New material of Kelba from several East African Miocene localities, most notably a skull from the Early Miocene locality of Songhor in Western Kenya, permits analysis of the affinities of Kelba and documents the lower dentition of this taxon. Morphological comparison of this new material clearly demonstrates that Kelba is a member of the order Ptolemaiida, a poorly understood group whose fossil record was previously restricted to the Oligocene Fayum deposits of northern Egypt. Phylogenetic analysis supports the monophyly of the Ptolemaiida, including Kelba, and recovers two monophyletic clades within the order. We provide new family names for these groups and an emended diagnosis for the order. The discovery of ptolemaiidans from the Miocene of East Africa is significant because it extends the known temporal range of the order by >10 million years and the geographic range by >3,200 km. Although the higher-level affinities of the Ptolemaiida remain obscure, their unique morphology and distribution through a larger area of Africa (and exclusively Africa) lend support to the idea that Ptolemaiida may have an ancient African origin. PMID:17372202

  9. Miocene marine incursions and marine/freshwater transitions: Evidence from Neotropical fishes

    NASA Astrophysics Data System (ADS)

    Lovejoy, Nathan R.; Albert, James S.; Crampton, William G. R.

    2006-03-01

    Amazonian rivers contain a remarkable fauna of endemic species derived from taxa that generally occur in oceans and seas. Several hypotheses have been proposed to explain the origin of marine-derived lineages, including opportunistic invasions via estuaries, vicariance related to uplift of the Andes, and vicariance related to Miocene marine incursions and connections. Here, we examine available data for marine-derived lineages of four groups: stingrays (Myliobatiformes), drums (Sciaenidae), anchovies (Engraulididae), and needlefish (Belonidae). Geographic distributions, age estimates (determined using fossils, biogeography, and molecular data sets), and phylogenies for these taxa are most compatible with origination during the Miocene from marine sister groups distributed along the northern coast of South America. We speculate that unique ecological and biogeographic aspects of the Miocene upper Amazonian wetland system, most notably long-term connections with marine systems, facilitated the evolutionary transition from marine to freshwater habitats.

  10. Miocene precursors to Great Barrier Reef

    SciTech Connect

    Davies, P.J.; Symonds, P.A.; Feary, D.A.; Pigram, C.

    1988-01-01

    Huge reefs of Miocene age are present in the Gulf of Papua north of the present-day Great Barrier Reef and to the east on the Marion and Queensland Plateaus. In the Gulf of Papua, Miocene barrier reefs formed the northern forerunner of the Great Barrier Reef, extending for many hundreds of kilometers along the eastern and northern margin of the Australian craton within a developing foreland basin. Barrier reefs, slope pinnacle reefs, and platform reefs are seen in seismic sections and drill holes. Leeside talus deposits testify to the high energy impinging on the eastern margin of these Miocene reefs. The Queensland Plateau is a marginal plateau east of the central Great Barrier Reef and separated from it by a rift trough. Miocene reefs occupied an area of about 50,000 km/sup 2/ and grew on salt-controlled highs on the western margin of the plateau and on a regional basement high extending from the platform interior to its southern margin. Reef growth has continued to the present day, although two major contractions in the area covered by reefs occurred during the Miocene. The Marion Plateau is present directly east of the Great Barrier Reef and during the Micoene formed a 30,000-km/sup 2/ platform with barrier reefs along its northern margin and huge platform reefs and laggons on the platform interior. These reefs grew on a flat peneplained surface, the whole area forming a large shallow epicontinental sea. In all three areas, the middle Miocene formed the acme of reef expansion in the region.

  11. Shark-bitten vertebrate coprolites from the Miocene of Maryland.

    PubMed

    Godfrey, Stephen J; Smith, Joshua B

    2010-05-01

    Coprolites (fossilized feces) preserve a wide range of biogenic components, from bacteria and spores to a variety of vertebrate tissues. Two coprolites from the Calvert Cliffs outcrop belt (Miocene-aged Chesapeake Group), MD, USA, preserve shark tooth impressions in the form of partial dental arcades. The specimens are the first known coprolites to preserve vertebrate tooth marks. They provide another example of trace fossils providing evidence of prehistoric animal behaviors that cannot be directly approached through the study of body fossils. Shark behaviors that could account for these impressions include: (1) aborted coprophagy, (2) benthic or nektonic exploration, or (3) predation.

  12. Fish Productivity in Open-Ocean Gyre Systems in the Late Oligocene and Miocene

    NASA Astrophysics Data System (ADS)

    Cuevas, J. M.; Sibert, E. C.; Norris, R. D.

    2015-12-01

    Understanding how marine ecosystems respond to climate change is very important as we continue to warm the climate. Fish represent a critical protein source for a significant portion of the global population, and as such, an understanding of fish production and its interactions with climate change may help better prepare for the future. Ichthyoliths, fossil fish teeth and shark scales, are a novel fossil group which can be used as an indicator for fish productivity. Several important climate events occurred during the Miocene (7 to 23 Ma), including the Middle Miocene Climatic Optimum. Here we reconstruct fish production from across the Miocene from Pacific and Atlantic Ocean gyres. South Atlantic samples, from Deep Sea Drilling Program (DSDP) Site 522 spanning from 30 to 20 Ma, show fairly variable numbers in the Oligocene (ranging from 100 to 800 ich/cm2/yr), but stabilization in the Early Miocene (around 400 ich/cm2/yr), suggesting that the beginning of the Miocene brought consistent conditions for fish production. In the North Pacific, our record from Ocean Drilling Program (ODP) Site 886 shows a distinct crash in fish productivity at 11 Ma, from 3500 ich/cm2/yr to a steady decline around 100 ich/cm2/yr for the next million years. This crash is followed by a marked increase in the presence of diatoms and biogenous opal. This is somewhat surprising, since in modern oceanic systems, an increase in diatoms and other large-celled phytoplankton is associated with shorter, more efficient food chains and higher levels of fish. It is also interesting to note that denticles remain consistently low at both sites, indicating consistently low shark populations through this time period. Together, these results suggest that the Late Oligocene and Miocene was a time of variable fish production and provide a window into understanding of dynamic ecosystem changes through the Miocene in open-ocean gyre ecosystems.

  13. Influence of extraction technique on the anti-oxidative potential of hawthorn (Crataegus monogyna) extracts in bovine muscle homogenates.

    PubMed

    Shortle, E; O'Grady, M N; Gilroy, D; Furey, A; Quinn, N; Kerry, J P

    2014-12-01

    Six extracts were prepared from hawthorn (Crataegus monogyna) leaves and flowers (HLF) and berries (HB) using solid-liquid [traditional (T) (HLFT, HBT), sonicated (S) (HLFS, HBS)] and supercritical fluid (C) extraction (HLFC, HBC) techniques. The antioxidant activities of HLF and HB extracts were characterised using in vitro antioxidant assays (TPC, DPPH, FRAP) and in 25% bovine muscle (longissimus lumborum) homogenates (lipid oxidation (TBARS), oxymyoglobin (% of total myoglobin)) after 24h storage at 4°C. Hawthorn extracts exhibited varying degrees of antioxidant potency. In vitro and muscle homogenate (TBARS) antioxidant activity followed the order: HLFS>HLFT and HBT>HBS. In supercritical fluid extracts, HLFC>HBC (in vitro antioxidant activity) and HLFC≈HBC (TBARS). All extracts (except HBS) reduced oxymyoglobin oxidation. The HLFS extract had the highest antioxidant activity in all test systems. Supercritical fluid extraction (SFE) exhibited potential as a technique for the manufacture of functional ingredients (antioxidants) from hawthorn for use in muscle foods.

  14. Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada

    SciTech Connect

    Not Available

    1981-11-04

    Site characteristics pertinent to the geothermal development are described, including: physiography, demography, economy, and goals and objectives of the citizens as they relate to geothermal development. The geothermal reservoir is characterized on the basis of available information. The probable drilling depth to the reservoir, anticipated water production rates, water quality, and resource temperature are indicated. Uses of the energy that seem appropriate to the situation both now and in the near future at Hawthorne are described. The essential institutional requirements for geothermal energy development are discussed, including the financial, environmental, and legal and regulatory aspects. The various steps that are necessary to accomplish the construction of the geothermal district heating system are described.

  15. Anti-inflammatory, gastroprotective, free-radical-scavenging, and antimicrobial activities of hawthorn berries ethanol extract.

    PubMed

    Tadić, Vanja M; Dobrić, Silva; Marković, Goran M; Dordević, Sofija M; Arsić, Ivana A; Menković, Nebojsa R; Stević, Tanja

    2008-09-10

    Hawthorn [Crataegus monogyna Jacq. and Crataegus oxyacantha L.; sin. Crataegus laevigata (Poiret) DC., Rosaceae] leaves, flowers, and berries are used in traditional medicine in the treatment of chronic heart failure, high blood pressure, arrhythmia, and various digestive ailments, as well as geriatric and antiarteriosclerosis remedies. According to European Pharmacopoeia 6.0, hawthorn berries consist of the dried false fruits of these two species or their mixture. The present study was carried out to test free-radical-scavenging, anti-inflammatory, gastroprotective, and antimicrobial activities of hawthorn berries ethanol extract. Phenolic compounds represented 3.54%, expressed as gallic acid equivalents. Determination of total flavonoid aglycones content yielded 0.18%. The percentage of hyperoside, as the main flavonol component, was 0.14%. With respect to procyanidins content, the obtained value was 0.44%. DPPH radical-scavenging capacity of the extract was concentration-dependent, with EC50 value of 52.04 microg/mL (calculation based on the total phenolic compounds content in the extract). Oral administration of investigated extract caused dose-dependent anti-inflammatory effect in a model of carrageenan-induced rat paw edema. The obtained anti-inflammatory effect was 20.8, 23.0, and 36.3% for the extract doses of 50, 100, and 200 mg/kg, respectively. In comparison to indomethacin, given in a dose producing 50% reduction of rat paw edema, the extract given in the highest tested dose (200 mg/kg) showed 72.4% of its activity. Gastroprotective activity of the extract was investigated using an ethanol-induced acute stress ulcer in rats with ranitidine as a reference drug. Hawthorn extract produced dose-dependent gastroprotective activity (3.8 +/- 2.1, 1.9 +/- 1.7, and 0.7 +/- 0.5 for doses of 50, 100, and 200 mg/kg, respectively), with the efficacy comparable to that of the reference drug. Antimicrobial testing of the extract revealed its moderate bactericidal

  16. A sphenodontine (Rhynchocephalia) from the Miocene of New Zealand and palaeobiogeography of the tuatara (Sphenodon)

    PubMed Central

    Jones, Marc E.H.; Tennyson, Alan J.D.; Worthy, Jennifer P.; Evans, Susan E.; Worthy, Trevor H.

    2009-01-01

    Jaws and dentition closely resembling those of the extant tuatara (Sphenodon) are described from the Manuherikia Group (Early Miocene; 19–16 million years ago, Mya) of Central Otago, New Zealand. This material is significant in bridging a gap of nearly 70 million years in the rhynchocephalian fossil record between the Late Pleistocene of New Zealand and the Late Cretaceous of Argentina. It provides the first pre-Pleistocene record of Rhynchocephalia in New Zealand, a finding consistent with the view that the ancestors of Sphenodon have been on the landmass since it separated from the rest of Gondwana 82–60 Mya. However, if New Zealand was completely submerged near the Oligo-Miocene boundary (25–22 Mya), as recently suggested, an ancestral sphenodontine would need to have colonized the re-emergent landmass via ocean rafting from a currently unrecorded and now extinct Miocene population. Although an Early Miocene record does not preclude that possibility, it substantially reduces the temporal window of opportunity. Irrespective of pre-Miocene biogeographic history, this material also provides the first direct evidence that the ancestors of the tuatara, an animal often perceived as unsophisticated, survived in New Zealand despite substantial local climatic and environmental changes. PMID:19203920

  17. Miocene reef carbonates of Mariana Islands

    SciTech Connect

    Siegrist, H.G. Jr.

    1988-01-01

    Miocene carbonates in the southern Mariana Islands are impressive for their lithologic diversity, thicknesses (over 250 m), and geographic extend (>20% combined outcrop coverage over four major high islands: Guam, Rota, Tinian and Saipan). Sections are dominated either by lagoonal algal-foraminiferal wackestones and mudstones with locally abundant high-energy shelly-skeletal facies, or by rubbly to muddy, fore-reef-to-bank deposits of packstones and grainstones with highly diverse and variable biogenic clasts. Fresh to deeply weathered volcaniclastic material may comprise at least 80% of some high-energy fore-reef facies, whereas lagoonal and bank deposits usually contain less than 0.5% terrigenous material. Surprisingly, the Miocene in the Marianas lacks almost completely any reef-core facies. Several poorly developed coral-rich mounds on Saipan and localized laminated red algal buildups on Guam appear to constitute the extant reef-wall facies in the Miocene. The lack of buildups may be a matter of differential survival; it may result from headland erosion and benching associated with emergency of narrow reef tracts as has been postulated by others for south Guam. Radiometric age dating of these reef carbonates has proven unsuccessful because pervasive diagenesis has transformed the entire Miocene section into low-magnesium calcite with minor and occasional dolomite. Freshwater phreatic diagenesis accounts for the principal porosity variation and trace element distribution.

  18. Metsulfuron spray drift reduces fruit yield of hawthorn (Crataegus monogyna L.).

    PubMed

    Kjaer, Christian; Strandberg, Morten; Erlandsen, Mogens

    2006-03-01

    This study was carried out to investigate whether spray drift of metsulfuron has a potential to negatively affect hawthorn (Crataegus monogyna) hedgerows near agricultural fields. For this purpose four doses of metsulfuron ranging from 5% to 40% of the field dose (4 g metsulfuron per hectare) were sprayed on trees in seven different hawthorn hedgerows. The actual deposition on the leaves was measured by means of a tracer (glycine). Spraying was conducted both at the bud stage and at early flowering. Leaves, flowers, green berries and mature berries were harvested and the number and weight of each were measured. The spraying at the bud stage caused a highly significant reduction in number and dry weight of berries, whereas it had no effects on leaf and flower production. The berry reduction was close to 100% at actual depositions relevant for spray drift under normal conditions. Spraying at early flowering also significantly reduced berries although the effect was smaller than for the spraying at bud stage. The early flower stage spraying caused no reduction in number and size of leaves. The possible ecological consequence is that metsulfuron spray drift from agricultural fields has a potential to reduce the amount of berries available for frugivorous birds in nearby hedgerows. A potential need for regulatory measures to reduce herbicide spray drift to hedgerows situated near agricultural fields with herbicide use is also indicated.

  19. Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada

    SciTech Connect

    Not Available

    1981-11-04

    The results of the analyses as well as a plan for the development of the geothermal resource are described. Site characteristics pertinent to the geothermal development are described. These characteristics include physiography, demography, economy, and goals and ojectives of the citizens as they would relate to geothermal development. The geothermal resource is described. The reservoir is characterized on the basis of available information. The probable drilling depth to the reservoir, anticipated water production rates, water quality, and resource temperatures ae indicated. Uses of the energy that seem appropriate to the situation both now and in the near future at Hawthorne are described. The amounts and types of energy currently consumed by end users are estimated. Using this data base, conceptual engineering designs and cost estimates for three alternative district heating systems are presented. In addition, the results of a life cycle cost analysis for these alternatives are discussed. The essential institutional requirements for geothermal energy development, including the financial, environmental, and legal and regulatory aspects are discussed. The various steps that are necessary to accomplish the construction of the geothermal district heating system at Hawthorne are described. A time-line chart shows the tasks, the time estimated to be required for each, and the interrelationships among the activities.

  20. Transcript Assembly and Quantification by RNA-Seq Reveals Differentially Expressed Genes between Soft-Endocarp and Hard-Endocarp Hawthorns

    PubMed Central

    Zhang, Feng; Liu, Zhongchi; Li, Xiaoming; Li, Wenran; Ma, Yue; Li, He; Liu, Yuexue; Zhang, Zhihong

    2013-01-01

    Hawthorn (Crataegus spp.) is an important pome with a long history as a fruit, an ornamental, and a source of medicine. Fruits of hawthorn are marked by hard stony endocarps, but a hawthorn germplasm with soft and thin endocarp was found in Liaoning province of China. To elucidate the molecular mechanism underlying the soft endocarp of hawthorn, we conducted a de novo assembly of the fruit transcriptome of Crataegus pinnatifida and compared gene expression profiles between the soft-endocarp and the hard-endocarp hawthorn varieties. De novo assembly yielded 52,673 putative unigenes, 20.4% of which are longer than 1,000 bp. Among the high-quality unique sequences, 35,979 (68.3%) had at least one significant match to an existing gene model. A total of 1,218 genes, represented 2.31% total putative unigenes, were differentially expressed between the soft-endocarp hawthorn and the hard-endocarp hawthorn. Among these differentially expressed genes, a number of lignin biosynthetic pathway genes were down-regulated while almost all the flavonoid biosynthetic pathway genes were strongly up-regulated, concomitant with the formation of soft endocarp. In addition, we have identified some MYB and NAC transcription factors that could potentially control lignin and flavonoid biosynthesis. The altered expression levels of the genes encoding lignin biosynthetic enzymes, MYB and NAC transcription factors were confirmed by quantitative RT-PCR. This is the first transcriptome analysis of Crataegus genus. The high quality ESTs generated in this study will aid future gene cloning from hawthorn. Our study provides important insights into the molecular mechanisms underlying soft endocarp formation in hawthorn. PMID:24039819

  1. Paleomagnetism of the Miocene Columbia River Basalt Group in Oregon and Washington from the Pacific Coast to the Columbia Plateau: Magnetostratigraphy, Vertical-Axis Rotations, Paleosecular Variation, and Remagnetization

    NASA Astrophysics Data System (ADS)

    Hagstrum, J. T.; Wells, R. E.; Evarts, R. C.; Niem, A. R.; Sawlan, M. G.; Blakely, R. J.

    2008-12-01

    Identification of individual flows within the Columbia River Basalt Group (CRBG) has mostly relied on minor differences in geochemistry, but magnetic polarity has also proved useful in differentiating flows and establishing a temporal framework. Within the thick, rapidly erupted Grande Ronde Basalt four major polarity chrons (R1 to N2) have been identified. Because cooling times of CRBG flows are brief compared to rates of paleosecular variation (PSV), within-flow paleomagnetic directions are expected to be constant across the extensive east-west reaches of these flows. Vertical-axis rotations in OR and WA, driven by northward-oblique subduction of the Juan de Fuca plate, thus can be measured by comparing directions for western sampling localities to directions for the same flow units on the relatively stable Columbia Plateau. Clockwise rotations calculated for outcrop locations within the Coast Range (CR) block are uniformly about 30° (N=102 sites). East of the northwest-trending en échelon Mt. Angel-Gales Creek, Portland Hills, and northern unnamed fault zones, as well as north of the CR block's northern boundary (~Columbia River), clockwise rotations abruptly drop to about 15° (N=39 sites), with offsets in these bounding fault zones corresponding to the Portland and Willamette pull-apart basins. The general agreement of vertical- axis rotation rates estimated from CRBG magnetizations with those determined from modern GPS velocities indicates a relatively steady rate over the last 10 to 15 Myr. Unusual directions due to PSV, field excursions, or polarity transitions could provide useful stratigraphic markers. Individual flow directions, however, have not been routinely used to identify flows. One reason this has been difficult is that remagnetization is prevalent, particularly in the Coast Ranges, coupled with earlier demagnetization techniques that did not completely remove overprint components. Except for the Ginkgo and Pomona flows of the Wanapum and Saddle

  2. El Nino-like events during Miocene

    SciTech Connect

    Casey, R.E.; Nelson, C.O.; Weinheimer, A.L.; Oeth, P.A.; Swanson, R.J.

    1988-03-01

    El Nino-like events have been recorded from the Miocene laminated siliceous facies of the Monterey Formation. These El Nino-like Miocene events are compared to El Nino events recorded from Holocene varved sediments deposited within the anoxic Santa Barbara basin. Strong El Nino events can be recognized from Holocene Santa Barbara basin sediments by increases in radiolarian flux to the sea floor during those events. For the last 100-plus years, frequency of strong El Ninos has been on the order of one extremely strong event about every 100 years, and one easily recognizable event about every 18 years. Frequencies in the laminated (varved) Miocene range from about every 4-5 years to over 20 years. The higher frequencies occur within generally warm intervals and the lower frequencies within generally cold intervals. Perhaps the frequencies of these events may, in fact, be an important indicator in determining whether the intervals were cold or warm. Reconstructions of the paleo-California Current system during El Nino-like periods have been made for the west coast from the Gulf of California to northern California. Strong El Nino-like events occurred 5.5 and 8 Ma, and a strong anti-El Nino-like event occurred at about 6.5 Ma. Evidence from the 5.5 and 8 Ma events combined with other evidence suggests that modern El Ninos, similar to today's, were initiated at 5.5 Ma or earlier.

  3. Miocene cercopithecoidea from the Tugen Hills, Kenya.

    PubMed

    Gilbert, Christopher C; Goble, Emily D; Hill, Andrew

    2010-11-01

    Miocene to Pleistocene fossiliferous sediments in the Tugen Hills span the time period from at least 15.5 Ma to 0.25 Ma, including time periods unknown or little known elsewhere in Africa. Consequently, the Tugen Hills deposits hold the potential to inform us about crucial phylogenetic events in African faunal evolution and about long-term environmental change. Among the specimens collected from this region are a number of discoveries already important to the understanding of primate evolution. Here, we describe additional cercopithecoid material from the Miocene deposits in the Tugen Hills sequence, including those from securely dated sites in the Muruyur Beds (16-13.4 Ma), the Mpesida Beds (7-6.2 Ma) and the Lukeino Formation (∼ 6.2-5.7 Ma). We also evaluate previously described material from the Ngorora Formation (13-8.8 Ma). Identified taxa include Victoriapithecidae gen. et sp. indet., cf. Parapapio lothagamensis, and at least two colobines. Specimens attributed to cf. Pp. lothagamensis would extend the species' geographic range beyond its type locality. In addition, we describe specimens sharing derived characters with modern African colobines (Tribe: Colobina), a finding that is congruent with previous molecular estimates of colobine divergence dates. These colobine specimens represent some of the earliest known members of the modern African colobine radiation and, in contrast to previous hypotheses, suggest that early African colobines were mainly arboreal and that semi-terrestrial Late Miocene and Plio-Pleistocene colobine taxa were secondarily derived in their locomotor adaptations.

  4. A unique Middle Miocene European hominoid and the origins of the great ape and human clade

    PubMed Central

    Moyà-Solà, Salvador; Alba, David M.; Almécija, Sergio; Casanovas-Vilar, Isaac; Köhler, Meike; De Esteban-Trivigno, Soledad; Robles, Josep M.; Galindo, Jordi; Fortuny, Josep

    2009-01-01

    The great ape and human clade (Primates: Hominidae) currently includes orangutans, gorillas, chimpanzees, bonobos, and humans. When, where, and from which taxon hominids evolved are among the most exciting questions yet to be resolved. Within the Afropithecidae, the Kenyapithecinae (Kenyapithecini + Equatorini) have been proposed as the sister taxon of hominids, but thus far the fragmentary and scarce Middle Miocene fossil record has hampered testing this hypothesis. Here we describe a male partial face with mandible of a previously undescribed fossil hominid, Anoiapithecus brevirostris gen. et sp. nov., from the Middle Miocene (11.9 Ma) of Spain, which enables testing this hypothesis. Morphological and geometric morphometrics analyses of this material show a unique facial pattern for hominoids. This taxon combines autapomorphic features—such as a strongly reduced facial prognathism—with kenyapithecine (more specifically, kenyapithecin) and hominid synapomorphies. This combination supports a sister-group relationship between kenyapithecins (Griphopithecus + Kenyapithecus) and hominids. The presence of both groups in Eurasia during the Middle Miocene and the retention in kenyapithecins of a primitive hominoid postcranial body plan support a Eurasian origin of the Hominidae. Alternatively, the two extant hominid clades (Homininae and Ponginae) might have independently evolved in Africa and Eurasia from an ancestral, Middle Miocene stock, so that the supposed crown-hominid synapomorphies might be homoplastic. PMID:19487676

  5. Miocene mass-transport sediments, Troodos Massif, Cyprus

    USGS Publications Warehouse

    Lord, A.R.; Harrison, R.W.; BouDagher-Fadel, M.; Stone, B.D.; Varol, O.

    2009-01-01

    Sediment mass-transport layers of submarine origin on the northern and southern flanks of the Troodos ophiolitic massif are dated biostratigraphically as early Miocene and late Miocene, respectively and therefore represent different seismogenic events in the uplift and erosional history of the Troodos terrane. Analysis of such events has potential for documenting Miocene seismic and uplift events regionally in the context of changing stress field directions and plate vectors through time. ?? 2009 The Geologists' Association.

  6. Isolation and quantification of oligomeric and polymeric procyanidins in leaves and flowers of Hawthorn (Crataegus spp.).

    PubMed

    Hellenbrand, N; Sendker, J; Lechtenberg, M; Petereit, F; Hensel, A

    2015-07-01

    Proanthocyanidins (PAs) constitute a class of polyphenols with flavan-3-ols as monomeric building blocks. These polyphenols are mostly quantified by colorimetric methods or by chromatographic determination of monomeric flavan-3-ols or low molecular oligomers as lead compounds. No reliable analytical methods are available for unambiguous identification of the homologues series of oligo- and polymeric PAs. For Hawthorn leaf and flower (Crataegi folium cum flore) from Crataegus spp. (Rosaceae) a protocol for preparative isolation of oligomeric and polymeric PAs from an acetone-water extract was developed, yielding procyanidin reference clusters with defined degree of polymerization (DP) from 2 to 10 besides a procyanidin-polymer. Identity and purity of these clusters were proven by HPLC, MS and in part NMR studies. For identification and quantification from Hawthorn an ICH-Q2 validated UHPLC method with fluorimetric detection and less than 10min runtime was developed. The method enabled quantification of procyanidin clusters with DP from 2 to 10 besides the polymer fraction. Batch analysis revealed procyanidin contents of about 20 to 45mg/g from a homologues series of oligomeric PAs and about 50% of polymer fraction. Monitoring of procyanidin distribution during seasonal growth of fresh plants of Crataegus monogyna showed more or less constant contents between 20 and 55mg/g dry weight of oligomeric procyanidins during the growing season in the different plant organs with strong accumulation in the flowers and fruits (55mg/g dry weight). From these data it can be speculated that procyanidins serve as part of the plants defense system in the reproductive organs of the plant.

  7. Miocene mollusks from the Simojovel area in Chiapas, southwestern Mexico

    NASA Astrophysics Data System (ADS)

    del Carmen Perrilliat, María; Vega, Francisco J.; Coutiño, Marco A.

    2010-11-01

    The fauna of gastropods and bivalves from the amber-bearing lithostratigraphic units of the Simojovel area, Chiapas is reported, including the description of two new species and one subspecies: Turbinella maya new species, Melongena corona tzeltal new subspecies and Agladrillia ( Eumetadrillia) vermeiji new species. Stratigraphic affinities of the previously described species suggest an Early Miocene age for the Mazantic Shale, and a Middle Miocene age for the overlying Balumtum Sandstone. One specimen of gastropod, with a relatively large piece of amber attached to the adapertural part of the shell is representative for an Early Miocene age and estuarine paleoenvironmental interpretation for the Mazantic Shale. Mollusca, Miocene, Chiapas, Amber, Mexico.

  8. Miocene mammal reveals a Mesozoic ghost lineage on insular New Zealand, southwest Pacific.

    PubMed

    Worthy, Trevor H; Tennyson, Alan J D; Archer, Michael; Musser, Anne M; Hand, Suzanne J; Jones, Craig; Douglas, Barry J; McNamara, James A; Beck, Robin M D

    2006-12-19

    New Zealand (NZ) has long been upheld as the archetypical example of a land where the biota evolved without nonvolant terrestrial mammals. Their absence before human arrival is mysterious, because NZ was still attached to East Antarctica in the Early Cretaceous when a variety of terrestrial mammals occupied the adjacent Australian portion of Gondwana. Here we report discovery of a nonvolant mammal from Miocene (19-16 Ma) sediments of the Manuherikia Group near St Bathans (SB) in Central Otago, South Island, NZ. A partial relatively plesiomorphic femur and two autapomorphically specialized partial mandibles represent at least one mouse-sized mammal of unknown relationships. The material implies the existence of one or more ghost lineages, at least one of which (based on the relatively plesiomorphic partial femur) spanned the Middle Miocene to at least the Early Cretaceous, probably before the time of divergence of marsupials and placentals > 125 Ma. Its presence in NZ in the Middle Miocene and apparent absence from Australia and other adjacent landmasses at this time appear to reflect a Gondwanan vicariant event and imply persistence of emergent land during the Oligocene marine transgression of NZ. Nonvolant terrestrial mammals disappeared from NZ some time since the Middle Miocene, possibly because of late Neogene climatic cooling.

  9. Palaeomagnetism of the Miocene Farellones formation (Chile)

    NASA Astrophysics Data System (ADS)

    Goguitchaichvili, A.; Chauvin, A.; Roperch, P.; Prévot, M.; Aguirre, L.; Vergara, M.

    2000-02-01

    We report on a detailed palaeomagnetic study of the Miocene Farellones volcanic formation in the Chilean Andes near Santiago (two sections, 37 sites, about 400 orientated cores). Petrological observations show evidence of low-grade metamorphism increasing downwards through the volcanic sequence. Optical observations of opaque minerals and magnetic experiments suggest that in many cases maghemitization is associated with hydrothermal alteration. However, thermal demagnetization data indicate that the low-grade metamorphism did not significantly modify the direction of the primary remanent magnetization recorded at the time of emplacement of the volcanic lava flows. Four intervals of polarity with two intermediate palaeodirections were observed in the ~650-m-thick composite section. According to the dispersion of flow average directions, palaeosecular variation was slightly larger than that observed in general during the Upper Cenozoic. The site mean directions obtained in this study differ significantly from the expected Miocene direction. Clockwise rotations of up to 20 deg of small blocks are probably associated with the deformation of the Andean Cordillera since middle Miocene times. Geomagnetic palaeointensity data were obtained, using the Thellier method, on 24 samples from eight distinct lava flows. The flow mean VDM varies from 1.4 to 4.0x1022Am-2. Altogether, our data seem to suggest the existence of a relatively low geomagnetic field undergoing large fluctuations. Although a linear relationship was observed between the natural remanent magnetization and the thermal remanent magnetization acquired during the Thellier-Thellier experiments, undetected chemical alteration of the magnetic minerals during hydrothermalism may also explain the unusually low palaeointensity obtained.

  10. The dietary adaptations of European Miocene catarrhines.

    PubMed Central

    Ungar, P S; Kay, R F

    1995-01-01

    European Miocene "apes" have been known for nearly a century and a half but their phylogenetic significance is only now becoming apparent with the recent discovery of many relatively complete remains. Some appear to be close in time and morphology to the last common ancestor of modern great apes and humans. The current study is an attempt to reconstruct the diets of these fossils on the basis of quantitative data. Results suggest that these primates varied more greatly in their diets than modern apes, with adaptations ranging from hard-object feeding to soft-object frugivory to folivory. PMID:7777533

  11. Structural analysis of proanthocyanidins isolated from fruit stone of Chinese hawthorn with potent antityrosinase and antioxidant activity.

    PubMed

    Chai, Wei-Ming; Chen, Chih-Min; Gao, Yu-Sen; Feng, Hui-Ling; Ding, Yu-Mei; Shi, Yan; Zhou, Han-Tao; Chen, Qing-Xi

    2014-01-08

    Proanthocyanidins were isolated from fruit stone of Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E.Br.). Their structures were analyzed and elucidated by methods of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS). The results demonstrated that these compounds are complicated mixtures of homo- and heteropolymers consisting of procyanidin/procyanidin gallate and prodelphinidin. They possessed structural heterogeneity in monomer units, polymer length, and interflavan linkage (A-type and B-type). Their antityrosinase and antioxidant activity were then investigated. The results revealed that they can inhibit tyrosinase activities, including the monophenolase activity and the diphenolase activity. In addition, proanthocyanidins possessed potent antioxidant activity. Our studies revealed that proanthocyanidins isolated from fruit stone of Chinese hawthorn may be applied in food, agriculture, pharmaceutical, and cosmetic industries.

  12. Antioxidant capacity of polyphenolic extracts from leaves of Crataegus laevigata and Crataegus monogyna (Hawthorn) subjected to drought and cold stress.

    PubMed

    Kirakosyan, Ara; Seymour, Elisabeth; Kaufman, Peter B; Warber, Sara; Bolling, Steven; Chang, Soo Chul

    2003-07-02

    Crataegus laevigata and Crataegus monogyna (hawthorn) were subjected to drought and cold stress treatments, and polyphenolic extracts from control and stress-treated plants were assayed for antioxidant capacities using a modified version of the Total Antioxidant Status Assay (Randox, San Francisco, CA). In addition, these plants were analyzed for levels of flavanol-type substance [(-)-epicatechin] and flavonoid (vitexin 2' '-O-rhamnoside, acetylvitexin 2' '-O-rhamnoside, and hyperoside) constituents that are important metabolites in hawthorn herbal preparations used to treat patients with heart disease. Drought and cold stress treatments caused increases in levels of (-)-epicatechin and hyperoside in both Crataegus species. Such treatments also enhanced the antioxidant capacity of the extracts. The results from this study thus indicate that these kinds of stress treatments can enhance the levels of important secondary metabolites and their total antioxidant capacities in leaves of Crataegus.

  13. Abundance of apple maggot, Rhagoletis pomonella, across different areas in central Washington, with special reference to black-fruited hawthorns.

    PubMed

    Yee, Wee L; Klaus, Michael W; Cha, Dong H; Linn, Charles E; Goughnour, Robert B; Feder, Jeffrey L

    2012-01-01

    The apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), infests non-commercial apple (Malus domestica (Borkh.) Borkh.) and native black-fruited hawthorns (mostly Crataegus douglasii Lindl.) in central Washington, but little has been published on the abundance of the fly in this region. In this paper, the abundance of R. pomonella across different sites near apple-growing areas in central Washington is documented in order to assess the threat of the fly to commercial apple orchards. The fly was first detected on traps in Klickitat, Yakima, and Kittitas Counties in 1981, 1995, and 1997, respectively. From 1981-2010 in Kittitas and Yakima Counties, only 0 to 4.7% of traps on apple, crabapple, and hawthorn trees were positive for flies, whereas in Klickitat County, located farther from commercial apple orchards, 0 to 41.9% of traps were positive. In 2008, in Yakima County and Goldendale in Klickitat County, 7.8% of black-fruited hawthorn trees were infested, with 0 to 0.00054 larvae per fruit. In 2010, in Kittitas and Yakima Counties and Goldendale in Klickitat County, 25.0% of C. douglasii trees were infested, with 0.00042 to 0.00248 larvae per fruit. In 2010, in a remote forested area of Klickitat County far from commercial apple orchards, 94.7% of C. douglasii trees were infested, with 0.20813 larvae per fruit. Overall results suggest R. pomonella is unlikely to develop high populations rapidly near major commercial apple-growing areas in central Washington, including in black-fruited hawthorns, increasing chances it can be kept out of commercial orchards.

  14. Abundance of Apple Maggot, Rhagoletis pomonella, Across Different Areas in Central Washington, with Special Reference to Black-Fruited Hawthorns

    PubMed Central

    Yee, Wee L.; Klaus, Michael W.; Cha, Dong H.; Linn, Charles E.; Goughnour, Robert B.

    2012-01-01

    The apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), infests non-commercial apple (Malus domestica (Borkh.) Borkh.) and native black-fruited hawthorns (mostly Crataegus douglasii Lindl.) in central Washington, but little has been published on the abundance of the fly in this region. In this paper, the abundance of R. pomonella across different sites near apple-growing areas in central Washington is documented in order to assess the threat of the fly to commercial apple orchards. The fly was first detected on traps in Klickitat, Yakima, and Kittitas Counties in 1981, 1995, and 1997, respectively. From 1981–2010 in Kittitas and Yakima Counties, only 0 to 4.7% of traps on apple, crabapple, and hawthorn trees were positive for flies, whereas in Klickitat County, located farther from commercial apple orchards, 0 to 41.9% of traps were positive. In 2008, in Yakima County and Goldendale in Klickitat County, 7.8% of black-fruited hawthorn trees were infested, with 0 to 0.00054 larvae per fruit. In 2010, in Kittitas and Yakima Counties and Goldendale in Klickitat County, 25.0% of C. douglasii trees were infested, with 0.00042 to 0.00248 larvae per fruit. In 2010, in a remote forested area of Klickitat County far from commercial apple orchards, 94.7% of C. douglasii trees were infested, with 0.20813 larvae per fruit. Overall results suggest R. pomonella is unlikely to develop high populations rapidly near major commercial apple-growing areas in central Washington, including in black-fruited hawthorns, increasing chances it can be kept out of commercial orchards. PMID:23451979

  15. Mammal extinctions in the Vallesian (Upper Miocene)

    NASA Astrophysics Data System (ADS)

    Agusti, J.; Moya-Sola, S.

    The term Vallesian was created by Crusafont (1950) to designate the first European Mammalian palaeofaunas containing the equid Hipparion, the remainder of the faunas being composed of typical elements coming from the Middle Miocene such as Micromeryx, Euprox, Sansanosmilus, Pseudaelurus, and Listriodon. Thus, the Aragonian-Vallesian boundary does not show a strong change among European Miocene mammalian faunas (Agusti et al., 1984). On the other hand, the Lower Vallesian/Upper Vallesian transition corresponds to a major biotic crisis. This boudnary is characterized by the disappearence of most of the Aragonian artiodactyl forms such as Protragocerus, Miotragocerus, Listriodon, Hyotherium, Parachleusastochoerus, etc. Among the rodents, this crisis affects the family Eomyidae and most of the cricetid and glirid species. On the other hand, a number of eastern elements appear in the area at the same time. This is the case of the suid Schizochoerus and the murid Progonomys. Other eastern forms are Tragoportax, Graecoryx, Adcrocuta, Paramachairodus, Microstonyx, etc. Most of these are typical elements of the next Mammal stage, the Turolian. Thus, whereas the Lower Vallesian fauna has a typical Aragonian composition except for Hipparion. After the Middle Vallesian event, the Upper Vallesian faunas are already largely Turolian in character. The possible factors involved in this extinction event are discussed.

  16. Convective drying of hawthorn fruit (Crataegus spp.): Effect of experimental parameters on drying kinetics, color, shrinkage, and rehydration capacity.

    PubMed

    Aral, Serdar; Beşe, Ayşe Vildan

    2016-11-01

    Thin layer drying characteristics and physicochemical properties of hawthorn fruit (Crataegus spp.) were investigated using a convective dryer at air temperatures 50, 60 and 70°C and air velocities of 0.5, 0.9 and 1.3m/s. The drying process of hawthorn took place in the falling rate period, and the drying time decreased with increasing air temperature and velocity. The experimental data obtained during the drying process were fitted to eleven different mathematical models. The Midilli et al.'s model was found to be the best appropriate model for explaining the drying behavior of hawthorn fruit. Effective moisture diffusion coefficients (Deff) were calculated by Fick's diffusion model and their values varied from 2.34×10(-10)m(2)/s to 2.09×10(-9)m(2)/s. An Arrhenius-type equation was applied to determine the activation energies. While the shrinkage decreased, the rehydration ratio increased with increasing air temperature and air velocity.

  17. Identification of fruit volatiles from green hawthorn (Crataegus viridis) and blueberry hawthorn (Crataegus brachyacantha) host plants attractive to different phenotypes of Rhagoletis pomonella flies in the southern United States.

    PubMed

    Cha, Dong H; Powell, Thomas H Q; Feder, Jeffrey L; Linn, Charles E

    2011-09-01

    The apple maggot fly, Rhagoletis pomonella, infests several hawthorn species in the southern USA. In a companion paper, we showed that R. pomonella flies infesting two different mayhaw species (Crataegus opaca and C. aestivalis) can discriminate between volatile blends developed for each host fruit, and that these blends are different from previously constructed blends for northern fly populations that infest domestic apple (Malus domestica), downy hawthorn (Crataegus mollis), and flowering dogwood (Cornus florida). Here, we show by using coupled gas chromatography and electroantennographic detection (GC-EAD), gas chromatography with mass spectrometry (GC-MS), and flight tunnel bioassays, that two additional southern hawthorn fly populations infesting C. viridis (green hawthorn) and C. brachyacantha (blueberry hawthorn) also can discriminate between volatile blends for each host fruit type. A 9-component blend was developed for C. viridis (3-methylbutan-1-ol [5%], butyl butanoate [19.5%], propyl hexanoate [1.5%], butyl hexanoate [24%], hexyl butanoate [24%], pentyl hexanoate [2.5%], 1-octen-3-ol [0.5%], pentyl butanoate [2.5%], and (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) [20.5%]) and an 8-component blend for C. brachyacantha (3-methylbutan-1-ol [0.6%], butyl acetate [50%], pentyl acetate [3.5%], butyl butanoate [9%], butyl hexanoate [16.8%], hexyl butanoate [16.8%], 1-octen-3-ol [0.3%], and pentyl butanoate [3%]). Crataegus viridis and C. brachyacantha-origin flies showed significantly higher levels of upwind oriented flight to their natal blend in flight tunnel assays compared to the alternate, non-natal blend and previously developed northern host plant blends. The presence of DMNT in C. viridis and butyl acetate in C. brachyacantha appeared to be largely responsible for driving the differential response. This sharp behavioral distinction underscores the diversity of odor response phenotypes in the southern USA, points to possible host race formation in these

  18. Distributional patterns of decapod crustaceans in the circum-Mediterranean area during the Oligo-Miocene

    NASA Astrophysics Data System (ADS)

    Hyžný, Matúš

    2015-04-01

    During the Oligocene and Miocene, the circum-Mediterranean area was a complex network of (mostly) shallow marine basins. Significant biogeographic differentiation of this area has been documented (Harzhauser et al. 2007), mainly during the Miocene, when connections between Proto-Mediterranean, Paratethys and Proto-Indo-West Pacific were intermittently opening and closing. These seaways allowed migration of marine faunas. Distributional patterns has so far been discussed for several different animal groups, especially for molluscs (e.g. Studencka et al. 1998; Harzhauser et al. 2002, 2003, 2007). To test these patterns with decapod crustaceans, a database has been compiled including all previously published Oligocene and Miocene decapod occurrences and newly gathered data from examined material deposited in the institutional collections. Decapod associations have been significant components of marine habitats since the Mesozoic times with ever-increasing importance throughout the Cenozoic. Müller (1979) argued that brachyuran decapods are among the best zoogeographical indicators. Although decapods were used as such indicators before (e.g. Schweitzer 2001; Feldmann & Schweitzer 2006), no detailed analysis of the circum-Mediterranean taxa has been conducted so far. Based on proposed anti-estuarine circulation pattern, decapods originated in the Proto-Mediterranean, and migrated both into the North Sea and the Paratethys. Moreover, during the Early Miocene the Rhine Graben served as a connection between the North Sea and the Paratethys which enabled faunal exchange. The Middle Miocene Proto-Mediterranean and Paratethys decapod assemblages as taken together were relatively homogeneous, although distinct due to increasing rate of endemites in the Paratethys during the Miocene. The research has been supported by FWF: Lise Meitner Program M 1544-B25. References Feldmann R.M. & Schweitzer C.E. 2006: Paleobiogeography of Southern Hemisphere decapod Crustacea. J. Paleontol

  19. Transcriptome Analysis and Ultrastructure Observation Reveal that Hawthorn Fruit Softening Is due to Cellulose/Hemicellulose Degradation

    PubMed Central

    Xu, Jiayu; Zhao, Yuhui; Zhang, Xiao; Zhang, Lijie; Hou, Yali; Dong, Wenxuan

    2016-01-01

    Softening, a common phenomenon in many fruits, is a well coordinated and genetically determined process. However, the process of flesh softening during ripening has rarely been described in hawthorn. In this study, we found that ‘Ruanrou Shanlihong 3 Hao’ fruits became softer during ripening, whereas ‘Qiu JinXing’ fruits remained hard. At late developmental stages, the firmness of ‘Ruanrou Shanlihong 3 Hao’ fruits rapidly declined, and that of ‘Qiu JinXing’ fruits remained essentially unchanged. According to transmission electron microscopy, the middle lamella of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruit flesh was largely degraded as the fruits matured. Microfilaments in ‘Qiu JinXing’ flesh were arranged close together and were deep in color, whereas those in ‘Ruanrou Shanlihong 3 Hao’ fruit flesh were arranged loosely, partially degraded and light in color. RNA-Seq analysis yielded approximately 46.72 Gb of clean data and 72,837 unigenes. Galactose metabolism and pentose and glucuronate interconversions are involved in cell wall metabolism, play an important role in hawthorn texture. We identified 85 unigenes related to the cell wall between hard- and soft-fleshed hawthorn fruits. Based on data analysis and real-time PCR, we suggest that β-GAL and PE4 have important functions in early fruit softening. The genes Ffase, Gns,α-GAL, PE63, XTH, and CWP, which are involved in cell wall degradation, are responsible for the different textures of hawthorn fruits. Thus, we hypothesize that the different textures of ‘Qiu JinXing’ and ‘Ruanrou Shanlihong 3 Hao’ fruits at maturity mainly result from cellulose/hemicelluloses degradation rather than from lamella degradation. Overall, we propose that different types of hydrolytic enzymes in cells interact to degrade the cell wall, resulting in ultramicroscopic Structure changes in the cell wall and, consequently, fruit softening. These results provide fundamental insight

  20. Paleotopography of the Miocene European Central Alps

    NASA Astrophysics Data System (ADS)

    Campani, M.; Mulch, A.; Kempf, O.; Schlunegger, F.; Mancktelow, N.

    2011-12-01

    Reconstructing the surface elevation, surface uplift, and relief evolution histories is fundamental to understanding the growth of mountain ranges, to explore their topographic limits, and relate these to geodynamic and Earth surface processes. Recent geologic and geodynamic models for the Central European Alps propose that the bulk of topography was built through the Pliocene, mainly based on the observation of a strong increase in sedimentation and erosion rates during the last 5-6 Ma, suggesting that the Alps never attained elevations as high as today. Here, we aim to quantify the Miocene (20-14 Ma) paleoelevation of the Central Alps through stable isotope paleoaltimetry. The novelty of the approach presented here, which renders it rather insensitive to past climate change, is to analyze stable isotope proxies of identical age, both from high internal parts of the Alpine orogen and from the adjacent foreland basin that was at or near sea level. We first exploit the hydrogen isotopic ratio in phyllosilicates (mica and chlorite) that interacted with meteoric water during activity of the Simplon detachment, a major normal fault that developed during orogen-parallel extension in high elevation regions. We then contrast the resulting meteoric water compositions with those recorded in carbonate-bearing paleosols of the North-Alpine foreland basin to provide an estimate of relative elevation differences. In the North-Alpine foreland basin, we present oxygen and carbon isotopic compositions of pedogenic mudstones and carbonate concretions. These terrestrial paleosols, dated with ca. 100 ka precision, serve as our point of reference for stable isotope paleoaltimetry, since they formed at or near sea level. Here, δ18O and δ13C values vary between +19 to +25% (SMOW) and -7 to +1% respectively and show close correspondence to global climate change during the mid-Miocene climatic optimum. In the Simplon fault zone, detachment-related muscovite (-126%) and chlorite (-135

  1. Miocene vertebrates and North Florida shorelines

    USGS Publications Warehouse

    Olsen, S.J.

    1968-01-01

    Vertebrate fossils from ten localities, spread across northern Florida, give evidence of shorelines and deltas that have previously been established on geologic evidence or invertebrates alone. Terrestrial mammal remains, in association with shallow-water forms, indicate a deltaic assemblage and in several instances specific animals suggest restricted water depths at the time of sediment deposition. Fortunately diagnostic fragments of Miocene horses, Merychippus and Parahippus, are present in these beds, allowing for a rather close age evaluation of these sediments. Adequate fossil material has been collected from these localities to suggest the past environment and ecological conditions for the forms represented. By utilizing a suggested course of experiments with stream table apparatus it is possible to use the orientation of the fossil vertebrate remains as aids in determining past conditions of sediment accumulation. ?? 1968.

  2. Sex determination in miocene catarrhine primates.

    PubMed

    Kelley, J

    1995-04-01

    Canines of fossil hominoids and primitive catarrhines from several early, middle, and late Miocene sites were analyzed according to the shape indices described in Kelley (1995) and compared to those of males and females of extant great apes. In bivariate plots of the fossil canines utilizing the indices, 90% of the upper canines and 85% of the lower canines fell within or just outside the exclusively male or exclusively female territories delimited by the extant great apes. The remainder fell in the male-female overlap zones. Sex assignments based on these distributions were nearly 100% concordant with classifications according to canine height, suggesting a high degree of accuracy. There were various taxon-specific shifts in bivariate space among fossil genera, reflecting subtle differences in canine shape between taxa within the overall pattern of similarity to extant great apes as a whole. In many cases these shifts are matched by particular extant-ape species and subspecies, while other fossil taxa have no exact analogue for canine shape among the extant great apes. However, the pattern of spatial segregation of canines identified as either male or female at each of the sites largely mirrors that of males and females within the extant-ape sample, indicating that Miocene catarrhines shared with extant great apes a common pattern of shape differences between male and female canines, regardless of taxon-specific morphologies. These observations demonstrate that the canines of fossil catarrhines can be sexed with a high degree of confidence based solely on intrinsic features of shape. This will permit more reliable characterizations of morphological sexual dimorphism among fossil species. It is also argued that canine shape is a more reliable indicator of sex in fossil taxa than are canine/molar size ratios.

  3. Hypolipidemic and cardioprotective benefits of a novel fireberry hawthorn fruit extract in the JCR:LA-cp rodent model of dyslipidemia and cardiac dysfunction.

    PubMed

    Diane, Abdoulaye; Borthwick, Faye; Wu, Sheng; Lee, Jeanette; Brown, Paula N; Dickinson, Timothy A; Croft, Kevin D; Vine, Donna F; Proctor, Spencer D

    2016-09-14

    Hawthorn is a widely used herbal alternative medicine for the treatment of various cardiovascular diseases. However, the attributed health benefits, purported to be due to the presence of phenolic compounds, may depend on both the specific species and plant part. Studies to date investigating effects of hawthorn on heart disease(s) have used well-described European and/or Asian species, while little is known regarding the bioactivity of species native to North America. Six weeks of supplementation of both fireberry hawthorn berry (native Crataegus chrysocarpa) and English hawthorn leaf (C. monogyna, naturalized in North America) in the JCR:LA-cp rat, resulted in a significant reduction in heart weight, fasting LDL-C and improved heart function (p < 0.05). Fasting triglyceride and myocardial fibrosis were also reduced, but only by the berry extract. We demonstrate that both of the Canadian-sourced hawthorn extracts (introduced leaf and native berry) have cardioprotective benefits, likely via increased availability of nitric oxide.

  4. Phenolic contents and cellular antioxidant activity of Chinese hawthorn "Crataegus pinnatifida".

    PubMed

    Wen, Lingrong; Guo, Xingbo; Liu, Rui Hai; You, Lijun; Abbasi, Arshad Mehmood; Fu, Xiong

    2015-11-01

    It is evident from various epidemiological studies that consumption of fruits and vegetables is essential to maintain health and in the disease prevention. Present study was designed to examine phenolic contents and antioxidant properties of three varieties of Crataegus pinnatifida (Chinese hawthorn). Shanlihong variety exhibited elevated levels of total phenolics and flavonoid contents, including free and bond phenolics. Procyanidin B2 was most abundant phenolic compound in all samples, followed by epicatechin, chlorogenic acid, hyperoside, and isoquercitrin. The free ORAC values, and free hydro-PSC values were 398.3-555.8 μmol TE/g DW, and 299.1-370.9 μmol VCE/g DW, respectively. Moreover, the free cellular antioxidant activity (CAA) values were 678-1200 μmol of QE/100 g DW in the no PBS wash protocol, and 345.9-532.9 μmol of QE/100 g DW in the PBS wash protocol. C. pinnatifida fruit could be valuable to promote consumer health.

  5. Increasing uncertainty in CNS clinical trials: the role of placebo, nocebo, and Hawthorne effects.

    PubMed

    Benedetti, Fabrizio; Carlino, Elisa; Piedimonte, Alessandro

    2016-06-01

    As modern research continues to unravel the details of the placebo phenomenon in CNS disorders, uncertainty about therapeutic outcomes in trials of treatments for several neurological conditions is growing. Advances in understanding the mechanisms of different placebo effects have emphasised the substantial challenges inherent in interpreting the results of CNS clinical trials. In the past few years, new mechanisms and concepts have emerged in the study of placebo, nocebo, and Hawthorne effects in CNS clinical trials. For example, the mere step of recruitment in a trial or social interaction among trial participants can change the baseline conditions and therefore affect the interpretation of therapeutic outcomes. Moreover, different genotypes have been shown to respond differently to placebos-eg, in studies of social anxiety, depression, and pain. Increasing recognition of these factors in the general population raises the question of whether attempts should be made to reduce placebo responses in CNS clinical trials. Both clinical trial design and medical practice could benefit from further investigation of these effects across a range of neuropsychiatric disorders.

  6. A new Mammutidae (Proboscidea, Mammalia) from the Late Miocene of Gansu Province, China.

    PubMed

    Mothé, Dimila; Avilla, Leonardo S; Zhao, Desi; Xie, Guangpu; Sun, Boyang

    2016-03-01

    The "Yanghecun specimen", a proboscidean specimen represented by a mandible from Miocene of China and previously described as Gomphotheriidae, is here reviewed and described as a new genus and species of Mammutidae: Sinomammut tobieni. This taxon is a longirostrine mastodon, lacking lower tusks, and bearing a wide last molar with oblique and non-inflated lophids, broad transverse interlophids, and yoke-like wear figures. Phylogenetic analysis of Mammutidae based on dental and mandibular features recovered S. tobieni as sister group of the mastodon Mammut. The longirostrine condition and the well-developed lower incisors seem to be primitive for Mammutidae, while the brevirostry is the derived condition, probably emerged during the middle Miocene (12-11 Mya). However, two derived conditions are recognized to the lower tusks: the absence of lower tusks (S. tobieni) and the occasional presence of vestigial lower tusks (Mammut).

  7. Miocene Shark and Batoid Fauna from Nosy Makamby (Mahajanga Basin, Northwestern Madagascar).

    PubMed

    Andrianavalona, Tsiory H; Ramihangihajason, Tolotra N; Rasoamiaramanana, Armand; Ward, David J; Ali, Jason R; Samonds, Karen E

    2015-01-01

    Madagascar is well known for producing exceptional fossils. However, the record for selachians remains relatively poorly known. Paleontological reconnaissance on the island of Nosy Makamby, off northwest Madagascar, has produced a previously undescribed assemblage of Miocene fossils. Based on isolated teeth, ten taxonomic groups are identified: Otodus, Carcharhinus, Galeocerdo, Rhizoprionodon, Sphyrna, Hemipristis, Squatina, Rostroraja, Himantura and Myliobatidae. Six are newly described from Madagascar for the Cenozoic (Galeocerdo, Rhizoprionodon, Sphyrna, Squatina, Rostroraja and Himantura). In association with these specimens, remains of both invertebrates (e.g., corals, gastropods, bivalves) and vertebrates (e.g., bony fish, turtles, crocodylians, and sirenian mammals) were also recovered. The sedimentary facies are highly suggestive of a near-shore/coastal plain depositional environment. This faunal association shares similarities to contemporaneous sites reported from North America and Europe and gives a glimpse into the paleoenvironment of Madagascar's Miocene, suggesting that this region was warm, tropical shallow-water marine.

  8. Miocene small-bodied ape from Eurasia sheds light on hominoid evolution.

    PubMed

    Alba, David M; Almécija, Sergio; DeMiguel, Daniel; Fortuny, Josep; Pérez de los Ríos, Miriam; Pina, Marta; Robles, Josep M; Moyà-Solà, Salvador

    2015-10-30

    Miocene small-bodied anthropoid primates from Africa and Eurasia are generally considered to precede the divergence between the two groups of extant catarrhines—hominoids (apes and humans) and Old World monkeys—and are thus viewed as more primitive than the stem ape Proconsul. Here we describe Pliobates cataloniae gen. et sp. nov., a small-bodied (4 to 5 kilograms) primate from the Iberian Miocene (11.6 million years ago) that displays a mosaic of primitive characteristics coupled with multiple cranial and postcranial shared derived features of extant hominoids. Our cladistic analyses show that Pliobates is a stem hominoid that is more derived than previously described small catarrhines and Proconsul. This forces us to reevaluate the role played by small-bodied catarrhines in ape evolution and provides key insight into the last common ancestor of hylobatids (gibbons) and hominids (great apes and humans).

  9. Miocene Shark and Batoid Fauna from Nosy Makamby (Mahajanga Basin, Northwestern Madagascar)

    PubMed Central

    Andrianavalona, Tsiory H.; Ramihangihajason, Tolotra N.; Rasoamiaramanana, Armand; Ward, David J.; Ali, Jason R.; Samonds, Karen E.

    2015-01-01

    Madagascar is well known for producing exceptional fossils. However, the record for selachians remains relatively poorly known. Paleontological reconnaissance on the island of Nosy Makamby, off northwest Madagascar, has produced a previously undescribed assemblage of Miocene fossils. Based on isolated teeth, ten taxonomic groups are identified: Otodus, Carcharhinus, Galeocerdo, Rhizoprionodon, Sphyrna, Hemipristis, Squatina, Rostroraja, Himantura and Myliobatidae. Six are newly described from Madagascar for the Cenozoic (Galeocerdo, Rhizoprionodon, Sphyrna, Squatina, Rostroraja and Himantura). In association with these specimens, remains of both invertebrates (e.g., corals, gastropods, bivalves) and vertebrates (e.g., bony fish, turtles, crocodylians, and sirenian mammals) were also recovered. The sedimentary facies are highly suggestive of a near-shore/coastal plain depositional environment. This faunal association shares similarities to contemporaneous sites reported from North America and Europe and gives a glimpse into the paleoenvironment of Madagascar’s Miocene, suggesting that this region was warm, tropical shallow-water marine. PMID:26075723

  10. Early Miocene granitoids from the Leo Pargil gneiss dome, northwest Himalaya

    NASA Astrophysics Data System (ADS)

    Hassett, W.; Leech, M. L.

    2007-12-01

    The Leo Pargil gneiss dome is comprised of upper amphibolite-facies metasedimentary rocks of the lower Tethyan Himalayan sequence (known as the Haimantas Group), that are intruded by numerous small granitoid bodies and leucogranite dikes. The dome is located in northern India/southwestern Tibet at the junction of the Sutlej and Spiti rivers, west of the Zada basin. U-Pb SHRIMP dating of zircon yield concordant ages ranging from Late Archean to Late Proterozoic for paragneisses (2.6 Ga to 970 Ma) corresponding to the Haimantas group, and Early Oligocene to Middle Miocene ages for granitoid intrusions (33 Ma to 15 Ma). Concordant analyses and lower intercept ages from Tera-Wasserburg concordia plots range from 28.1-17.2 Ma. Late Oligocene to Early Miocene ages are from zircon domains with consistently high U contents (1500 to over 25000 ppm). Linear regression of age vs. U content scatter plots show a trend toward younger ages (22-20 Ma) corresponding to ages from zircon with lower U contents (1000-3000 ppm) and that is consistent with lower intercept ages. These Early Miocene ages for Leo Pargil granitoids correspond to the ages for the widespread leucogranite bodies exposed throughout the Himalaya and granites from the North Himalayan gneiss domes further east.

  11. Wet Winters in the Eastern Siberian Arctic during the Miocene

    NASA Astrophysics Data System (ADS)

    Schubert, B.; Jahren, H.; Davydov, S. P.

    2015-12-01

    Eastern Siberia (a 7.3 million km2 area, similar to Australia in size) features numerous plant fossil localities, many with spectacularly preserved Neogene fossils (e.g., Baekovo and Nekkeiveem; Khapchan-Timmerdekh; Mamontova Gora). Although these sites have been described in full using classical methods (e.g., Baranova and Grinenko, 1989; Baranova et al., 1970; Biske, 1970; Dorofeev, 1969; Grinenko et al., 1989; Nikitin, 2006, 2007), geochemical proxy techniques have not yet been applied. Here we report the first stable isotope analyses of fossil wood from northeastern Siberia: 512 high-resolution intra-ring analyses of carbon isotopes (IRA-δ13C) in 6 specimens of Miocene wood from the Finish Creek site, located near Cherskiy, Sakha Republic, Russia. Using our model for reconstructing the ratio of summer to winter precipitation (Ps/Pw) from IRA-δ13C (Schubert and Jahren, 2011, GCA), we quantified the seasonal precipitation in far northeastern Siberia (~69 oN) during the Miocene. Although the median value for Ps/Pw during the Miocene was similar to today (Ps/Pw = ~2), we observed much greater variability in Ps/Pw during the Miocene than today. Specifically, years with Ps/Pw < 1/2 occurred ~4 times more frequently during the Miocene than today. When taken with independent estimates of mean annual precipitation based on nearest living relatives (581 to 1206 mm; Popova et al., 2012), our Miocene values for Ps/Pw suggest at least 2.8 times greater winter precipitation during the Miocene relative to today, and at least 5.5 times greater winter precipitation than today in ~10% of years sampled (6-month winter precipitation averages ~70 mm/yr today). Our result differentiates the Siberian Arctic Miocene from the Canadian Arctic Eocene which featured wet summers in the Eocene Arctic of Canada using similar methods, highlighting spatial and temporal variability in the Arctic paleoclimate record of the middle Cenozoic.

  12. Miocene biochronology and paleoceanography of the North Pacific

    USGS Publications Warehouse

    Keller, G.

    1981-01-01

    Biostratigraphic correlation based on microfossil datum levels, directly or indirectly tied to the paleomagnetic time scale, provides a high resolution time control for the Miocene in the equatorial and middle latitude North Pacific. Faunal changes and abundance fluctuations of planktic foraminiferal species combined with the oxygen Pacific. Faunal changes and abundance fluctuations of planktic foraminiferal species combined with the oxygen isotope record of foraminifers, reveal the paleoclimatic and paleoceanographic history. The planktic foraminiferal assemblage change in the early Miocene, extinction of Oligocene fauna and rise of a highly diverse Neogene fauna, appears to be related to increased water mass stratification in the world oceans presumably resulting from the establishment of circum-Antarctic circulation. An increase in the siliceous productivity in the eastern equatorial Pacific region between 20 and 18 Ma suggests that the vertical and horizontal circulation was intensified at that time. Climates cooled rapidly during the middle Miocene between 14 and 13 Ma suggesting the growth of a major east Antarctic ice sheet. Paleoclimatic conditions remained generally cool, although oscillating, during the late Miocene. In the late early to middle Miocene faunal provincialism developed between low and middle latitudes, and by late Miocene time a distinct provincialism similar to the present was established. ?? 1981.

  13. "The most important technique …": Carl Rogers, Hawthorne, and the rise and fall of nondirective interviewing in sociology.

    PubMed

    Lee, Raymond M

    2011-01-01

    In the 1940s, interviewing practice in sociology became decisively influenced by techniques that had originally been developed by researchers in other disciplines working within a number of therapeutic or quasi-therapeutic contexts, in particular the "nondirective interviewing" methods developed by Carl Rogers and the interviewing procedures developed during the Hawthorne studies. This article discusses the development of nondirective interviewing and looks at how in the 1930s and '40s the approach came to be used in sociology. It examines the factors leading to both the popularity of the method and its subsequent fall from favor.

  14. InSAR Analysis of the 2011 Hawthorne (Nevada) Earthquake Swarm: Implications of Earthquake Migration and Stress Transfer

    NASA Astrophysics Data System (ADS)

    Zha, X.; Dai, Z.; Lu, Z.

    2015-12-01

    The 2011 Hawthorne earthquake swarm occurred in the central Walker Lane zone, neighboring the border between California and Nevada. The swarm included an Mw 4.4 on April 13, Mw 4.6 on April 17, and Mw 3.9 on April 27. Due to the lack of the near-field seismic instrument, it is difficult to get the accurate source information from the seismic data for these moderate-magnitude events. ENVISAT InSAR observations captured the deformation mainly caused by three events during the 2011 Hawthorne earthquake swarm. The surface traces of three seismogenic sources could be identified according to the local topography and interferogram phase discontinuities. The epicenters could be determined using the interferograms and the relocated earthquake distribution. An apparent earthquake migration is revealed by InSAR observations and the earthquake distribution. Analysis and modeling of InSAR data show that three moderate magnitude earthquakes were produced by slip on three previously unrecognized faults in the central Walker Lane. Two seismogenic sources are northwest striking, right-lateral strike-slip faults with some thrust-slip components, and the other source is a northeast striking, thrust-slip fault with some strike-slip components. The former two faults are roughly parallel to each other, and almost perpendicular to the latter one. This special spatial correlation between three seismogenic faults and nature of seismogenic faults suggest the central Walker Lane has been undergoing southeast-northwest horizontal compressive deformation, consistent with the region crustal movement revealed by GPS measurement. The Coulomb failure stresses on the fault planes were calculated using the preferred slip model and the Coulomb 3.4 software package. For the Mw4.6 earthquake, the Coulomb stress change caused by the Mw4.4 event increased by ~0.1 bar. For the Mw3.9 event, the Coulomb stress change caused by the Mw4.6 earthquake increased by ~1.0 bar. This indicates that the preceding

  15. Effect of Temperature on Demographic Parameters of the Hawthorn Red Midget Moth, Phyllonorycter corylifoliella, on Apple

    PubMed Central

    Amiri, Abbas; Talebi, Ali Asghar; Zamani, Abbas Ali; Kamali, Karim

    2010-01-01

    The hawthorn red midget moth, Phyllonorycter corylifoliella (Hübner) (Lepidoptera: Gracillariidae), is one of the most serious pests of apple and pear orchards in Iran, however little is known about its biology and relationship with environmental factors. The reproduction and population growth parameters of P. corylifoliella were examined at six constant temperatures (15, 20, 25, 30, 33 and 35° C) on apple var. golden delicious. At 35° C, P. corylifoliella failed to develop beyond the first instar. The lowest (13%) and highest (64%) mortality rates of immature stages occurred at 25 and 33° C, respectively. The life expectancies (ex) decreased with increasing of age and the life expectancies of one-day-old larvae were estimated to be 38.68, 33.34, 35.11, 26.28 and 16.11 days at 15, 20, 25, 30 and 33° C, respectively. The highest intrinsic rate of natural increase (rm), net reproductive rate (Ro) and finite rate of increase (λ) at 25° C were 0.100 ± 0.003, 47.66 ± 5.47 and 1.11 ± 0.00, respectively. The mean generation time (T) decreased with increasing temperatures from 86.86 ± 0.53 days at 15° C to 33.48 ± 0.16 days at 30° C. Doubling time (DT) varied significantly with temperature and the shortest doubling time was obtained at 25° C. The results of this study provide direction for future research on evaluating the performance of P. corylifoliella and the efficiency of its natural enemies in apple orchards under variable environmental conditions. PMID:20883137

  16. Phenolic constituents and antioxidant capacities of Crataegus monogyna (Hawthorn) callus extracts.

    PubMed

    Bahorun, Theeshan; Aumjaud, Esha; Ramphul, Hemlata; Rycha, Maheshwaree; Luximon-Ramma, Amitabye; Trotin, Francis; Aruoma, Okezie I

    2003-06-01

    Crataegus (Hawthorn) has long been used as a folk medicine and is widely utilized in pharmaceutical preparations mainly because of its neuro- and cardiosedative actions and its low toxicity. The pharmacological effects of Crataegus have mainly been attributed to the polyphenolic contents. In this study, the production of polyphenols by ten-year-old Crataegus monogyna calli was studied in relation to growth variation and antioxidant capacity within a subculture period. Assays based on the Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and stability in oil-in-water emulsion were used to characterize the antioxidant actions of the callus cultures. High TEAC (3.66 micromol/g dry weight) and FRAP (208.19 micromol Fe2+/g dry weight) values were observed when maximal growth was reached(days 30-35), and this seemed to be influenced by optimum total phenol (47.40 mg/g dry weight), proanthocyanidin (20.81 mg/g dry weight), flavonoid (7.01 mg/g dry weight), anthocyanin (6.18 mg/g dry weight), (-)-epicatechin (1.77 mgl/g dry weight), procyanidin B2 (3.97 mg/g dry weight), and chlorogenic acid (1.11 mg/g dry weight) production during that period. The TEAC values were strongly associated with total flavonoids and to a lesser extent with total phenols, anthocyanins and total proanthocyanidins. The FRAP antioxidant values correlated to total phenols, proanthocyanidins and flavonoids, respectively. The polyphenolic rich calli were as effective as butylated hydroxytoluene (BHT) in preventing hydroperoxide and conjugated diene formation in a 30% oil-in-water emulsion prepared with stripped sunflower oil, during 7days storage at 30 degrees C. Crataegus monogyna cell culture represents an important alternative source for natural antioxidants.

  17. The late Miocene Panama isthmian strait

    NASA Astrophysics Data System (ADS)

    Collins, Laurel S.; Coates, Anthony G.; Berggren, William A.; Aubry, Marie-Pierre; Zhang, Jijun

    1996-08-01

    Miocene sediments of the Caribbean Gatun and Chagres formations, Panama Canal basin, were deposited within an archipelagic strait that connected Caribbean and Pacific waters. Shallow-water (˜ 25 m) benthic foraminifera of the Gatun Formation have a strong Caribbean affinity, indicating that a significant interoceanic, biogeographic barrier had formed at ˜ 8 Ma. However, benthic foraminifera of the overlying Chagres Formation are bathyal and markedly Pacific in affinity, indicating that at ˜ 6 Ma, waters of the Panama isthmian strait deepened to ˜ 200 500 m and Pacific bathyal waters flowed into the Caribbean. The Chagres Formation crops out at the Caribbean entrance to the Panama Canal in a large wedge of cross-laminated sandstone and coquina. The cross-laminations and coarse grain size indicate high-energy currents atypical of bathyal settings. We infer that a jet of the Pacific North Equatorial Countercurrent Equatorial Undercurrent passed through the Panama isthmian strait to deposit these sediments on the Caribbean side. This later entry of Pacific taxa into the Caribbean had no apparent effect on the subsequent composition of Caribbean faunas.

  18. Global dominance of coralline red-algal facies: A response to Miocene oceanographic events

    NASA Astrophysics Data System (ADS)

    Halfar, Jochen; Mutti, Maria

    2005-06-01

    Rhodoliths (free-living coralline red algae) can thrive under a wide range of temperatures, reduced light, and increased nutrient levels, and often form a distinct so-called rhodalgal lithofacies that is an important component of Cenozoic shallow-water carbonates. Global distributions illustrate that from the late-early to early-late Miocene (Burdigalian early Tortonian), rhodalgal facies reached peak abundances and commonly replaced coral-reef environments, accompanied by a decline in other carbonate-producing phototrophs. We argue that the dominance of red algae over coral reefs was triggered in the Burdigalian by enhanced trophic resources associated with a global increase in productivity, as evidenced by a long-term shift toward higher carbon isotope values. Rhodalgal lithofacies expanded further in the middle Miocene when strengthened thermal gradients associated with the establishment of the East Antarctic Ice Sheet led to enhanced upwelling while climate change generated increased weathering rates, introducing land-derived nutrients into the oceans. Globally cooler temperatures following a climatic optimum in the early-middle Miocene contributed to sustain the dominance of red algae and prevented the recovery of coral reefs. The global shift in nearshore shallow-water carbonate producers to groups tolerant of higher levels of trophic resources provides further evidence for increased nutrient levels during that time interval and shows the sensitivity of shallow-water carbonate facies as indicators of past oceanographic conditions.

  19. Early Miocene hippopotamids (Cetartiodactyla) constrain the phylogenetic and spatiotemporal settings of hippopotamid origin

    PubMed Central

    Orliac, Maeva; Boisserie, Jean-Renaud; MacLatchy, Laura; Lihoreau, Fabrice

    2010-01-01

    The affinities of the Hippopotamidae are at the core of the phylogeny of Cetartiodactyla (even-toed mammals: cetaceans, ruminants, camels, suoids, and hippos). Molecular phylogenies support Cetacea as sister group of the Hippopotamidae, implying a long ghost lineage between the earliest cetaceans (∼53 Ma) and the earliest hippopotamids (∼16 Ma). Morphological studies have proposed two different sister taxa for hippopotamids: suoids (notably palaeochoerids) or anthracotheriids. Evaluating these phylogenetic hypotheses requires substantiating the poorly known early history of the Hippopotamidae. Here, we undertake an original morphological phylogenetic analysis including several “suiform” families and previously unexamined early Miocene taxa to test previous conflicting hypotheses. According to our results, Morotochoerus ugandensis and Kulutherium rusingensis, until now regarded as the sole African palaeochoerid and the sole African bunodont anthracotheriid, respectively, are unambiguously included within the Hippopotamidae. They are the earliest known hippopotamids and set the family fossil record back to the early Miocene (∼21 Ma). The analysis reveals that hippopotamids displayed an unsuspected taxonomic and body size diversity and remained restricted to Africa during most of their history, until the latest Miocene. Our results also confirm the deep nesting of Hippopotamidae within the paraphyletic Anthracotheriidae; this finding allows us to reconstruct the sequence of dental innovations that links advanced selenodont anthracotheriids to hippopotamids, previously a source of major disagreements on hippopotamid origins. The analysis demonstrates a close relationship between Eocene choeropotamids and anthracotheriids, a relationship that potentially fills the evolutionary gap between earliest hippopotamids and cetaceans implied by molecular analyses. PMID:20547829

  20. Chaungtha, a new Middle Miocene mammal locality from the Irrawaddy Formation, Myanmar

    NASA Astrophysics Data System (ADS)

    Chavasseau, Olivier; Chaimanee, Yaowalak; Tun, Soe Thura; Soe, Aung Naing; Barry, John C.; Marandat, Bernard; Sudre, Jean; Marivaux, Laurent; Ducrocq, Stéphane; Jaeger, Jean-Jacques

    2006-12-01

    We describe here a mammalian assemblage originating from the locality of Chaungtha (Irrawaddy Formation, Myanmar). It represents one of the rare descriptions of a precisely located, in space, vertical section and time, fossil mammal fauna from the Irrawaddy Formation. Classically the fossil record of Irrawaddy Formation is essentially known from isolated fossils of imprecise or unknown provenance, especially concerning the stratigraphic position of the fossils along several hundred meter thick sections. The Chaungtha faunal association consists of the rhino Brachypotherium fatehjangense, the pig Conohyus thailandicus, the ruminants cf. Siamotragulus sanyathanai, cf. Siamotragulus sp. and a gomphotheriid proboscidean. This assemblage indicates that the locality is Miocene in age, and not Late Eocene as previously claimed, and roughly contemporaneous with the Chinji Formation of India-Pakistan (ca. 14-11 Ma) and with the Mae Moh Group of northern Thailand. The Chaungtha fauna, even if it displays regional characteristics, shows a strong resemblance to those of the Middle Miocene of India-Pakistan and of Thailand and reinforces the idea that South-East Asia and Pakistan were part of the same biogeographical province during the Middle Miocene.

  1. A new calymmate mimosoid polyad from the Miocene of Argentina.

    PubMed

    Caccavari; Barreda

    2000-05-01

    A palynomorph with an unequivocal relationship to the eight-grain polyads of the mimosoid genus Calliandra Benth., is described from the Miocene sediments of San Juan Province, Argentina. Comparison of the fossil palynomorph with polyads of the extant Calliandra species shows a resemblance to those which have one, highly specialized, appendiculate monad. The new palynomorph has a rudimentary appendix, apparently transitional in the path leading to the more highly developed appendiculate forms in the extant Calliandra group. This specialized polyad type is considered to be one of the most highly evolved forms in subfamily Mimosoideae. The closest affinity of the new fossil polyad is with the eight-grain calymmate polyads of Calliandra chilensis Benth., a species which has developed in the extra-tropical, xerophilous shrub, habitat of north-central Chile. The disappearance of Calliandra species in San Juan Province is thought to be related to the culmination of the Andean rising, and the consequent interruption to the Pacific Ocean climatic influence. This new discovery is the first fossil record of Calliandra for Argentina, as well as being the most southerly and the oldest. It reinforces the hypothesis of an early origin and diversification for the Leguminosae in Tropical America.

  2. Peatmoss (Sphagnum) diversification associated with Miocene Northern Hemisphere climatic cooling?

    PubMed

    Shaw, A Jonathan; Devos, Nicolas; Cox, Cymon J; Boles, Sandra B; Shaw, Blanka; Buchanan, Alex M; Cave, Lynette; Seppelt, Rodney

    2010-06-01

    Global climate changes sometimes spark biological radiations that can feed back to effect significant ecological impacts. Northern Hemisphere peatlands dominated by living and dead peatmosses (Sphagnum) harbor almost 30% of the global soil carbon pool and have functioned as a net carbon sink throughout the Holocene, and probably since the late Tertiary. Before that time, northern latitudes were dominated by tropical and temperate plant groups and ecosystems. Phylogenetic analyses of mosses (phylum Bryophyta) based on nucleotide sequences from the plastid, mitochondrial, and nuclear genomes indicate that most species of Sphagnum are of recent origin (ca. <20 Ma). Sphagnum species are not only well-adapted to boreal peatlands, they create the conditions that promote development of peatlands. The recent radiation that gave rise to extant diversity of peatmosses is temporally associated with Miocene climatic cooling in the Northern Hemisphere. The evolution of Sphagnum has had profound influences on global biogeochemistry because of the unique biochemical, physiological, and morphological features of these plants, both while alive and after death.

  3. Miocene reef facies of Pelagian Block, central Mediterranean

    SciTech Connect

    Pedley, H.M.

    1988-01-01

    Miocene reefs outcrop in the Maltese Islands, southeastern Sicily, and the pelagian island of Lampedusa. Several rapid eustatic sea level fluctuations affected these late Tortonian-early Messinian build-ups; normal salinities appear to have been maintained during these events. Substrate, topography, sedimentation rate, and tectonic/eustatic events controlled reef development, which can be grouped into three settings: The most stable situation, the oldest Maltese and southeastern Sicilian reefs, has a ramp profile 15-30 km wide. The outermost zone consists of a broad belt of the large benthic foraminifer Heterostegina (compared with the underyling Oligocene beds rich in Lepidocyclina). Coralline algal carbonates, commonly rhodolitic, form a broad biostromal up-ramp association, kilometers in width, which commonly extends into the shallowest parts of the shelf. Scattered across the shallower ramp areas, in water depths generally less than 10 m, are coral-algal patch reefs, rarely larger than 20-50 m in diameter, commonly with truncated tops, and dominated by crustose coralline algae and the corals Porites and Tarbellastraea.

  4. Polyphenols from hawthorn peels and fleshes differently mitigate dyslipidemia, inflammation and oxidative stress in association with modulation of liver injury in high fructose diet-fed mice.

    PubMed

    Han, Xiao; Li, Wenfeng; Huang, Di; Yang, Xingbin

    2016-09-25

    Hawthorn ingestion is linked to health benefits due to the various polyphenols. The present study investigated the differential effects of polyphenols-enriched extracts from hawthorn fruit peels (HPP) and fleshes (HFP) against liver injury induced by high-fructose diet in mice. It was found that the main species of polyphenols in hawthorn was chlorogenic acid, epicatechin, rutin and hyperoside, and their contents in HPP were all higher than those in HFP. Administration of HPP was better than HFP to alleviate liver injury and hepatocyte apoptosis, reflected by the reduction of ALT, AST and ALP activities, as well as the ratio of Bax/Bcl-2 in mice. Meanwhile, HPP was also more effective than HFP to mitigate liver inflammation and oxidative stress by inhibiting inflammatory cytokine (TNF-α, IL-1 and IL-6) release, and elevating antioxidant enzyme activities and PPARα expression, while reducing Nrf-2 and ARE expression in mice. Interestingly, HPP-treated mice also showed the lower levels of TC, TG, LDL-C, VLDL-C and Apo-B, and the higher levels of HDL-C and Apo-A1 than HFP-treated mice via reducing FAS express. These results together with the histopathology of the liver with H&E and oil red O staining suggest that hawthorn fruit, especially its peel, is an excellent source of natural polyphenolic chemopreventive agents in the treatment of liver disorders.

  5. The new LOCI digoxin assay on the Vista 1500 analyzer is virtually free from interferences of herbal supplements hawthorn and ashwagandha (Indian ginseng).

    PubMed

    Dasgupta, Amitava; Johnson, Myrtle J; Wahed, Amer

    2012-07-01

    Herbal supplements hawthorn and ashwagandha (Indian ginseng) are indicated for cardiac illnesses and may be taken by patients receiving digoxin therapy. Because both hawthorn and ashwagandha are known to interfere with serum digoxin measurements using certain digoxin immunoassays, we investigated potential interference of these two herbal supplements with the new homogenous sequential chemiluminescent assay for digoxin based on the luminescent oxygen channeling technology (LOCI digoxin) for application on the Dimension and Vista platform. When aliquots of a drug-free serum pool were supplemented with various amounts of hawthorn (three different commercial preparations) or ashwagandha (two different commercial preparations) and apparent digoxin values were measured using LOCI digoxin assay on Dimension Vista 1500 analyzer we observed none-detected values except when aliquots were supplemented with very high amounts of the herbal extracts. When aliquots of a serum digoxin pool (prepared by pooling specimens from patients receiving digoxin) where further supplemented with various amounts of these supplements and digoxin concentrations were remeasured, statistically significant falsely higher digoxin values were observed only in specimens containing very high amounts of these supplements. Such interference may not be clinically significant. We conclude that new LOCI digoxin assay is virtually free from interferences of herbal supplements, hawthorn, and ashwagandha.

  6. New method to estimate paleoprecipitation using fossil amphibians and reptiles and the middle and late Miocene precipitation gradients in Europe

    NASA Astrophysics Data System (ADS)

    Böhme, M.; Ilg, A.; Ossig, A.; Küchenhoff, H.

    2006-06-01

    Existing methods for determining paleoprecipitation are subject to large errors (±350 400 mm or more using mammalian proxies), or are restricted to wet climate systems due to their strong facies dependence (paleobotanical proxies). Here we describe a new paleoprecipitation tool based on an indexing of ecophysiological groups within herpetological communities. In recent communities these indices show a highly significant correlation to annual precipitation (r2 = 0.88), and yield paleoprecipitation estimates with average errors of ±250 280 mm. The approach was validated by comparison with published paleoprecipitation estimates from other methods. The method expands the application of paleoprecipitation tools to dry climate systems and in this way contributes to the establishment of a more comprehensive paleoprecipitation database. This method is applied to two high-resolution time intervals from the European Neogene: the early middle Miocene (early Langhian) and the early late Miocene (early Tortonian). The results indicate that both periods show significant meridional precipitation gradients in Europe, these being stronger in the early Langhian (threefold decrease toward the south) than in the early Tortonian (twofold decrease toward the south). This pattern indicates a strengthening of climatic belts during the middle Miocene climatic optimum due to Southern Hemisphere cooling and an increased contribution of Arctic low-pressure cells to the precipitation from the late Miocene onward due to Northern Hemisphere cooling.

  7. Miocene high-elevation landscape of the eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Liu, Xiaohui; Ding, Lin

    2016-10-01

    The high topography of central Asia is the most distinctive expression of the India-Asia collision, yet a broad understanding of the timing and processes involved in the development of the Tibetan Plateau remains elusive. Here we investigate the Neogene Songpan Basin located on the eastern margin of the plateau using oxygen isotope paleoaltimetry to determine when the steep Longmen Shan margin obtained its present elevations. Hydrologically open lacustrine and fluvial-alluvial authigenic carbonates from the basin record the paleoelevations of the eastern Tibetan Plateau and suggest that the area has attained near-present elevations of ˜3000 m by the late Miocene. This reconstruction is consistent with the results from the comparison of pollen fossils to their nearest living relatives in this area (2750-3050 m). We propose that the eastern Tibetan Plateau may have attained significant elevations prior to the late Miocene through an uplift scenario involving eastward growth of the plateau between the Eocene and the Miocene. Two tectonic processes, either crustal shortening in the Oligocene-Miocene or eastward propagation of weakened lower crust starting in the Eocene, most likely thickened the crust and raised the surface of the eastern Tibetan Plateau to its present elevation by the late Miocene.

  8. A molecular organic carbon isotope record of miocene climate changes

    SciTech Connect

    Schoell, M. ); Schouten, S.; Sinninghe Damste', J.S.; Leeuw, J.W. de ); Summons, R.E. )

    1994-02-25

    The difference in carbon-13 ([sup 13]C) contents of hopane and sterane biomarkers in the Monterey formation (Naples Beach, California) parallels the Miocene inorganic record of the change in [sup 18]O ([delta][sup 18]O), reflecting the Miocene evolution from a well-mixed to a highly stratified photic zone (upper 100 meters) in the Pacific. Steranes ([delta][sup 13]C = 25.4 [+-] 0.7 per mil versus the Pee Dee belemnite standard) from shallow photic-zone organisms do not change isotopically throughout the Miocene. In contrast, sulfur-bound C[sub 35] hopanes (likely derived from bacterial plankton living at the base of the photic zone) have systematically decreasing [sup 13]C concentrations in Middle and Late Miocene samples ([delta][sup 13]C = 29.5 to [minus]31.5 per mil), consistent with the Middle Miocene formation of a carbon dioxide-rich cold water mass at the base of the photic zone.

  9. The Late Miocene climate response to a modern Sahara desert

    NASA Astrophysics Data System (ADS)

    Micheels, Arne; Eronen, Jussi; Mosbrugger, Volker

    2009-06-01

    The climate cooling and vegetation changes in the Miocene/Pliocene are generally well documented by various proxy data. Some important ecosystem changes occurred at that time. Palaeobotanical evidence suggests that the Sahara desert first appeared in the Pliocene, whereas in the Miocene North Africa was green. In the present study, we investigate the Late Miocene climate response to the appearance of the Sahara desert from a climate modelling sensitivity experiment. We compare a model experiment, which includes a full set of Late Miocene boundary conditions, with another one using the same boundary conditions except that the North African vegetation refers to the present-day situation. Our sensitivity study demonstrates that the introduction of the Sahara desert leads to a cooling and an aridification in Africa. In addition, we observe teleconnection patterns related to the North African desertification at around the Miocene/Pliocene boundary. From our sensitivity experiment, we observe that the Sahara contributes to a cooling in Central Asia and in North America. As compared to hypsodonty data for Central Asia, an increased aridity is underestimated in the Sahara experiment. Finally, we observe that the introduction of the Sahara leads to a cooling in the northern high latitudes. Hence, our sensitivity experiment indicates that the appearance of the Sahara desert is one piece to better understand Late Cenozoic climate cooling being most pronounced in the high latitudes.

  10. Interpretation of a 3D Seismic-Reflection Volume in the Basin and Range, Hawthorne, Nevada

    NASA Astrophysics Data System (ADS)

    Louie, J. N.; Kell, A. M.; Pullammanappallil, S.; Oldow, J. S.; Sabin, A.; Lazaro, M.

    2009-12-01

    A collaborative effort by the Great Basin Center for Geothermal Energy at the University of Nevada, Reno, and Optim Inc. of Reno has interpreted a 3d seismic data set recorded by the U.S. Navy Geothermal Programs Office (GPO) at the Hawthorne Army Depot, Nevada. The 3d survey incorporated about 20 NNW-striking lines covering an area of approximately 3 by 10 km. The survey covered an alluvial area below the eastern flank of the Wassuk Range. In the reflection volume the most prominent events are interpreted to be the base of Quaternary alluvium, the Quaternary Wassuk Range-front normal fault zone, and sequences of intercalated Tertiary volcanic flows and sediments. Such a data set is rare in the Basin and Range. Our interpretation reveals structural and stratigraphic details that form a basis for rapid development of the geothermal-energy resources underlying the Depot. We interpret a map of the time-elevation of the Wassuk Range fault and its associated splays and basin-ward step faults. The range-front fault is the deepest, and its isochron map provides essentially a map of "economic basement" under the prospect area. There are three faults that are the most readily picked through vertical sections. The fault reflections show an uncertainty in the time-depth that we can interpret for them of 50 to 200 ms, due to the over-migrated appearance of the processing contractor’s prestack time-migrated data set. Proper assessment of velocities for mitigating the migration artifacts through prestack depth migration is not possible from this data set alone, as the offsets are not long enough for sufficiently deep velocity tomography. The three faults we interpreted appear as gradients in potential-field maps. In addition, the southern boundary of a major Tertiary graben may be seen within the volume as the northward termination of the strong reflections from older Tertiary volcanics. Using a transparent volume view across the survey gives a view of the volcanics in full

  11. Criteria for successful exploration for Miocene reef production in the Philippines

    SciTech Connect

    Downey, M.W. )

    1990-06-01

    An abundance of modern geologic, geophysical, and geochemical data has been provided to interested members of the petroleum industry by the Philippine government, in cooperation with the World Bank. These data have been analyzed to assess whether more, and larger, Miocene reef fields should be expected in the Philippines. In the past decade, exploration by Cities Service (OXY), Amoco, Alcorn, and others has resulted in the discovery of several small Miocene reef and Miocene sandstone oil fields in offshore Palawan. Phillips/Shell also made a significant gas discovery of about 750 bcf in a Palawan Miocene reef that is currently uneconomic to develop given the water depth (1,090 ft) and distance from users. Miocene reefs are commonly buried within Miocene clastics, and, where these impinging clastics are porous, they allow pathways for hydrocarbons to leak from the Miocene reefs. Drape closure is an important positive factor in assessing seal risk for Philippine Miocene reefs. Source rocks to charge middle and upper Miocene reefs are typically restricted to lower Miocene horizons. Geothermal gradients are modest in much of the Philippine offshore, and only select areas provide sufficient burial to mature and expel significant hydrocarbons. It is predicted by the author that additional, larger, and highly profitable Miocene reef fields will be found by future explorers in areas where Miocene reefs have drape closure top seals and are adjacent to deeply buried Miocene source rocks.

  12. Chad Basin: Paleoenvironments of the Sahara since the Late Miocene

    NASA Astrophysics Data System (ADS)

    Schuster, Mathieu; Duringer, Philippe; Ghienne, Jean-François; Roquin, Claude; Sepulchre, Pierre; Moussa, Abderamane; Lebatard, Anne-Elisabeth; Mackaye, Hassan Taisso; Likius, Andossa; Vignaud, Patrick; Brunet, Michel

    2009-08-01

    Since the mid 1990s, the Mission paléoanthropologique francotchadienne (MPFT) conducts yearly paleontological field investigations of the Miocene-Pliocene of the Chad Basin. This article synthesizes some of the results of the MPFT, with focus on the Chad Basin development during the Neogene. We propose an overview of the depositional paleoenvironments of this part of Africa at different scales of time and space, based on a multidisciplinary approach (sedimentary geology, geomorphology, geophysic, numerical simulations and geochronology). The Miocene-Pliocene paleoenvironments are examined through the sedimentary archives of the early hominids levels and the Holocene Lake Mega-Chad episode illustrates the last major paleoenvironmental change in this area. The sedimentary record of the Chad Basin since the Late Miocene can be schematized as the result of recurrent interactions from lake to desert environments.

  13. Interpretive mineralogy: examples from Miocene coastal plain sediments

    SciTech Connect

    Isphording, W.C.

    1983-09-01

    Gulf Coast Miocene sediments are among the most lithologically complex in the entire nation. This varied lithology stems in part from multiple source areas that were active during this interval; but also if reflects major tectonic events that influenced depositional patterns throughout the Gulf Coast during the Miocene. Because fossils are scarce or lacking in many of the units, important questions relating to a number of geologic problems have been discussed illustrating how such analyses can be used to: (1) clarify stratigraphic relationships between units in contact, (2) define environmental conditions in the depositional basin, (3) reconstruct paleoclimate conditions, and (4) identify provenance area. A major anomaly in the mineralogy of central Gulf Coast Miocene sediments is explained by postulating a major ancestral Tennessee River originating in the southern Appalachians and flowing southwestward across Alabama and Mississippi to a terminus in the ancient Gulf of Mexico.

  14. Early, middle, and late Miocene basin development, California

    SciTech Connect

    Bachman, S.B.

    1988-03-01

    Contrary to earlier models of progressive basin development related to northward migration of the Mendocino triple junction, it can now be documented that the major basins of coastal California developed at about the same time in the late Oligocene to early Miocene. This basin development is marked by rapid deepening of basin floors, subsequent changes in depositional facies from nonmarine and shallow marine to deep marine, and widespread volcanism dated at 23-20 Ma. The coastal basins likely formed by rifting and subsidence linked to the proximity of the Farallon-pacific spreading ridge and the subduction of hot young oceanic crust, but cannot be correlated to any existing models of triple junction migration. Indeed, strike-slip restored positions of the coastal basins at their inception indicate that the basins were spread out over about 800 km of the southern coast of California. The Miocene basins were likely larger than the present coastal basins, although their configurations are obscured by late Neogene faulting and erosion. It is likely, however, that paleohighs separated at least some of the margin into proximal and distal basins. With local exceptions, structuring in the Miocene basins was primarily extensional, with widespread strike-slip and thrust tectonics restricted mainly to latest Miocene and younger events. Plate reconstructions suggest several hundred kilometers of transform motion occurred along the California margin during the Miocene, but there is only limited evidence of this movement in the known history of either the basins or the major faults of California. Sedimentation during the Miocene was controlled by both oceanic conditions (biogenic component) and the relative abundance of clastic input. The clastic input was controlled by a combination of proximal vs distal basinal positions, eustatic sea level changes, and local tectonics.

  15. Interpretation of Samburupithecus, an upper Miocene hominoid from Kenya

    NASA Astrophysics Data System (ADS)

    Pickford, Martin; Ishida, Hidemi

    1998-02-01

    Samburupithecus, an extinct great ape from upper Miocene (9.5 Ma) deposits in Kenya, is compared with other fossil and extant hominoids. It possesses features which are derived in comparison with Proconsul and other Lower and Middle Miocene hominoids, but it has none of the derived features which characterize the Eurasian large apes. It possesses characters which indicate that its closest relationships lie with the AAH clade (extant African apes and man). Within this clade it is closest dentally to primitive hominids such as Praeanthropus.

  16. Late miocene tidal deposits in the amazonian foreland basin.

    PubMed

    Räsänen, M E; Linna, A M; Santos, J C; Negri, F R

    1995-07-21

    Late Miocene tidal sediments of Acre, Brazilian Amazonia, were deposited in an embayment or interior seaway located in the sub-Andean zone. This late Tertiary embayment system may once have connected the Caribbean with the South Atlantic. The tidal coasts of the embayment-seaway have provided an avenue for the earliest waif (over water) dispersal phases of the great American biotic interchange in the late Miocene. The subsequent change from semimarine to terrestrial environments is of value in assessing the importance of earlier hypotheses on the evolution of the westem Amazonian landscape and gives insight into the formation of several observed biogeographic patterns, especially of aquatic biota.

  17. Late Miocene Tidal Deposits in the Amazonian Foreland Basin

    NASA Astrophysics Data System (ADS)

    Rasanen, Matti E.; Linna, Ari M.; Santos, Jose C. R.; Negri, Francisco R.

    1995-07-01

    Late Miocene tidal sediments of Acre, Brazilian Amazonia, were deposited in an embayment or interior seaway located in the sub-Andean zone. This late Tertiary embayment system may once have connected the Caribbean with the South Atlantic. The tidal coasts of the embayment-seaway have provided an avenue for the earliest waif (over water) dispersal phases of the great American biotic interchange in the late Miocene. The subsequent change from semimarine to terrestrial environments is of value in assessing the importance of earlier hypotheses on the evolution of the western Amazonian landscape and gives insight into the formation of several observed biogeographic patterns, especially of aquatic biota.

  18. Report: Examination of Costs Claimed under EPA Grant X96906001 Awarded to Walker Lake Working Group, Hawthorne, Nevada

    EPA Pesticide Factsheets

    Report #10-2-0054, January 6, 2010. The grantee did not meet financial management requirements specified by Title 40 Code of Federal Regulations Part 30 and Title 2 Code of Federal Regulations Part 30.

  19. Isolation and identification of flavonoids, including flavone rotamers, from the herbal drug 'Crataegi folium cum flore' (hawthorn).

    PubMed

    Rayyan, S; Fossen, T; Solheim Nateland, H; Andersen, O M

    2005-01-01

    Twelve flavonoids, including seven flavones, four flavonols and one flavanone, were isolated from methanolic extract of the herbal drug 'Crataegi folium cum flore' (hawthorn leaves and flowers) by a combination of CC (over Amberlite XAD-7 and Sephadex LH-20) and preparative HPLC. Their structures, including that of the novel flavonol 8-methoxykaempferol 3-O-(6"-malonyl-beta-glucopyranoside), were elucidated by homo- and heteronuclear NMR and electrospray/MS. The 1H- and 13C-NMR of all compounds, including rotameric pairs of five flavone C-glycosides, were assigned. The presence and relative proportion of each rotamer was shown by various NMR experiments, including two-dimensional nuclear Overhauser and exchange spectroscopy, to depend on solvent, linkage position and structure of the C-glycosyl substituent.

  20. First record of Mylagaulid rodents (Rodentia, Mammalia) from the Miocene of Eastern Siberia (Olkhon Island, Baikal Lake, Irkutsk Region, Russia).

    PubMed

    Tesakov, A S; Lopatin, A V

    2015-01-01

    A new genus and species of rodent, Lamugaulus olkhonensis, belonging to the subfamily Promylagaulinae of the family Mylagaulidae, is described on the basis of isolated teeth from the Khalagay Formation of the Lower Miocene Tagay locality (Olkhon island, Lake Baikal, Irkutsk Region). This is the first record of mylagaulids in Eastern Siberia, significantly expanding the data on the distribution of this mainly North American group of rodents in Asia and showing its presence outside the Central Asian arid zone.

  1. Two New Mylagaulid Rodents from the Early Miocene of China

    PubMed Central

    Lu, Xiaoyu; Ni, Xijun; Li, Lüzhou; Li, Qiang

    2016-01-01

    Mylagaulid fossorial rodents are a common component of North American Miocene fossil faunas. However outside of North America, only three species are known from Asia. Here we report two new mylagaulids, Irtyshogaulus minor gen. et sp. nov. and Irtyshogaulus major gen. et sp. nov., recovered from early Miocene sediments in the Junggar Basin in northwestern China. The two new taxa are small-sized, high-crowned promylagauline rodents. Their lower molars possess high metastylid crests, small mesostylids, broad and posterolingually expanded labial inflections, and transversely extending metalophid IIs. The mesoconid is absent in both species. The anterior and posterior fossettids are large and equally developed. Their upper M1-2s possess a square occlusal surface with five deep fossettes. The two new taxa are distinguished from each other mainly by their size, the morphology of fossettes and fossettids, development of mesial and distal lophs, posterior reduction of M3, and the orientation of m2 hypolophid. Our phylogenetic analysis indicates that Irtyshogaulus and Lamugaulus (another early Miocene Asian mylagaulid) are sister taxa. The two genera are nested among the North American promylagaulines, and share a common ancestor from North America, indicating early Miocene intercontinental dispersal within this clade of rodents. PMID:27486803

  2. A Transitional Gundi (Rodentia: Ctenodactylidae) from the Miocene of Israel.

    PubMed

    López-Antoñanzas, Raquel; Gutkin, Vitaly; Rabinovich, Rivka; Calvo, Ran; Grossman, Aryeh

    2016-01-01

    We describe a new species of gundi (Rodentia: Ctenodactylidae: Ctenodactylinae), Sayimys negevensis, on the basis of cheek teeth from the Early Miocene of the Rotem Basin, southern Israel. The Rotem ctenodactylid differs from all known ctenodactylid species, including Sayimys intermedius, which was first described from the Middle Miocene of Saudi Arabia. Instead, it most resembles Sayimys baskini from the Early Miocene of Pakistan in characters of the m1-2 (e.g., the mesoflexid shorter than the metaflexid, the obliquely orientated hypolophid, and the presence of a strong posterolabial ledge) and the upper molars (e.g., the paraflexus that is longer than the metaflexus). However, morphological (e.g., presence of a well-developed paraflexus on unworn upper molars) and dimensional (regarding, in particular, the DP4 and M1 or M2) differences between the Rotem gundi and Sayimys baskini distinguish them and testify to the novelty and endemicity of the former. In its dental morphology, Sayimys negevensis sp. nov. shows a combination of both the ultimate apparition of key-characters and incipient features that would be maintained and strengthened in latter ctenodactylines. Thus, it is a pivotal species that bridges the gap between an array of primitive ctenodactylines and the most derived, Early Miocene and later, gundis.

  3. A Transitional Gundi (Rodentia: Ctenodactylidae) from the Miocene of Israel

    PubMed Central

    López-Antoñanzas, Raquel; Gutkin, Vitaly; Rabinovich, Rivka; Calvo, Ran; Grossman, Aryeh

    2016-01-01

    We describe a new species of gundi (Rodentia: Ctenodactylidae: Ctenodactylinae), Sayimys negevensis, on the basis of cheek teeth from the Early Miocene of the Rotem Basin, southern Israel. The Rotem ctenodactylid differs from all known ctenodactylid species, including Sayimys intermedius, which was first described from the Middle Miocene of Saudi Arabia. Instead, it most resembles Sayimys baskini from the Early Miocene of Pakistan in characters of the m1-2 (e.g., the mesoflexid shorter than the metaflexid, the obliquely orientated hypolophid, and the presence of a strong posterolabial ledge) and the upper molars (e.g., the paraflexus that is longer than the metaflexus). However, morphological (e.g., presence of a well-developed paraflexus on unworn upper molars) and dimensional (regarding, in particular, the DP4 and M1 or M2) differences between the Rotem gundi and Sayimys baskini distinguish them and testify to the novelty and endemicity of the former. In its dental morphology, Sayimys negevensis sp. nov. shows a combination of both the ultimate apparition of key-characters and incipient features that would be maintained and strengthened in latter ctenodactylines. Thus, it is a pivotal species that bridges the gap between an array of primitive ctenodactylines and the most derived, Early Miocene and later, gundis. PMID:27049960

  4. Late Miocene global cooling and the rise of modern ecosystems

    NASA Astrophysics Data System (ADS)

    Herbert, Timothy D.; Lawrence, Kira T.; Tzanova, Alexandrina; Peterson, Laura Cleaveland; Caballero-Gill, Rocio; Kelly, Christopher S.

    2016-11-01

    During the late Miocene epoch, about seven million years ago, large areas of the continents experienced drying, enhanced seasonality, and a restructuring of terrestrial plant and animal communities. These changes are seen throughout the subtropics, but have typically been attributed to regional tectonic forcing. Here we present a set of globally distributed sea surface temperature records spanning the past 12 million years based on the alkenone unsaturation method. We find that a sustained late Miocene cooling occurred synchronously in both hemispheres, and culminated with ocean temperatures dipping to near-modern values between about 7 and 5.4 million years ago. The period of maximum cooling coincides with evidence for transient glaciations in the Northern Hemisphere and with a steepening of the pole-to-equator temperature gradient, as well. We thus infer that late Miocene aridity and terrestrial ecosystem changes occurred in a global context of increasing meridional temperature gradients. We conclude that a global forcing mechanism, such as the previously hypothesized decline in atmospheric CO2 levels between eight and six million years ago, is required to explain the late Miocene changes in temperature, climate and ecosystems.

  5. Provenance study conflict Miocene eolian deposit in central China

    NASA Astrophysics Data System (ADS)

    Liu, S.; Stockli, D. F.; Li, J.; Song, C.

    2013-12-01

    The dispute of fine-grained Miocene sediments from Tianshui Basin, northeastern Tibetan Plateau as eolian loess-paleosol or neptunian mudflat/distal fan is an unresolved hot topic in Cenozoic palaeoclimatology , impacting further research of Asian monsoon and the mechanism of its variations. Tratigraphic correlation and constraining the sedimentary age with paleomagnetic method show that hundreds miles of foreland basin stratums occurred in north of West Qinling mountain belt in Miocene. The tratums are about 2000 m thick in the south foredeep range, thinning to less than 300 m thick in the north backbulge range. Similar heavy minerals composition and detrital ziron U/Pb ages distribution also show that the materials in the basin were from the same denuded regions. Such evidences conform that the Miocene sedimentary sections identified as loess in Tianshui basin could be distal fan and flood plain in the united foreland basin system. Comprehensive provenance techniques of heavy minerals and detrital zircon U/Pb ages show differences between Miocene Tianshui sediments and Pliocene- Quaternary loess- red clay from Chinese loess Plateau. Specifically, samples from Tianshui basin have more than 20% of Magnetite and 30% of Epidote, but Amphibole is lacking. Loess-red clay samples consist of 21% Amphibole on average. Classifying degree of correction of Amphibole proves that weathering erosion is not the reason for this dissimilarity. More Amphibole rich iginous rocks or matemorphoic rocks could exist widely in loess's source region. Most zircon U/Pb ages in this study fall into similar ranges, especially from 200Ma to 500Ma. There is a significant age peak from 200Ma to 250Ma in Tianshui sediments and modern river sands originating from West Qinling mountain belt, which is rare in loess-red clay samples. A part of zircons from loess and red clay contain very low U and Th elements, implying some of Mafic or intermediate rocks in eolian source area. Both Mafic and

  6. The early to mid-Miocene environment of Antarctica

    NASA Astrophysics Data System (ADS)

    Ashworth, A. C.; Lewis, A.

    2012-12-01

    Paleoecological studies in the Transantarctic Mountains of the McMurdo region provide evidence that the climate was both warmer and wetter in the early to mid-Miocene than it was during the late Miocene. The climate change was accompanied by a shift from wet- to cold-based glaciation in the TAM and the probable growth of the polar ice sheet. Terrestrial and freshwater aquatic fossil assemblages from the Friis Hills (77°S) and the Olympus Range (77°S), with endpoint 40Ar/39Ar ages on tephras of 19.76 Ma and 14.07 Ma, respectively, indicate climatic cooling during the interval. At c.14 Ma, the temperature dropped below the threshold required to support the plants and insects of a tundra biome, and they became extinct. This interpretation is supported by pollen studies from Ross Sea cores. The extinction of the tundra biota on the continent appears to have been time-transgressive, occurring at 12.8 Ma on the Antarctic Peninsula. Evidence of climatic cooling from early to mid-Miocene is based on a decrease in biodiversity. During interglacial phases of the early Miocene, the poorly drained valley of the Friis Hills supported a sexually-reproducing moss community dominated by Campylium cf. polygamum, which today grows on the margins of lakes and in soil between boulders. Wood and leaves of Nothofagus (Southern Beech), and the seeds of at least five other angiosperm species are preserved as fossils. In addition, there are abundant megaspores and spiny, curved leaves of the aquatic lycopod Isoetes (Quillwort), as well as chitinous remains of curculionid beetles and Chironomidae (midges). During glacial phases, the only fossils found are Nothofagus leaves of a species which appears to be different than that associated with the interglacial phases. Pollen supports the interpretation that there was more than one species of Nothofagus in the vegetation. The types and numbers of species indicate that the vegetation was a shrub tundra. The closest modern analog for the fossil

  7. On the Miocene Cyprideis species flock (Ostracoda; Crustacea) of Western Amazonia (Solimões Formation): Refining taxonomy on species level

    PubMed Central

    Gross, Martin; Ramos, Maria Ines F.; Piller, Werner E.

    2016-01-01

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic ostracod fauna. Among them, especially the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400 m long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. We evaluate the diagnostic value of shell characters and provide an extensive illustration of the intraspecific variability of species. Based on comparative morphology, the 20 recorded Cyprideis species are arranged in groups and subgroups. The “smooth” group comprises C. amazonica, C. kotzianae, C. kroemmelbeini, C. machadoi, C. multiradiata, C. olivencai, C. paralela and C. simplex; the “ornate” group C. curucae nom. nov., C. cyrtoma, C. aff. graciosa, C. inversa, C. ituiae n. sp., C. matorae n. sp., C. minipunctata, C. munoztorresi nom. nov., C. pebasae, C. reticulopunctata, C. schedogymnos and C. sulcosigmoidalis. Five species have been revalidated, two renamed, two synonymised and two are new descriptions. Along with 10 further formally established species, for which a review is pending, Cyprideis keeps at least 30 endemic species in that region during Miocene times. Up to 12 Cyprideis species have been found to occur sympatrically, representing >90 % of the entire ostracod fauna. Ostracod index species enable a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones, corresponding to a late Middle to early Late Miocene age (late Serravallian–early Tortonian). PMID:25543674

  8. On the Miocene Cyprideis species flock (Ostracoda; Crustacea) of Western Amazonia (Solimões Formation): Refining taxonomy on species level.

    PubMed

    Gross, Martin; Ramos, Maria Ines F; Piller, Werner E

    2014-12-18

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic ostracod fauna. Among them, especially the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400 m long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. We evaluate the diagnostic value of shell characters and provide an extensive illustration of the intraspecific variability of species. Based on comparative morphology, the 20 recorded Cyprideis species are arranged in groups and subgroups. The "smooth" group comprises C. amazonica, C. kotzianae, C. kroemmelbeini, C. machadoi, C. multiradiata, C. olivencai, C. paralela and C. simplex; the "ornate" group C. curucae nom. nov., C. cyrtoma, C. aff. graciosa, C. inversa, C. ituiae n. sp., C. matorae n. sp., C. minipunctata, C. munoztorresi nom. nov., C. pebasae, C. reticulopunctata, C. schedogymnos and C. sulcosigmoidalis. Five species have been revalidated, two renamed, two synonymised and two are new descriptions. Along with 10 further formally established species, for which a review is pending, Cyprideis keeps at least 30 endemic species in that region during Miocene times. Up to 12 Cyprideis species have been found to occur sympatrically, representing >90% of the entire ostracod fauna. Ostracod index species enable a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones, corresponding to a late Middle to early Late Miocene age (late Serravallian-early Tortonian).

  9. Stratigraphical and palaeontological characteristics of the Miocene deposits at Soluq area, NE Libya: First Results

    NASA Astrophysics Data System (ADS)

    Abdulsamad, E. O.; El Zanati, S. M.

    2012-04-01

    The north-south scarp that runs in the middle of Soluq area, about 70 km southeast of Benghazi, attains altitudes towards the north, reaching a maximum of about 300 meters above sea level at wadi al Qattarah. The scarp fades gradually towards the south till at Antelat area and is represented by few meters high hills. The plateau, however, extends eastwards rising to altitudes more than 450 meters above sea level. The plain (known as Soluq plain) extends westwards till near the Mediterranean coast with average width of about 50 kilometers. Several outcrops along the main escarpment have been visited and spot sampled and two carbonate rock units separated by reduced deposits of clastic origin have been recognised based on lithology and faunal contents. The oldest rock unit is representing by the Benghazi Formation and the youngest rock unit is representing by Wadi al Qattarah Formation. Both rock units, nevertheless, are belonging to the Miocene Ar Rajmah Group and cover the greater part of the Soluq area. The lower Benghazi Formation has been dated as Middle Miocene based on the presence of Lepidocyclina (Eulepidina) dilatat (Michelotti) and Borelis melo melo (Fichiteli). The latter taxon was recognized in different local areas of the same time-interval. The inconsistent occurrences and broken nature of tests of Borelis melo melo in some levels in the upper Wadi al Qattarah Formation, however, indicates that this taxon has been subjected to extensive reworking and Late Miocene age is ascribed to the major deposits of the later rock unit. This assumption may explain the occurrences of a number of lenses and irregular bodies of gypsum of the Messenian event in study region. The high variety of the microfacies and fossil assemblages recognised in this study reflects (1) the variety of environmental settings and (2) the effect of the lithofacies on the fossil recovery. In general, larger and small foraminifera from the Miocene Ar Rajmah Group are a mix of infaunal and

  10. Droughts in the Miocene of the Black Sea region

    NASA Astrophysics Data System (ADS)

    Vasiliev, Iuliana; Reichart, Gert-Jan; Grothe, Arjen; Krijgsman, Wout

    2016-04-01

    Since Miocene the Black Sea has been highly sensitive to fluctuations in the hydrological cycle. These fluctuations were principally determined by Black Sea's recurrently restricted connections to the Open Ocean and by its specific paleogeographic location between the dry Mediterranean domain and more humid higher northern latitudes. To determine the nature of changes in the hydrological budget of the Black Sea occurring during the late Miocene we use compound-specific hydrogen isotope ratios on terrestrial and aquatic biomarkers extracted from two different locations: 1) the sedimentary succession of Zhelezniy Rog land based section of Taman in Russia and 2) the deep sea sedimentary succession recovered in 1975 from the Black Sea (DSDP 42B, Hole 380A). The carbon and hydrogen isotopic composition of n-alkanes as well as alkenones and palynology indicate large environmental changes in the Black Sea and/or in the sources of the water entering the Black Sea during the late Miocene. The hydrogen isotopes of alkenones, showing an enrichment of more than 80 ‰ at the end of the Miocene, imply a major shift in basin hydrology, possibly resulting in severely increased salinity. These changes in hydrogen isotopic composition of the alkenones concur both with sharp shifts in reconstructed sea surface temperature and palynological assemblages. Two intervals with negative water budget were identified, most likely caused by enhanced evaporation. The older and longer dry/evaporative phase predates the Maeotian/Pontian boundary (regional stages) at ~6.1 Ma. The younger negative water budget phase is partly coeval to the Messinian salinity crisis of Mediterranean. Both shifts to highly evaporative conditions are recorded in both Taman Peninsula (Russia) and DSDP 42B 380A locations. These recurrent dryer phases were, most likely, the result of important hydrological changes over a significantly larger area around the Black Sea area during the upper Miocene.

  11. A new pitheciin primate from the middle Miocene of Argentina.

    PubMed

    Kay, R F; Johnson, D; Meldrum, D J

    1998-01-01

    We report here a new fossil primate from the middle Miocene of Argentina. The material consists of isolated teeth, mandibular fragments, and a talus. The fossils were collected in the Collón Cura formation at Cañadón del Tordillo in Neuquén Province. An age of 15.71 +/- 0.07 Ma has been reported for the Pilcaniyeu Ignimbrite, which lies just below the paleosols in which the fossils were found. This material is thus the youngest occurrence of fossil primates in Argentina (hitherto documented in the Santacrucian and older land mammal ages) but still is older than the middle Miocene platyrrhine primates from La Venta, Colombia, in particular the pitheciins Nuciruptor and Cebupithecia. The material is recognized as a new genus and species of Pitheciinae, Propithecia neuquenensis. The mesiodistally compressed, high-crowned incisors are specialized and similar to species in the tribe Pithecini and to the nonpitheciin Soriacebus (early Miocene, Patagonia). We rule out a phylogenetic relationship to the latter because of differences in molar morphology. Propithecia does, however, fit well into the pattern of pitheciin evolution, being more derived than the middle Miocene pitheciin Nuciruptor but not as much as another middle Miocene taxon, Cebupithecia. As such, this makes Propithecia the oldest taxon that can be confidently placed within this modern New World monkey subfamily. By analogy with the molar structures and diets of extant platyrrhines, Propithecia has a molar structure consistent with a variety of low-fiber diets ranging from fruit and gum to seeds. Its incisors suggest seed-eating in much the same way as extant pitheciins, like Pithecia. The talus resembles that of Callicebus, suggesting arboreal quadrupedal locomotion.

  12. Palynology of latest Neogene (Middle Miocene to late Pliocene) strata in the Delmarva Peninsula of Maryland and Virginia

    USGS Publications Warehouse

    Sirkin, L.; Owens, J.P.

    1998-01-01

    Palynology of Miocene and Pliocene formations in the Delmarva Peninsula of Maryland and Virginia reveals a significant representation of exotic pollen interspersed in pollen assemblages that are otherwise comparable to those from the modern vegetation of the Mid-Alantic coastal plain region. The late Tertiary arboreal pollen (AP) assemblages are dominated by oak, hickory, pine, birch and alder with minor amounts of mid- and southern coastal tree taxa, as well as minor spruce and hemlock and a trace of fir. Nonarboreal pollen (NAP) include grass, sedge, composite and aquatic taxa. Exotic pollen in these assemblages represent plants now foreign to this region. They may be placed in three categories. First, there are extinct forms, such as Labrapollis, Plicatopollis, and Multiporopollenites, that can be traced from the Cretaceous or Early Tertiary into the Late Tertiary. The second group includes forms, such as Podocarpus, Engelhardtia, Pterocarya, Ephedra, Eucommia, Ulmus-Zelkova, Glyptostrobus, Palmae, and Cyathea, that are not found in this region today and not found in early Pleistocene sediments in the eastern United States. Many of these taxa are subtropical or greatly restricted in geographic range. A third group of exotics, mainly Cyrilla, Planera, Gordonia, Jussiaea, and Sapotacaea, including Minusops, are generally found south of the study area or have their northern limit here at this time. The lack of the extinct or distant exotics in early to mid-Pleistocene sediments in the mid-Atlantic coastal plain and the last appearance of Pterocarya, as the last exotic taxon in the early Pleistocene of western Europe, support the stratigraphic assignment of the Pliocene units. The number of exotic taxa diminish markedly between the Miocene pollen assemblages and those of the Late Pliocene. Climatic fluctuations characterize the Late Tertiary environments. The Miocene, for example, incorporates a warming trend between the upper, middle Miocene and the Manokin beds

  13. Systematics and Evolution of the Miocene Three-Horned Palaeomerycid Ruminants (Mammalia, Cetartiodactyla)

    PubMed Central

    Sánchez, Israel M.; Cantalapiedra, Juan L.; Ríos, María; Quiralte, Victoria; Morales, Jorge

    2015-01-01

    Palaeomerycids were strange three-horned Eurasian Miocene ruminants known through fossils from Spain to China. We here study their systematics, offering the first cladistic phylogeny of the best-known species of the group, and also reassess their phylogenetic position among ruminants, which is currently disputed. The beautifully preserved remains of a new palaeomerycid from middle Miocene deposits of Spain, Xenokeryx amidalae gen. et sp. nov., helps us to better understand palaeomerycid anatomy, especially that of the nuchal region in the skull, significantly improving our current knowledge on these enigmatic ruminants. Our results show two main lineages of palaeomerycids, one containing the genus Ampelomeryx diagnosed by a characteristic type of cranium / cranial appendages and some dental derived traits, and another one that clusters those forms more closely related to Triceromeryx than to Ampelomeryx, characterized by a more derived dentition and a set of apomorphic cranial features. Xenokeryx branches as a basal offshoot of this clade. Also, we find that Eurasian palaeomerycids are not closely related to North American dromomerycids, thus rejecting the currently more accepted view of palaeomerycids as the Eurasian part of the dromomerycid lineage. Instead of this, palaeomerycids are nested with the African Miocene pecoran Propalaeoryx and with giraffoids. On the other hand, dromomerycids are closely related to cervids. We define a clade Giraffomorpha that includes palaeomerycids and giraffids, and propose an emended diagnosis of the Palaeomerycidae based on cranial and postcranial characters, including several features of the cranium not described so far. We also define the Palaeomerycidae as the least inclusive clade of pecorans containing Triceromeryx and Ampelomeryx. Finally, we reassess the taxonomy of several palaeomerycid taxa. PMID:26630174

  14. Systematics and Evolution of the Miocene Three-Horned Palaeomerycid Ruminants (Mammalia, Cetartiodactyla).

    PubMed

    Sánchez, Israel M; Cantalapiedra, Juan L; Ríos, María; Quiralte, Victoria; Morales, Jorge

    2015-01-01

    Palaeomerycids were strange three-horned Eurasian Miocene ruminants known through fossils from Spain to China. We here study their systematics, offering the first cladistic phylogeny of the best-known species of the group, and also reassess their phylogenetic position among ruminants, which is currently disputed. The beautifully preserved remains of a new palaeomerycid from middle Miocene deposits of Spain, Xenokeryx amidalae gen. et sp. nov., helps us to better understand palaeomerycid anatomy, especially that of the nuchal region in the skull, significantly improving our current knowledge on these enigmatic ruminants. Our results show two main lineages of palaeomerycids, one containing the genus Ampelomeryx diagnosed by a characteristic type of cranium / cranial appendages and some dental derived traits, and another one that clusters those forms more closely related to Triceromeryx than to Ampelomeryx, characterized by a more derived dentition and a set of apomorphic cranial features. Xenokeryx branches as a basal offshoot of this clade. Also, we find that Eurasian palaeomerycids are not closely related to North American dromomerycids, thus rejecting the currently more accepted view of palaeomerycids as the Eurasian part of the dromomerycid lineage. Instead of this, palaeomerycids are nested with the African Miocene pecoran Propalaeoryx and with giraffoids. On the other hand, dromomerycids are closely related to cervids. We define a clade Giraffomorpha that includes palaeomerycids and giraffids, and propose an emended diagnosis of the Palaeomerycidae based on cranial and postcranial characters, including several features of the cranium not described so far. We also define the Palaeomerycidae as the least inclusive clade of pecorans containing Triceromeryx and Ampelomeryx. Finally, we reassess the taxonomy of several palaeomerycid taxa.

  15. High richness of insect herbivory from the early Miocene Hindon Maar crater, Otago, New Zealand

    PubMed Central

    Lee, Daphne E.; Wappler, Torsten

    2017-01-01

    Plants and insects are key components of terrestrial ecosystems and insect herbivory is the most important type of interaction in these ecosystems. This study presents the first analysis of associations between plants and insects for the early Miocene Hindon Maar fossil lagerstätte, Otago, New Zealand. A total of 584 fossil angiosperm leaves representing 24 morphotypes were examined to determine the presence or absence of insect damage types. Of these leaves, 73% show signs of insect damage; they comprise 821 occurrences of damage from 87 damage types representing all eight functional feeding groups. In comparison to other fossil localities, the Hindon leaves display a high abundance of insect damage and a high diversity of damage types. Leaves of Nothofagus(southern beech), the dominant angiosperm in the fossil assemblage, exhibit a similar leaf damage pattern to leaves from the nearby mid to late Miocene Dunedin Volcano Group sites but display a more diverse spectrum and much higher percentage of herbivory damage than a comparable dataset of leaves from Palaeocene and Eocene sites in the Antarctic Peninsula. PMID:28224051

  16. Occlusal enamel complexity in middle miocene to holocene equids (Equidae: Perissodactyla) of North America.

    PubMed

    Famoso, Nicholas A; Davis, Edward Byrd

    2014-01-01

    Four groups of equids, "Anchitheriinae," Merychippine-grade Equinae, Hipparionini, and Equini, coexisted in the middle Miocene, but only the Equini remains after 16 Myr of evolution and extinction. Each group is distinct in its occlusal enamel pattern. These patterns have been compared qualitatively but rarely quantitatively. The processes influencing the evolution of these occlusal patterns have not been thoroughly investigated with respect to phylogeny, tooth position, and climate through geologic time. We investigated Occlusal Enamel Index, a quantitative method for the analysis of the complexity of occlusal patterns. We used analyses of variance and an analysis of co-variance to test whether equid teeth increase resistive cutting area for food processing during mastication, as expressed in occlusal enamel complexity, in response to increased abrasion in their diet. Results suggest that occlusal enamel complexity was influenced by climate, phylogeny, and tooth position through time. Occlusal enamel complexity in middle Miocene to Modern horses increased as the animals experienced increased tooth abrasion and a cooling climate.

  17. Paleomagnetic Evidence for Spatially Distributed Post-Miocene Rotation of Western Washington and Oregon

    NASA Astrophysics Data System (ADS)

    Sheriff, Steven D.

    1984-06-01

    Anomalous paleomagnetic directions have been determined for 17 sites in the Frenchmans Springs member of the Wanapum basalt formation, Columbia River basalt group. These sites are located in the Ginkgo flows from near Vantage, Washington, to Portland, Oregon, a distance of approximately 300 km. The average paleomagnetic direction for six of these sites, centered around Vantage is D = 147°, I = 41°, α95 = 4.5°. The expected Miocene field direction is D = 355°, I = 65°. At some localities there are two distinct Ginkgo flows, in direct stratigraphic succession, with statistically identical anomalous directions. Their anomalous paleomagnetic direction makes these flows a valuable marker horizon in the Columbia River basalt group. The nondipole field direction of the Ginkgo flows correlates well with available results from the Miocene Cape Foulweather basalts of Oregon. This correlation strongly supports the hypothesis that these coastal basalts of Oregon are the distal ends of Columbia Plateau derived basalt flows. The spatial distribution of these anomalous field directions suggests about 14° of clockwise rotation between Vantage and Portland. Combining these data with data from the Oregon Coast basalts allows a maximum declination difference of about 35°. The increase in declination can be best explained by clockwise rotation, about nearby vertical axes, increasing to the southwest across the Columbia Plateau and Oregon coast.

  18. A New Late Miocene Odobenid (Mammalia: Carnivora) from Hokkaido, Japan Suggests Rapid Diversification of Basal Miocene Odobenids

    PubMed Central

    Tanaka, Yoshihiro; Kohno, Naoki

    2015-01-01

    The modern walrus, Odobenus rosmarus, is specialized and only extant member of the family Odobenidae. They were much more diversified in the past, and at least 16 genera and 20 species of fossil walruses have been known. Although their diversity increased in the late Miocene and Pliocene (around 8–2 Million years ago), older records are poorly known. A new genus and species of archaic odobenid, Archaeodobenus akamatsui, gen. et sp. nov. from the late Miocene (ca. 10.0–9.5 Ma) top of the Ichibangawa Formation, Hokkaido, northern Japan, suggests rapid diversification of basal Miocene walruses. Archaeodobenus akamatsui is the contemporaneous Pseudotaria muramotoi from the same formation, but they are distinguishable from each other in size and shape of the occipital condyle, foramen magnum and mastoid process of the cranium, and other postcranial features. Based on our phylogenetic analysis, A. akamatsui might have split from P. muramotoi at the late Miocene in the western North Pacific. This rapid diversification of the archaic odobenids occurred with a combination of marine regression and transgression, which provided geological isolation among the common ancestors of extinct odobenids. PMID:26244784

  19. A New Late Miocene Odobenid (Mammalia: Carnivora) from Hokkaido, Japan Suggests Rapid Diversification of Basal Miocene Odobenids.

    PubMed

    Tanaka, Yoshihiro; Kohno, Naoki

    2015-01-01

    The modern walrus, Odobenus rosmarus, is specialized and only extant member of the family Odobenidae. They were much more diversified in the past, and at least 16 genera and 20 species of fossil walruses have been known. Although their diversity increased in the late Miocene and Pliocene (around 8-2 Million years ago), older records are poorly known. A new genus and species of archaic odobenid, Archaeodobenus akamatsui, gen. et sp. nov. from the late Miocene (ca. 10.0-9.5 Ma) top of the Ichibangawa Formation, Hokkaido, northern Japan, suggests rapid diversification of basal Miocene walruses. Archaeodobenus akamatsui is the contemporaneous Pseudotaria muramotoi from the same formation, but they are distinguishable from each other in size and shape of the occipital condyle, foramen magnum and mastoid process of the cranium, and other postcranial features. Based on our phylogenetic analysis, A. akamatsui might have split from P. muramotoi at the late Miocene in the western North Pacific. This rapid diversification of the archaic odobenids occurred with a combination of marine regression and transgression, which provided geological isolation among the common ancestors of extinct odobenids.

  20. Anatomical and developmental study of petrified Quercus (Fagaceae) fruits from the Middle Miocene, Yakima Canyon, Washington, USA.

    PubMed

    Borgardt, S J; Pigg, K B

    1999-03-01

    The first reported petrified acorns to show internal anatomical structure are here described from Middle Miocene (∼15.6 million years old) chert of the Columbia River Basalt Group in Yakima Canyon, Washington. Quercus hiholensis Borgardt et Pigg sp. nov. is described from anatomical and morphological fruit features, as well as a little recognized anatomical feature, the umbilical complex. Acorns, each comprising a nut and its cupule, are up to 15.3 mm long and 18.8 mm wide with helically arranged, imbricate, tuberculate cupule scales. They show basal aborted ovules, short styles, broad stigmas, and lack grooves in their cotyledons. These characters and the developmental pattern seen in these fossil acorns demonstrate that Q. hiholensis conforms to genus Quercus (Fagaceae), subgenus Quercus, section Quercus (the white oaks). The correspondence of Q. hiholensis to the modern section Quercus reveals that the derived floral and fruit characters that distinguish section Quercus within the genus had evolved by the Middle Miocene.

  1. Coarse-grained deltaic sedimentation in the Miocene Cuyama strike-slip basin, California Coast Ranges

    USGS Publications Warehouse

    Alan, Bartow J.

    1990-01-01

    The Cuyama basin, located in the southern Coast Ranges of California southwest of the San Andreas fault, developed early in the history of the San Andreas transform system. The Miocene marine basin formed in a transtensional setting along a dextral strike-slip fault of the transform system following Oligocene non-marine basin formation in an extensional setting. The lower and middle Miocene Vaqueros Formation in the northwestern part of the basin, which represents the first of two transgressive-regressive cycles, is described here in terms of nine facies in two broad facies groups. The 400-m-thick Soda Lake Shale Member (of the Vaqueros) comprises deep-basin and starved-basin facies. A thin transgressive facies occurs locally at the base of the formation. The overlying Painted Rock Sandstone Member (of the Vaqueros), which is more than 2200 m thick and consists mostly of coarse-grained sandstone and pebbly sandstone, constitutes a delta complex of prodelta, slope channel, delta front, tide-influenced distributary channel, interdistributary bay, and fluvial channel facies. The basinal depositional system consisted of turbidite mud and sand, and hemipelagic and pelagic sediments of the basinal facies deposited in a rapidly subsiding basin. The delta depositional system consisted of the delta complex facies that prograded into the deep basin and had a steep prodelta slope that extended to bathyal depths. The delta is inferred to be a mixed fluvial-wave-dominated fan delta, analogous in its delta-front morphology and processes to a fjord delta, in which coarse sediment delivered to the delta front by braided streams was transported down the prodelta slope into deep water by sediment gravity flows. Transgression and rapid deepening of the basin in the early Miocene coincided with rapid tectonic subsidence. Deepening culminated with deposition of a starved-basin facies or condensed section at the time of maximum transgression, which was followed by the beginning of a

  2. C4 expansion in the central Inner Mongolia during the latest Miocene and early Pliocene

    NASA Astrophysics Data System (ADS)

    Zhang, Chunfu; Wang, Yang; Deng, Tao; Wang, Xiaoming; Biasatti, Dana; Xu, Yingfeng; Li, Qiang

    2009-10-01

    The emergence of C4 photosynthesis in plants as a significant component of terrestrial ecosystems is thought to be an adaptive response to changes in atmospheric CO 2 concentration and/or climate during Neogene times and has had a profound effect on the global terrestrial biosphere. Although expansion of C4 grasses in the latest Miocene and Pliocene has been widely documented around the world, the spatial and temporal variations in the C4 expansion are still not well understood and its driving mechanisms remain a contentious issue. Here we present the results of carbon and oxygen isotope analyses of fossil and modern mammalian tooth enamel samples from the central Inner Mongolia. Our samples represent a diverse group of herbivorous mammals including deer, elephants, rhinos, horses and giraffes, ranging in age from the late Oligocene to modern. The δ13C values of 91 tooth enamel samples of early late-Miocene age or older, with the exception of two 13 Ma rhino samples (- 7.8 and - 7.6‰) and one 8.5 Ma suspected rhino sample (- 7.6‰), were all less than - 8.0‰ (VPDB), indicating that there were no C4 grasses present in their diets and thus probably few or no C4 grasses in the ecosystems of the central Inner Mongolia prior to ~ 8 Ma. However, 12 out of 26 tooth enamel samples of younger ages (~ 7.5 Ma to ~ 3.9 Ma) have δ13C values higher than - 8.0‰ (up to - 2.4‰), indicating that herbivores in the area had variable diets ranging from pure C3 to mixed C3-C4 vegetation during that time interval. The presence of C4 grasses in herbivores' diets (up to ~ 76% C4) suggests that C4 grasses were a significant component of the local ecosystems in the latest Miocene and early Pliocene, consistent with the hypothesis of a global factor as the driving mechanism of the late Miocene C4 expansion. Today, C3 grasses dominate grasslands in the central Inner Mongolia area. The retreat of C4 grasses from this area after the early Pliocene may have been driven by regional

  3. Paleosecular variation record of geomagnetic full vector during late Miocene, from the Nayarit area, Mexico

    NASA Astrophysics Data System (ADS)

    Goguitchaichvili, Avto; Alva Valdivia, Luis M.; Elguera, Jose Rosas; Fucugauchi, Jaime Urrutia; Cervantes, Miguel Angel; Morales, Juan

    2002-11-01

    We have sampled a sequence of 45 late Miocene consecutive lava flows in the Tepic area (Nayarit State, Mexico). The age of the volcanic units lies between 8 and 9 million years (Ma) according to available radiometric data. All samples were stepwise demagnetized, partly with alternating field (AF), partly thermally with very similar results. Most of the rocks exhibited well-defined one component remanent magnetisation with high unblocking temperatures (mostly above 525 °C) and high median destructive fields (MDF) (40-50 mT). Rock-magnetic experiments combined with microscopy show that, in most cases, the main magnetic mineral is Ti-poor titanomagnetite associated with exsoluted ilmenite. Continuous susceptibility measurements with temperature and hysteresis experiments yield in most cases nearly reversible curves with Curie points close to that of magnetite and pseudo-single-domain characteristics. Characteristic remanent magnetisations (ChRM) isolated after the first steps of demagnetisation are all normal polarity. According to the dispersion of virtual geomagnetic pole (VGP) directions, paleosecular variation was abnormally lower than the one observed in general during Miocene. Considering our paleomagnetic results together with available radiometric data, it seems that the volcanic units have been emplaced during a very short time span of about 0.08 million years. The mean paleomagnetic directions obtained from this study do not differ significantly from that expected for the middle Miocene. Thirty-one samples from eight individual flows yielded acceptable paleointensity estimates. The site mean paleointensities range from 27.8±0.9 to 42.0±7.9 μT. The virtual dipole moments (VDM) range from 5.9 to 9.5×10 22 Am 2. This corresponds to a mean value of 7.6±1.4×10 22 Am 2, which is higher than the average VDM value for late Miocene. Altogether our data suggest the existence of relatively high geomagnetic field strength undergoing low fluctuations. These

  4. Chemical evolution of Miocene wood: Example from the Belchatow brown coal deposit, central Poland

    USGS Publications Warehouse

    Drobniak, A.; Mastalerz, Maria

    2006-01-01

    Miocene conifer wood samples from the Belchatow brown coal deposit in Poland were studied in order to discuss a range of chemical variations that occur as a result of biochemical coalification. Petrographic analysis, ultimate analysis, electron microprobe technique, and FTIR spectroscopy were used in this study. Our data show several progressive trends in functional groups distribution that take place during the wood transformation from group 1 to group 4, such as an overall increase in aromaticity, an increase in lignin/cellulose ratio, and an increase in oxygen functionalities. Other observations include an increase in aliphatic stretching and bending functionalities from groups 1 to 3; followed by a decrease in the wood of group 4; appearance of aliphatic out-of-plane bands in group 3 and increase in group 4; an increase in CH2/CH3 in group 4 compared to the other groups; and decrease in O-H groups in group 4 compared to other groups. These observations, together with other chemical and petrological observations, indicate that the progressive elimination of cellulose and modification of lignin are dominant processes of the wood transformation. ?? 2005 Elsevier B.V. All rights reserved.

  5. Mid Miocene Terrestrial Ecosystems: Information from Mammalian Herbivore Communities.

    NASA Astrophysics Data System (ADS)

    Janis, C. M.; Damuth, J.; Theodor, J. M.

    2001-05-01

    In present day ecosystems the numbers and proportions of different kinds of ecologically distinct ungulates (hoofed mammals) provide an indicator of the nature of the vegetation in the habitat. Different vegetation types (such as forest, savanna, or grassland) are characteristically associated with different arrays of ungulates, with species exhibiting differences in diet, body size, and type of digestive fermentation system. These biological attributes can also be inferred for fossil ungulate species, the first two from quantitative assessment of skull and dental anatomy, and the last from phylogenetic affinity. Thus fossil ungulate communities may be used as indicators of the vegetation types of the habitats in which they lived. Vegetation types, in turn, are determined largely by a number of physical environmental factors. Typical ungulate communities of the late early to early middle Miocene (17 - 15 Ma) from the Great Plains of North America contained a diversity of browsing (leaf-eating) and grazing (grass-eating) species, with proportions of dietary types and a diversity of body sizes indicative of a woodland savanna habitat. Paleobotanical evidence also indicates a woodland savanna type of vegetation. However, these communities included a much larger number of ungulate species than can be found in any present-day community. The "excess" ungulate species were primarily browsers. Throughout the rest of the middle Miocene both species numbers and the proportion of browsers in ungulate communities appear to have declined steadily. During this decline in browser species the numbers of grazer species remained relatively constant. Within-community species numbers comparable to the present day were attained by the late Miocene. We suggest that the early Miocene browser-rich communities, and their subsequent decline, carry an important paleoenvironmental signal. In particular, communities "over rich" in browsers may reflect higher levels of primary productivity in

  6. First Hominoid from the Late Miocene of the Irrawaddy Formation (Myanmar)

    PubMed Central

    Jaeger, Jean-Jacques; Naing Soe, Aung; Chavasseau, Olivier; Coster, Pauline; Emonet, Edouard-Georges; Guy, Franck; Lebrun, Renaud; Maung, Aye; Aung Khyaw, Aung; Shwe, Hla; Thura Tun, Soe; Linn Oo, Kyaw; Rugbumrung, Mana; Bocherens, Hervé; Benammi, Mouloud; Chaivanich, Kamol; Tafforeau, Paul; Chaimanee, Yaowalak

    2011-01-01

    For over a century, a Neogene fossil mammal fauna has been known in the Irrawaddy Formation in central Myanmar. Unfortunately, the lack of accurately located fossiliferous sites and the absence of hominoid fossils have impeded paleontological studies. Here we describe the first hominoid found in Myanmar together with a Hipparion (s.l.) associated mammal fauna from Irrawaddy Formation deposits dated between 10.4 and 8.8 Ma by biochronology and magnetostratigraphy. This hominoid documents a new species of Khoratpithecus, increasing thereby the Miocene diversity of southern Asian hominoids. The composition of the associated fauna as well as stable isotope data on Hipparion (s.l.) indicate that it inhabited an evergreen forest in a C3-plant environment. Our results enlighten that late Miocene hominoids were more regionally diversified than other large mammals, pointing towards regionally-bounded evolution of the representatives of this group in Southeast Asia. The Irrawaddy Formation, with its extensive outcrops and long temporal range, has a great potential for improving our knowledge of hominoid evolution in Asia. PMID:21533131

  7. Himalayan uplift shaped biomes in Miocene temperate Asia: evidence from leguminous Caragana

    PubMed Central

    Zhang, Ming-Li; Xiang, Xiao-Guo; Xue, Juan-Juan; Sanderson, Stewart C.; Fritsch, Peter W.

    2016-01-01

    Caragana, with distinctive variation in leaf and rachis characters, exhibits three centers of geographic distribution, i.e., Central Asia, the Qinghai-Tibetan Plateau (QTP), and East Asia, corresponding to distinct biomes. Because Caragana species are often ecologically dominant components of the vegetation in these regions, it is regarded as a key taxon for the study of floristic evolution in the dry regions of temperate Asia. Based on an expanded data set of taxa and gene regions from those previously generated, we employed molecular clock and biogeographical analyses to infer the evolutionary history of Caragana and link it to floristic patterns, paleovegetation, and paleoclimate. Results indicate that Caragana is of arid origin from the Junggar steppe. Diversification of crown group Caragana, dated to the early Miocene ca. 18 Ma and onwards, can be linked to the Himalayan Motion stage of QTP uplift. Diversification of the major clades in the genus corresponding to taxonomic sections and morphological variation is inferred to have been driven by the uplift, as well as Asian interior aridification and East Asian monsoon formation, in the middle to late Miocene ca. 12~6 Ma. These findings demonstrate a synchronous evolution among floristics, vegetation and climate change in arid Central Asia, cold arid alpine QTP, and mesophytic East Asia. PMID:27827446

  8. Himalayan uplift shaped biomes in Miocene temperate Asia: evidence from leguminous Caragana.

    PubMed

    Zhang, Ming-Li; Xiang, Xiao-Guo; Xue, Juan-Juan; Sanderson, Stewart C; Fritsch, Peter W

    2016-11-09

    Caragana, with distinctive variation in leaf and rachis characters, exhibits three centers of geographic distribution, i.e., Central Asia, the Qinghai-Tibetan Plateau (QTP), and East Asia, corresponding to distinct biomes. Because Caragana species are often ecologically dominant components of the vegetation in these regions, it is regarded as a key taxon for the study of floristic evolution in the dry regions of temperate Asia. Based on an expanded data set of taxa and gene regions from those previously generated, we employed molecular clock and biogeographical analyses to infer the evolutionary history of Caragana and link it to floristic patterns, paleovegetation, and paleoclimate. Results indicate that Caragana is of arid origin from the Junggar steppe. Diversification of crown group Caragana, dated to the early Miocene ca. 18 Ma and onwards, can be linked to the Himalayan Motion stage of QTP uplift. Diversification of the major clades in the genus corresponding to taxonomic sections and morphological variation is inferred to have been driven by the uplift, as well as Asian interior aridification and East Asian monsoon formation, in the middle to late Miocene ca. 12~6 Ma. These findings demonstrate a synchronous evolution among floristics, vegetation and climate change in arid Central Asia, cold arid alpine QTP, and mesophytic East Asia.

  9. Late Miocene biogeography and paleoclimatology of the central North Atlantic

    USGS Publications Warehouse

    Poore, R.Z.

    1981-01-01

    Quantitative analyses of planktonic foraminiferal assemblages from Deep Sea Drilling Project (DSDP) Holes 334 and 410 demonstrate that subpolar and subtropical faunal provinces existed in the North Atlantic during the late Miocene. Climatic oscillations are clearly recorded in Hole 410 by variations in abundance of the Neogloboquadrina subpolar assemblage. These climatic oscillations have a period of about 1 m.y. Higher frequency oscillations with a periodicity of one to several hundred thousand years are evident from about 6.5 to 7.5 m.y. and are probably present throughout the entire late Miocene. A revised age of 7.0 m.y. is proposed for the first occurrence of the calcareous nannofossil Amaurolithus primus (the Amaurolithus datum). ?? 1981.

  10. Upper Miocene reef complex of Mallorca, Balearic Islands, Spain

    SciTech Connect

    Pomar, L.

    1988-02-01

    The late Tortonian-Messinian coral reef platform of south Mallorca onlaps a folded middle late Miocene carbonate platform on which progradation of up to 20 km occurs. Vertical sea cliffs (up to 100 m high) superbly show the last 5 km of this progradation and complement the numerous water-well cores from the island interior. The Mallorca reef presents the most complete facies zonation of the Miocene reefs of the western Mediterranean. The reef wall framework is up to 20 m thick and shows (1) erosional reef flat with reef breccia and small corals; (2) spur-and-grove zone with large, massive corals; (3) deep buttresses and pinnacles with terraces of branching corals; and (4) deep reef wall with flat, laminar coral colonies, branching red algae, and Halimeda sands.

  11. Paleoproductivity And Carbon Cycling During The Middle Miocene Monterey Excursion

    NASA Astrophysics Data System (ADS)

    Billups, K.; Diester-Haass, L.; Emeis, K.; François, L.; Jacquemin, I.; Lefebvre, V.

    2010-05-01

    A prominent middle Miocene (17.5 to 13.5 Ma) carbon-isotope excursion (the so-called Monterey event) is punctuated by six distinct carbon isotope maxima (CM). Orbital tuning of carbon isotope records links each CM event with the long term component of eccentricity (400 kyr) highlighting the importance of insolation control on the global carbon cycle (Holbourn et al., 2008). Here we use proxy reconstructions (benthic foraminiferal accumulation rates) from six sites in the Atlantic and Pacific Oceans combined with geochemical modelling to investigate whether there is a link between long term insolation forcing and the marine carbon isotope record via marine productivity and thus atmospheric CO2 levels. Our results show that none of the CM events are associated with distinctly large changes in paleoproductivity. This observation is consistent with our previous finding that the overall mid Miocene carbon isotope maximum is not associated with a change in marine productivity (Diester-Haass et al., 2009). There are, albeit minor, fluctuations in productivity that can be related to the 400 kyr variability in the carbon isotope records with several productivity maxima between CM events, whereas CM events often show minima in productivity. Only the last of the CM events (CM 6), which occurs in close association with the major step in mid Miocene Antarctic ice growth, is accompanied by an ocean-wide increase in paleoproductivity. To tentatively explain the observed 400 kyr variability of the deep ocean carbon isotope record an improved version of the geochemical box model used Diester-Haass et al. (2009) has been forced by sealevel fluctuations reconstructed for the middle Miocene (Holbourn pers. comm., 2009). Calculations indicate that the induced changes in weathering rates and carbon cycle can explain the temporal variability of the carbon isotope record, but not the observed amplitude.

  12. Across the Pacific: Climate Evolution in the Middle Miocene

    NASA Astrophysics Data System (ADS)

    Fox, L. R.; Wade, B.; Holbourn, A. E.; Leng, M. J.

    2013-12-01

    We present the first high-resolution (3 kyr) astronomically-tuned record of δ18O and δ13C from planktonic foraminifera for the equatorial Pacific Ocean (16.5-13.5 Myr). Our data provides exciting new information on sea surface temperatures and primary productivity changes at the tropics during the middle Miocene at a resolution not achieved in any previous study, which sheds new light on the middle Miocene climatic transition (MMCT) and associated carbon-isotope excursion. Reliable sea surface temperature estimates are crucial to any reconstruction and modelling of past ocean salinity and density, water column stratification, thermohaline circulation, and ice volume. Despite extensive studies of benthic foraminifera, existing planktonic foraminiferal records of this interval are extremely scarce and of low resolution, with samples representing time intervals of 2x105 and 5x105 years. Previous studies have been hindered by the absence of biogenic carbonate (e.g., Leg 199). Consequently the impact of global warming and cooling on tropical surface waters and the propagation of orbital cycles in the Earth System are unknown. In 2009 Integrated Ocean Drilling Program Expedition 320/321 recovered lower-middle Miocene sediments with high sedimentation rates (30m/myr), continuous recovery, and orbital cyclicity from the east equatorial Pacific Ocean. At Site U1338 planktonic foraminifera are abundant and diverse in the lower and middle Miocene sediments and exceptionally well preserved. Scanning electron microscope studies revealed open pore spaces, little evidence of calcitic overgrowth on the wall surface and in many cases preserved spines (Fox and Wade, in press). We compare our data from Site U1338 to Site 1146 in the western equatorial Pacific Ocean, to reconstruct bottom and surface water conditions and changes in ocean dynamics across the equatorial Pacific during this highly complex interval of climate history.

  13. Across the Pacific: Climate Evolution in the Middle Miocene

    NASA Astrophysics Data System (ADS)

    Fox, Lyndsey; Wade, Bridget; Holbourn, Ann; Leng, Melanie

    2014-05-01

    We present the first high-resolution (3 kyr) astronomically-tuned record of δ18O and δ13C from planktonic foraminifera for the equatorial Pacific Ocean (16.5-13.5 Myr). Our data provides exciting new information on sea surface temperatures and primary productivity changes at the tropics during the middle Miocene at a resolution not achieved in any previous study, which sheds new light on the middle Miocene climatic transition (MMCT) and associated carbon-isotope excursion. Reliable sea surface temperature estimates are crucial to any reconstruction and modelling of past ocean salinity and density, water column stratification, thermohaline circulation, and ice volume. Despite extensive studies of benthic foraminifera, existing planktonic foraminiferal records of this interval are extremely scarce and of low resolution, with samples representing time intervals of 2x105and 5x105 years. Previous studies have been hindered by the absence of biogenic carbonate (e.g., Leg 199). Consequently the impact of global warming and cooling on tropical surface waters and the propagation of orbital cycles in the Earth System are unknown. In 2009 Integrated Ocean Drilling Program Expedition 320/321 recovered lower-middle Miocene sediments with high sedimentation rates (30m/myr), continuous recovery, and orbital cyclicity from the east equatorial Pacific Ocean. At Site U1338 planktonic foraminifera are abundant and diverse in the lower and middle Miocene sediments and exceptionally well preserved. Scanning electron microscope studies revealed open pore spaces, little evidence of calcitic overgrowth on the wall surface and in many cases preserved spines (Fox and Wade, 2013). We compare our data from Site U1338 to Site 1146 in the western equatorial Pacific Ocean, to reconstruct bottom and surface water conditions and changes in ocean dynamics across the equatorial Pacific during this highly complex interval of climate history.

  14. New Miocene Fossils and the History of Penguins in Australia.

    PubMed

    Park, Travis; Fitzgerald, Erich M G; Gallagher, Stephen J; Tomkins, Ellyn; Allan, Tony

    2016-01-01

    Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring 'giant penguins' after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia.

  15. Miocene reef platforms from northwestern Tuamotu Islands, central Pacific

    SciTech Connect

    Montaggioni, L.F.; Mnhn-Ephe, A.

    1988-02-01

    Reef deposits of Miocene age occur on several northwestern Tuamotu atolls as either pointed residual and scattered reliefs through the Holocene reef sequence (Mataiva, Rangiroa, Tikehau, Kaukura) or elevated atoll-shaped platforms (Makatea). Throughout the region considered, the depositional/diagenetic history of Miocene reefs can be reconstructed as follows. During early Miocene times (e-f range-biozones), reef platforms developed on top of older carbonate banks, capping a midplate volcanic ridge of early Tertiary age. More than 100 m thick, these platforms displayed concentrically zoned environments of deposition: a peripheral subemergent rim composed of coralgalforaminiferal boundstones, and a very shallow central area in which foraminiferal and molluscan fine sands and muds were subhorizontally deposited. Local evidence of internal unconformity surfaces and subaerially produced features indicates that periods of relative emergency occurred as the reef piles grew upward. The ultimate stage of platform development is believed to have been a complete upfilling of the back-reef areas and subsequent emergence. Correlatively, a freshwater lens would have been formed close to the surface level of each of the so-formed islands. Dolomitization may have been initiated in the marine water/freshwater phreatic mixing zone. During lowstands, severe meteoric alteration affected emergent carbonate deposits, forming incipient cavity systems; the usual atoll morphology is considered to have been initiated at this time (presumably middle Micoene).

  16. New Miocene Fossils and the History of Penguins in Australia

    PubMed Central

    Park, Travis; Fitzgerald, Erich M. G.; Gallagher, Stephen J.; Tomkins, Ellyn; Allan, Tony

    2016-01-01

    Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring ‘giant penguins’ after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia. PMID:27115739

  17. Connectivity controls on the late Miocene eastern Mediterranean fish fauna

    NASA Astrophysics Data System (ADS)

    Agiadi, Konstantina; Antonarakou, Assimina; Kontakiotis, George; Kafousia, Nefeli; Moissette, Pierre; Cornée, Jean-Jacques; Manoutsoglou, Emmanouil; Karakitsios, Vasileios

    2016-06-01

    Environmental change significantly affects the production of fish resources and their dependent societies. The paleontological record offers unique insight into the effects of long-term paleoenvironmental variability on the fish species' distributions and abundances. In the present study, we investigate the late Miocene (7.5-6.5 Ma) fish assemblages of the Potamida section in western Crete (eastern Mediterranean). The determined fish taxa are examined in a paleobiogeographic context, with regard to their geographic and stratigraphic distribution from the early Miocene (~13 Ma) through today. In addition, present-day ecological data are used to reconstruct the paleoenvironmental conditions in the study area. Planktonic foraminifer biostratigraphy significantly improves the earlier dating of the studied sequence. The late Miocene fish fauna of Potamida includes 35 taxa (seven in open nomenclature) from 13 teleost families. The eastern Mediterranean biostratigraphic and geographic distribution of 32 taxa is significantly expanded into the Tortonian, whereas 13 species are recorded for the first time from the Messinian. Four stages are distinguished in the area's paleoenvironmental evolution. (1) The Potamida area was an open marine environment with depths exceeding 150 m between ~7.5-7.45 Ma. (2) Between 7.45-7.36 Ma, the results suggest depths between 300-400 m. (3) The depositional depth increases between 7.36-7.28 Ma to 400-550 m. (4) Later on, approximately between 6.8-6.6 Ma, the depth is again estimated around 100-150 m.

  18. Miocene Oaks from Eastern Zhejiang, China and their Paleoenvironmental Significance

    NASA Astrophysics Data System (ADS)

    Jia, Hui; Ferguson, David

    2015-04-01

    The intertrappean fluvial-lacustrine beds belonging to the Upper Miocene Shengxian Formation in eastern China contain many exquisitely preserved plant fossils, e.g., leaves, fruits and seeds as well as plentiful pollen. The Fagaceae is the dominant taxon represented by 5 genera and 15 species, four of which belong to Quercus subgenus Cyclobalanopsis. Quercus species (oaks) are highly sensitive to environmental changes. The correlation between climate and trichome base density of Quercus glauca and Quercus delavayi of subg. Cyclobalanopsis, which are the NLRs of two fossil species, Quercus paraglauca and Quercus aff. delavayi, indicates that the trichome base density of Quercus glauca is comprehensively affected by various climate factors, but most influenced by solar radiation and latitude. The trichome base parametrics of Quercus paraglauca and the comparison of epidermal cell characteristics between Quercus paraglauca and Quercus aff. delavayi and their NLR species of subg. Cyclobalanopsis, show that the climate was warmer and more humid in the late Miocene than that of today in eastern Zhejiang, China. A study of the stomatal index of Quercus glauca and Quercus delavayi, collected in different years, demonstrates that they are very sensitive to the variation of atmospheric CO2 concentration. By comparing the stomatal ratio between the two fossil species and their NLRs, the paleoatmospheric CO2 concentration in the late Miocene is reconstructed as ca. 400 ppmv, i.e. higher than the present natural CO2 concentration eliminating the industrial influence.

  19. Early Miocene elevation in northern Tibet estimated by palaeobotanical evidence.

    PubMed

    Sun, Bin; Wang, Yu-Fei; Li, Cheng-Sen; Yang, Jian; Li, Jin-Feng; Li, Ye-Liang; Deng, Tao; Wang, Shi-Qi; Zhao, Min; Spicer, Robert A; Ferguson, David K; Mehrotra, Rakesh C

    2015-05-15

    The area and elevation of the Tibetan Plateau over time has directly affected Asia's topography, the characteristics of the Asian monsoon, and modified global climate, but in ways that are poorly understood. Charting the uplift history is crucial for understanding the mechanisms that link elevation and climate irrespective of time and place. While some palaeoelevation data are available for southern and central Tibet, clues to the uplift history of northern Tibet remain sparse and largely circumstantial. Leaf fossils are extremely rare in Tibet but here we report a newly discovered early Miocene barberry (Berberis) from Wudaoliang in the Hoh-Xil Basin in northern Tibet, at a present altitude of 4611 ± 9 m. Considering the fossil and its nearest living species probably occupied a similar or identical environmental niche, the palaeoelevation of the fossil locality, corrected for Miocene global temperature difference, is estimated to have been between 1395 and 2931 m, which means this basin has been uplifted ~2-3 km in the last 17 million years. Our findings contradict hypotheses that suggest northern Tibet had reached or exceeded its present elevation prior to the Miocene.

  20. Early Miocene elevation in northern Tibet estimated by palaeobotanical evidence

    PubMed Central

    Sun, Bin; Wang, Yu-Fei; Li, Cheng-Sen; Yang, Jian; Li, Jin-Feng; Li, Ye-Liang; Deng, Tao; Wang, Shi-Qi; Zhao, Min; Spicer, Robert A.; Ferguson, David K.; Mehrotra, Rakesh C.

    2015-01-01

    The area and elevation of the Tibetan Plateau over time has directly affected Asia’s topography, the characteristics of the Asian monsoon, and modified global climate, but in ways that are poorly understood. Charting the uplift history is crucial for understanding the mechanisms that link elevation and climate irrespective of time and place. While some palaeoelevation data are available for southern and central Tibet, clues to the uplift history of northern Tibet remain sparse and largely circumstantial. Leaf fossils are extremely rare in Tibet but here we report a newly discovered early Miocene barberry (Berberis) from Wudaoliang in the Hoh-Xil Basin in northern Tibet, at a present altitude of 4611 ± 9 m. Considering the fossil and its nearest living species probably occupied a similar or identical environmental niche, the palaeoelevation of the fossil locality, corrected for Miocene global temperature difference, is estimated to have been between 1395 and 2931 m, which means this basin has been uplifted ~2–3 km in the last 17 million years. Our findings contradict hypotheses that suggest northern Tibet had reached or exceeded its present elevation prior to the Miocene. PMID:25976244

  1. Estimates of CO2 since the mid-Miocene

    NASA Astrophysics Data System (ADS)

    Stoll, Heather

    2016-04-01

    For past warm climates, direct CO2 determinations are unavailable. Our inferences of Antarctic ice sheet thresholds and climate sensitivity to CO2 are therefore strongly conditioned by the reliability of CO2 proxy reconstructions. For the Miocene, these rely heavily on proxies using the carbon isotopic fractionation of marine phytoplankton during photosynthesis (ep). While recent records are beginning to reveal more clearly the long term CO2 trends since the middle Miocene , the absolute CO2 concentrations are subject to higher uncertainty. This in turn influences the ability of models to simulate dynamic Antarctic ice sheet behavior in the context of expected ice sheet hysteresis. In this contribution, I discuss a new approach for estimating CO2 from published and new measurements of phytoplankton carbon isotopic fractionation using the ACTI-CO cell model. This approach accounts for the physiological adaptations made by phytoplankton cells to avoid falling below optimal photosynthetic rates as CO2 declines, the carbon concentrating mechanism. The model yields CO2 estimates which can be significantly (up to 2-fold) higher than those estimated from classic equations. Given the large degree of cooling since the late Miocene in extratropical sea surface temperature records, such CO2 estimates are consistent with a more conservative estimate of climate sensitivity over the last 12 Ma.

  2. Preliminary assessment of injection, storage, and recovery of freshwater in the lower Hawthorn aquifer, Cape Coral, Florida

    USGS Publications Warehouse

    Quinones-Aponte, Vicente; Wexler, Eliezer J.

    1995-01-01

    A preliminary assessment of subsurface injection, storage and recovery of fresh canal water was made in the naturally brackish lower Hawthorn aquifer in Cape Coral, southwestern Florida. A digital modeling approach was used for this preliminary assessment, incorporating available data on hydrologic conditions, aquifer properties, and water quality to simulate density-dependent ground-water flow and advective-dispersive transport of a conservative ground-water solute (chloride ion). A baseline simulation was used as reference to compare the effects of changing various operational factors on the recovery efficiency. A recovery efficiency of 64 percent was estimated for the baseline simulation. Based on the model, the recovery efficiency increases if the injection rate and recovery rates are increased and if the ratio of recovery rate to injection rate is increased. Recovery efficiency decreases if the amount of water injected is increased; slightly decreases if the storage time is increased; is not changed significantly if the water is injected to a specific flow zone; increases with successive cycles of injection, storage, and recovery; and decreases if the chloride concentrations in either the injection water or native aquifer water are increased. In everal hypothetical tests, the recovery efficiency fluctuated between 22 and about 100 percent. Two successive cycles could bring the recovery efficiency from 60 to about 80 percent. Interlayer solute mass movement across the upper and lower boundaries seems to be the most important factor affecting the recovery efficiency. A sensitivity analysis was performed applying a technique in which the change in the various factors and the corresponding model responses are normalized so that meaningful comparisons among the responses could be made. The general results from the sensitivity analysis indicated that the permeabilities of the upper and lower flow zones were the most important factors that produced the greatest

  3. Ostracods (Crustacea) and their palaeoenvironmental implication for the Solimões Formation (Late Miocene; Western Amazonia/Brazil)

    PubMed Central

    Gross, Martin; Ramos, Maria Ines; Caporaletti, Marco; Piller, Werner E.

    2013-01-01

    Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ18O- and δ13C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, “brackish” water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene. PMID:26523090

  4. Ostracods (Crustacea) and their palaeoenvironmental implication for the Solimões Formation (Late Miocene; Western Amazonia/Brazil).

    PubMed

    Gross, Martin; Ramos, Maria Ines; Caporaletti, Marco; Piller, Werner E

    2013-03-01

    Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ(18)O- and δ(13)C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, "brackish" water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene.

  5. Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca) of the Western and Central Paratethys.

    PubMed

    Hyžný, Matúš

    2016-10-01

    Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19(th) century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic "Schlier"-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene

  6. Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca) of the Western and Central Paratethys

    NASA Astrophysics Data System (ADS)

    Hyžný, Matúš

    2016-10-01

    Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic "Schlier"-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene

  7. Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca) of the Western and Central Paratethys

    PubMed Central

    Hyžný, Matúš

    2017-01-01

    Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic “Schlier”-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene

  8. Biofacies zonation of middle Miocene benthic foraminifera, southeastern San Joaquin basin, California

    SciTech Connect

    Olson, H.C.

    1987-05-01

    The quantitative distribution of benthic foraminifera across the middle Miocene margin of the southeastern San Joaquin basin constitutes a useful tool in applying benthic biofacies zonation to the interpretation of marine paleoenvironments. A middle Miocene transect (near the Luisian/Relizian boundary) was completed across the margin of the southeastern San Joaquin basin near Bakersfild, California. Surface and subsurface fauna encompass strandline through bathyal environments. Quantitative analyses of these fauna result in a useful biofacies zonation for the middle Miocene which can be applied to the interpretation of middle Miocene paleobathymetric and paleogeographic reconstructions, basin analysis, and subsidence histories of the San Joaquin basin. In addition, these data suggest that vertical faunal migration of continental slope fauna has occurred between the middle Miocene and Recent. During the early and middle Miocene, marine temperatures were warmer than today and lower latitudinal gradients prevailed. Stepwise climatic cooling since the middle Miocene has been accompanied by the latitudinal adjustment of surface isotherms, strengthening of the permanent thermocline, and the associated migration of temperature-sensitive planktonic and benthic biofacies. Sedimentologic and seismic evidence in the southeastern San Joaquin basin suggests that present-day lower bathyal biofacies may have been at shallower depths during the middle Miocene. Such migrations would have a significant impact on paleoenvironmental interpretations. Middle Miocene faunal transects from the southeastern San Joaquin basin are compared with equivalent Holocene transects from the eastern Pacific, and differences are discussed in light of this proposal.

  9. Decrease in coccolithophore calcification and CO2 since the middle Miocene.

    PubMed

    Bolton, Clara T; Hernández-Sánchez, María T; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M

    2016-01-14

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity.

  10. Decrease in coccolithophore calcification and CO2 since the middle Miocene

    PubMed Central

    Bolton, Clara T.; Hernández-Sánchez, María T.; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M.

    2016-01-01

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity. PMID:26762469

  11. The genus Macroteleia Westwood in Middle Miocene amber from Peru (Hymenoptera, Platygastridae s.l., Scelioninae)

    PubMed Central

    Perrichot, Vincent; Antoine, Pierre-Olivier; Salas-Gismondi, Rodolfo; Flynn, John J.; Engel, Michael S.

    2014-01-01

    Abstract A new species of the scelionine genus Macroteleia Westwood (Platygastridae s.l., Scelioninae) is described and figured from a female beautifully preserved in Middle Miocene amber from Peru. Macroteleia yaguarum Perrichot & Engel, sp. n., shows a unique combination of characters otherwise seen independently within its congeners. It is most similar to the modern M. surfacei Brues, but differs from it by the non-foveolate notauli, the contiguous punctures of the vertex, and the continuous propodeum. The new species is the first New World fossil of the genus, suggesting a Cretaceous origin for the group and a relatively old age of the South American, tropical African, and Australian faunas, and a younger age of the modern Holarctic faunas. PMID:25147461

  12. Decrease in coccolithophore calcification and CO2 since the middle Miocene

    NASA Astrophysics Data System (ADS)

    Bolton, Clara T.; Hernández-Sánchez, María T.; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M.

    2016-01-01

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone εp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity.

  13. Middle Miocene closure of the Central American Seaway

    NASA Astrophysics Data System (ADS)

    Montes, C.; Cardona, A.

    2014-12-01

    The final closure of the Panama Isthmus and permanent separation of Caribbean and Pacific waters is thought to have modified their salinity, faunistic assemblages, and ultimately, ocean circulation patterns and global climate. The Great American Biotic Interchange (GABI) is thought to have been the result of Plio-Pleistocene closure of the Isthmus that allowed land animals to massively cross the Isthmus. Similarly, the separation of Caribbean and Pacific waters by a rising Isthmus is thougth to be a prime example of vicariance. The role of Isthmus closure on global changes, however, remains controversial due in part to the difficulty of establishing a precise chronology of seaway closure. While timing of glaciation is well established, new data on the chronology of Isthmus emergence suggests that the process of closure is more complex, long, and old than previously thought. We sampled fluvial and shallow marine strata in northwesternmost South America to recover zircon grains for provenance analyses in the immediate vicinity of the docking site. Because the ages of magmatic provinces in northwestern South America and the Panama Isthmus are mutually exclusive, detrital zircon analyses provides a tool to evaluate land connections. We found that an uniquely Panamanian, 40-45 Ma (early Lutetian) detrital zircon fingerprint is abundant in middle Miocene strata, but absent in underlying lower Miocene and Oligocene strata of the northern Andes. This fingerprint represents the beginning of fluvial detrital exchange between the Panama arc and South America, and therefore marks the time of docking and the end of deep-water, and probably shallow-water connections by middle Miocene times.

  14. Multiple Miocene Melastomataceae dispersal between Madagascar, Africa and India.

    PubMed Central

    Renner, Susanne S

    2004-01-01

    Melastomataceae sensu stricto (excluding Memecylaceae) comprise some 3000 species in the neotropics, 1000 in Asia, 240 in Africa, and 230 in Madagascar. Previous family-wide morphological and DNA analyses have shown that the Madagascan species belong to at least three unrelated lineages, which were hypothesized to have arrived by trans-oceanic dispersal. An alternative hypothesis posits that the ancestors of Madagascan, as well as Indian, Melastomataceae arrived from Africa in the Late Cretaceous. This study tests these hypotheses in a Bayesian framework, using three combined sequence datasets analysed under a relaxed clock and simultaneously calibrated with fossils, some not previously used. The new fossil calibration comes from a re-dated possibly Middle or Upper Eocene Brazilian fossil of Melastomeae. Tectonic events were also tentatively used as constraints because of concerns that some of the family's fossils are difficult to assign to nodes in the phylogeny. Regardless of how the data were calibrated, the estimated divergence times of Madagascan and Indian lineages were too young for Cretaceous explanations to hold. This was true even of the oldest ages within the 95% credibility interval around each estimate. Madagascar's Melastomeae appear to have arrived from Africa during the Miocene. Medinilla, with some 70 species in Madagascar and two in Africa, too, arrived during the Miocene, but from Asia. Gravesia, with 100 species in Madagascar and four in east and west Africa, also appears to date to the Miocene, but its monophyly has not been tested. The study afforded an opportunity to compare divergence time estimates obtained earlier with strict clocks and single calibrations, with estimates based on relaxed clocks and different multiple calibrations and taxon sampling. PMID:15519967

  15. Life-history traits of the Miocene Hipparion concudense (Spain) inferred from bone histological structure.

    PubMed

    Martinez-Maza, Cayetana; Alberdi, Maria Teresa; Nieto-Diaz, Manuel; Prado, José Luis

    2014-01-01

    Histological analyses of fossil bones have provided clues on the growth patterns and life history traits of several extinct vertebrates that would be unavailable for classical morphological studies. We analyzed the bone histology of Hipparion to infer features of its life history traits and growth pattern. Microscope analysis of thin sections of a large sample of humeri, femora, tibiae and metapodials of Hipparion concudense from the upper Miocene site of Los Valles de Fuentidueña (Segovia, Spain) has shown that the number of growth marks is similar among the different limb bones, suggesting that equivalent skeletochronological inferences for this Hipparion population might be achieved by means of any of the elements studied. Considering their abundance, we conducted a skeletechronological study based on the large sample of third metapodials from Los Valles de Fuentidueña together with another large sample from the Upper Miocene locality of Concud (Teruel, Spain). The data obtained enabled us to distinguish four age groups in both samples and to determine that Hipparion concudense tended to reach skeletal maturity during its third year of life. Integration of bone microstructure and skeletochronological data allowed us to identify ontogenetic changes in bone structure and growth rate and to distinguish three histologic ontogenetic stages corresponding to immature, subadult and adult individuals. Data on secondary osteon density revealed an increase in bone remodeling throughout the ontogenetic stages and a lesser degree thereof in the Concud population, which indicates different biomechanical stresses in the two populations, likely due to environmental differences. Several individuals showed atypical growth patterns in the Concud sample, which may also reflect environmental differences between the two localities. Finally, classification of the specimens' age within groups enabled us to characterize the age structure of both samples, which is typical of

  16. Life-History Traits of the Miocene Hipparion concudense (Spain) Inferred from Bone Histological Structure

    PubMed Central

    Martinez-Maza, Cayetana; Alberdi, Maria Teresa; Nieto-Diaz, Manuel; Prado, José Luis

    2014-01-01

    Histological analyses of fossil bones have provided clues on the growth patterns and life history traits of several extinct vertebrates that would be unavailable for classical morphological studies. We analyzed the bone histology of Hipparion to infer features of its life history traits and growth pattern. Microscope analysis of thin sections of a large sample of humeri, femora, tibiae and metapodials of Hipparion concudense from the upper Miocene site of Los Valles de Fuentidueña (Segovia, Spain) has shown that the number of growth marks is similar among the different limb bones, suggesting that equivalent skeletochronological inferences for this Hipparion population might be achieved by means of any of the elements studied. Considering their abundance, we conducted a skeletechronological study based on the large sample of third metapodials from Los Valles de Fuentidueña together with another large sample from the Upper Miocene locality of Concud (Teruel, Spain). The data obtained enabled us to distinguish four age groups in both samples and to determine that Hipparion concudense tended to reach skeletal maturity during its third year of life. Integration of bone microstructure and skeletochronological data allowed us to identify ontogenetic changes in bone structure and growth rate and to distinguish three histologic ontogenetic stages corresponding to immature, subadult and adult individuals. Data on secondary osteon density revealed an increase in bone remodeling throughout the ontogenetic stages and a lesser degree thereof in the Concud population, which indicates different biomechanical stresses in the two populations, likely due to environmental differences. Several individuals showed atypical growth patterns in the Concud sample, which may also reflect environmental differences between the two localities. Finally, classification of the specimens’ age within groups enabled us to characterize the age structure of both samples, which is typical of

  17. Miocene shale tectonics in the Moroccan margin (Alboran Sea)

    NASA Astrophysics Data System (ADS)

    Do Couto, D.; El Abbassi, M.; Ammar, A.; Gorini, C.; Estrada, F.; Letouzey, J.; Smit, J.; Jolivet, L.; Jabour, H.

    2011-12-01

    The Betic (Southern Spain) and Rif (Morocco) mountains form an arcuate belt that represents the westernmost termination of the peri-mediterranean Alpine mountain chain. The Miocene Alboran Basin and its subbasins is located in the hinterland of the Betic-Rif belt. It is considered to be a back-arc basin that developed during the coeval westward motion of the Alboran domain and the extensional collapse of previously thickened crust of the Betic-Rif belt. The Western Alboran Basin (WAB) is the major sedimentary depocenter with a sediment thickness in excess of 10 km, it is bordered by the Gibraltar arc, the volcanic Djibouti mounts and the Alboran ridge. Part of the WAB is affected by shale tectonics and associated mud volcanism. High-quality 2D seismic profiles acquired on the Moroccan margin of the Alboran Basin during the last decade reveal the multiple history of the basin. This study deals with the analysis of a number of these seismic profiles that are located along and orthogonal to the Moroccan margin. Seismic stratigraphy is calibrated from industrial wells. We focus on the interactions between the gravity-driven tectonic processes and the sedimentation in the basin. Our seismic interpretation confirms that the formation of the WAB began in the Early Miocene (Aquitanian - Burdigalian). The fast subsidence of the basin floor coeval to massive sedimentation induced the undercompaction of early miocene shales during their deposition. Downslope migration of these fine-grained sediments initiated during the deposition of the Langhian siliciclastics. This gravity-driven system was accompanied by continuous basement subsidence and induced disharmonic deformation in Mid Miocene units (i.e. not related to basement deformation). The development of shale-cored anticlines and thrusts in the deep basin is the result of compressive deformation at the front of the gravity-driven system and lasted for ca. 15 Ma. The compressive front has been re-activated by strong

  18. Miocene reef facies of pelagian block, central Mediterranean

    SciTech Connect

    Pedley, H.M.

    1988-02-01

    Miocene reefs outcrop in the Maltese Islands, southeastern Sicily, and the pelagian island of Lampedusa. Several rapid eustatic sea level fluctuations affected these late Tortonian-early Messinian build-ups; normal salinities appear to have been maintained during these events. In addition to sea floor topography, reef development appears to have been controlled by turbulence. Encruster-dominated patch reefs are typical of platform and shallow ramp situations where turbulence is high. Branching and massive coral assemblages are typical of fore-reef curtains and steep slope substrates.

  19. The beaver Anchitheriomys from the Miocene of Central Europe

    SciTech Connect

    Stefen, C.; Mors, T.

    2008-09-15

    New finds of teeth and mandibles of Anchitheriomys from the Hambach opencast lignite mine in Northwest Germany and the first detailed descriptions of other mandibles from South Germany and Switzerland allow a review of the Central European specimens of this rare beaver genus. The metric variation of cheek teeth and especially the great differences in dimensions of incisors can be much better assessed. The observed range in size can be attributed to ontogenetic changes, and all material is assigned to Anchitheriomys suevicus. Stratigraphically, this species is restricted to the early middle Miocene, European Mammalian Neogene biozones MN 5-6.

  20. Paleoceanographic implications of Miocene deep-sea hiatuses.

    USGS Publications Warehouse

    Keller, G.; Barron, J.A.

    1983-01-01

    Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms. The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. -from Authors

  1. Miocene phosphate-rich sediments in Salento (southern Italy)

    NASA Astrophysics Data System (ADS)

    Föllmi, Karl B.; Hofmann, Hélène; Chiaradia, Massimo; de Kaenel, Eric; Frijia, Gianluca; Parente, Mariano

    2015-08-01

    The upper Middle to lower Upper Miocene (Serravallian to Tortonian) sedimentary succession in Salento (southern Italy) includes glauconite- and phosphate-rich deposits, which are associated with pelagic micrite. In Baia del Ciolo and Marittima (southern Salento), the succession is composed of shallow-water platform carbonates of Late Oligocene age (Chattian; Porto Badisco Formation), which are overlain by a 20- to 30-cm-thick level of glauconite-rich micrite with abundant reworked particles and fossils of the underlying Porto Badisco Formation. This interval is in turn covered by an up to 15 cm thick phosphatic crust ("Livello ad Aturia"), which itself is overlain either by a hemipelagic chalk-like carbonate of Middle to Late Miocene age ("Pietra Leccese"; Marittima) or directly by a micrite of Late Miocene age (Messinian; Novaglie Formation; Baia del Ciolo), which shallows upwards into a shallow-water platform carbonate. A large hiatus is present in this succession, which likely includes the Lower and lower Middle Miocene. In the region of Lecce, two discrete levels enriched in glauconite and phosphate-each associated with a major discontinuity-occur within the Pietra Leccese. The strontium-isotope ages derived on phosphate nodules and phosphatized and non-phosphatized fossils and calcareous nannofossil ages indicate a time interval of phosphogenesis between 13.5 and 7.5 Ma, with two clusters at 12 and 10.5 Ma. The glauconite and phosphate-rich sediments resulted from a current-dominated regime, which was characterized by low overall sedimentation rates, erosion and sediment reworking, and authigenesis. This regime was likely related to a generally westward-directed bottom current, which was forced to upwell once it arrived at the western border of the eastern Mediterranean basin. The timing of the principal phosphogenic phases can only partly be correlated to those of other occurrences in this part of the Mediterranean (Malta, Gozo, southern Sicily, Matese

  2. A new Miocene baleen whale from the Peruvian desert

    PubMed Central

    Kohno, Naoki

    2016-01-01

    The Pisco-Ica and Sacaco basins of southern Peru are renowned for their abundance of exceptionally preserved fossil cetaceans, several of which retain traces of soft tissue and occasionally even stomach contents. Previous work has mostly focused on odontocetes, with baleen whales currently being restricted to just three described taxa. Here, we report a new Late Miocene rorqual (family Balaenopteridae), Incakujira anillodefuego gen. et sp. nov., based on two exceptionally preserved specimens from the Pisco Formation exposed at Aguada de Lomas, Sacaco Basin, southern Peru. Incakujira overall closely resembles modern balaenopterids, but stands out for its unusually gracile ascending process of the maxilla, as well as a markedly twisted postglenoid process of the squamosal. The latter likely impeded lateral (omega) rotation of the mandible, in stark contrast with the highly flexible craniomandibular joint of extant lunge-feeding rorquals. Overall, Incakujira expands the still meagre Miocene record of balaenopterids and reveals a previously underappreciated degree of complexity in the evolution of their iconic lunge-feeding strategy. PMID:27853573

  3. Late Miocene hominids from the Middle Awash, Ethiopia.

    PubMed

    Haile-Selassie, Y

    2001-07-12

    Molecular studies suggest that the lineages leading to humans and chimpanzees diverged approximately 6.5-5.5 million years (Myr) ago, in the Late Miocene. Hominid fossils from this interval, however, are fragmentary and of uncertain phylogenetic status, age, or both. Here I report new hominid specimens from the Middle Awash area of Ethiopia that date to 5.2-5.8 Myr and are associated with a wooded palaeoenvironment. These Late Miocene fossils are assigned to the hominid genus Ardipithecus and represent the earliest definitive evidence of the hominid clade. Derived dental characters are shared exclusively with all younger hominids. This indicates that the fossils probably represent a hominid taxon that postdated the divergence of lineages leading to modern chimpanzees and humans. However, the persistence of primitive dental and postcranial characters in these new fossils indicates that Ardipithecus was phylogenetically close to the common ancestor of chimpanzees and humans. These new findings raise additional questions about the claimed hominid status of Orrorin tugenensis, recently described from Kenya and dated to approximately 6 Myr.

  4. Upper Miocene reef complex of Mallorca, Balearic Islands, Spain

    SciTech Connect

    Pomar, L.

    1988-01-01

    The late Tortonian-Messinian coral reef platform of south Mallorca onlaps a folded middle late Miocene carbonate platform on which progradation of up to 20 km occurs. Vertical sea cliffs (up to 100 m high) superbly show the last 5 km of this progradation and complement the numerous water-well cores from the island interior. The coral reef platform consists of a series of progradational-accretional sequences and erosion surfaces of different orders of magnitude. The first-order sequence is bounded by significant erosion surfaces with breccias, major facies shifts, and vertical accretion. The second-order sequences show accretional events of up to 100 m thick with 1 to 2 km of progradation, and the third-order sequences occur in packages of tens of meters. Individual reef units are bounded by minor erosional surfaces and define the fourth-order sequences. This composite accretional-progradational architecture implies cyclic variations of relative sea level. Episodes of sea level rise were responsible for the vertical accretion. Sea level falls produced the erosional surfaces; most progradation occurred during lowering sea level episodes. This sedimentological framework of the Mallorca reef suggests late Miocene glacio-eustatic fluctuations of sea level similar to the Quaternary.

  5. Plate-induced Miocene extension in southern California

    SciTech Connect

    Stuart, W.D. Univ. of California, Santa Barbara, CA )

    1992-01-01

    Miocene crustal extension in southern California can be explained by the interaction of tectonic plates in relative motion. The Pacific, Juan de Fuca, and Farallon (Guadalupe) plates are represented by flat elastic plates surrounded by an infinite elastic plate, the eastern part of which represents the North America plate. Forcing is by assigned subduction pull, and tractions at all plate boundaries satisfy a viscous constitutive law. Plate bottoms are stress-free. In the first part of the solution plate velocities and boundary tractions are found from static equilibrium. Then principal horizontal stresses and strains in plate interiors caused by tractions and subduction pull are found by a boundary element procedure. Using plate boundary geometry from Stock and Hodges for early- and mid-Miocene times, it is found that the portion of the North America plate margin between the Mendocino and Rivera triple junctions has maximum extensional strain directed westward. This result is generally consistent with directions associated with metamorphic core complex formation in southern California. The model is also consistent with extensional strain and rotation sense of crustal blocks in the vicinity of Los Angeles, as inferred by Luyendyk and others from paleomagnetic data. In the model the greatest extensional strain of the North America plate occurs near the Pacific-North America transform, in the area above the absent Farallon slab. Extension direction varies from northwest to southwest according to plate geometry, subduction pull (Juan de Fuca and Guadalupe), and plate boundary tractions.

  6. A new Miocene baleen whale from the Peruvian desert.

    PubMed

    Marx, Felix G; Kohno, Naoki

    2016-10-01

    The Pisco-Ica and Sacaco basins of southern Peru are renowned for their abundance of exceptionally preserved fossil cetaceans, several of which retain traces of soft tissue and occasionally even stomach contents. Previous work has mostly focused on odontocetes, with baleen whales currently being restricted to just three described taxa. Here, we report a new Late Miocene rorqual (family Balaenopteridae), Incakujira anillodefuego gen. et sp. nov., based on two exceptionally preserved specimens from the Pisco Formation exposed at Aguada de Lomas, Sacaco Basin, southern Peru. Incakujira overall closely resembles modern balaenopterids, but stands out for its unusually gracile ascending process of the maxilla, as well as a markedly twisted postglenoid process of the squamosal. The latter likely impeded lateral (omega) rotation of the mandible, in stark contrast with the highly flexible craniomandibular joint of extant lunge-feeding rorquals. Overall, Incakujira expands the still meagre Miocene record of balaenopterids and reveals a previously underappreciated degree of complexity in the evolution of their iconic lunge-feeding strategy.

  7. A new Miocene baleen whale from the Peruvian desert

    NASA Astrophysics Data System (ADS)

    Marx, Felix G.; Kohno, Naoki

    2016-10-01

    The Pisco-Ica and Sacaco basins of southern Peru are renowned for their abundance of exceptionally preserved fossil cetaceans, several of which retain traces of soft tissue and occasionally even stomach contents. Previous work has mostly focused on odontocetes, with baleen whales currently being restricted to just three described taxa. Here, we report a new Late Miocene rorqual (family Balaenopteridae), Incakujira anillodefuego gen. et sp. nov., based on two exceptionally preserved specimens from the Pisco Formation exposed at Aguada de Lomas, Sacaco Basin, southern Peru. Incakujira overall closely resembles modern balaenopterids, but stands out for its unusually gracile ascending process of the maxilla, as well as a markedly twisted postglenoid process of the squamosal. The latter likely impeded lateral (omega) rotation of the mandible, in stark contrast with the highly flexible craniomandibular joint of extant lunge-feeding rorquals. Overall, Incakujira expands the still meagre Miocene record of balaenopterids and reveals a previously underappreciated degree of complexity in the evolution of their iconic lunge-feeding strategy.

  8. Composition and provenance of the Puente Formation (Miocene), Los Angeles Basin

    SciTech Connect

    Critelli, S. ); Rumelhart, P.E.; Ingersoll, R.V. )

    1994-04-01

    The Puente Formation (PFm) is a middle to upper Miocene clastic unit lying unconformably on the middle to lower Miocene El Modeno Volcanics and Topanga Group, within the Los Angeles basin (LAB). The PFm, about 3900m thick, is composed of sandstone, conglomerate, and mudrock deposited on a submarine fan at bathyal depths. Several intrabasinal discordances suggest active tectonics during deposition. The succession consists of two main upward thickening and coarsening megacycles reflecting submarine fan progradation. The PFm is characterized up-section by: (1) thin-bedded fine sandstone and shale (La Vida M.) grading to thick-bedded coarse sandstone an conglomerate (soquel M.); (2) thin-bedded siltstone, mudrock and sandstone (Yorba M.) grading to thick- to very thick-bedded coarse-grained sandstone and conglomerate (Sycamore Canyon M.). Sandstones of the PFm are quartzofeldspathic and suggest a probable local provenance from the plutonic, volcanic, and metamorphic rocks of the San Gabriel Mountains. Petrological parameters, however, suggest variable contribution of these source rock units through time. Coarse-grained plutonic rock fragments are abundant for the entire succession and consist of plagioclase-rich plutonic rocks perhaps sourced from the Lowe granodiorite. Microlitic, lathwork to felsitic volcanic lithic grains are also present in the lower and middle part. In the Yorba M. there is a local increase of volcanic detritus (Lv/L - 0.80), represented by larger volcanic lithics and abundant volcaniclastic matrix. Metamorphic detritus is not very abundant; it is concentrated in the La Vida M. the PFm represents sedimentation during tectonically active time in the evolution of southern California.

  9. The Costa Rican Jurassic to Miocene oceanic complexes: Origin, tectonics and relations

    NASA Astrophysics Data System (ADS)

    Denyer, Percy; Gazel, Esteban

    2009-12-01

    The occurrences of oceanic assemblages on the Pacific shore of Costa Rica are part of an intricate group of complexes with different tectonic origins. Although they are dismembered and disrupted, they are the only available inland source of information to decipher the evolution of this active margin. Six main regions are described in this paper: (1) Santa Elena Peninsula, constituted by a supra-subduction zone (Santa Elena Nappe), that is overthrusting an igneous-sedimentary Aptian-Cenomanian sequence (Santa Rosa Accretionary Complex), which includes OIB (Ocean Island Basalts) portions, (2) the Nicoya Complex, which is a Jurassic-Cretaceous chert sediment pile disrupted and detached from its original basement by multiple magmatic events that occurred during the formation of the CLIP (Caribbean Large Igneous Province), (3) the Tortugal area formed by the Tortugal Suite with OIB signature and surrounded by Nicoya Complex outcrops, (4) the Herradura Block composed of the Tulín Formation to Maastrichtian to Lower Eocene OIB accreted oceanic island and the Nicoya Complex as basement, (5) Quepos Block correlated with the Tulín Formation, (6) the Osa-Burica Block composed of the Golfito and Burica Terranes (geochemically and chronologically correlated to the Nicoya Complex), Rincón Block (Early Paleocene to Early Eocene accreted seamounts), and the Miocene Osa-Caño Accretionary Complex. The Santa Rosa Accretionary Complex together with the Tortugal Suite have OIB signatures and possibly without Galapagos hotspot geochemical affinity. These coincidences would be explained by the hypothetical existence of an "autochthonous" Cretaceous basement formed by these two regions together with the rest of the Caribbean. Costa Rican basement is constituted by several CLIP portions and seamounts accreted from the end of Cretaceous in the northwest to the Miocene in the southeast, forming the diverse oceanic occurrences of the Pacific, which are mainly connected to the Galapagos

  10. First North American fossil monkey and early Miocene tropical biotic interchange

    NASA Astrophysics Data System (ADS)

    Bloch, Jonathan I.; Woodruff, Emily D.; Wood, Aaron R.; Rincon, Aldo F.; Harrington, Arianna R.; Morgan, Gary S.; Foster, David A.; Montes, Camilo; Jaramillo, Carlos A.; Jud, Nathan A.; Jones, Douglas S.; MacFadden, Bruce J.

    2016-05-01

    New World monkeys (platyrrhines) are a diverse part of modern tropical ecosystems in North and South America, yet their early evolutionary history in the tropics is largely unknown. Molecular divergence estimates suggest that primates arrived in tropical Central America, the southern-most extent of the North American landmass, with several dispersals from South America starting with the emergence of the Isthmus of Panama 3-4 million years ago (Ma). The complete absence of primate fossils from Central America has, however, limited our understanding of their history in the New World. Here we present the first description of a fossil monkey recovered from the North American landmass, the oldest known crown platyrrhine, from a precisely dated 20.9-Ma layer in the Las Cascadas Formation in the Panama Canal Basin, Panama. This discovery suggests that family-level diversification of extant New World monkeys occurred in the tropics, with new divergence estimates for Cebidae between 22 and 25 Ma, and provides the oldest fossil evidence for mammalian interchange between South and North America. The timing is consistent with recent tectonic reconstructions of a relatively narrow Central American Seaway in the early Miocene epoch, coincident with over-water dispersals inferred for many other groups of animals and plants. Discovery of an early Miocene primate in Panama provides evidence for a circum-Caribbean tropical distribution of New World monkeys by this time, with ocean barriers not wholly restricting their northward movements, requiring a complex set of ecological factors to explain their absence in well-sampled similarly aged localities at higher latitudes of North America.

  11. First North American fossil monkey and early Miocene tropical biotic interchange.

    PubMed

    Bloch, Jonathan I; Woodruff, Emily D; Wood, Aaron R; Rincon, Aldo F; Harrington, Arianna R; Morgan, Gary S; Foster, David A; Montes, Camilo; Jaramillo, Carlos A; Jud, Nathan A; Jones, Douglas S; MacFadden, Bruce J

    2016-05-12

    New World monkeys (platyrrhines) are a diverse part of modern tropical ecosystems in North and South America, yet their early evolutionary history in the tropics is largely unknown. Molecular divergence estimates suggest that primates arrived in tropical Central America, the southern-most extent of the North American landmass, with several dispersals from South America starting with the emergence of the Isthmus of Panama 3-4 million years ago (Ma). The complete absence of primate fossils from Central America has, however, limited our understanding of their history in the New World. Here we present the first description of a fossil monkey recovered from the North American landmass, the oldest known crown platyrrhine, from a precisely dated 20.9-Ma layer in the Las Cascadas Formation in the Panama Canal Basin, Panama. This discovery suggests that family-level diversification of extant New World monkeys occurred in the tropics, with new divergence estimates for Cebidae between 22 and 25 Ma, and provides the oldest fossil evidence for mammalian interchange between South and North America. The timing is consistent with recent tectonic reconstructions of a relatively narrow Central American Seaway in the early Miocene epoch, coincident with over-water dispersals inferred for many other groups of animals and plants. Discovery of an early Miocene primate in Panama provides evidence for a circum-Caribbean tropical distribution of New World monkeys by this time, with ocean barriers not wholly restricting their northward movements, requiring a complex set of ecological factors to explain their absence in well-sampled similarly aged localities at higher latitudes of North America.

  12. Petrology of Early Miocene volcanic rocks from Okushiri Island, Japan: geochemical characteristics of lithospheric mantle beneath the back-arc side of the NE Japan arc.

    NASA Astrophysics Data System (ADS)

    Sato, M.; Shuto, K.; Ishimoto, H.; Yagi, M.; Takazawa, E.

    2004-12-01

    The Sr and Nd isotopic studies on Tertiary to Quaternary basaltic rocks of the NE Japan arc have shown that isotopic characteristics of basaltic rocks found on the back-arc side of the NE Japan arc changed drastically from an undepleted isotopic signature (initial 87Sr/86Sr (SrI)=0.7040-0.7060 and initial 143Nd/144Nd (NdI)=0.51260-0.51284) to a depleted isotopic signature (SrI=0.7030-0.7040 and NdI=0.70284-0.51308) at around 15 Ma (Shuto et., 2004). This feature may have resulted from changes around 15 Ma in the isotopic compositions of the magma source beneath the back-arc side in the NE Japan arc due to the thinning of the undepleted subcontinental lithospheric mantle by upwelling of depleted asthenospheric mantle material during the opening of Japan Sea. Based on major and trace element data as well as SrI and NdI values for Early Miocene basaltic rocks from the back-arc side of the NE Japan arc, we examined geochemical characterization of the magma source (lithospheric mantle) for these basaltic rocks. Early Miocene (23-18 Ma) basalts and associated more felsic volcanic rocks form seven volcanic fields (Okushiri Is., Matsumae Pen., Fukaura, Oga Pen., Honjo, Atsumi and Sado Is.) delineating a 500 km-long array in the back-arc side of the NE Japan arc. In terms of major, trace element and Nd isotopic compositions, two groups of Early Miocene basalts can be distinguished. Group 1 is composed of tholeiitic basalts and alkali basalts, and is characterized by high TiO2 contents (1.5-2.5 %) and high (La/Yb)n ratios (>5.5), and high Zr/Y ratios (>6). These samples show the chondrite-normalized LREE-enriched patterns and have NdI values ranging from 0.51259 to 0.51282. Group 2 is composed of tholeiitic basalts, and is different from Group 1 by lower TiO2 contents (<1.5 %), lower (La/Yb)n ratios (<5) and lower Zr/Y ratios (<5.5). These samples show modelately LREE-enriched patterns and have NdI values ranging from 0.51250 to 0.51278. In contrast, Middle Miocene (after 15

  13. Ostracoda (Arthropoda, Crustacea) in a Miocene oxygen minimum zone, Trinidad, West Indies: A test of the Platycopid Signal Hypothesis

    NASA Astrophysics Data System (ADS)

    Wilson, Brent; Coimbra, João C.; Hayek, Lee-Ann C.

    2014-10-01

    Studies of Recent ostracodes around the area of South America shed little light on the paleoenvironmental interpretation of Miocene assemblages. Consequently, interpretations of the Miocene ostracode assemblages must be supplemented using evidence from better documented taxa. Benthic foraminifera in samples from the Lower to Middle Miocene Brasso Formation at Brasso Village, Trinidad, have previously been used to distinguish three sample groupings (Beneath, Within and Above) around an oxygen minimum zone (OMZ), this being a layer of water within which dissolved oxygen concentrations can be as low as 0.1-1.0 mL/L. Using these same samples and the foraminiferal assemblage demarcations relative to the OMZ, this paper examines the associated and rich ostracode fauna of the Brasso Formation. The mean recovery of ostracode valves per sample was approximately three times greater in the Within OMZ sample group than in either of the Beneath OMZ or Above OMZ groups, perhaps reflecting the exclusion of macro-predators from within the OMZ. Individual rarefaction of species richness S to N = 300 valves was conducted for each sample group. This showed that S did not differ between the sample groups, ranging from 22.4 to 24.8. We used all ostracode species to model group separation. Based upon the Mahalanobis' criterion, we obtained significant group separation using a model with four taxa: Munseyella ex gr. minuta, Argilloecia posterotruncata, Munseyella sp. and Xestoleberis sp., while a fifth, Argilloecia spp., provided a significant but minor increase in separation probabilities over all groups. The two most abundant species (Bradleya sp., Gangamocytheridea reticulata) were thus not the best species for detecting the OMZ. Platycopid ostracodes of the genus Cytherella were found throughout the section, rather than concentrated within the OMZ, which contradicts the Platycopid Signal Hypothesis that OMZs are characterized by platycopid dominance. The total distribution and

  14. Understanding the Miocene-Pliocene - The Mediterranean Point of View

    NASA Astrophysics Data System (ADS)

    Simon, D.; Marzocchi, A.; Lunt, D. J.; Flecker, R.; Hilgen, F. J.; Meijer, P. T.

    2015-12-01

    During the Miocene-Pliocene the Mediterranean region experienced major changes in paleogeography. Today, its only connection to the global ocean is the Strait of Gibraltar. This restricted nature causes the Mediterranean basin to react more sensitive to climatic and tectonic related phenomena than the global ocean: Not just eustatic sea-level and regional river run-off, but also gateway tectonics and connectivity between sub-basins are leaving an enhanced fingerprint in its geological record. To understand its evolution, it is crucial to understand how these different effects are coupled. The Miocene-Pliocene sedimentary record of the Mediterranean alternates in composition and colour. Around the Miocene-Pliocene Boundary the most extreme changes occur in the Mediterranean Sea: About 6% of the salt in the global ocean got deposited in the Mediterranean Region, forming an approximately 2km thick salt layer, which is still present today. This extreme event is named the Messinian Salinity Crisis (MSC, 5.97-5.33Ma). Before (and also after) the MSC, the sedimentary record demonstrates "marl dominated" alternations with variations in organic content (e.g. higher organic content = sapropel). During the MSC these change to mainly "evaporite (e.g. gypsum or halite) dominated" alternations, but also to brackish Black Sea-type of deposits towards the end of the crisis. Due to its relative short geological time span, the period before, during and after the MSC is ideal to study these extreme changes in sedimentation. We are investigating these couplings and evolutions in a box/budget model. With such a model we can study the responses to basin water exchange dynamics under the effect of different regional and global climatic and tectonic forcings, to predict the evolution of basin properties (e.g. salinity). By doing so we can isolate certain climatic and tectonic effects, to better understand their individual contribution, their interaction, but also the consequences due to

  15. Porosity evolution of upper Miocene reefs, Almeria Province, southern Spain

    USGS Publications Warehouse

    Armstrong, A.K.; Snavely, P.D.; Addicott, W.O.

    1980-01-01

    Sea cliffs 40 km east of Almeria, southeastern Spain, expose upper Miocene reefs and patch reefs of the Plomo formation. These reefs are formed of scleractinian corals, calcareous algae, and mollusks. The reef cores are as much as 65 m thick and several hundred meters wide. Fore-reef talus beds extend 1,300 m across and are 40 m thick. The reefs and reef breccias are composed of calcific dolomite. They lie on volcanic rocks that have a K-Ar date of 11.5 m.y. and in turn are overlain by the upper Miocene Vicar Formation. In the reef cores and fore-reef breccia beds, porosity is both primary and postdepositional. Primary porosity is of three types: (a) boring clam holes in the scleractinian coral heads, cemented reef rocks, and breccias; (b) intraparticle porosity within the corals, Halimeda plates, and vermetid worm tubes; and (c) interparticle porosity between bioclastic fragments and in the reef breccia. Postdepositional moldic porosity was formed by the solution of aragonitic material such as molluscan and coral fragments. The Plomo reef carbonate rocks have high porosity and permeability, and retain a great amount of depositional porosity. Pores range in size from a few micrometers to 30 cm. The extensive intercrystalline porosity and high permeability resulted from dolomitization of micritic matrix. Dolomite rhombs are between 10 and 30 μ across. More moldic porosity was formed by the dissolution of the calclte bioclasts. Some porosity reduction has occurred by incomplete and partial sparry calcite infilling of interparticular, moldic, and intercrystalline voids. The high porosity and permeability of these reefs make them important targets for petroleum exploration in the western Mediterranean off southern Spain. In these offshore areas in the subsurface the volcanic ridge and the Plomo reef complex are locally onlapped or overlapped by 350 m or more of Miocene(?) and Pliocene fine-grained sedimentary rocks. The possibility exists that the buried Plomo reef

  16. Comments to Middle Miocene closure of the Central American Seaway

    USGS Publications Warehouse

    Coates, A.G.; Stallard, Robert F.

    2016-01-01

    In a recent paper proposing an early (mid-Miocene) closure of the Central American Seaway (CAS), Montes et al. 2015 (1) disregard existing paleogeographic data that invalidate Panama as a source for zircons, and inappropriately ignore the evidence for trans-isthmian marine connections until 4-3 Ma. They also fail to cite previous work (2, 3), that had reconstructed the Central American arc already docked with South America by 12 Ma. Montes et al. 2015 (1) (Fig. 1) disregard the Atrato-San Juan sedimentary basin (3), a shallowing Oligocene to Pliocene, Pacific to Caribbean seaway (3, 4, 5). This deep graben (6) is filled with thousands of meters of Pre-Pliocene marine sediments (3, 5, 6) that now occupy a lowland between the Baudo uplift to the west and the Western Cordillera to the east. The Mande Batholith and numerous Eocene and younger volcanic rocks (4), the most proximal source of the zircons, are situated to the east of this seaway and would have shed zircons eastward towards the Cordillera Central. There is no evidence for any rivers crossing the seaway (3, 5), and thus no Panamanian source of zircons. Instead this seaway is evidence of a significant marine connection between the Pacific and Atlantic oceans into the Pliocene. The authors assume that the middle Miocene closure of the CAS effectively creates a continuous land bridge connecting North and South America and separating the Atlantic from the Pacific. They acknowledge, but then discount, marine connections across the Isthmus until 4-3 Ma even though these satisfactorily explain (Coates and Stallard, 2014 (6)) the oceanographic, molecular and Great American Biological Interchange events ignore unexplained by Montes et al. 2015. Only by conspicuously ignoring these events can they imply that the Isthmus was formed at 15-13 Ma. References 1. C. Montes et al., Middle Miocene closure of the Central American Seaway. Science 348, 226-229 (2015). 2. A. G. Coates, R. F. Stallard, How old is the Isthmus of

  17. Late Miocene shortening of the Northern Apennines back-arc

    NASA Astrophysics Data System (ADS)

    Bonini, Marco; Sani, Federico; Stucchi, Eusebio M.; Moratti, Giovanna; Benvenuti, Marco; Menanno, Giovanni; Tanini, Chiara

    2014-03-01

    The inner Northern Apennines (western Tuscany and Tyrrhenian basin) is characterized by a relatively thin continental crust (˜20-25 km), high heat flow (>100 mW m-2), and the presence of relevant tectonic elision of stratigraphic sequences, a setting known as Serie Ridotta. These features are normally ascribed to an extensional deformation that affected the back-arc area above the subducting Adria plate since the Early-Middle Miocene (˜16 Ma). However, various geophysical studies image the continental crust to be currently affected by W-dipping thrust faults (and associated basement uplifts) that have not been obliterated by this claimed long-lasting extensional process. These observations raise the question whether the thrusts are older or younger than the continental extension. To address this question we have reprocessed and interpreted the deep seismic reflection profile CROP03/c that crosses the onshore hinterland sector, and investigated the structural setting of some of the Late Miocene-Pliocene hinterland basins (Cinigiano-Baccinello, Siena-Radicofani, Tafone, Albegna and Radicondoli basins) that are situated at the front or in-between the basement uplifts. The analysis of field structures and commercial seismic profiles has allowed the recognition that both substratum and basins' infill have been intensely shortened. These findings and the architecture of the basins suggest that the latter developed under a contractional regime, which would have started around 8.5 Ma with the onset of the continental sedimentation. This compressive stress state followed an earlier phase of continental extension that presumably started at ˜16 Ma (with the blocking of the Corsica-Sardinia rotation), and thinned both the continental crust and sedimentary cover producing most of the Serie Ridotta. The main phases of basin shortening are bracketed between 7.5 and 3.5 Ma, and thus overlap with the increase in the exhumation rate of the metamorphic cores at ˜6-4 Ma determined

  18. Paleosols and paleoenvironments of the middle Miocene, Maboko Formation, Kenya.

    PubMed

    Retallack, Gregory J; Wynn, Jonathan G; Benefit, Brenda R; Mccrossin, Monte L

    2002-06-01

    The middle Miocene (15 Ma) Maboko Formation of Maboko Island and Majiwa Bluffs, southwestern Kenya, has yielded abundant fossils of the earliest known cercopithecoid monkey (Victoriapithecus macinnesi), and of a kenyapithecine hominoid (Kenyapithecus africanus), as well as rare proconsuline (Simiolus leakeyorum, cf. Limnopithecus evansi) and oreopithecine apes (Mabokopithecus clarki, M. pickfordi), and galagids (Komba winamensis). Specific habitat preferences can be interpreted from large collections of primate fossils in different kinds of paleosols (pedotypes). Fossiliferous drab-colored paleosols with iron-manganese nodules (Yom pedotype) are like modern soils of seasonally waterlogged depressions (dambo). Their crumb structure and abundant fine root-traces, as well as scattered large calcareous rhizoconcretions indicate former vegetation of seasonally wet, wooded grassland. Other fossiliferous paleosols are evidence of nyika bushland (Ratong), and early-successional riparian woodland (Dhero). No fossils were found in Mogo paleosols interpreted as saline scrub soils. Very shallow calcic horizons (in Yom, Ratong, and Mogo paleosols) and Na-montmorillonite (in Mogo) are evidence of dry paleoclimate (300-500 mm MAP=mean annual precipitation). This is the driest paleoclimate and most open vegetation yet inferred as a habitat for any Kenyan Miocene apes or monkeys. Victoriapithecus was abundant in dambo wooded grassland (Yom) and riparian woodland (Dhero), a distribution like that of modern vervet monkeys. Kenyapithecus ranged through all these paleosols, but was the most common primate in nyika bushland paleosols (Ratong), comparable to baboons and macaques today. Mabokopithecus was virtually restricted to riparian woodland paleosols (Dhero), and Simiolus had a similar, but marginally wider, distribution. Habitat preferences of Mabokopithecus and Simiolus were like those of modern colobus monkeys and mangabeys. A single specimen of Komba was found in dambo wooded

  19. Separation of vitexin-4″-O-glucoside and vitexin-2″-O-rhamnoside from hawthorn leaves extracts using macroporous resins.

    PubMed

    Li, Hongjuan; Liu, Ying; Jin, Haizhu; Liu, Sujing; Fang, Shengtao; Wang, Chunhua; Xia, Chuanhai

    2015-12-15

    Vitexin-4″-O-glucoside and vitexin-2″-O-rhamnoside are the major flavonoids of hawthorn leaves. In this work, the adsorption and desorption characteristics of vitexin-4″-O-glucoside and vitexin-2″-O-rhamnoside on seven macroporous resins were evaluated. Among the tested resins, the HPD-400 resin showed the best adsorption and desorption capacities. Adsorption isotherms were constructed for the HPD-400 resin and well fitted to Langmuir and Freundlich models. Dynamic adsorption and desorption tests were performed on column packed with the HPD-400 resin to optimize the chromatographic parameters. After one run treatment with the HPD-400 resin, the contents of vitexin-4″-O-glucoside and vitexin-2″-O-rhamnoside in the product were increased 8.44-fold and 8.43-fold from 0.720% and 2.63% to 6.08% and 22.2% with recovery yields of 79.1% and 81.2%, respectively. These results show that the developed method is a promising basis for the large-scale purification of vitexin-4″-O-glucoside and vitexin-2″-O-rhamnoside from hawthorn leaves and other plant materials.

  20. Major triterpenoids in Chinese hawthorn "Crataegus pinnatifida" and their effects on cell proliferation and apoptosis induction in MDA-MB-231 cancer cells.

    PubMed

    Wen, Lingrong; Guo, Ruixue; You, Lijun; Abbasi, Arshad Mehmood; Li, Tong; Fu, Xiong; Liu, Rui Hai

    2017-02-01

    The cytotoxicity and antiproliferative effect of phytochemicals presenting in the fruits of Chinese hawthorn (Crataegus pinnatifida) were evaluated. Shanlihong (Crataegus pinnatifida Bge. var. major N.E.Br.) variety possessed significant levels of flavonoids and triterpenoids, and showed potent antiproliferative effect against HepG2, MCF-7 and MDA-MB- 231 human cancer cells lines. Triterpenoids-enriched fraction (S9) prepared by Semi-preparative HPLC, and its predominant ingredient ursolic acid (UA) demonstrated remarkably antiproliferative activities for all the tested cancer cell lines. DNA flow cytometric analysis showed that S9 fraction and UA significantly induced G1 arrest in MDA-MB-231 cells in a dose-dependent manner. Western blotting analysis revealed that S9 fraction and UA significantly induced PCNA, CDK4, and Cyclin D1 downregulation in MDA-MB-231 cells, followed by p21(Waf1/Cip1) up-regulation. Additionally, flow cytometer and DNA ladder assays indicated that S9 fraction and UA significantly induced MDA-MB-231 cells apoptosis. Mitochondrial death pathway was involved in this apoptosis as significantly induced caspase-9 and caspase-3 activation. These results suggested that triterpenoids-enriched fraction and UA exhibited antiproliferative activity through the cell cycle arrest and apoptosis induction, and was majorly responsible for the potent anticancer activity of Chinese hawthorn.

  1. A mantle plume beneath California? The mid-Miocene Lovejoy Flood Basalt, northern California

    USGS Publications Warehouse

    Garrison, N.J.; Busby, C.J.; Gans, P.B.; Putirka, K.; Wagner, D.L.

    2008-01-01

    The Lovejoy basalt represents the largest eruptive unit identified in California, and its age, volume, and chemistry indicate a genetic affinity with the Columbia River Basalt Group and its associated mantle-plume activity. Recent field mapping, geochemical analyses, and radiometric dating suggest that the Lovejoy basalt erupted during the mid-Miocene from a fissure at Thompson Peak, south of Susanville, California. The Lovejoy flowed through a paleovalley across the northern end of the Sierra Nevada to the Sacramento Valley, a distance of 240 km. Approximately 150 km3 of basalt were erupted over a span of only a few centuries. Our age dates for the Lovejoy basalt cluster are near 15.4 Ma and suggest that it is coeval with the 16.1-15.0 Ma Imnaha and Grande Ronde flows of the Columbia River Basalt Group. Our new mapping and age dating support the interpretation that the Lovejoy basalt erupted in a forearc position relative to the ancestral Cascades arc, in contrast with the Columbia River Basalt Group, which erupted in a backarc position. The arc front shifted trenchward into the Sierran block after 15.4 Ma. However, the Lovejoy basalt appears to be unrelated to volcanism of the predominantly calc-alkaline Cascade arc; instead, the Lovejoy is broadly tholeiitic, with trace-element characteristics similar to the Columbia River Basalt Group. Association of the Lovejoy basalt with mid-Miocene flood basalt volcanism has considerable implications for North American plume dynamics and strengthens the thermal "point source" explanation, as provided by the mantle-plume hypothesis. Alternatives to the plume hypothesis usually call upon lithosphere-scale cracks to control magmatic migrations in the Yellowstone-Columbia River basalt region. However, it is difficult to imagine a lithosphere-scale flaw that crosses Precambrian basement and accreted terranes to reach the Sierra microplate, where the Lovejoy is located. Therefore, we propose that the Lovejoy represents a rapid

  2. A Miocene submarine volcano at Low Layton, Jamaica

    NASA Technical Reports Server (NTRS)

    Wadge, G.

    1982-01-01

    A submarine fissure eruption of Upper Miocene age produced a modest volume of alkaline basalt at Low Layton, on the north coast of Jamaica. The eruption occurred in no more than a few hundred meters of water and produced a series of hyaloclastites, pillow breccias and pillow lavas, massive lavas, and dikes with an ENE en echelon structure. The volcano lies on the trend of one of the island's major E-W strike-slip fault zones; the Dunavale Fault Zone. The K-Ar age of the eruption of 9.5 plus or minus 0.5 Ma. B.P. corresponds to an extension of the Mid-Cayman Rise spreading center inferred from magnetic anomalies and bathymetry of the Cayman Trough to the north and west of Jamaica. The Low Layton eruption was part of the response of the strike-slip fault systems adjacent to this spreading center during this brief episode of tectonic readjustment.

  3. Miocene to Pleistocene osmium isotopic records of the Mediterranean sediments

    NASA Astrophysics Data System (ADS)

    Kuroda, Junichiro; Jiménez-Espejo, Francisco J.; Nozaki, Tatsuo; Gennari, Rocco; Lugli, Stefano; Manzi, Vinicio; Roveri, Marco; Flecker, Rachel; Sierro, Francisco J.; Yoshimura, Toshihiro; Suzuki, Katsuhiko; Ohkouchi, Naohiko

    2016-01-01

    In the late Miocene the Mediterranean Sea experienced a salinity crisis and thick sequences of evaporites precipitated across the deep and marginal basins. In this study we report Os isotopic records from Deep Sea Drilling Project and Ocean Drilling Project cores in the Mediterranean: the Balearic Sea (Site 372), the Tyrrhenian Sea (Site 654), the Ionian Basin (Site 374), and the Florence Rise (Sites 375-376), as well as Integrated Ocean Drilling Project Site U1387 in Gulf of Cadiz, North Atlantic. Pliocene-Pleistocene sediments at all sites show 187Os/188Os values close to that of the coeval ocean water, indicating that the Mediterranean was connected to the North Atlantic. Evaporitic sediments deposited during the latest Miocene, however, have 187Os/188Os values significantly lower than coeval ocean water values. The offset of the Mediterranean evaporite 187Os/188Os is attributed to limited exchange with the North Atlantic during the Messinian salinity crisis. The source of unradiogenic Os is likely to be weathering of ultramafic rocks (ophiolites) cropping out in the Mediterranean's drainage basins. Based on a box model we estimated the amount of unradiogenic Os and the Atlantic-Mediterranean exchange rate to explain this offset. Os isotopic ratios of the pre-evaporite sediments in the western Mediterranean are almost identical to that of the coeval ocean water. In contrast, equivalent sediments from the Florence Rise have significantly lower 187Os/188Os values. The offset in the Os isotopic ratio on the Florence Rise is attributed either to limited water exchange between eastern and western Mediterranean or to local effects associated with exhumation of the Troodos ophiolites (Cyprus).

  4. Miocene reef and nonreef carbonate rocks in Japan

    SciTech Connect

    Konishi, K.

    1988-01-01

    Japan's main islands experienced temperature climates throughout the Neogene with a tropical invasion around 16 Ma (early middle Miocene). This climatic warming, accompanied by a eustatic sea level rise, caused the unusual occurrence of reef facies, mangrove deposits, and lateritic beds in Japan. In cooler climates both before and after reef growth, sediments rich in bryozoan and algal material were widespread. Reef rocks emplaced as penecontemporaneous olistoliths in deep-water clastics at the Pacific coast of central Honshu are characterized by a wide lithologic spectrum, ranging from grainstone to bindstone. These rocks include rudstone and floatstone, which are rich in coralline algae (encrusting forms such as Lithophyllum and Mesophyllum and articulate forms such as Amphiroa) and codiacean algae (Halimeda) with hermatypic corals and large benthic formainifera (e.g., Nephrolepidina and Miogypsina) being less common. Two types of dolomite occur: (1) limpid dolomite with O/sup 18/ = -5.77 and with bipyramidal quartz and (2) microcrystalline dolomite with O/sup 18/ = 2.00 and with length-slow chalcedony. While microcrystalline dolomite tends to predominate in muddy matrix material, limpid dolomite appears to fill pores, some of which are moldic. Younger nonreef carbonate rocks, as occur on the Noto Peninsula of central Honshu, are commonly cross-bedded, contain Bryozoa, mollusks, small foraminifera, and echinoids, and are locally dolomitized. These dolomites are ascribed to a mixed-water origin. A different type of nonreef, yet reservoir-forming, dolostone occurs in the late middle Miocene of northeast Honshu and is interpreted to have formed as a transformation from bathyal opal.

  5. Biostratigraphic sequence analysis of two Lower Miocene to Pliocene sections, Eastern Falcon, Northwestern Venezuela

    SciTech Connect

    Diaz De Gamero, M.L. ); Giffuni, G.; Castro Mora, M. )

    1993-02-01

    The eastern region of the Falcon Basin in northwestern Venezuela comprises a thick sedimentary sequence deposited from a deep marine bathyal to neritic environment, ranging in age from the Middle Eocene to the Pliocene. A detailed biostratigraphic study (foraminifera and calcareous nannoplankton) was carried out in two sedimentary sequences outcropping in Cumarebo and Piritu, adjacent areas of eastern Falcon, representing: platform, slope and basinal settings. The Cumarebo section is continuous in the studied interval, from the Middle Miocene to the Pliocene. The Piritu section is continuous from the Lower to the lower Upper Miocene, terminating unconformably beneath a thin interval of middle Pliocene platform sediments, indicating tectonism during the latest Miocene. The sequence stratigraphical interpretation was based on the biostratigraphic analysis of the benthic and planktonic fossils, facies distribution and sedimentological data. Systems tracts, sequence boundaries and maximum flooding surfaces from cycles TB2.4 to TB3.5 of the cycle chart were identified. In the Cumarebo section, the upper Middle and Upper Miocene is mostly composed of shales, with some turbiditic sands belonging to a LSW system tract. The upper most Miocene contains a thick carbonate buildup (HST), and it is overlain by a Pliocene section that shallows upward from upper slope to outer shelf depositional environments. In the basinal (Piritu) section, most of the sediments are deep-water shales belonging to a LSW system tract, with some turbiditic sands in the upper Lower Miocene. TST and HST sediments, with scattered carbonate buildups in the upper Middle Miocene were also identified.

  6. Gulf of Mexico miocene CO₂ site characterization mega transect

    SciTech Connect

    Meckel, Timothy; Trevino, Ramon

    2014-12-01

    This project characterized the Miocene-age sub-seafloor stratigraphy in the near-offshore portion of the Gulf of Mexico adjacent to the Texas coast. The large number of industrial sources of carbon dioxide (CO₂) in coastal counties and the high density of onshore urbanization and environmentally sensitive areas make this offshore region extremely attractive for long-term storage of carbon dioxide emissions from industrial sources (CCS). The study leverages dense existing geologic data from decades of hydrocarbon exploration in and around the study area to characterize the regional geology for suitability and storage capacity. Primary products of the study include: regional static storage capacity estimates, sequestration “leads” and prospects with associated dynamic capacity estimates, experimental studies of CO₂-brine-rock interaction, best practices for site characterization, a large-format ‘Atlas’ of sequestration for the study area, and characterization of potential fluid migration pathways for reducing storage risks utilizing novel high-resolution 3D (HR3D) seismic surveys. In addition, three subcontracted studies address source-to-sink matching optimization, offshore well bore management and environmental aspects. The various geologic data and interpretations are integrated and summarized in a series of cross-sections and maps, which represent a primary resource for any near-term commercial deployment of CCS in the area. The regional study characterized and mapped important geologic features (e.g., Clemente-Tomas fault zone, the regionally extensive Marginulina A and Amphistegina B confining systems, etc.) that provided an important context for regional static capacity estimates and specific sequestration prospects of the study. A static capacity estimate of the majority of the Study area (14,467 mi2) was estimated at 86 metric Gigatonnes. While local capacity estimates are likely to be lower due to reservoir-scale characteristics, the

  7. A new family of bizarre durophagous carnivorous marsupials from Miocene deposits in the Riversleigh World Heritage Area, northwestern Queensland.

    PubMed

    Archer, M; Hand, S J; Black, K H; Beck, R M D; Arena, D A; Wilson, L A B; Kealy, S; Hung, T-T

    2016-05-27

    A new specimen of the bizarrely specialised Malleodectes mirabilis from middle Miocene deposits in the Riversleigh World Heritage Area provides the first and only information about the molar dentition of this strange group of extinct marsupials. Apart from striking autapomorphies such as the enormous P3, other dental features such as stylar cusp D being larger than B suggest it belongs in the Order Dasyuromorphia. Phylogenetic analysis of 62 craniodental characters places Malleodectes within Dasyuromorphia albeit with weak support and without indication of specific relationships to any of the three established families (Dasyuridae, Myrmecobiidae and Thylacinidae). Accordingly we have allocated Malleodectes to the new family, Malleodectidae. Some features suggest potential links to previously named dasyuromorphians from Riversleigh (e.g., Ganbulanyi) but these are too poorly known to test this possibility. Although the original interpretation of a steeply declining molar row in Malleodectes can be rejected, it continues to seem likely that malleodectids specialised on snails but probably also consumed a wider range of prey items including small vertebrates. Whatever their actual diet, malleodectids appear to have filled a niche in Australia's rainforests that has not been occupied by any other mammal group anywhere in the world from the Miocene onwards.

  8. A new family of bizarre durophagous carnivorous marsupials from Miocene deposits in the Riversleigh World Heritage Area, northwestern Queensland

    PubMed Central

    Archer, M.; Hand, S. J.; Black, K. H.; Beck, R. M. D.; Arena, D. A.; Wilson, L. A. B.; Kealy, S.; Hung, T.-t.

    2016-01-01

    A new specimen of the bizarrely specialised Malleodectes mirabilis from middle Miocene deposits in the Riversleigh World Heritage Area provides the first and only information about the molar dentition of this strange group of extinct marsupials. Apart from striking autapomorphies such as the enormous P3, other dental features such as stylar cusp D being larger than B suggest it belongs in the Order Dasyuromorphia. Phylogenetic analysis of 62 craniodental characters places Malleodectes within Dasyuromorphia albeit with weak support and without indication of specific relationships to any of the three established families (Dasyuridae, Myrmecobiidae and Thylacinidae). Accordingly we have allocated Malleodectes to the new family, Malleodectidae. Some features suggest potential links to previously named dasyuromorphians from Riversleigh (e.g., Ganbulanyi) but these are too poorly known to test this possibility. Although the original interpretation of a steeply declining molar row in Malleodectes can be rejected, it continues to seem likely that malleodectids specialised on snails but probably also consumed a wider range of prey items including small vertebrates. Whatever their actual diet, malleodectids appear to have filled a niche in Australia’s rainforests that has not been occupied by any other mammal group anywhere in the world from the Miocene onwards. PMID:27229325

  9. A new family of bizarre durophagous carnivorous marsupials from Miocene deposits in the Riversleigh World Heritage Area, northwestern Queensland

    NASA Astrophysics Data System (ADS)

    Archer, M.; Hand, S. J.; Black, K. H.; Beck, R. M. D.; Arena, D. A.; Wilson, L. A. B.; Kealy, S.; Hung, T.-T.

    2016-05-01

    A new specimen of the bizarrely specialised Malleodectes mirabilis from middle Miocene deposits in the Riversleigh World Heritage Area provides the first and only information about the molar dentition of this strange group of extinct marsupials. Apart from striking autapomorphies such as the enormous P3, other dental features such as stylar cusp D being larger than B suggest it belongs in the Order Dasyuromorphia. Phylogenetic analysis of 62 craniodental characters places Malleodectes within Dasyuromorphia albeit with weak support and without indication of specific relationships to any of the three established families (Dasyuridae, Myrmecobiidae and Thylacinidae). Accordingly we have allocated Malleodectes to the new family, Malleodectidae. Some features suggest potential links to previously named dasyuromorphians from Riversleigh (e.g., Ganbulanyi) but these are too poorly known to test this possibility. Although the original interpretation of a steeply declining molar row in Malleodectes can be rejected, it continues to seem likely that malleodectids specialised on snails but probably also consumed a wider range of prey items including small vertebrates. Whatever their actual diet, malleodectids appear to have filled a niche in Australia’s rainforests that has not been occupied by any other mammal group anywhere in the world from the Miocene onwards.

  10. Ethanol extract of Zhongtian hawthorn lowers serum cholesterol in mice by inhibiting transcription of 3-hydroxy-3-methylglutaryl-CoA reductase via nuclear factor-kappa B signal pathway.

    PubMed

    Hu, Hai-Jie; Luo, Xue-Gang; Dong, Qing-Qing; Mu, Ai; Shi, Guo-Long; Wang, Qiu-Tong; Chen, Xiao-Ying; Zhou, Hao; Zhang, Tong-Cun; Pan, Li-Wen

    2016-03-01

    Hawthorn is a berry-like fruit from the species of Crataegus. In China, it has another more famous name, Shan-Zha, which has been used to improve digestion as a traditional Chinese medicine or food for thousands of years. Moreover, during the last decades, hawthorn has received more attention because of its potential to treat cardiovascular diseases. However, currently, only fruits of C. pinnatifida and C. pinnatifida var. major are included as Shan-Zha in the Chinese Pharmacopoeia. In this study, our results showed that the ethanol extract of Zhongtian hawthorn, a novel grafted cultivar of C. cuneata (wild Shan-Zha), could markedly reduce body weight and levels of serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, and liver cholesterol of hyperlipidemia mice. It could suppress the stimulation effect of high-fat diet on the transcription of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and p65, and counteract the downregulation of CYP7A1 and LDLR. In addition, the results of luciferase reporter assay and Western blot showed that the transcriptional activity of HMGCR promoter was inhibited by Zhongtian hawthorn ethanol extract in a dose-dependent manner, while overexpression of p65 could reverse this transcriptional repression effect. These results suggested that Zhongtian hawthorn could provide health benefits by counteracting the high-fat diet-induced hypercholesteolemic and hyperlipidemic effects in vivo, and the mechanism underlying this event was mainly dependent on the suppressive effect of Zhongtian hawthorn ethanol extract on the transcription of HMGCR via nuclear factor-kappa B (NF-κB) signal pathway. Therefore, this novel cultivar of hawthorn cultivar which has much bigger fruits, early bearing, high yield, cold resistance, and drought resistance, might be considered as a good alternative to Shan-Zha and has great value in the food and medicine industry. In addition, to our best knowledge, this is also the first report that the

  11. Late Miocene teeth from Middle Awash, Ethiopia, and early hominid dental evolution.

    PubMed

    Haile-Selassie, Yohannes; Suwa, Gen; White, Tim D

    2004-03-05

    Late Miocene fossil hominid teeth recovered from Ethiopia's Middle Awash are assigned to Ardipithecus kadabba. Their primitive morphology and wear pattern demonstrate that A. kadabba is distinct from Ardipithecus ramidus. These fossils suggest that the last common ancestor of apes and humans had a functionally honing canine-third premolar complex. Comparison with teeth of Sahelanthropus and Orrorin, the two other named late Miocene hominid genera, implies that these putative taxa are very similar to A. kadabba. It is therefore premature to posit extensive late Miocene hominid diversity on the basis of currently available samples.

  12. Miocene climate seasonality in southern India - first direct evidence for a weak Indian monsoon during the Middle Miocene Climate Optimum

    NASA Astrophysics Data System (ADS)

    Piller, W. E.; Reuter, M.; Kern, A. K.; Harzhauser, M.

    2012-04-01

    The Asian monsoon is an integral component of the global climate system. This large-scale atmospheric circulation comprises the East Asian summer and winter monsoon and the Indian monsoon subsystems, all characterized by seasonal reversing winds and precipitation changes associated with asymmetric heating of land and sea. The Neogene monsoon history is mainly reconstructed from chemical and physical weathering rates recorded in widely continuous marine sequences of the Indus Fan, Bengal Fan and South China Sea, which, depending on the source, physiography and sediment, indicate drier or wetter climates. These indirect climate proxies display an unusually dry period during the Middle Miocene Climate Optimum (MMCO, 16.5-15 Ma). As part of the FWF-projects P18189, P21414 and P23492, we present an Early/Middle Miocene coastal palynoflora record from the siliciclastic Ambalapuzha Formation at the coastal cliff of Varkala (Kerala Basin, SW India). Pollen assemblages and facies document a coastal wetland with mangrove vegetation. The Coexistence Approach was applied for palaeoclimatic reconstructions. This method uses climatic tolerances of all nearest living relatives known for a fossil flora by assuming that the tolerances of a fossil taxon are not significantly different from its modern counterpart. The maximum overlap of the environmental tolerances of all nearest living relatives (coexistence interval) is then regarded as being indicative of the most likely palaeoenvironment. By enquiring the Palaeoflora Database (http://www.palaeoflora.de/), the palaeoclimatic parameters of the pollen flora were calculated. The reconstructed climatic parameters for the MMCO show a seasonal precipitation pattern with a dry and a wet period and moderate rainfalls during the warmest period, which is comparable to the present day annual precipitation cycle in coastal Kerala, and affirms the presence of a monsoon-like atmospheric circulation over South India during the MMCO. However, the

  13. Herds Overhead: Nimbadon lavarackorum (Diprotodontidae), Heavyweight Marsupial Herbivores in the Miocene Forests of Australia

    PubMed Central

    Black, Karen H.; Camens, Aaron B.; Archer, Michael; Hand, Suzanne J.

    2012-01-01

    The marsupial family Diprotodontidae (Diprotodontia, Vombatiformes) is a group of extinct large-bodied (60–2500 kg) wombat-like herbivores that were common and geographically widespread in Cenozoic fossil deposits of Australia and New Guinea. Typically they are regarded to be gregarious, terrestrial quadrupeds and have been likened in body form among placental groups to sheep, rhinoceros and hippopotami. Arguably, one of the best represented species is the zygomaturine diprotodontid Nimbadon lavarackorum which is known from exceptionally well-preserved cranial and postcranial material from the middle Miocene cave deposit AL90, in the Riversleigh World Heritage Area, northwestern Queensland. Here we describe and functionally analyse the appendicular skeleton of Nimbadon lavarackorum and reveal a far more unique lifestyle for this plesiomorphic and smallest of diprotodontids. Striking similarities are evident between the skeleton of Nimbadon and that of the extant arboreal koala Phascolarctos cinereus, including the powerfully built forelimbs, highly mobile shoulder and elbow joints, proportionately large manus and pes (both with a semi-opposable digit I) and exceedingly large, recurved and laterally compressed claws. Combined with the unique (among australidelphians) proportionately shortened hindlimbs of Nimbadon, these features suggest adept climbing ability, probable suspensory behaviour, and an arboreal lifestyle. At approximately 70 kg, Nimbadon is the largest herbivorous mammal to have occupied the forest canopies of Australia - an ecological niche that is no longer occupied in any Australian ecosystem and one that further expands the already significant niche diversity displayed by marsupials during the Cenozoic. PMID:23185250

  14. A partial hominoid innominate from the Miocene of Pakistan: Description and preliminary analyses

    PubMed Central

    Morgan, Michèle E.; Lewton, Kristi L.; Kelley, Jay; Otárola-Castillo, Erik; Barry, John C.; Flynn, Lawrence J.; Pilbeam, David

    2015-01-01

    We describe a partial innominate, YGSP 41216, from a 12.3 Ma locality in the Siwalik Group of the Potwar Plateau in Pakistan, assigned to the Middle Miocene ape species Sivapithecus indicus. We investigate the implications of its morphology for reconstructing positional behavior of this ape. Postcranial anatomy of extant catarrhines falls into two distinct groups, particularly for torso shape. To an extent this reflects different although variable and overlapping positional repertoires: pronograde quadrupedalism for cercopithecoids and orthogrady for hominoids. The YGSP innominate (hipbone) is from a primate with a narrow torso, resembling most extant monkeys and differing from the broader torsos of extant apes. Other postcranial material of S. indicus and its younger and similar congener Sivapithecus sivalensis also supports reconstruction of a hominoid with a positional repertoire more similar to the pronograde quadrupedal patterns of most monkeys than to the orthograde patterns of apes. However, Sivapithecus postcranial morphology differs in many details from any extant species. We reconstruct a slow-moving, deliberate, arboreal animal, primarily traveling above supports but also frequently engaging in antipronograde behaviors. There are no obvious synapomorphic postcranial features shared exclusively with any extant crown hominid, including Pongo. PMID:25489095

  15. Herds overhead: Nimbadon lavarackorum (Diprotodontidae), heavyweight marsupial herbivores in the Miocene forests of Australia.

    PubMed

    Black, Karen H; Camens, Aaron B; Archer, Michael; Hand, Suzanne J

    2012-01-01

    The marsupial family Diprotodontidae (Diprotodontia, Vombatiformes) is a group of extinct large-bodied (60-2500 kg) wombat-like herbivores that were common and geographically widespread in Cenozoic fossil deposits of Australia and New Guinea. Typically they are regarded to be gregarious, terrestrial quadrupeds and have been likened in body form among placental groups to sheep, rhinoceros and hippopotami. Arguably, one of the best represented species is the zygomaturine diprotodontid Nimbadon lavarackorum which is known from exceptionally well-preserved cranial and postcranial material from the middle Miocene cave deposit AL90, in the Riversleigh World Heritage Area, northwestern Queensland. Here we describe and functionally analyse the appendicular skeleton of Nimbadon lavarackorum and reveal a far more unique lifestyle for this plesiomorphic and smallest of diprotodontids. Striking similarities are evident between the skeleton of Nimbadon and that of the extant arboreal koala Phascolarctos cinereus, including the powerfully built forelimbs, highly mobile shoulder and elbow joints, proportionately large manus and pes (both with a semi-opposable digit I) and exceedingly large, recurved and laterally compressed claws. Combined with the unique (among australidelphians) proportionately shortened hindlimbs of Nimbadon, these features suggest adept climbing ability, probable suspensory behaviour, and an arboreal lifestyle. At approximately 70 kg, Nimbadon is the largest herbivorous mammal to have occupied the forest canopies of Australia - an ecological niche that is no longer occupied in any Australian ecosystem and one that further expands the already significant niche diversity displayed by marsupials during the Cenozoic.

  16. Late Miocene uplift and doming of Madagascar: topographic implications

    NASA Astrophysics Data System (ADS)

    Delaunay, Antoine; Robin, Cecile; Guillocheau, François; Dall'Asta, Massimo; Calves, Gérôme

    2016-04-01

    Madagascar is an Archean to Neoproterozoic continental crust surrounded by transform, oblique and divergent margins: the oblique Morondava Basin to the west, pounded by the Davie Fracture Zone, and to the north, the divergent Mahajanga (Majunga) Basin connected to the Somali Oceanic Basin. This 1600 km long island is a high axial plateau with elevations from 1200 to 1800m. The top of the plateau corresponds to weathered planation surfaces (etchplains), bounded by more or less high scarps. We here present geological arguments for the age and the timing of the Madagascar Plateau. This analysis is based on a double, coupled analysis of the onshore geomorphology (stepped planation surfaces) and the offshore margin stratigraphy (seismic stratigraphy and wells). The geomorphological analysis is based on a characterization, a mapping and dating of stepped planation surfaces (mantled to stripped etchplains, pediments to pediplains). The dating is based on their geometrical relationships with dated magmatic rocks. The difference of elevation between two planation surfaces (corresponding to local base level) provides a proxy of the uplift. The sequence stratigraphic analysis is based on a biostratigraphic reevaluation of 4 industrial wells (foraminifers and nannofossils on cuttings). Uplift periods are characterized by (1) seaward tiltings of the margins overlain by planar reflectors, (2) forced regression wedges and (3) upstream erosions of older sediments recorded by fauna/flora reworking. (1) During Paleocene to Middle Miocene times (66 to 13 Ma), Madagascar is a quite flat low elevation domain with remnants of an oldest pre-Madagascar Trap (90 Ma) surface. This low relief is highly weathered with growth of numerous lateritic profiles and surrounded by large carbonate platforms with no siliciclastic sands influx. (2) The Late Miocene is the paroxysm of uplift with (1) a tilting of the margin (Morondova), (2) an increase of the siliciclastic sand flux since middle Miocene

  17. Significant Role of the East Antarctic Ice Sheet in Miocene Global Climate Change

    NASA Astrophysics Data System (ADS)

    Cook, C. P.; Martin, E. E.

    2015-12-01

    The Miocene was a period of climatic extremes, with indirect records suggesting major retreat and advance of Antarctica's ice sheets. Climatic warmth of the Early Miocene and Miocene Climatic Optimum (MCO; ~17-15 Ma) was followed by cooler conditions and growth of the East Antarctic ice sheet (EAIS) during the middle Miocene Climate Transition (MMCT; ~14-15 Ma). This cooling occured with decreasing CO2 levels and deepening of the CCD. Weathering on Antarctica associated with ice sheet variability likely played a role in global climate, but the temporal and spatial evolution of the EAIS is not constrained well enough to characterize this relationship. We use Pb and Nd isotopes of authigenic Fe-Mn oxide coatings, which preserve bottom water compositions, and associated detrital bulk deep sea sediments, to provide new insights into continental weathering and ice sheet evolution during the Miocene. Comparison of Pb IC's of coupled detrital and authigenic phases are used to reconstruct chemical weathering patterns. In contrast, Nd IC's provide insights into bedrock erosion and ocean circulation patterns. Study sites are located on Maud Rise (ODP Sites 689 and 690) in the Atlantic sector, and on Kerguelen Plateau (ODP Site 744) off of Prydz Bay. Results reveal increased offsets between seawater and detrital Pb IC's during the Early Miocene and MCO, and decreased values and offsets during the MMCT and Late Miocene for all three sites, a pattern that is most pronounced at Maud Rise. There is a long-term trend to more unradiogenic Nd IC and more radiogenic Pb IC values of detrital sediments during the MMCT and Late Miocene. Comparison with modern day coretop data suggest this pattern indicates increased supply of local continental material. Our data suggest enhanced chemical weathering accompanied reduced ice volume and high atmospheric CO2 during the Early Miocene and MCO, likely contributing to the drawdown of CO2 that lead to the MMCT, as well as deepening of the CCD

  18. Late Miocene lineage divergence and ecological differentiation of rare endemic Juniperus blancoi: clues for the diversification of North American conifers.

    PubMed

    Moreno-Letelier, Alejandra; Mastretta-Yanes, Alicia; Barraclough, Timothy G

    2014-07-01

    Western North America and Mexico contain a large number of conifer species. This diversity could be the product of orographic and climate changes of the late Tertiary and Quaternary. In this study, we focus on the evolutionary history of Juniperus blancoi, in order to determine the impact of climate change and environmental heterogeneity on population differentiation. We estimated the population structure, phylogenetic relationships and historical demography of J. blancoi populations using nuclear genes. We correlated genetic structure with ecological differentiation, divergence times and changes in population size. Populations of J. blancoi are differentiated into three lineages that correspond to low-, mid- and high-altitude populations. The three groups diversified in the late Miocene, early Pliocene, with only a few events of gene flow since then. Two lineages in the north exhibited a pattern of population growth during the Pleistocene that could be linked to climate changes. Populations of J. blancoi experienced significant ecological differentiation and early divergence events, which correspond to periods of global cooling and mountain uplift during the Miocene. This suggests that mountain ranges in tropical and subtropical latitudes play an important role in the speciation and persistence of conifer taxa in diversity hotspots, by providing diverse environmental conditions.

  19. A new genus and species of Planopinae (Xenarthra: Tardigrada) from the Miocene of Santa Cruz Province, Argentina.

    PubMed

    Carlini, Alfredo A; Brandoni, Diego; Dal Molin, Carlos N

    2013-01-01

    Prepoplanops boleadorensis, a new genus and species of Planopinae (Xenarthra, Tardigrada), is described herein. The new taxon is based on a nearly complete specimen recovered from the Cerro Boleadoras Formation (Miocene, Rio Zeballos Group), in northwestern Santa Cruz Province, Argentina. The shape and length of the predentary region of the skull and the length of the diastema of Prepoplanops boleadorensis differ from those present in the species of Planops. The posterolateral opening of the mandibular canal and the position of the posterior margin of the mandibular symphysis differ from those of species of Prepotherium. In addition, Prepoplanops boleadorensis differs from Planops martini in the size of the humeral tuberosities, the development of the deltoid crest, the position of the distal margin of the humeral trochlea, the shape and position of the olecranon, the development of the femoral epicondyles, and the shape of the medial margins of the patellar trochlea and medial condyle. On the other hand, it differs from Prepotherium potens in the shape of the medial margin of the medial condyle. The recognition of Prepoplanops boleadorensis increases the diversity of Planopinae for the Miocene of Patagonia, Argentina.

  20. A new genus of the family Jaculinidae (Cheilostomata, Bryozoa) from the Miocene of the tropical western Atlantic.

    PubMed

    Zágoršek, Kamil; Ramalho, Laís V; Berning, Björn; De Araújo Távora, Vladimir

    2014-07-16

    Pirabasoporella gen. nov. is introduced for three new bryozoan species from the Early Miocene of the tropical western Atlantic. The genus is placed in the family Jaculinidae Zabala, a peculiar group of cheilostome bryozoans characterised by reticulate colonies formed by uni- or biserial branches that are connected by kenozooidal struts. This colonial morphology superficially resembles colonies of the Paleozoic order Fenestrata (Stenolaemata) and some Recent Cyclostomata. As jaculinid colonies are anchored to soft sediments via rhizoids, however, they differ in life habit from Paleozoic and modern fenestrate colonies, which are firmly attached to stable substrata by an encrusting base.        The three new species are Pirabasoporella atalaiaensis n. sp. from the Brazilian Pirabas Formation, Pirabasoporella baitoae n. sp. from the Baitoa Formation (Dominican Republic), and Pirabasoporella chipolae n. sp. from the Floridan Chipola Formation. Their presence in the Early Miocene western Atlantic represents the earliest record of Jaculinidae, and suggests that the origin of the family, the only living species of which are known from the eastern Atlantic and Mediterranean Sea, extends well into the Paleogene.        The Jaculinidae is here transferred from the lepraliomorph superfamily Schizoporelloidea Jullien to the umbonulomorph Lepralielloidea Vigneaux owing to the partly umbonuloid frontal shield and non-schizoporelloid ovicell.

  1. Megalictis, the Bone-Crushing Giant Mustelid (Carnivora, Mustelidae, Oligobuninae) from the Early Miocene of North America

    PubMed Central

    Valenciano, Alberto; Baskin, Jon A.; Abella, Juan; Pérez-Ramos, Alejandro; Álvarez-Sierra, M. Ángeles; Morales, Jorge; Hartstone-Rose, Adam

    2016-01-01

    We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and “M.” petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America. PMID:27054570

  2. Megalictis, the Bone-Crushing Giant Mustelid (Carnivora, Mustelidae, Oligobuninae) from the Early Miocene of North America.

    PubMed

    Valenciano, Alberto; Baskin, Jon A; Abella, Juan; Pérez-Ramos, Alejandro; Álvarez-Sierra, M Ángeles; Morales, Jorge; Hartstone-Rose, Adam

    2016-01-01

    We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and "M." petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America.

  3. Evolution of a Miocene sag basin in the Alboran Sea

    NASA Astrophysics Data System (ADS)

    Do Couto, D.; Gorini, C.; Jolivet, L.; Letouzey, J.; Smit, J.; d'Acremont, E.; Auxietre, J. L.; Le Pourhiet, L.; Estrada, F.; Elabassi, M.; Ammar, A.; Jabour, H.; Vendeville, B.

    2012-04-01

    The Alboran domain represents the westernmost termination of the peri-Mediterranean Alpine orogen. Its arcuate shape, delimited to the North by the Betic range and to the South by the Rif range, is the result of subduction, collision and slab migration processes. During the Neogene, several sedimentary basins formed on the Betics metamorphic basement, mainly due to the extensional collapse of the previously thickened crust of the Betic-Rif belt. The major sedimentary depocentre, the Western Alboran Basin (WAB), is surrounded by the Gibraltar arc, the volcanic Djibouti mounts and the Alboran ridge, and is partly affected by shale tectonics and associated mud volcanism. High-quality 2-D seismic profiles acquired along the Moroccan margin during the last decade reveal a complete history of the basin. Our study deals with the analysis of seismic profiles oriented parallel and orthogonal to the Mediterranean Moroccan margin. The stratigraphy was calibrated using well data from offshore Spain and Morocco. Our study focuses particularly on the tectono-stratigraphic reconstruction of the basin. The formation of the WAB began in the Early Miocene (Aquitanian - Burdigalian). A massive unit of Early Miocene to Lower Langhian shales and olistostromes forms a thick mobile décollement layer that controls and accommodates deformation of the basin fill. From the Upper Langhian to the Upper Tortonian, the basin is filled by a thick sequence of siliciclastic deposits. Stratigraphic geometries identified on seismic data clearly indicate that deformation of the basin fill started during deposition of Upper Langhian to the Upper Tortonian clastics. Shale tectonic deformation was re-activated recently, during the Messinian desiccation of the Mediterranean Sea (and the following catastrophic Pliocene reflooding) or during the Quaternary contourite deposition The sedimentary layers gently dip towards the basin centre and "onlaps" onto the basin margin, especially onto the basement high

  4. Early Miocene origin and cryptic diversification of South American salamanders

    PubMed Central

    2013-01-01

    Background The currently recognized species richness of South American salamanders is surprisingly low compared to North and Central America. In part, this low richness may be due to the salamanders being a recent arrival to South America. Additionally, the number of South American salamander species may be underestimated because of cryptic diversity. The aims of our present study were to infer evolutionary relationships, lineage diversity, and timing of divergence of the South American Bolitoglossa using mitochondrial and nuclear sequence data from specimens primarily from localities in the Andes and upper Amazon Basin. We also estimated time of colonization of South America to test whether it is consistent with arrival via the Panamanian Isthmus, or land bridge connection, at its traditionally assumed age of 3 million years. Results Divergence time estimates suggest that Bolitoglossa arrived in South America from Central America by at least the Early Miocene, ca. 23.6 MYA (95% HPD 15.9-30.3 MYA), and subsequently diversified. South American salamanders of the genus Bolitoglossa show strong phylogeographic structure at fine geographic scales and deep divergences at the mitochondrial gene cytochrome b (Cytb) and high diversity at the nuclear recombination activating gene-1 (Rag1). Species often contain multiple genetically divergent lineages that are occasionally geographically overlapping. Single specimens from two southeastern localities in Ecuador are sister to the equatoriana-peruviana clade and genetically distinct from all other species investigated to date. Another single exemplar from the Andes of northwestern Ecuador is highly divergent from all other specimens and is sister to all newly studied samples. Nevertheless, all sampled species of South American Bolitoglossa are members of a single clade that is one of several constituting the subgenus Eladinea, one of seven subgenera in this large genus. Conclusions The ancestors of South American salamanders

  5. Deformation of the late Miocene to Pliocene Inyo Surface, eastern Sierra region, California

    USGS Publications Warehouse

    Jayko, A.S.

    2009-01-01

    A middle and late Miocene erosion surface, the Inyo Surface, underlies late Miocene mafic flows in the White Mountains and late Miocene and (or) early Pliocene flows elsewhere in the eastern Sierra region. The Inyo Surface is correlated with an erosion surface that underlies late Miocene mafic flows in the central and northern Sierra Nevada. The mafic flows had outpourings similar to flood basalts, although of smaller volume, providing paleohorizontal and paleolowland indicators. The flows filed and locally topped the existing landscape forming broad plateau-like flats. Topographic relief in the region was characterized by weathered and rounded slopesp rior to late Miocene mafic magmatism. Relicts of the older landscape lie adjacent to late Miocene and early Pliocene basalt-covered lowlands that now occur within the crests of ranges that have 2500-3000 m relief and dramatically steep escarpments. Late Miocene mafic flows that lie on the crest of the Sierra Nevada adjacent to the White Mountains predate significant activity on the Sierra Nevada frontal fault zone. These deposits and accompanying erosion surfaces provide excellent strain markers for reconstructing part of the Walker Lane north of the Garlock fault and west of the Amargosa drainage, here referred to as the eastern Sierra region. The Inyo Surface is a compound erosional surface that records at least four major erosion events during the Cenozoic. These four surfaces were first recognized on the Kern Plateau and named from oldest to youngest, the Summit Upland, the Subsummit Plateau, the Chagoopa Plateau, and the Canyon. The three older surfaces have also been subsequently modifi ed by Pleistocene glaciation. The compound erosion surface, which is locally overlain by late Miocene mafic flows in the northern and central Sierra Nevada, is here referred to as the Lindgren Surface. Correlatives in the eastern Sierra region are found in the White Mountains, Inyo Mountains, Darwin Plateau, Coso Range, and

  6. Widespread Miocene deep-sea hiatuses: coincidence with periods of global cooling.

    USGS Publications Warehouse

    Barron, J.A.; Keller, G.

    1982-01-01

    High-resolution biostratigraphic analyses of Miocene deep-sea cores reveal eight intervals of widespread hiatuses in the world ocean. In complete sections these hiatuses correspond to intervals of cool faunal and floral assemblages, rapid enrichment of delta 18O, and sea-level regressions. These factors suggest that Miocene deep-sea hiatuses result from an increased intensity of circulation and corrosiveness of bottom currents during periods of increased polar refrigeration.-Authors

  7. Plant wax isotope records of spatial and temporal change to climate and hydrology in western North America during the Miocene and Middle Miocene Climatic Optimum

    NASA Astrophysics Data System (ADS)

    Hren, M. T.

    2015-12-01

    The Miocene Epoch marks a prolonged period of terrestrial cooling and aridification in the late Cenozoic in concert with the long-term development of the Antarctic Ice sheet. Within the Miocene, the Middle Miocene Climatic Optimum (MMCO) represents a period of overall global warmth between 15-17 Ma, with mid-latitude temperatures of up to ~3-6°C hotter than modern. This interval of global warmth and possible decrease in Antarctic ice volume is argued to have occurred during a period with relatively modest, but highly variable atmospheric CO2 (300-500 ppm) on a roughly 100-kyr timescale. Effects of prolonged Middle Miocene and peak MMCO warmth are readily observed in marine and terrestrial sediments, however there is considerable debate over the impact of globally-warm and peak MMCO conditions on spatial patterns of precipitation and temperature on land. Here we present hydrogen and carbon isotope data from Miocene-aged higher plant waxes across western North America to evaluate large-scale spatial patterns of isotope hydrology and climate during the Middle Miocene period. These data are coupled with modern regional biomarker C and H isotopic data and records through the interval including the Middle Miocene Climatic Optimum (~17-13) to assess temporal changes in isotope hydrology and climate during high-frequency atmospheric CO2 fluctuations. Regional and high-resolution terrestrial wax data show generally wetter and warmer conditions than today in western North America during the Middle Miocene (~15 Ma) with short-timescale perturbations to regional hydrology during the MMCO. These terrestrial changes are coincident with the pacing of change observed in the marine realm and show two periods of hydrogen and carbon isotopic enrichment. Spatial patterns of middle Miocene leaf wax δD and temperature and short timescale fluctuations in δD and δ13C during the MMCO indicate close coupling of the continental system to short-duration variations observed in the marine

  8. The history of Post-Miocene sea level change: Inferences from stratigraphic modeling of Enewetak Atoll

    NASA Astrophysics Data System (ADS)

    Quinn, Terrence M.

    1991-04-01

    The history of post-Miocene sea level change has been investigated using a quantitative, one-dimensional stratigraphic forward model. The stratigraphic model produces synthetic stratigraphies, including mineralogy and sediment age versus depth, in response to changes in sea level, subsidence, sedimentation, and diagenesis. Model outputs, using sea level curves inferred from passive margin sequence stratigraphy and deep-sea foraminiferal oxygen isotope stratigraphy, were compared to the post-Miocene stratigraphy of Enewetak Atoll. Modeling results support high-frequency (104 to 105 years) fluctuations of post-Miocene sea level. Post-Miocene sea level elevations significantly greater than modern sea level elevation are not easily reconciled with the stratigraphy of Enewetak Atoll. Model/data fit is maximized when a rapid subsidence rate for Enewetak Atoll is used. Alternatively, model/data fit may be maximized using a lower subsidence rate for Enewetak and having post-Miocene sea level elevations significantly lower than modem sea level elevation. Given the present state of knowledge, much work is still needed to accurately decipher the record of post-Miocene sea level change.

  9. Configuration of Miocene Basins Along the Santa Cruz-Catalina Ridge, California Continental Borderland

    NASA Astrophysics Data System (ADS)

    Stoller, A. R.; Legg, M.; Malone, D. H.

    2015-12-01

    Miocene basins associated with the oblique rifting of the Inner Continental Borderland offshore Southern California are preserved along the flanks of the transpressional Santa Cruz-Catalina Ridge. Using 184 lines of two-dimensional seismic data including high resolution records from Oregon State University and deep penetration data from Western Geco archived in USGS/NAMSS, we were able to map the configuration of the Miocene basin along the flanks of the northern core complex on the Santa Cruz-Catalina Ridge. There are distinct early and middle Miocene basins along the flanks of the ridge, which we are using to try to define the initial configuration of the Inner Borderland Rift. Along the hinge, between the uplifted ridge and the sub-horizontal basement in the Santa Monica Basin, lies the thickest part of the sequence. Pliocene to Recent sediments lap on to the tilted and uplifted Miocene basin sequences and constrain timing of uplift when transpression commenced. Segmentation and other distinctive character of the basin along the ridge flank may be correlated with similar features in the Miocene basin on the conjugate margin of the rift. Our working model for oblique rifting in the Borderland resembles of the Gulf of California, where right-stepping echelon transform faults link left-stepping extensional basins. The objective of our project is to reconstruct the configuration of the middle Miocene rift and to further our quest to understand the rifting process and tectonic evolution of the Pacific-North American plate boundary.

  10. Late Oligocene–early Miocene birth of the Taklimakan Desert

    PubMed Central

    Zheng, Hongbo; Wei, Xiaochun; Tada, Ryuji; Clift, Peter D.; Wang, Bin; Jourdan, Fred; Wang, Ping; He, Mengying

    2015-01-01

    As the world’s second largest sand sea and one of the most important dust sources to the global aerosol system, the formation of the Taklimakan Desert marks a major environmental event in central Asia during the Cenozoic. Determining when and how the desert formed holds the key to better understanding the tectonic–climatic linkage in this critical region. However, the age of the Taklimakan remains controversial, with the dominant view being from ∼3.4 Ma to ∼7 Ma based on magnetostratigraphy of sedimentary sequences within and along the margins of the desert. In this study, we applied radioisotopic methods to precisely date a volcanic tuff preserved in the stratigraphy. We constrained the initial desertification to be late Oligocene to early Miocene, between ∼26.7 Ma and 22.6 Ma. We suggest that the Taklimakan Desert was formed as a response to a combination of widespread regional aridification and increased erosion in the surrounding mountain fronts, both of which are closely linked to the tectonic uplift of the Tibetan–Pamir Plateau and Tian Shan, which had reached a climatically sensitive threshold at this time. PMID:26056281

  11. Late Oligocene-early Miocene birth of the Taklimakan Desert.

    PubMed

    Zheng, Hongbo; Wei, Xiaochun; Tada, Ryuji; Clift, Peter D; Wang, Bin; Jourdan, Fred; Wang, Ping; He, Mengying

    2015-06-23

    As the world's second largest sand sea and one of the most important dust sources to the global aerosol system, the formation of the Taklimakan Desert marks a major environmental event in central Asia during the Cenozoic. Determining when and how the desert formed holds the key to better understanding the tectonic-climatic linkage in this critical region. However, the age of the Taklimakan remains controversial, with the dominant view being from ∼ 3.4 Ma to ∼ 7 Ma based on magnetostratigraphy of sedimentary sequences within and along the margins of the desert. In this study, we applied radioisotopic methods to precisely date a volcanic tuff preserved in the stratigraphy. We constrained the initial desertification to be late Oligocene to early Miocene, between ∼ 26.7 Ma and 22.6 Ma. We suggest that the Taklimakan Desert was formed as a response to a combination of widespread regional aridification and increased erosion in the surrounding mountain fronts, both of which are closely linked to the tectonic uplift of the Tibetan-Pamir Plateau and Tian Shan, which had reached a climatically sensitive threshold at this time.

  12. Porosity evolution of upper Miocene reefs, Almeria Province, Southern Spain

    SciTech Connect

    Armstrong, A.K.; Snavely, P.D. Jr.; Addicott, W.O.

    1980-02-01

    In the reef cores and fore-reef breccia beds, porosity in both primary and postdepositional. Primary porosity is of three types: (a) boring clam holes in the scleractinian coral heads, cemented reef rocks, and breccias; (b) intraparticle porosity within the corals, Halimeda plates, and vermetid worm tubes; and (c) interparticle porosity between bioclastic fragments and in the reef breccia. Postdepositional moldic porosity was formed by the solution of aragonitic material such as molluscan and coral fragments. The Polomo reef carbonate rocks have high porosity and permeability, and retain a great amount of depositional porosity. Pores range in size from a few micrometers to 30 cm. The extensive intercrystalline porosity and high permeability resulted from dolomitization of micritic matrix. Some porosity reduction has occured by incomplete and partial sparry calcite infilling of interparticular, moldic, and intercrystalline voids. The high porosity and permeability of these reefs make them important targets for petroleum exploration in the western Mediterranean off southern Spain. In these offshore areas in the subsuface the volcanic ridge and the Plomo reef complex are locally onlapped or overlapped by 350 m or more of Miocene and Pliocene fine-grained sedimentary rocks. The possibility exists that the buried Plomo reef deposits may form traps for oil and gas in the offshore areas southwest of the type locality. Stratigraphic traps also may occur where the Neogene sequence above the Plomo reef complex onlaps the volcanic ridge. 17 figures.

  13. Late Miocene calcareous nannofossil genus Catinaster: taxonomy, evolution and magnetobiochronology

    USGS Publications Warehouse

    Peleo-Alampay, A.; Bukry, D.; Liu, L.; Young, J.R.

    1998-01-01

    A systematic study on the evolution and stratigraphic distribution of the species of Catinaster from several DSDP/ODP sites with magnetostratigraphic records is presented. The evolution of Catinaster from Discoaster is established by documentation of a transitional nannofossil species, Dicoaster transitus. Two new subspecies, Catinaster coalitus extensus and Catinaster calyculus rectus are defined which appear to be intermediates in the evolution of Catinaster coalitus coalitus to Catinaster calyculus calyculus. The first occurrence of C. coalitus is shown to be in the lower part of C5n.2n at 10.7-10.9 Ma in the low to mid-latitude Atlantic and Pacific oceans. The last occurrence of C. coalitus coalitus varies from the upper part of C5n.2n to the lower portion of C4A. Magnetobiostratigraphic evidence suggests that the FO of C. calyculus rectus is diachronous. Catinaster mexicanus occurs in the late Miocene and has been found only in the eastern equatorial Pacific, the Indian Ocean and the Gulf of Mexico.

  14. Miocene lacustrine algal reefs—southwestern Snake River Plain, Idaho

    NASA Astrophysics Data System (ADS)

    Straccia, Frances G.; Wilkinson, Bruce H.; Smith, Gerald R.

    1990-04-01

    The Hot Spring limestone is a shallow-water algal carbonate within a late Tertiary transgressive lacustrine sequence exposed in the southwestern Snake River Plain. This 5 m thick lensoid sequence crops out over an 80 km 2 area that closely approximates original areal extent of nearshore carbonate accumulation. Reefal bodies consist of closely packed algal cylinders, several decimeters in height, each of which includes a dense laminated carbonate wall surrounding porous digitate carbonate that radiates outward and upward from one or more hollow tubes. These coalesce upsection into separate vertical columns several meters in diameter. Moderately well-sorted terrigenous and molluscan debris deposited between columns during growth indicates these structures were resistant to wave erosion and, therefore, were true reefs. Thick rings of littoral carbonate surrounding the upper walls of each column record the final stages of reef development. Structural attributes exhibited by these Miocene carbonate bodies are also common to a number of Tertiary and Quaternary algal buildups reported from other lacustrine settings. Although features within the Hot Spring limestone are complex in gross morphology and structural detail, both columnar reefs and algal cylinders display little variation in size, shape, or internal structure between areas of varying water depth and wave energy, thus reflecting the importance of biological processes as well as physical processes during reef development.

  15. The rainbow range, British Columbia: A miocene peralkaline shield volcano

    NASA Astrophysics Data System (ADS)

    Bevier, Mary Lou

    1981-12-01

    The Rainbow Range is a Late Miocene shield volcano (30 km diameter, 370 km 3) whose stratiform flanks surround a complex central zone. Over a 2-m.y. interval, extrusion of low viscosity, silicic peralkaline lavas and minor basaltic lavas built up the gently sloping (5-8°) flanks, forming a shield volcano rather than a composite cone. Comenditic trachytes are the lowest flows exposed on the north flank of the volcano. Thin mugearite flows rest unconformably on the comenditic trachytes. Comendites unconformably overlie the mugearites and account for at least 75% of the volume of flows within the flank zone. These lavas are distinguished from the comenditic trachytes by lower Al 2O 3 (13%), higher total iron as Fe 2O 3, (7%), and extremely depleted Sr (1-10 ppm) and Ba (10-100 ppm). Strontium isotopic studies combined with petrologic data suggest that Rainbow Range lavas originated from alkali basalt magma trapped in an intracrustal magma chamber and tapped at several intervals after it underwent crystal fractionation. A best-fit mathematical model for the origin of the suite involves step-wise derivation of the lavas in the order hawaiite → mugeartite → comenditic trachyte → comendite, with the major phases precipitating in the order: olivine, clinopyroxene, plagioclase, iron-titanium oxides, and alkali feldspar.

  16. Miocene detachment faulting predating EPR propagation: Southern Baja California

    NASA Astrophysics Data System (ADS)

    Bot, Anna; Geoffroy, Laurent; Authemayou, Christine; Bellon, Hervé; Graindorge, David; Pik, Raphaël.

    2016-05-01

    At the southern tip of the Baja California peninsula, we characterize the onshore structures and kinematics associated with crustal necking leading up to the Pliocene breakup and early East Pacific Rise seafloor spreading. From a combination of tectonic field investigations, K-Ar and cosmogenic isotope dating and geomorphology, we propose that the Los Cabos block represents the exhumed footwall of a major detachment fault. This north trending detachment fault is marked by a conspicuous low-dipping brittle-ductile shear zone showing a finite displacement with top to the SE ending to the ESE. This major feature is associated with fluid circulations which led to rejuvenation of the deformed Cretaceous magmatic rocks at a maximum of 17.5 Ma. The detachment footwall displays kilometer-scale corrugations controlling the present-day drainage pattern. This major detachment is synchronous with the development of the San José del Cabo Basin where syntectonic sedimentation took place from the middle Miocene to probably the early Pliocene. We propose that this seaward dipping detachment fault accommodates the proximal crustal necking of the Baja California passive margin, which predates the onset of formation of the East Pacific Rise spreading axis in the Cabo-Puerto Vallarta segment. Our data illustrate an apparent anticlockwise rotation of the stretching direction in Baja California Sur from ~17 Ma to the Pliocene.

  17. Dispersals of Hyoscyameae and Mandragoreae (Solanaceae) from the New World to Eurasia in the early Miocene and their biogeographic diversification within Eurasia.

    PubMed

    Tu, Tieyao; Volis, Sergei; Dillon, Michael O; Sun, Hang; Wen, Jun

    2010-12-01

    The cosmopolitan Solanaceae contains 21 tribes and has the greatest diversity in South America. Hyoscyameae and Mandragoreae are the only tribes of this family distributed exclusively in Eurasia with two centers of diversity: the Mediterranean-Turanian (MT) region and the Tibetan Plateau (TP). In this study, we examined the origins and biogeographical diversifications of the two tribes based on the phylogenetic framework and chronogram inferred from a combined data set of six plastid DNA regions (the atpB gene, the ndhF gene, the rps16-trnK intergenic spacer, the rbcL gene, the trnC-psbM region and the psbA-trnH intergenic spacer) with two fossil calibration points. Our data suggest that Hyoscyameae and Mandragoreae each forms a monophyletic group independently derived from different New World lineages in the early Miocene. Phylogenetic relationships within both tribes are generally well resolved. All genera of Hyoscyameae are found to be monophyletic and they diversified in middle to late Miocene. At nearly the same time, Mandragoreae split into two clades, corresponding to the MT region and the TP region, respectively. Both the phylogenetic relationships and the estimated ages of Hyoscyameae and Mandragoreae support two independent dispersal events of their ancestors from the New World into Eurasia. After their arrivals in Eurasia, the two tribes diversified primarily in the MT region and in the TP region via multiple biogeographic processes including vicariance, dispersal, recolonization or being preserved as relicts, from the mid Miocene to the late Quaternary.

  18. Hawthorn (Crataegus oxyacantha L.) bark extract regulates antioxidant response element (ARE)-mediated enzyme expression via Nrf2 pathway activation in normal hepatocyte cell line.

    PubMed

    Krajka-Kuźniak, Violetta; Paluszczak, Jarosław; Oszmiański, Jan; Baer-Dubowska, Wanda

    2014-04-01

    Hawthorn (Crataegus oxyacantha L.), a plant used in traditional medicine, is a rich source of procyanidins which have been reported to exhibit antioxidant and anti-carcinogenic activity. In this study, we assessed the effect of hawthorn bark extract (HBE) on Nrf2 pathway activation in THLE-2 and HepG2 cells. Treatment with 1.1 µg/mL, 5.5 µg/mL and 11 µg/mL of HBE resulted in the translocation of Nrf2 from the cytosol to the nucleus in both cell lines; however, the accumulation of phosphorylated Nrf2 was observed only in THLE-2. Accordingly, treatment of cells with HBE was associated with an increase in the mRNA and protein level of such Nrf2-dependent genes as glutathione S-transferases (GSTA, GSTP, GSTM, GSTT), NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) (0.2-1.1-fold change, p < 0.05), however, only in normal THLE-2 hepatocytes. The induction of NQO1 correlated with an increased level of p53 (0.21-0.42-fold change, p < 0.05). These effects may be related to induction of phosphorylation of upstream ERK and JNK kinases. Collectively, the results suggest that the Nrf2/ARE pathway may play an important role in the regulation of procyanidin-mediated antioxidant/detoxifying effects in hepatocytes, and this may explain the hepatoprotective and chemopreventive properties of these phytochemicals.

  19. Late Miocene ignimbrites at the southern Puna-northern Sierras Pampeanas border (˜27°S): Stratigraphic correlation

    NASA Astrophysics Data System (ADS)

    Montero-López, Carolina; Guzmán, Silvina; Barrios, Fabiola

    2015-10-01

    New field observations and petrographic and geochemical data of pyroclastic deposits exposed along the Las Papas valley (border between southern Puna and northern Sierras Pampeanas, Argentina) and further north, lead us to propose a new stratigraphic correlation and classification of the late Miocene volcanism in this area. We redefine the Las Papas, Las Juntas, Aguada Alumbrera and Rosada ignimbrites and define the Agua Caliente and Del Medio ignimbrites. The whole set of ignimbrites are rhyolites and less frequently dacites of calc-alkaline affinity. In the present contribution we divide ignimbrites into the Agua Negra and Rincón groups, based mainly on their geochemical signature. The Agua Negra Group is formed by the Las Papas and Las Juntas ignimbrites, indurated and welded, lithic-rich, with crystal-poor pumices and crystal-rich matrix. The Rincón Group comprises the Agua Caliente, Aguada Alumbrera, Rosada and Del Medio ignimbrites, with variable welding degrees, lithic and crystal content. The greater enrichment of crystals in the matrix in comparison with the crystal content in pumices indicates significant elutriation during flow transport and thus volume estimations are to be considered lower bounds for the actual erupted volume. The total minimum estimated volume for the ignimbrites of the Agua Negra and Rincón groups is 2.8 km3 (2.3 km3 DRE). Field relationships and new analytical data indicate that the different acid ignimbrites that crop out in this small area are related to at least two different magma chambers. The widespread Quaternary volcanism in this area covers the older deposits, thus making it difficult to recognize the volcanic centers that produced these late Miocene ignimbrites.

  20. Oligo-Miocene foraminiferal record (Miogypsinidae, Lepidocyclinidae and Nummulitidae) from the Western Taurides (SW Turkey): Biometry and implications for the regional geology

    NASA Astrophysics Data System (ADS)

    Özcan, Ercan; Less, György; Báldi-Beke, Mária; Kollányi, Katalin; Acar, Ferhat

    2009-05-01

    The marine Oligo-Miocene units of western Taurides, deposited under different tectonic regimes (in Bey Dağları platform in foreland and coeval sequences in hinterland), were studied to establish a high-resolution biostratigraphic framework. Biometric study of the full spectrum of larger foraminifera in a regional scale allowed us correlating them with the shallow benthic zonation (SBZ) system introduced by [Cahuzac, B., Poignant, A., 1997. Essai de biozonation de l'Oligo-Miocène dans les bassins européens à l'aide des grands foraminifères néritiques. Bulletin de la Société géologique de France 168, 155-169], and to determine the ages of these sites on zonal precision for the first time. In correlating these assemblages to standard shallow benthic zones, planktonic data were also used whenever possible. Taxa, classified under the genera Nummulites, Miogypsina, Miolepidocyclina, Nephrolepidina, Eulepidina, Heterostegina, Operculina and Cycloclypeus (?) and their assemblages, closely resemble to the fauna described from European basins. These groups characterize the SBZ 22B to 25 zones referring to a time interval from early Chattian to Burdigalian. However, a main gap in late Chattian (SBZ 23) and in early part of the Aquitanian (SBZ 24) is also recorded in the platform succession. In the meantime, rare Eulepidina in the Burdigalian levels suggest a clear Indo-Pacific influence. Based on the discovery of early Chattian (SBZ 22B) deposits (previously mapped under Eocene/Miocene units), the Oligo-Miocene stratigraphy of the Bey Dağları platform is also revised. A more precise chronology for regional Miocene transgression is presented based on the miogypsinid evolutionary scale.

  1. A new species of Metopocetus (Cetacea, Mysticeti, Cetotheriidae) from the Late Miocene of the Netherlands.

    PubMed

    Marx, Felix Georg; Bosselaers, Mark E J; Louwye, Stephen

    2016-01-01

    The family Cetotheriidae has played a major role in recent discussions of baleen whale phylogenetics. Within this group, the enigmatic, monotypic Metopocetus durinasus has been interpreted as transitional between herpetocetines and other members of the family, but so far has been restricted to a single, fragmentary cranium of uncertain provenance and age. Here, we expand the genus and shed new light on its phylogenetic affinities and functional morphology by describing Metopocetus hunteri sp. nov. from the Late Miocene of the Netherlands. Unlike the holotype of M. durinasus, the material described here is confidently dated and preserves both the tympanic bulla and additional details of the basicranium. M. hunteri closely resembles M. durinasus, differing primarily in its somewhat less distally expanded compound posterior process of the tympanoperiotic. Both species are characterised by the development of an unusually large fossa on the ventral surface of the paroccipital process, which extends anteriorly on to the compound posterior process and completely floors the facial sulcus. In life, this enlarged fossa may have housed the posterior sinus and/or the articulation of the stylohyal. Like other cetotheriids, Metopocetus also bears a well-developed, posteriorly-pointing dorsal infraorbital foramen near the base of the ascending process of the maxilla, the precise function of which remains unclear.

  2. An overview of lithotype associations of Miocene lignite seams exploited in Poland

    NASA Astrophysics Data System (ADS)

    Widera, Marek

    2016-09-01

    Currently, three stratigraphically distinct lignite seams of Early to Middle Miocene age are exploited in Poland, namely the third Ścinawa lignite seam (ŚLS-3), the second Lusatian lignite seam (LLS-2) and the first Mid-Polish lignite seam (MPLS-1). All of these are composed of numerous macroscopically distinguishable layers defined as lignite lithotypes. In the present paper, the lithotypes of Polish lignites are grouped into seven major lithotype associations that originated in various types of mire. Therefore, an approximate reconstruction of mire type can be based on lignite lithotypes. Within the Polish lignite seams examined, the commonest in order of importance are: xylodetritic (XDL), detroxylitic (DXL), detritic (DL) and xylitic (XL) lithotype associations, mostly with a massive (m) or horizontal (h) structure. They are particularly dominant in lignite opencasts belonging to the Konin and Adamów mines. However, in the lowermost seams at the Turów and Bełchatów mines, a substantial part of the seams comprises the bitumen-rich (BL) lithotype association. These seams also lignite lithotypes that in large quantities have a gelified (g) and/or nodular (n) structure. In contrast, lignites from the Sieniawa mine are characterised by an admixture of the best-developed lithotype associations of both fusitic (FL) and weathered (WL) lignites. Moreover, the vast majority of these lignites have a folded (fo) and/or faulted (fa) structure, because they were completely deformed by glaciotectonics.

  3. Miocene dispersal drives island radiations in the palm tribe Trachycarpeae (Arecaceae).

    PubMed

    Bacon, Christine D; Baker, William J; Simmons, Mark P

    2012-05-01

    The study of three island groups of the palm tribe Trachycarpeae (Arecaceae/Palmae) permits both the analysis of each independent radiation and comparisons across the tribe to address general processes that drive island diversification. Phylogenetic relationships of Trachycarpeae were inferred from three plastid and three low-copy nuclear genes. The incongruent topological position of Brahea in CISP5 was hypothesized to be caused by a gene duplication event and was addressed using uninode coding. The resulting phylogenetic trees were well-resolved and the genera were all highly supported except for Johannesteijsmannia and Serenoa. Divergence time analysis estimated the stem of the tribe to be approximately 86 Ma and the crown to be 38 Ma, indicating that significant extinction may have occurred along this branch. Historical biogeographic analysis suggested that Trachycarpeae are of southern North American, Central American, or Caribbean origin and supports previous hypotheses of a Laurasian origin. The biogeography and disjunctions within the tribe were interpreted with respect to divergence times, the fossil record, and geological factors such as the formation of the Greater Antilles--Aves Ridge, the Bering and the North Atlantic land bridges, tectonic movement in Southeast Asia, climatic shifts between the Eocene and Pliocene, and volcanism in the Pacific basin. In considering the three major island radiations within Trachycarpeae, Miocene dispersal appears to have been the driving force in allopatric speciation and is highlighted here as an emerging pattern across the tree of life.

  4. A new species of Metopocetus (Cetacea, Mysticeti, Cetotheriidae) from the Late Miocene of the Netherlands

    PubMed Central

    Bosselaers, Mark E.J.; Louwye, Stephen

    2016-01-01

    The family Cetotheriidae has played a major role in recent discussions of baleen whale phylogenetics. Within this group, the enigmatic, monotypic Metopocetus durinasus has been interpreted as transitional between herpetocetines and other members of the family, but so far has been restricted to a single, fragmentary cranium of uncertain provenance and age. Here, we expand the genus and shed new light on its phylogenetic affinities and functional morphology by describing Metopocetus hunteri sp. nov. from the Late Miocene of the Netherlands. Unlike the holotype of M. durinasus, the material described here is confidently dated and preserves both the tympanic bulla and additional details of the basicranium. M. hunteri closely resembles M. durinasus, differing primarily in its somewhat less distally expanded compound posterior process of the tympanoperiotic. Both species are characterised by the development of an unusually large fossa on the ventral surface of the paroccipital process, which extends anteriorly on to the compound posterior process and completely floors the facial sulcus. In life, this enlarged fossa may have housed the posterior sinus and/or the articulation of the stylohyal. Like other cetotheriids, Metopocetus also bears a well-developed, posteriorly-pointing dorsal infraorbital foramen near the base of the ascending process of the maxilla, the precise function of which remains unclear. PMID:26835183

  5. Studies in Neotropical paleobotany. XIII. An Oligo-Miocene palynoflora from Simojovel (Chiapas, Mexico).

    PubMed

    Graham, A

    1999-01-01

    A plant microfossil assemblage of 24 identified and five unknown pollen and spore types is reported from the early Miocene La Quinta Formation near Simojovel, Chiapas, Mexico. The taxa group into seven paleocommunities representing versions of the modern mangroves (Pelliciera, Rhizophora), swamp and lowland riparian forest (Ceratopteris, Crudia, Pachira), tropical rain forest (Selaginella, cf. Antrophyum, Pteris, Sphaeropteris/Trichipteris, cf. Aguiaria, Crudia, Guarea, Pachira), lower montane rain forest (Alfaroa/Oreomunnea, possibly Eugenia), evergreen cloud forest [Picea, Pinus, Podocarpus, Ericaceae (possibly Cavendishia/Vaccinium)], evergreen seasonal forest (Hymenaea, Ilex, possibly Eugenia), and tropical deciduous forest (Cedrela). Elements of arid and high-elevation habitats were absent or few, and northern temperate elements (Picea, Pinus?) were few or rare. Paleoelevations are estimated at 1000-1200 m (present average 2000 m, maximum 3004 m), MAT (mean annual temperature) at least as warm as the present 24°C, and annual rainfall near the present ∼2500 mm but more evenly distributed. The La Quinta (Simojovel) and other Tertiary floras from the region reflect a trend toward higher altitudes, more seasonal rainfall, cooling tempertures, increased introduction of cool-temperate elements from the north after ∼15 Ma (million years), and increased introduction of tropical elements from the south after completion of the isthmian land bridge ∼3.5 Ma ago.

  6. Tectono-sedimentary constraints to the Oligocene-to-Miocene evolution of the Peloritani thrust belt (NE Sicily)

    NASA Astrophysics Data System (ADS)

    Giunta, G.; Nigro, F.

    1999-12-01

    The Peloritani thrust belt belongs to the southern sector of the Calabrian Arc and is formed by a set of south-verging tectonic units, including crystalline basement and sedimentary cover (from the top: Aspromonte U.; Mela U.; Mandanici U.; Fondachelli U.; Longi-Taormina U.), piled up starting from Late Oligocene. At least two main terrigenous clastic formations lie with complicated relationships on top of the previous units: the Frazzanò Fm (Oligocene) and the Stilo-Capo d'Orlando Fm (Late Oligocene?-Early Miocene), as syn-to-post-tectonic deposits. These clastic deposits have different characteristics, in space and time, representing or flysch-like sequences involved in several thrust events (Frazzanò Fm) or molassic-like sequences (Stilo-Capo d'Orlando Fm), which unconformably overlie the tectonic units. In the present paper we describe a kinematic model of the progressive foreland migration of the Peloritani thrust belt, starting from Oligocene, carrying piggy-back basins and incorporating foredeep deposits, recognised in the Frazzanò-Stilo-Capo d'Orlando terrigenous successions. In general, the facies and structural observations on the overall Oligo-Miocene clastic sequences, outcropping in the Western Peloritani Mts, indicate: (a) the distal character of the Frazzanò Fm; (b) a complex group of terrigenous facies of the Stilo-Capo d'Orlando Fm, with lateral-to-vertical organisation, characterised by a distal-to-proximal-to-distal facies trend; (c) facies analogies of the basal portions of the Stilo-Capo d'Orlando Fm with the Frazzanò Fm; (d) the involvement of the Frazzanò Fm in lowermost and more external thrusting, and of the basal (Late Oligocene?) distal Stilo-Capo d'Orlando facies in the higher and inner thrusting during the early stages of deformation; (e) the involvement of the proximal Stilo-Capo d'Orlando facies in the tectonic edifice during the Early Miocene deformation; (f) the generally unconformable stratigraphical contacts of the higher

  7. New insights to the middle Miocene pCO2 problem (Invited)

    NASA Astrophysics Data System (ADS)

    Badger, M. P.; Foster, G. L.; Lear, C. H.; Pancost, R. D.; Bailey, T. R.; Leng, M. J.; Abels, H. A.

    2013-12-01

    The climate of the middle Miocene was substantially different to today with a much warmer world with boundary conditions (plate configurations, ocean circulation etc) that were very different to the present. The sustained warmth of the 'Middle Miocene Climate Optimum' prevailed prior to the second step of the descent into the ice-house - with the major expansion of Antarctic ice sheet and global cooling at the middle Miocene Climate Transition. Coincident with these major changes in global temperatures and the cryosphere were substantial perturbations of the carbon cycle, as documented by the large fluctuations in oceanic carbonate δ13C values during the 'Monterey Excursion' as well as the various 'CM' events superimposed upon it. Critical to our understanding of Miocene climate and carbon cycle dynamics is a full understanding of atmospheric pCO2 during this fascinating time. A number of Miocene atmospheric pCO2 estimates are now available (Kürschner, Kvaček and Dilcher, 2008; Foster, Lear and Rae, 2012; Badger et al., 2013) that help to better understand this relationship but differences between these new records and older published records (ie Pagani et al., 1999; Pearson and Palmer, 2000) raise interesting questions as to the drivers of Miocene climate and carbon cycling. Here we will discuss the implications of our records for the Monterey Excursion and the CM events, as well as presenting a novel probabilistic re-assessment of new and existing atmospheric pCO2 records. The combination of a larger dataset and more quantitative approach allows us to answer some of the outstanding questions about the operation of the Miocene climate system, and help to explain the apparent disparity between atmospheric pCO2 records and proxy temperature estimates.

  8. Middle Miocene Hominoids dispersion and radiation: impact of climate and vegetation changes in Europe

    NASA Astrophysics Data System (ADS)

    Hamon, N.; Sepulchre, P.; Contoux, C.; Jaeger, J.-J.; Ramstein, G.

    2012-04-01

    The middle Miocene is a time of important climatic changes, and a crucial period for ape's evolution. The Middle Miocene Climatic Optimum (MMCO), that occurred approximately 17 to 15 Ma, was one of the last global warming event of the Cenozoic. This period also corresponds to the first dispersion of apes from Africa to Europe, which was made possible by tectonic and environmental changes, in particular the expansion of hominoids habitat: (sub-)tropical forest. Following the MMCO, an abrupt global cooling occurred that coincides with an important radiation of European hominoids. The most common view is that the widening of hominoids habitat during the MMCO was the main factor of their dispersion from Africa to Europe. Moreover, the major climatic change that followed induced an opening of the environment because of cooler and dryer conditions, which should have lead to a fragmentation of hominoids' habitat. This imply that hominoids evolved separately in refuges during the end of the Miocene, so the radiation observed in the fossil record of European Miocene apes is interpreted as a divergent evolution in a fragmented habitat. However, no study has yet demonstrated this evolutionary scenario. Our aim is to study the environmental changes during the middle Miocene, in particular climate and vegetation changes, and to link them with these two major events of hominoids' evolution. Using climate and vegetation models, we investigate the role of environmental variation in hominoids' evolution during the middle Miocene, in particular between 17 and 14 Ma. We perform two climatic experiments (16Ma and 14Ma) with the atmospheric general circulation model LMDZ. The results of these experiments will then be used to force the dynamic vegetation model CARAIB. This should help us to simulate hominoids' habitat for the two time period chosen, and to discuss the role of important climate change for Miocene apes evolution.

  9. Miocene Coral Skeleton Rare Earth Element Patterns Reflect River Discharge

    NASA Astrophysics Data System (ADS)

    Mertz-Kraus, R.; Brachert, T. C.; Jochum, K. P.

    2010-12-01

    Rare Earth Element (REE) patterns of modern coral skeletons usually reflect the REE composition of ambient seawater which is characterized by heavy REE enriched relative to light REE with NASC (North American Shale Composite) normalized La/Lu ratios of typically <0.4. The REE concentration in coral aragonite is enriched by 3 to 4 orders of magnitude compared to ambient seawater. Here we report trace element data including REE of coral skeletons of Late Miocene age (~9 Ma, Tortonian) from Crete (Eastern Mediterranean). Analyses were done using a 213 nm Nd:YAG laser coupled to an Element2 ICP-MS along the growth axis of the coral skeletons. The profiles show that Ba/Ca ratios have a seasonally induced pattern with high values around the winter months which are identified by δ18O analyses. REE/Ca ratios co-vary with Ba/Ca ratios. Since the Ba/Ca ratio is a proxy used to monitor river discharge, the co-variation suggests the REE/Ca ratio to be a proxy of comparable quality. NASC-normalized REE patterns of the Tortonian corals have negative Ce anomalies like modern corals. However, the Tortonian corals have REE patterns highly enriched in LREE with (La/Lu)N ratios of 4 to 30 which is 1 to 2 orders of magnitude higher compared to modern corals. Al concentrations are low (<10 ppm) and do not correlate with REE concentrations indicating an insignificant fraction of terrigenous material included in the skeleton. Applying distribution coefficients typical for modern corals, the REE composition of the Tortonian ambient water yields (La/Lu)N of about 2 to 16. This range can be explained by binary mixing of modern Eastern Mediterranean sea surface water ((La/Lu)N=0.35, sea surface salinity (SSS) ~38 ‰) with highly LREE-enriched river water ((La/Lu)N >3, salinity ~0.5 ‰) transporting suspended and colloid phases, also highly enriched, especially in LREE, at a ratio of ~9 (seawater):1 (river water). The river water component is considered because paleoenvironmental

  10. Late Miocene “washhouse” climate in Europe

    NASA Astrophysics Data System (ADS)

    Böhme, Madelaine; Ilg, August; Winklhofer, Michael

    2008-11-01

    We present two eight-million year long proxy records of precipitation for Southwest and Central Europe, covering the middle to late Miocene (5.3-13 Ma) at a temporal resolution of about 60 kyr and 150 kyr, respectively. The estimates of precipitation are based on the ecophysiological structure of herpetological assemblages (amphibians and reptiles). From 13.0 Ma until about 9 Ma, both records show a similar trend, evolving from a long dry period (13-11 Ma) into a "washhouse climate" (10.2-9.8 Ma), characterized by global warm conditions and several times more precipitation than present. The transition from washhouse to a dryer climate between 9.7 and 9.5 Ma and the concomitant cooling episode appear to have triggered a severe biotic event known as the Vallesian crisis, which included the extinction of hominoids in Western Europe. A second washhouse period (9.0-8.5 Ma), coeval with a global warm episode, was unprecedentedly intense in Southwest Europe, but less pronounced in Central Europe. From 8 Ma onward, a divergence in the two precipitation records is observed, with Southwest Europe staying wetter and Central Europe becoming dryer than present. Both precipitation records are combined into a common run-off curve as a measure of the relative intensity of the hydrological cycle for moderate latitudes of continental Europe. The run-off curve shows a remarkable positive correlation with Atlantic deep-water temperatures from Ceará Rise by Lear et al. (2003), which are significantly higher (up to + 3 °C) during the two washhouse periods and show no other positive excursion of comparable magnitude. We discuss potential links and the role of the coeval temporary restriction of the Central American Seaway on ocean and atmosphere circulation.

  11. Seismic reflection profiling around the hypocentral area of the 2003 Miyagi-ken Hokubu earthquake (Mj6.4): Reactivated thrust faulting of a Miocene normal fault.

    NASA Astrophysics Data System (ADS)

    Yokokura, T.; Yamaguchi, K.; Kano, N.; Yokota, T.; Tanaka, A.; Ohtaki, T.

    2004-12-01

    The 2003 Miyagi-ken Hokubu (northern Miyagi) earthquake occurred on July 26, which was preceded by the largest foreshock of Mj5.6 and was followed by the largest aftershock of Mj5.5. Although these earthquakes were not so large in magnitude, they caused large damages. The earthquakes occurred just beneath the Asahiyama hills, where exist the active Asahiyama flexure. Aftershock observations delineate a clear fault plane that extends toward the Sue hills in the east, not toward the Asahiyama hills. However neither surface ruptures nor active fault assocciated with the earthquakes were observed in this region. To clarify both the surface extension of the fault and geologic structure of this region, we conducted 17km-long seismic reflection profiling, using a 17.5-ton vibrator. Geologically, this region was subjected rapid EW extension in middle Miocene and thus produced rift basin was filled by the Matsushima-wan Group (syn-rift sediments) which was bounded by a normal fault, the Ishinomaki-wan fault, in the eastern side of the basin. The Matsushima-wan Group was unconformably overlain by the Shida Group (Miocene post-rift sediments). The Shida Group was unconformably overlain by the Pliocene and post-Pliocene sediments. Deformed Pliocene strata show thrust faulting, indicating EW compression after early Pliocene. Detailed data processing reveals that the seismic profile is essentially concordant with the structure inferred from surface geology. A west-dipping fault with about 50 degrees is found beneath the southeastern extension of the Sue hills where the Ishinomaki-wan fault was supposed to extend. The deeper part of the fault extends toward the earthquake fault plane determined by aftershocks and the shallower part shows a thrust-like structure, which indicate basin inversion using this fault. Thus the 2003 Miyagi-ken Hokubu earthquake occurred as reactivated thrust faulting of the Miocene normal fault bounding the eastern side of the rift basin.

  12. Provenance of the lower Miocene of the Gulf of Mexico from detrital zircon double dating

    NASA Astrophysics Data System (ADS)

    xu, J.

    2013-12-01

    The lower Miocene interval of the Gulf of Mexico (GOM) has recently gained increasing attention from oil and gas industry due to its hydrocarbon potential below the salt canopy. However, it has been less well studied than both the underlying Oligocene and overlying middle Miocene strata. The lower Miocene worldwide is a transitional period of tectonic, climatic, and oceanographic change. In particular, it is a period of major tectonic reorganization in the western interior of North America (Rocky Mountains), involving a shift from the Oligocene thermal phase, with abundant volcanic activity recorded in the thick Frio/Vicksburg succession of the GOM, to the Miocene Basin-Range extensional phase. Climatic conditions also changed from a relatively arid Oligocene to wetter Miocene, resulting in increased sediment yields from exhumed tectonic structures. Previous provenance studies used proportions of quartz, feldspar and lithic fragments and consideration of likely river courses through known paleogeomorphological elements. Only limited detrital zircon (DZ) U-Pb studies on Paleocene strata have been undertaken and there has been no previous U-Pb and (U-Th)/He double dating in the GOM. In this study we apply the latest analytical approaches, such as DZ U-Pb dating to gain robust source terranes ages and more fully elucidate the complex sediment provenance and dispersal history of GOM. We also employ DZ (U-Th)/He (ZHe) dating, combined with DZ U-Pb, to not only define sedimentary provenance but also the exhumation histories of detrital source regions. Samples of lower Miocene outcrop exposures in Texas and Louisiana have been collected to discriminate the varied tectonic and drainage system changes across the basin in lateral. In addition, samples from the Eocene, Oligocene and middle Miocene have been obtained to reveal vertical shift of source terranes contributions. Our initial age data show detrital zircons of lower Miocene sediments come from a wide range of source

  13. The late Miocene 'paradox' of the CO2 climate sensitivity (Invited)

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Pagani, M.

    2013-12-01

    Ancient climates provide opportunities for studying the impact of CO2 change on global temperatures. While advances in CO2-reconstruction techniques are yielding a clearer picture of the Cenozoic history of CO2 (Beerling and Royer, 2011), the late Miocene (~12-5 Ma) remains enigmatic. For example, recent sea-surface temperature reconstructions from 12-5 Ma have shown that mid-latitude and equatorial regions of the Pacific cooled 6°C (LaRiviere et al., 2012) and 2°C (Zhang et al., 2013), respectively. This cooling trend was probably initiated at the mid-Miocene climate transition (14 Ma), and continued into the Plio-Pleistocene. However, existing compilation of late Miocene - Pliocene CO2 records show little variability, with some indicating a rise in CO2 concurrent with global cooling. Here we present four continuous alkenone-based CO2 records using Pacific sediment samples (ODP Sites 769, 806, 850 and 1143), from late Miocene to Pliocene. Compound-specific carbon isotope measurements show a broad decrease in alkenone δ13C values in all four sites, suggesting increasing pCO2 levels in the late Miocene. Decreasing ocean temperature and increasing pCO2 in the late Miocene appears to challenge a leading climatic role for CO2 during this time. Alternatively, alkenone-CO2 estimates are flawed in the late Miocene because factors other than CO2, such as algal growth rate, cell geometry, and carbon-fixation pathways, can influence carbon isotopic fractionation during algae growth. We explore the uncertainty of the alkenone-CO2 methodology and assess the potential influence that non-CO2 variables have in producing spurious CO2 estimates and trends. Beerling, D.J., Royer, D.L., 2011. Convergent Cenozoic CO2 history. Nat. Geosci. 4, 418-420. LaRiviere, J.P., Ravelo, A.C., Crimmins, A., Dekens, P.S., Ford, H.L., Lyle, M., Wara, M.W., 2012. Late Miocene decoupling of oceanic warmth and atmospheric carbon dioxide forcing. Nature 486, 97-100. Zhang, Y.G., Pagani, M., Liu, Z

  14. Miocene-Pliocene transition in the southern Cyprus basins: The sedimentary expression of regional tectonic events

    SciTech Connect

    Orzag-Sperber, F.; Rouchy, J.M. )

    1988-08-01

    In the southern part of Cyprus, a Maastrichtian-Pleistocene sedimentary area fringes Troodos Mountain, a fragment of an ancient crust. During the Neogene, three basins formed in this area: Polemi, Pissouri, and Psematismenos. A deep marine condition has prevailed since the Maastrichtian. During the Paleocene and early Miocene, the sea gradually become shallower until the Messinian, where the most spectacular sedimentary event concerns the deposition of evaporites contemporaneous with other Mediterranean evaporites. Some sedimentary phenomena express the tectonic instability during the upper Miocene. A well-known tectonic event affecting the east Mediterranean region generally referred to as the Miocene-Pliocene phase occurs at the Miocene-Pliocene limit. Recent sedimentological studies indicate this event is in fact complex. The Tortonian-lower Pliocene period is marked by a constraint involving an N20 distension in the Polemi and Pissouri basins and an N100 distension in the Psematismenos basin. Sedimentologic studies have demonstrated three tectonic pulsations during the Messinian prior to the Pliocene transgression. These are expressed by two episodes of seismic brecciation and a paleoemersion indicated by paleosols and detrital discharges. These phenomena suggest brief tectonic instability during the Messinian. Microtectonic studies reveal that the main change in tectonic constraint does not coincide with the Miocene-Pliocene contact but occurs at the top of the lower Pliocene.

  15. Organic geochemical evaluations of bituminous rock and coals in Miocene Himmetoglu basin (Bolu, Turkey)

    SciTech Connect

    Sari, A.; Geze, Y.

    2008-07-01

    The studied area is a lake basin located in Bolu basin in Turkey. In the basin, from Upper Cretaceous to Upper Miocene 3,000-m thickness sediments were deposited. Upper Miocene Himmetoglu formation consisted of sandstone, claystone, and marl. To the middle level of the formation are located coal, bituminous limestone, and bituminous shales. In the basin, there are two coal beds whose thicknesses range from 1 to 13 m. The coals are easily breakable and black in color. In the coal beds exists some bituminous limestone and bituminous shales, and their thicknesses are between 5 and 45 cm. The amount of organic matter of the bituminous rocks from the Upper Miocene Himmetoglu formation are between 6.83 and 56.34 wt%, and the amount of organic matter of the bituminous limestone from the formation are between 13.58 and 57.16 wt%. These values indicate that these rocks have very good source potential. According to hydrogen index (HI), S2/S3, HI-T{sub max}, and HI-OI (oxygen index) parameters, kerogen types of the bituminous rocks and coals belonging to Upper Miocene Himmetoglu formation are Type I, Type II, and Type III. In accordance with HI, S2/S3, HI-T{sub max}, and HI-OI parameters, the bituminous rocks and coals from the Upper Miocene Himmetoglu formation are mostly immature.

  16. Distribution history and climatic controls of the Late Miocene Pikermian chronofauna.

    PubMed

    Eronen, Jussi T; Ataabadi, Majid Mirzaie; Micheels, Arne; Karme, Aleksis; Bernor, Raymond L; Fortelius, Mikael

    2009-07-21

    The Late Miocene development of faunas and environments in western Eurasia is well known, but the climatic and environmental processes that controlled its details are incompletely understood. Here we map the rise and fall of the classic Pikermian fossil mammal chronofauna between 12 and 4.2 Ma, using genus-level faunal similarity between localities. To directly relate land mammal community evolution to environmental change, we use the hypsodonty paleoprecipitation proxy and paleoclimate modeling. The geographic distribution of faunal similarity and paleoprecipitation in successive timeslices shows the development of the open biome that favored the evolution and spread of the open-habitat adapted large mammal lineages. In the climate model run, this corresponds to a decrease in precipitation over its core area south of the Paratethys Sea. The process began in the latest Middle Miocene and climaxed in the medial Late Miocene, about 7-8 million years ago. The geographic range of the Pikermian chronofauna contracted in the latest Miocene, a time of increasing summer drought and regional differentiation of habitats in Eastern Europe and Southwestern Asia. Its demise at the Miocene-Pliocene boundary coincides with an environmental reversal toward increased humidity and forestation, changes inevitably detrimental to open-adapted, wide-ranging large mammals.

  17. Miocene fluvial-tidal sedimentation in a residual forearc basin of the Northeastern Pacific Rim: Cook Inlet, Alaska case study

    SciTech Connect

    Stricker, G.D.; Flores, R.M. )

    1996-01-01

    Cook Inlet in southern Alaska represents a Cenozoic residual forearc basin in a convergent continental margin, where the Pacific Plate is being subducted beneath the North American Plate. This basin accumulated the >6,700-m-thick, mainly nonmarine, Eocene-Pliocene Kenai Group. These rocks contain biogenic coal-bed methane estimated to be as high as 245 TCF. Lignites to subbituminous coals with subsurface R[sub o] ranging from 0.38 to 0.73 percent and the stage of clay-mineral diagenesis and expandibility indicate a thermally [open quotes]cool[close quotes] basin. Miocene Tyonek and Beluga Formations compose 65 percent (>4,300 m thick) of the Kenai Group. The Tyonek includes conglomeratic sandstones, siltstones, mudstones, coals, and carbonaceous shales, interpreted as braided- stream deposits. These fluvial deposits are interbecided with burrowed, lenticular, and flaser-bedded sandstones, siltstones, and mudstones, interpreted as tidal deposits. Tyonek framework conglomerates formed in wet alluvial fans incised on paleovalleys of the Chugach terrane. Coal-forming mires are well developed on abandoned braided-stream deposits. Tyonek drainages formed in high-gradient alluvial plains inundated by tides similar to environments in the modern upper Cook Inlet. The upper Miocene Beluga consists of sandstones, siltstones, mudstones, carbonaceous shales, and coals deposited in meandering (low sinuosity) and anastomosed fluvial systems. These fluvial deposits alternated vertically with deposits of coal-forming mires. The Beluga drainages formed in low-gradient alluvial plains. The high-gradient Tyonek alluvial plain was probably controlled by provenance uplift and eustatic change, whereas the low-gradient Beluga alluvial plain was influenced by subdued provenance uplift and rapid basin subsidence. Rapid sedimentation on both these low- and high-gradient alluvial plains, which kept up with subsidence, produced a thermally [open quotes]cool[close quotes] basin.

  18. Miocene fluvial-tidal sedimentation in a residual forearc basin of the Northeastern Pacific Rim: Cook Inlet, Alaska case study

    SciTech Connect

    Stricker, G.D.; Flores, R.M.

    1996-12-31

    Cook Inlet in southern Alaska represents a Cenozoic residual forearc basin in a convergent continental margin, where the Pacific Plate is being subducted beneath the North American Plate. This basin accumulated the >6,700-m-thick, mainly nonmarine, Eocene-Pliocene Kenai Group. These rocks contain biogenic coal-bed methane estimated to be as high as 245 TCF. Lignites to subbituminous coals with subsurface R{sub o} ranging from 0.38 to 0.73 percent and the stage of clay-mineral diagenesis and expandibility indicate a thermally {open_quotes}cool{close_quotes} basin. Miocene Tyonek and Beluga Formations compose 65 percent (>4,300 m thick) of the Kenai Group. The Tyonek includes conglomeratic sandstones, siltstones, mudstones, coals, and carbonaceous shales, interpreted as braided- stream deposits. These fluvial deposits are interbecided with burrowed, lenticular, and flaser-bedded sandstones, siltstones, and mudstones, interpreted as tidal deposits. Tyonek framework conglomerates formed in wet alluvial fans incised on paleovalleys of the Chugach terrane. Coal-forming mires are well developed on abandoned braided-stream deposits. Tyonek drainages formed in high-gradient alluvial plains inundated by tides similar to environments in the modern upper Cook Inlet. The upper Miocene Beluga consists of sandstones, siltstones, mudstones, carbonaceous shales, and coals deposited in meandering (low sinuosity) and anastomosed fluvial systems. These fluvial deposits alternated vertically with deposits of coal-forming mires. The Beluga drainages formed in low-gradient alluvial plains. The high-gradient Tyonek alluvial plain was probably controlled by provenance uplift and eustatic change, whereas the low-gradient Beluga alluvial plain was influenced by subdued provenance uplift and rapid basin subsidence. Rapid sedimentation on both these low- and high-gradient alluvial plains, which kept up with subsidence, produced a thermally {open_quotes}cool{close_quotes} basin.

  19. Hidden oil leg: Case study of lower D1 Miocene sandstone, Dulang field, offshore Peninsular Malaysia

    SciTech Connect

    Solomon, G.J.; Chandramohan, S.; Karra, S.; Sonrexa, K.

    1995-10-01

    The Dulang Field is located offshore east coast of Peninsular Malaysia in water depths of approximately 75 m. The field, discovered in 1981, is about 24 km by 3.5 km. After drilling 14 exploration/appraisal wells by both Carigali and its partner Esso Production Malaysia Inc., the central part of the field was developed as a unitized area in November 1990. Three 32-slot platforms have been installed in the unitized area, and development drilling is ongoing. Production commenced in March 1991 and is currently maintained at approximately 50,000 BOPD. The estimated OIIP (oil-initially-in-place) for the unitized area is in the order of 700 million barrels. There are 19 reservoir sands in Groups D and E which are of Middle-Late Miocene age. During the exploration/appraisal phase, oil and gas were encountered in the Group E and only gas in the Lower D1 reservoirs. Wireline formation pressure test data taken in the Lower D1 reservoir in these wells plotted along a common trend with a gradient of 0.06 psi/ft. The lowermost gas pressure point was only 6 m above the normal hydrostatic gradient. It was therefore concluded that an oil column, even if present, would be thin. At the time, it was understandable that the gas pressures plotted along the same trend because the hydrocarbon column of the Lower D1 reservoir was large and extended beyond the limits of the major faults, suggesting a common pool. However, during the development drilling phase, it was discovered that the Lower D1 sandstone was a major oil reservoir, with estimated oil-in-place of about 100 million barrels. Oil columns of 75 m and 40 m have been proven up in the northern and southern flanks of the field, respectively, in the Lower D1. In addition, development plans were flexible enough to be able to effectively exploit the discovery.

  20. A Miocene basanite peperitic dyke at Stanley, northwestern Tasmania, Australia

    NASA Astrophysics Data System (ADS)

    Goto, Yoshihiko; McPhie, Jocelyn

    1996-11-01

    A Miocene basanite dyke at Stanley, northwestern Tasmania, Australia, displays well preserved peperite texture. The dyke is 2 m wide and has intruded basaltic breccia ("host sediment"). One contact of the dyke is fluidally shaped, and amoeboid apophyses 10-25 cm long extend into the host sediment, whereas the other contact is characterized by blocky peperite texture comprising tabular to wedge-shaped clasts up to 30 cm across separated by host sediment. The clasts have internal spherical fractures and some show splinter texture. Vesicles are common in the clasts, and those intersected by clast margins have been filled with sediment. The interior of the dyke comprises close-packed blocky peperite consisting of tabular, wedge-shaped and polyhedral clasts tens of centimetres across separated by host sediment. These clasts show well developed jigsaw-fit texture. The textures and structures in the basanite dyke are inferred to have formed in two stages: an earlier, hotter, apophysis-forming stage and a later, cooler, angular clast-forming stage, both of which occurred during the intrusion of magma into wet, poorly consolidated sediment in a shallow marine environment. During the apophysis-forming stage, the magma had relatively low viscosity and progressively displaced wet sediment. The wet sediment around the dyke was partly fluidized by vaporization of pore water. The angular clast-forming stage reflects a change in the rheological behaviour of the magma from ductile to brittle, most likely in response to decreasing temperature. The chilled parts of the dyke were subject to stress arising from cooling contraction and also from continued, pulsatory movement of hotter, still ductile magma in the interior of the dyke, resulting in brittle fragmentation. Brittle fragmentation was accompanied by movement of host sediment into the newly created open spaces, forming blocky peperite. Spherical fractures, splinter texture and sediment-filled vesicles formed during the angular

  1. Major Mid-Miocene Climate Change In The Transantarctic Mountains

    NASA Astrophysics Data System (ADS)

    Ashworth, A. C.; Lewis, A. R.; Marchant, D. R.

    2007-12-01

    Independent lines of evidence from paleoecology, glacial geology and marine isotopes indicate major climate change in the Dry Valley sector of the Transantarctic Mountains (TAM) at c.14 Ma. A fossil assemblage of pollen and spores, freshwater diatoms, ostracods, mosses, and insect remains has been recovered from lacustrine sediments preserved in a small morainic lake basin in the western Olympus Range. The diatom assemblage indicates that the lake existed for >103yr and was ice-free during summers. Based on the moss and insect fossils the minimum mean summer temperature (MST- Dec-Feb) was 2°C but could have been as high as 5°C. Today at the site the MST is c. -15°C. The lake-marginal vegetation was a sparse tundra dominated by mosses and liverworts. Based on pollen, Nothofagus (southern beech) was part of the lowland regional vegetation and individual dwarfed shrubs may have grown on the slopes surrounding the lake basin. The age of the deposits is well-constrained by an 40Ar/39Ar age of 14.11 ± 0.11 Ma from an in situ volcanic ash within related lacustrine sediments. Based on an independent study of the glacial stratigraphy of the western Wright and McKelvey valleys, diamictites of a wet-based glacial regime had been replaced by those of cold-based regime by 13.85 ± 0.03 Ma. The drop in temperatures and the cessation of meltwater at c. 14 Ma would have caused the regional extinction of all plant and insect life with the exception of the hardiest of soil-dwelling organisms. Paleobotanical evidence indicates that Antarctica had likely been vegetated throughout the Cenozoic, with forests replaced by tundra during the early Oligocene. The mid-Miocene extinction marks the end of tundra in the interior of Antarctica and its replacement by the polar desert biota which exists today. Changes in δ18O and Mg/Ca ratios from different sectors of the Southern Ocean indicate sea surface temperature cooling and ice sheet growth between 13.8 - 14.2 Ma. The close correlation

  2. Early Miocene Antarctic glacial history: new insights from heavy mineral analysis from ANDRILL AND-2A drill core sediments

    NASA Astrophysics Data System (ADS)

    Iacoviello, Francesco; Giorgetti, Giovanna; Turbanti Memmi, Isabella; Passchier, Sandra

    2015-04-01

    The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL—SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6-20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene and it collected a variety of terrigenous lithologies. The heavy mineral assemblages of the lower 650-m-thick sedimentary succession were analyzed through SEM observations and SEM-EDS microanalyses on heavy mineral grains. The heavy mineral analysis shows that the sediments are a mix of detritus dominated by McMurdo Volcanic Group sources most likely located in the present-day Mount Morning area (Proto-Mount Morning) with minor contribution from Transantarctic Mountains source rocks located west of the drill site. The heavy mineral assemblages in Interval 1 indicate that between 20.2 and 20.1 Ma, the grounding line of the ice sheet advanced to a position near the present-day Mount Morning volcanic center. During deposition of Interval 2 (20.1-19.3 Ma), the ice sheet most likely experienced a dynamic behavior with interval of ice advance alternating with periods of ice retreat, while Interval 3 (19.3-18.7 Ma) records further retreat to open water conditions. A dynamic behavior is noted in Interval 4 (18.7-17.6 Ma) with a decreasing contribution of materials derived from the basalts of the Mount Morning volcanic center located to the south of the drill site and a consequent increasing contribution of materials derived from the Transantarctic Mountains to the west of the drill site.

  3. First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae)

    PubMed Central

    López-Antoñanzas, Raquel; Knoll, Fabien; Maksoud, Sibelle; Azar, Dany

    2015-01-01

    Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis. PMID:26250050

  4. First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae).

    PubMed

    López-Antoñanzas, Raquel; Knoll, Fabien; Maksoud, Sibelle; Azar, Dany

    2015-08-07

    Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

  5. The impact of Miocene atmospheric carbon dioxide fluctuations on climate and the evolution of terrestrial ecosystems.

    PubMed

    Kürschner, Wolfram M; Kvacek, Zlatko; Dilcher, David L

    2008-01-15

    The Miocene is characterized by a series of key climatic events that led to the founding of the late Cenozoic icehouse mode and the dawn of modern biota. The processes that caused these developments, and particularly the role of atmospheric CO2 as a forcing factor, are poorly understood. Here we present a CO2 record based on stomatal frequency data from multiple tree species. Our data show striking CO2 fluctuations of approximately 600-300 parts per million by volume (ppmv). Periods of low CO2 are contemporaneous with major glaciations, whereas elevated CO2 of 500 ppmv coincides with the climatic optimum in the Miocene. Our data point to a long-term coupling between atmospheric CO2 and climate. Major changes in Miocene terrestrial ecosystems, such as the expansion of grasslands and radiations among terrestrial herbivores such as horses, can be linked to these marked fluctuations in CO2.

  6. Relation of peralkaline magmatism to heterogeneous extension during the Middle Miocene, southeastern Nevada

    USGS Publications Warehouse

    Scott, R.B.

    1995-01-01

    Volcanism migrated southward in the northern Basin and Range province in the Oligocene and early Miocene to produce voluminous calcalkaline silicic ash flow tuffs. Alkaline volcanism became dominant by middle Miocene (17-14 Ma) as smaller volumes of rhyolite-trachyte-basalt suites were erupted from the relatively small Kane Springs Wash caldera complex in southeastern Nevada. Only minor extension affected the Kane Wash area before the end of calcalkaline activity, but extension expressed by rate of progressive stratal tilt peaked (15-13.5 Ma) with peralkaline magmatism (14.7-14.4 Ma). Variations in distribution, degree, style, and timing of deformation demonstrate heterogeneous extension in the Kane Wash area. Only minor extension and tilting persisted post-middle Miocene (<12 Ma). All major eruptive sources overlap domains of rapid extension. -from Authors

  7. Miocene non-marine diatoms from the western Cordillera basins of northern Peru

    USGS Publications Warehouse

    Fourtanier, E.; Gasse, F.; Bellier, O.; Bonhomme, M.G.; Robles, I.

    1993-01-01

    Diatom assemblages are documented from diatomite layers of two Miocene fluvio-lacustrine units from the basins of the western Cordillera of northern Peru: the Namora Formation and the Cajabamba Formation. Emphasis is given to taxa of particular stratigraphic interest. The diatom assemblages indicate for the Namora Formation the occurrence of swampy conditions with very dilute, low alkalinity water. The diatom assemblages of the Cajabamba Formation reflect the occurrence of fresh, slightly alkaline, eutrophic lakes with deep water in some samples, and swampy conditions with relatively high salt content in other samples. The Namora formation is late Miocene in age based on the diatom assemblages and radiometric analyses. The diatom layers of the Cajabamba Formation are dated as late middle to early late Miocene. -from Authors

  8. The thumb of Miocene apes: new insights from Castell de Barberà (Catalonia, Spain).

    PubMed

    Almécija, Sergio; Alba, David M; Moyà-Solà, Salvador

    2012-07-01

    Primate hands display a major selective compromise between locomotion and manipulation. The thumb may or may not participate in locomotion, but it plays a central role in most manipulative activities. Understanding whether or not the last common ancestor of humans and Pan displayed extant-ape-like hand proportions (i.e., relatively long fingers and a short thumb) can be clarified by the analysis of Miocene ape hand remains. Here we describe new pollical remains-a complete proximal phalanx and a partial distal phalanx-from the middle/late Miocene site of Castell de Barberà (ca., 11.2-10.5 Ma, Vallès-Penedès Basin), and provide morphometric and qualitative comparisons with other available Miocene specimens as well as extant catarrhines (including humans). Our results show that all available Miocene taxa (Proconsul, Nacholapithecus, Afropithecus, Sivapithecus, Hispanopithecus, Oreopithecus, and the hominoid from Castell de Barberà) share a similar phalangeal thumb morphology: the phalanges are relatively long, and the proximal phalanges have a high degree of curvature, marked insertions for the flexor muscles, a palmarly bent trochlea and a low basal height. All these features suggest that these Miocene apes used their thumb with an emphasis on flexion, most of them to powerfully assist the fingers during above-branch, grasping arboreal locomotion. Moreover, in terms of relative proximal phalangeal length, the thumb of Miocene taxa is intermediate between the long-thumbed humans and the short-thumbed extant apes. Together with previous evidence, this suggests that a moderate-length hand with relatively long thumb-involved in locomotion-is the original hand morphotype for the Hominidae.

  9. Stratigraphical investigations on a new Miocene fossil-bearing sequence in Central Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Kaakinen, Anu; Aziz, Hayfaa Abdul; Passey, Benjamin H.; Zhang, Zhaoqun; Liu, Liping; Krijgsman, Wout; Fortelius, Mikael

    2014-05-01

    Central Inner Mongolia has been an area of great paleontological interest since the beginning of the 20th century. Although the area has produced numerous diverse collections of Miocene faunas, fossil records from the early Miocene of Inner Mongolia are relatively rare. The localities occur mainly as scattered faunal horizons and their stratigraphy is challenging owing to lack of continuous vertical exposures. Consequently, most age estimations of these Miocene sites are based on paleontological evidence alone, with very few sites having been dated independently based on paleomagnetics. The Damiao site in Siziwang Qi, Inner Mongolia, was discovered in 2006, and during the following four years extensive field activities were undertaken. The focus was on paleontological studies and on the stratigraphy of the Neogene sediments. The field survey led to the recovery of approximately 30 new fossiliferous localities, which have produced a rich mammalian fauna, including pliopithecid remains. The bulk of the vertebrate fossils and localities have been recovered from three main fossil horizons. We have interpreted the Damiao sequence as the remains of a fluvio-lacustrine system comprising channels, subaerially exposed floodplains and ephemeral/marginal lacustrine environments. This study presents the litho- and magnetostratigraphy of the Damiao area and provides age estimations for the important fossil-bearing localities. The two local stratigraphic sections measured and sampled for paleomagnetic analysis coincide with important vertebrate fossil localities. The western section is about 30 m thick and includes fossil locality DM16 while the eastern section spans up 40 m and comprises localities DM01 and DM02. The paleomagnetic results and faunal evidence suggest a correlation in the magnetozones C6Ar through C5r with an age range of ca 21 to 11 Ma. The interval of reversed polarity at the base of the section (C6Ar) coincides with fossil locality DM16. The pliopithecid

  10. A giant termite from the Late Miocene of Styria, Austria (Isoptera)

    NASA Astrophysics Data System (ADS)

    Engel, Michael S.; Gross, Martin

    2009-02-01

    A giant termite is described and figured from the Late Miocene of the Styrian Basin in southeastern Austria. Gyatermes styriensis gen. n. et sp. n. is represented by a relatively complete forewing, with basal scale. The fossil approximates in size the largest of all termites today and is the largest fossil termite on record. The presence of this species in the Late Miocene fauna of Europe indicates that climatic conditions were appropriate for the persistence of species and colonies requiring relatively stable, warm conditions. The genus is primitive in overall features but shares some similarity with the dampwood termites.

  11. Upper Miocene-Eopleistocene terrestrial sediments of the northwestern Ciscaucasia region

    NASA Astrophysics Data System (ADS)

    Beluzhenko, E. V.; Pis'mennaya, N. S.

    2016-07-01

    On the basis of their stratigraphic, lithological, and genetic features, the Upper Miocene-Eopleistocene terrestrial sediments of the northwestern Ciscaucasia region are subdivided into the following local stratigraphic units (formations): Azov-Kuban, Srednyaya Kuban, Novoaleksandrovsk, Temizhbekskaya. The paleontological and paleomagnetic data are used for determining or specifying their age and correlating the formations between each other and with the regional stratigraphic scale. The obtained data make it possible to improve the Upper Miocene-Eopleistocene stratigraphic scale of the northwestern Ciscaucasia region.

  12. Miocene Blanca Fan, Northern Channel Islands, California: Small fans reflecting tectonism and volcanism

    NASA Astrophysics Data System (ADS)

    McLean, Hugh; Howell, D. G.

    1984-06-01

    Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively.

  13. Miocene Blanca Fan, Northern Channel Islands, California: Small fans reflecting tectonism and volcanism

    USGS Publications Warehouse

    McLean, H.; Howell, D.G.

    1984-01-01

    Blanca fan is a submarine fan composed of Miocene volcaniclastic strata. Parts of the fan system are exposed on Santa Cruz and Santa Rosa Islands, and possibly correlative strata crop out on San Miguel and Santa Catalina Islands. The Blanca fan and underlying breccia reflect regional transcurrent faulting in the California Continental Borderland and development of a system of rapidly subsiding basins and uplifted linear ridges during early and middle Miocene time. Erosion of uplifted crystalline basement rocks followed by the onset of silicic volcanism created linear sediment sources for the alluvial and submarine fans, respectively. ?? 1984 Springer-Verlag New York Inc.

  14. Partial record of a Miocene geomagnetic field excursion: Paleomagnetic data from the Paiute Ridge volcanic center, southern Nevada

    SciTech Connect

    Ratcliff, C.D.; Geissman, J.W.; Perry, F.V. ); Crowe, B.M. )

    1993-04-01

    In the Palute Ridge area, northern Halfpint Range, a complex system of late Miocene (about 8.5 Ma) intrusive and extrusive alkaline mafic rocks crops out over an area of about 25km[sup 2]. Post-magmatic faulting and erosion have resulted in excellent exposure of this sub-volcanic center, allowing for a detailed study of mechanisms and timing of magma emplacement. Paleomagnetic data have been obtained from over 50 sites in mafic rocks, and host ash-flow tuffs and carbonate strata, to better understand the duration of magmatic activity. Magnetizations, isolated in progressive alternating field and thermal demagnetization, for most of the sites at Palute Ridge deviate significantly from expected directions for a time-averaged late Miocene field. Demagnetization data show that there are two types of sample behavior. First, samples with close to expected reverse polarity directions (e.g., the chilled margin of a sill, D=209.2, l=[minus]36.4, [alpha]95=13.2, N=5, k=34.8). Second, and far more common, are samples giving magnetizations of southwest to northwest declination, with both shallow to moderate positive and negative inclination. Within this second grouping are several sites, including syenite pods which differentiated in situ from a large lopolith, having mean declinations that are due west and of shallow inclination. Contact tests performed at several sites are positive and show a clear correlation between sample position and isolated remanence direction. The authors preferred interpretation of the anomalously directed magnetization is that these rocks acquired a TRM during either a high amplitude excursion, or the transitional portion of a field reversal. Thermal models based on larger intrusions [+-] 10m thick at Paiute Ridge indicate that the magmas could cool through estimated magnetization blocking temperatures within weeks or months of emplacement.

  15. Paleomagnetic Study of a Miocene Deformation in a Region Close to the Camargo Volcanic Field, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Wogau-Chong, K.; Bohnel, H.; Aranda Gomez, J.

    2009-05-01

    The Sierra the Aguachile is a Miocene volcanic sequence located in the SE of Chihuahua State NW of the Camargo volcanic field and belongs to the Agua Mayo Group, which unconformably overlays Mesozoic calcareous units. The Sierra de Aguachile sequence defines a structure that may be interpreted as a plunging fold, which could be the result of a reactivation of the San Marcos Fault. This major fault is well known more to the east but may extend into the study area where it would be covered by the younger volcanic sequences; its main activity has been reported to be during the the Neocomian with reactivation phases in the Paleogene and Miocene. To test if the observed structure is the result of a tectonic deformation that happened after the emplacement of the volcanic sequence, a paleomagnetic study was carried out. A total of 14 sites were sampled from different parts of the structure, all in the capping ignimbrite layers. Site mean directions were determined using AF demagnetization. The fold test was applied to analyze if the remanence was acquired in situ or before the proposed folding. Precision parameters k before and after application of the tectonic corrections are 25.38 and 31.43, respectively. This indicates that the Sierra de Aguachile indeed was folded after emplacement of the ignimbrites, which restricts the age of the corresponding tectonic event to be younger than 31.3 +/- 0.7 Ma. Due to the gentle folding though, the difference in precision parameters is not significant at the 95% probability level.

  16. Paleomagnetism, rock magnetism, and PIXE Analysis of Oligocene-Miocene sediments (Bennett County, South Dakota)

    NASA Astrophysics Data System (ADS)

    Karbalaei Saleh, F.; Martin, J.; Sidorovskaia, N.; Richter, C.; Hollerman, W. A.

    2013-12-01

    We present paleo- and rock magnetic results together with Particle Induced X-ray Emission (PIXE) data from an Oligocene-Miocene aged section in central South Dakota. Sediment samples recovered by the High-Plains Aquifer Drilling Program of the South Dakota Geological Survey retrieved well-preserved core material for paleomagnetic and geochemical analysis. A 250 m long core was retrieved from the Tertiary Arikaree Group, which consists predominantly of fine-grained sandstones and limestones with interbedded silt and clay. Paleomagnetic and rock magnetic measurements were carried out at 30 cm resolution on more than 200 discrete samples, and geochemical analysis using PIXE at the Louisiana Accelerator Center on twenty selected samples, with the goal of extracting a geomagnetic polarity time scale and to reconstruct paleoenvironmental conditions. Stepwise demagnetization of the natural remnant magnetization yields excellent to poor demagnetization behavior, with a viscous isothermal remnant magnetization drilling overprint effectively removed during the 20 mT demagnetization step. Paleomagnetic data are characterized by normal and reversed inclinations, consistent with the site position in South Dakota. Magnetic susceptibility measurements of the sediments correlate well with the observed changes in lithology. PIXE sample preparation procedures and calibration techniques to obtain absolute concentrations of heavy elements in the core samples are discussed. An empirical correlation between susceptibility measurements and concentration of the magnetic materials in the core obtained from PIXE will be presented. The results are promising in augmenting traditional paleomagnetic studies to develop a quantitative relationship between the measured magnetization and the concentration of magnetic materials needed for relative paleointensity studies. The PIXE analysis shows also potential in deciphering paleoenvironmental and paleoclimatic conditions during the deposition of the

  17. Provenance Analysis of Lower Miocene Sediments in the Lower Austrian Molasse Basin

    NASA Astrophysics Data System (ADS)

    Knierzinger, Wolfgang; Palzer, Markus; Wagreich, Michael

    2015-04-01

    In the Early Miocene (Late Ottnangian) a global drop of the sea level and the continuous rise of the Alps caused a regression of the Paratethys. During this time interval the Traisen Formation (formerly Oncophora beds) was deposited in the Lower Austrian Molasse Basin. These yellowish-brownish to greyish mica-rich and carbonate-free sands and silts with clayish interlayers were originally named after a brackish water bivalve ("Oncophora"- now Rzehakia). The southeastern part of the TF partly interfingers with finer sands of the Dietersdorf Formation (DF). The Pixendorf Group combines the TF and the DF [coarse sands, conglomerates, blocks] of the Upper Ottnangian lithostratigraphic units in Lower Austria. West to the Waschberg Zone a deeper-water environment (so called Oncophora beds in former literature, herein [informally] renamed to Wildendürnbach Member) with sediment gravity flows (turbidites, muddy/sandy slumps) is inferred from OMV well data. Examinations of these fine sandstones, silts and laminated pelites have been carried out on the basis of the Wildendürnbach-4 OMV drilling core. Analyses of the TF revealed rather homogenous heavy mineral assemblages, dominated by high amounts of garnet (~65%) and relatively high amounts of epidote/zoisite (~10%) and amphiboles (~10%). Conducted surveys point towards a primary influence of metamorphic (metapelitic) source rocks of Austroalpine Crystalline Complexes of the rising Eastern Alps. Heavy mineral analysis of the WDK-4 drilling core showed even higher amounts of garnet (~80%) combined with minor amounts of rutile, staurolite, apatite, epidote/zoisite, tourmalines, zircon and amphiboles. Consistent heavy mineral assemblages and chemical data (EMPA) suggest a stratigraphical correlation with the Křepice Formation and the Ždánice-Hustopeče Formation in the Czech Republic and sedimentary influence from the Western Carpathian Flysch Belt.

  18. Middle Miocene Pierolapithecus provides a first glimpse into early hominid pelvic morphology.

    PubMed

    Hammond, Ashley S; Alba, David M; Almécija, Sergio; Moyà-Solà, Salvador

    2013-06-01

    Here we describe the pelvis from the holotype specimen of Pierolapithecus catalaunicus (IPS-21350), a middle Miocene (11.9 Ma [millions of years ago]) stem hominid from Barranc de Can Vila 1 in Abocador de Can Mata (Catalonia, Spain) for which a partial skeleton is preserved. This skeleton includes the oldest known great ape pelvic materials, which have implications for reconstructing the basal hominid body plan from which later hominids evolved. The P. catalaunicus pelvis is composed of a fragment from the ilium (IPS-21350.38) and one from the ischium (IPS-21350.39). Although the P. catalaunicus ischium consists of just a small fragment from the caudal acetabulum, the preserved morphology is consistent with the basal hominoid Proconsul nyanzae. The ilium is similar to Pr. nyanzae in its concave gluteal surface and linea arcuata form, which suggests much of the iliac and pubic form was primitive. However, the ilium was relatively more flaring than Pr. nyanzae and most monkeys, and could be within the range of extant lesser apes. In addition, the iliac tuberosity width was probably intermediate between extant great apes and monkeys, although maximum and minimum estimates could be accommodated within either group. The P. catalaunicus ilium reflects incipient modifications of the basal hominoid torso for the more frequent use of orthograde behaviors described for this taxon on the basis of other preserved anatomical regions, and also supports claims that extant ape pelvic morphology could be homoplastic given the hypothesized phylogenetic positions of Pierolapithecus.

  19. Diagenetic gypsum related to sulfur deposits in evaporites (Libros Gypsum, Miocene, NE Spain)

    NASA Astrophysics Data System (ADS)

    Ortí, Federico; Rosell, Laura; Anadón, Pere

    2010-07-01

    The Libros Gypsum is the thickest evaporite unit of the Miocene infill of the Teruel Basin in NE Spain. During the deposition of this unit, intense bacterial sulfate-reducing (BSR) activity in the lake depocenter generated a native sulfur deposit. Diagenetic gypsum resulted from subsequent sulfur oxidation. The different processes involved in these transformations were first investigated by Anadón et al. (1992). The present paper is concerned with this diagenetic gypsum from the stratigraphic, petrographic, isotopic and genetic points of view. Diagenetic gypsum occurs mainly as continuous or discontinuous layers, individual levels or lenses, irregular masses, nodules and micronodules, and veins. Its main textures are coarse-crystalline anhedral and fine-grained (alabastrine), both of which can replace any former lithology (carbonate, gypsum, and sulfur). The following sequence of processes and mineral/textural transformations is deduced: primary gypsum deposition — BSR and biodiagenetic carbonate/H 2S production — growth of native sulfur — growth of diagenetic gypsum — partial recrystallization of the diagenetic gypsum textures. The gypsification of the native sulfur generated two types of banded structures in the diagenetic gypsum: (1) concentric structures of centripetal growth, and (2) expansive, roughly concentric structures. In the first type, the gypsification operated from the outer boundaries towards the inner parts. In the second type, part of the carbonate hosting the sulfur was also gypsified (replaced/cemented). In the diagenetic gypsum, the δ34S values are in agreement with a native sulfur and H 2S provenance. The δ18O sulfate values, however, enable us to differentiate two main groups of values: one with positive values and the other with negative values. In the group of positive values, interstitial (evaporated) solutions participated in the sulfur oxidation; this process presumably occurred in a first oxidation stage during shallow

  20. Carbonate pseudotachylite? from a Miocene extensional detachment, W. Cyclades, Greece.

    NASA Astrophysics Data System (ADS)

    Rice, A. Hugh N.; Grasemann, Bernhard

    2016-04-01

    Most pseudotachylites, both impact- and fault-related, occur in silicate-rich rocks, typically with 'granitoid' compositions. Examples of melting in carbonate rocks, excluding magmatic sources, are restricted to impact-events, except for a carbonate pseudotachylite in the Canalone Fault, S. Italy (Viganò et al. 2011). Another potential example of carbonate pseudotachylite, shown here, comes from the Miocene-aged W. Cycladic Detachment System, in Greece. Top-SSE ductile to brittle movement on this detachment, with a maximum displacement estimated at tens of kilometers, exhumed of HP-rocks. The carbonate pseudotachylite occurs within an <200 mm thick zone of cataclasites developed between footwall carbonate ultramylonites, containing thin layers and cm-scale boudins of quartzite, and hanging wall breccias; no contacts with the footwall ultramylonites or hanging wall breccias has been found (yet). The cataclasite zone, which can be traced along-strike for at least 90 m, over ~20 m elevation, comprises several distinct layers. In the sample described, five layers occur. The lowest (A; >43 mm thick), consists of dark (hematitic) red, ultra-fine grained unlayered carbonate with up to 40x10 mm rather rounded clasts of earlier generations of cataclasite, many with a quartzite composition. These clasts are fractured and partially separated, with a fine red carbonate matrix. No layering of the matrix or clasts is apparent. The clasts become finer and more abundant towards the boundary with Layer B. Layers B and D (~57 & ~20 mm thick) dominantly comprises protocataclasite with greyish quartz fragments separated by a carbonate matrix along narrow fractures. Zone C and E (~23 m & >15 mm thick) comprise pale pink carbonate-dominated rocks with abundant <30x5 mm-sized red carbonate clasts (+/- quartz fragments) of earlier cataclasite generations. These elongate clasts lie parallel to the overall banding, which is parallel to the ultramylonitic foliation (detachment surface

  1. Tracking Arabia-India motion from Miocene to Present

    NASA Astrophysics Data System (ADS)

    Chamot-Rooke, N. R.; Fournier, M.

    2009-12-01

    Although small, the present-day Arabia-India motion has been captured by several global and regional geodetic surveys that consistently show dextral motion of a few mm/yr, either transpressive or transtensive (Fournier et al., 2008). This motion is accommodated along the Owen Fracture Zone, an active strike-slip boundary that runs for more than 700 km from the Somalia-India-Arabia triple junction in the south to the Dalrymple trough in the north. Two recent marine cruises conducted along this fault aboard the BHO Beautemps-Beaupré (AOC 2006 and OWEN 2009) using a high resolution multibeam sounder (Simrad EM120, 10 m vertical resolution) provided a complete map of the active fault and confirmed a present-day pure dextral motion. The surface breaks closely follow a small circle of the Arabia-India motion, with several pull-part basins at the junctions between the main segments of the fault. Geomorphologic offsets reach 10 km, suggesting that the mapped fault has been active with the same style for past several million years. When did this motion start? The difficulty in tracking the past Arabia-India motion is that there is no direct kinematic indicator available, since the boundary has been strike-slip and/or convergent during the Tertiary. Motion was most probably sinistral during the rapid northward travelling of India towards Eurasia in the early Tertiary, Arabia being rigidly attached to Africa until the opening of the Gulf of Aden. However, the nature and location of the Arabia-India boundary at that time remain speculative. Throughout the Miocene, the relative motion between India and Arabia has been indirectly recorded at the Sheba and Carslberg ridges, the former recording Arabia-Somalia motion (opening of the Gulf of Aden) and the latter India-Somalia motion (Indian Ocean opening). Both ridges have been studied with some details recently, using up to date magnetic lineations identification (Merkouriev and DeMets, 2006; Fournier et al., 2009). We combine

  2. High-resolution record of Early to Middle Miocene climate variability from Site 1195, Marion Plateau, NE Queensland margin

    NASA Astrophysics Data System (ADS)

    Lowery, C.; Browning, E.; Leckie, R. M.; John, C. M.

    2012-12-01

    Constraining and quantifying eustatic variations has been a priority for stratigraphers since the publication of the first global sea level curves by the Exxon research group in the late 1970s. Quantifying the glacio-eustatic component of sea level signals has become a greater focus as more recent work has demonstrated that far-field effects like ice-sheet gravitation and isostasy imprint on the "true" eustatic signal of waxing and waning ice sheets so that coeval signals from disparate sites may show significantly different local sea level variations. To this end, the Miocene sediments on the Marion Plateau, a drowned carbonate platform on the Queensland margin of Australia, were drilled by ODP Leg 194 to provide an independent, southern hemisphere test of the sea level record of the New Jersey Margin of North America, the most complete and oft-cited record of Cenozoic sea level variability. A high-resolution record is critical to compare sea level variations across hemispheres. Natural Gamma Ray (NGR) logs of core holes can provide a complete, high-resolution record independent of any problems with core recovery or sampling interval. We here present a NGR record of ODP Site 1195 tied to recently completed nannofossil assemblage data, planktic/benthic foraminiferal ratios, sedimentary particle counts, and benthic foraminifera stable isotopes. Peaks in glauconite and clay content correspond to peaks in NGR. The largest of these peaks correspond to sequence boundaries (lowstands), as glauconite accumulates during periods of low sedimentation along this carbonate-dominated margin. These sequence boundaries, in turn, are each associated with marine oxygen isotope events ("Mi Events") and correlate to sequences on the New Jersey margin, the Gulf of Papua, Great Australian Bight, and McMurdo Sound, indicating that these sequences are eustatically controlled. Although sedimentary particle counts only show strong peaks of glauconite at sequence boundaries, the NGR record

  3. Evidence for ice-free summers in the late Miocene central Arctic Ocean.

    PubMed

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-04-04

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate.

  4. Evidence for ice-free summers in the late Miocene central Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-04-01

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate.

  5. Oligo-Miocene rift of Sardinia and the early history of the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Cherchi, A.

    1982-08-01

    The geodynamic evolution of the Western Mediterranean Basin, in spite of many studies, is still uncertain. There is some consensus for interpreting this basin as a kind of small oceanic marginal basin. Its opening has generally been related to a subduction process which was active during the Oligocene-Miocene somewhere east of Sardinia-Corsica1-7. As the margins of the basin are deeply buried below Miocene-to-present sediments, direct lithological and stratigraphical data which could explain the events responsible for its formation are rare8-10 or missing altogether. To obtain such data, detailed field studies have been undertaken in Sardinia (Fig. 1), and the first results are presented here. This approach is justified by the fact that in that island, Oligocene and Miocene sediments were deposited in a rift (fossa tettonica sarda of Verdabasso11), which is the easternmost arm of the complex rift system that affected the European plate during Oligocene and Miocene times. One of these arms evolved towards a small oceanic basin-the Western Mediterranean or Algero-Provençal Basin-while others such as the Gulf of Valencia and the Sardinia rift aborted and remained at the rift stage. Its exceptional exposures make it possible to examine the Sardinia rift to clarify the sequence of events which created it, and to establish a sedimentological model which we believe is directly applicable to the Western Mediterranean Basin.

  6. A remarkable new pygmy grasshopper (Orthoptera, Tetrigidae) in Miocene amber from the Dominican Republic

    PubMed Central

    Heads, Sam W.; Thomas, M. Jared; Wang, Yinan

    2014-01-01

    Abstract A new genus and species of pygmy grasshopper (Orthoptera: Tetrigidae) is described from Early Miocene (Burdigalian) Dominican amber. Electrotettix attenboroughi Heads & Thomas, gen. et sp. n. is assigned to the subfamily Cladonotinae based on the deeply forked frontal costa, but is remarkable for the presence of tegmina and hind wings, hitherto unknown in this subfamily. PMID:25147472

  7. Evidence for ice-free summers in the late Miocene central Arctic Ocean

    PubMed Central

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-01-01

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate. PMID:27041737

  8. Integrated Chronology, Flora and Faunas, and Paleoecology of the Alajuela Formation, Late Miocene of Panama.

    PubMed

    MacFadden, Bruce J; Jones, Douglas S; Jud, Nathan A; Moreno-Bernal, Jorge W; Morgan, Gary S; Portell, Roger W; Perez, Victor J; Moran, Sean M; Wood, Aaron R

    2017-01-01

    The late Miocene was an important time to understand the geological, climatic, and biotic evolution of the ancient New World tropics and the context for the Great American Biotic Interchange (GABI). Despite this importance, upper Miocene deposits containing diverse faunas and floras and their associated geological context are rare in Central America. We present an integrated study of the geological and paleontological context and age of a new locality from Lago Alajuela in northern Panama (Caribbean side) containing late Miocene marine and terrestrial fossils (plants, invertebrates, and vertebrates) from the Alajuela Formation. These taxa indicate predominantly estuarine and shallow marine paleoenvironments, along with terrestrial influences based on the occurrence of land mammals. Sr-isotope ratio analyses of in situ scallop shells indicate an age for the Alajuela Formation of 9.77 ± 0.22 Ma, which also equates to a latest Clarendonian (Cl3) North American Land Mammal Age. Along with the roughly contemporaneous late Miocene Gatun and Lago Bayano faunas in Panama, we now have the opportunity to reconstruct the dynamics of the Central America seaway that existed before final closure coincident with formation of the Isthmus of Panama.

  9. Antarctic ice sheet sensitivity to atmospheric CO2 variations in the early to mid-Miocene.

    PubMed

    Levy, Richard; Harwood, David; Florindo, Fabio; Sangiorgi, Francesca; Tripati, Robert; von Eynatten, Hilmar; Gasson, Edward; Kuhn, Gerhard; Tripati, Aradhna; DeConto, Robert; Fielding, Christopher; Field, Brad; Golledge, Nicholas; McKay, Robert; Naish, Timothy; Olney, Matthew; Pollard, David; Schouten, Stefan; Talarico, Franco; Warny, Sophie; Willmott, Veronica; Acton, Gary; Panter, Kurt; Paulsen, Timothy; Taviani, Marco

    2016-03-29

    Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3-4 °C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major disconformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (∼280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (∼500 ppm) atmospheric CO2 These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.

  10. Antarctic ice sheet sensitivity to atmospheric CO2 variations in the early to mid-Miocene

    NASA Astrophysics Data System (ADS)

    Levy, Richard; Harwood, David; Florindo, Fabio; Sangiorgi, Francesca; Tripati, Robert; von Eynatten, Hilmar; Gasson, Edward; Kuhn, Gerhard; Tripati, Aradhna; DeConto, Robert; Fielding, Christopher; Field, Brad; Golledge, Nicholas; McKay, Robert; Naish, Timothy; Olney, Matthew; Pollard, David; Schouten, Stefan; Talarico, Franco; Warny, Sophie; Willmott, Veronica; Acton, Gary; Panter, Kurt; Paulsen, Timothy; Taviani, Marco; SMS Science Team; Acton, Gary; Askin, Rosemary; Atkins, Clifford; Bassett, Kari; Beu, Alan; Blackstone, Brian; Browne, Gregory; Ceregato, Alessandro; Cody, Rosemary; Cornamusini, Gianluca; Corrado, Sveva; DeConto, Robert; Del Carlo, Paola; Di Vincenzo, Gianfranco; Dunbar, Gavin; Falk, Candice; Field, Brad; Fielding, Christopher; Florindo, Fabio; Frank, Tracy; Giorgetti, Giovanna; Grelle, Thomas; Gui, Zi; Handwerger, David; Hannah, Michael; Harwood, David M.; Hauptvogel, Dan; Hayden, Travis; Henrys, Stuart; Hoffmann, Stefan; Iacoviello, Francesco; Ishman, Scott; Jarrard, Richard; Johnson, Katherine; Jovane, Luigi; Judge, Shelley; Kominz, Michelle; Konfirst, Matthew; Krissek, Lawrence; Kuhn, Gerhard; Lacy, Laura; Levy, Richard; Maffioli, Paola; Magens, Diana; Marcano, Maria C.; Millan, Cristina; Mohr, Barbara; Montone, Paola; Mukasa, Samuel; Naish, Timothy; Niessen, Frank; Ohneiser, Christian; Olney, Mathew; Panter, Kurt; Passchier, Sandra; Patterson, Molly; Paulsen, Timothy; Pekar, Stephen; Pierdominici, Simona; Pollard, David; Raine, Ian; Reed, Joshua; Reichelt, Lucia; Riesselman, Christina; Rocchi, Sergio; Sagnotti, Leonardo; Sandroni, Sonia; Sangiorgi, Francesca; Schmitt, Douglas; Speece, Marvin; Storey, Bryan; Strada, Eleonora; Talarico, Franco; Taviani, Marco; Tuzzi, Eva; Verosub, Kenneth; von Eynatten, Hilmar; Warny, Sophie; Wilson, Gary; Wilson, Terry; Wonik, Thomas; Zattin, Massimiliano

    2016-03-01

    Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3-4 °C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major disconformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (˜280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (˜500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.

  11. Integrated Chronology, Flora and Faunas, and Paleoecology of the Alajuela Formation, Late Miocene of Panama

    PubMed Central

    MacFadden, Bruce J.; Jones, Douglas S.; Jud, Nathan A.; Moreno-Bernal, Jorge W.; Morgan, Gary S.; Portell, Roger W.; Perez, Victor J.; Moran, Sean M.; Wood, Aaron R.

    2017-01-01

    The late Miocene was an important time to understand the geological, climatic, and biotic evolution of the ancient New World tropics and the context for the Great American Biotic Interchange (GABI). Despite this importance, upper Miocene deposits containing diverse faunas and floras and their associated geological context are rare in Central America. We present an integrated study of the geological and paleontological context and age of a new locality from Lago Alajuela in northern Panama (Caribbean side) containing late Miocene marine and terrestrial fossils (plants, invertebrates, and vertebrates) from the Alajuela Formation. These taxa indicate predominantly estuarine and shallow marine paleoenvironments, along with terrestrial influences based on the occurrence of land mammals. Sr-isotope ratio analyses of in situ scallop shells indicate an age for the Alajuela Formation of 9.77 ± 0.22 Ma, which also equates to a latest Clarendonian (Cl3) North American Land Mammal Age. Along with the roughly contemporaneous late Miocene Gatun and Lago Bayano faunas in Panama, we now have the opportunity to reconstruct the dynamics of the Central America seaway that existed before final closure coincident with formation of the Isthmus of Panama. PMID:28107398

  12. Evidence for sediment fan deposition on outer Texas shelf during Miocene eustatic sea level highstands

    SciTech Connect

    Riese, W.C.; Olsen, R.S.; Rosen, R.N.

    1988-02-01

    Four types of data were reviewed in an attempt to clearly define the environments of deposition for reservoir sands in the Matagorda 668 field: well log curve shapes, seismic amplitude responses, micropaleontology, and thin section sedimentary petrology. All four lines of evidence support the interpretation that these lower Miocene sands were deposited as fan complexes.

  13. Simulating a Dynamic Antarctic Ice Sheet in the Early to Middle Miocene

    NASA Astrophysics Data System (ADS)

    Gasson, E.; DeConto, R.; Pollard, D.; Levy, R. H.

    2015-12-01

    There are a variety of sources of geological data that suggest major variations in the volume and extent of the Antarctic ice sheet during the early to middle Miocene. Simulating such variability using coupled climate-ice sheet models is problematic due to a strong hysteresis effect caused by height-mass balance feedback and albedo feedback. This results in limited retreat of the ice sheet once it has reached the continental size, as likely occurred prior to the Miocene. Proxy records suggest a relatively narrow range of atmospheric CO2 during the early to middle Miocene, which exacerbates this problem. We use a new climate forcing which accounts for ice sheet-climate feedbacks through an asynchronous GCM-RCM coupling, which is able to better resolve the narrow Antarctic ablation zone in warm climate simulations. When combined with recently suggested mechanisms for retreat into subglacial basins due to ice shelf hydrofracture and ice cliff failure, we are able to simulate large-scale variability of the Antarctic ice sheet in the Miocene. This variability is equivalent to a seawater oxygen isotope signal of ~0.5 ‰, or a sea level equivalent change of ~35 m, for a range of atmospheric CO2 between 280 - 500 ppm.

  14. The Miocene avifauna of the Li Mae Long locality, Thailand: systematics and paleoecology

    NASA Astrophysics Data System (ADS)

    Cheneval, Jacques; Ginsburg, Léonard; Mourer-Chauvire, Cécile; Ratanasthien, Benjavun

    The Miocene avifauna from Li Mae Long includes an anhinga, a heron, a new species of lesser flamingo, Phoeniconaias siamensis n. sp., two Anatidae, a Phasianidae, three Rallidae, and a Strigidae. The landscape indicated by the mammalian and avian faunas corresponds to a large swampy depression, with probably saline or alkaline waters, surrounded by humid forests, under a warm climate.

  15. Late Miocene Coral faunas of Iran (Zagros, Aghar, Firuz abad, Fars) palaeoecology and palaeobiogeography

    NASA Astrophysics Data System (ADS)

    Dehbozorgi, M.; Yazdi, M.; Torabi, H.

    2009-04-01

    Late Miocene Corals assemblage from Zagros Iran are investigated with respect to their palaeoecology and palaeobiogeography implications. This Corals are compared with fauna from Mediterranean Tethys and the Indopacific. Small foraminifers are used for biogeography and to support paleoecology interpretation. The studied section situated in the Zagros Mishan F.m is last depositions sea. A distinct horizon characterized by Porites- Antiguastrea assemblage associated Milliolid and Rotalia is interpreted a shallow bioclastic shoal. Patch reef with a porites and faviidae assemblage are a common feature of Oligocene and Miocene coral occurrence and indicate water depth of less than 20m. The diversity of corals in this area are low and all corals are hematypic. Miocene Corals from Mishan F.m Comprise 7 genera and occur in the single horizon or patch reef. This Corals and patch reefs are compared with corals and patch reefs in Qom F.m Central Iran. This corals report from this section: Antiguastrea sp., Monastrea sp., Favites sp., Porites sp., Dichocoenia sp., Asterohelia sp., Leptoria sp. Keywords: Miocene- Iran- Mishan-Zagros- Formation- Tethys seaway- Corals- Palaeoecology- palaeobiogeography.

  16. Late Oligocene and Early Miocene Muroidea of the Zinda Pir Dome

    PubMed Central

    Lindsay, Everett H.; Flynn, Lawrence J.

    2016-01-01

    A series of Oligocene through Early Miocene terrestrial deposits preserved in the foothills of the Zinda Pir Dome of western Pakistan produce multiple, superposed fossil mammal localities. These include small mammal assemblages that shed light on the evolution of rodent lineages, especially Muroidea, in South Asia. Nine small mammal localities span approximately 28–19 Ma, an interval encompassing the Oligocene–Miocene boundary. The Early Miocene rodent fossil assemblages are dominated by muroid rodents, but muroids are uncommon and archaic in earlier Oligocene horizons. The Zinda Pir sequence includes the evolutionary transition to modern Muroidea at about the Oligocene–Miocene boundary. We review the muroid record for the Zinda Pir Dome, which includes the early radiation of primitive bamboo rats (Rhizomyinae) and early members of the modern muroid radiation, which lie near crown Cricetidae and Muridae. The Zinda Pir record dates diversification of modern muroids in the Indian Subcontintent and establishment by 19 Ma of muroid assemblages characteristic of the later Siwaliks. PMID:26681836

  17. San Luis Obispo Transform Fault and Middle Miocene rotation of the Western Transverse Ranges, California

    NASA Astrophysics Data System (ADS)

    Hall, Clarence A., Jr.

    1981-02-01

    A fault-disrupted, linear belt of lower middle Miocene pyroclastic and volcanic rocks was erupted 15-17 m.y. B.P. along a trend 140 to 200 km long in the southern Coast Ranges and along the northern flank of the western Transverse Ranges of California. Offset segments of the belt are coincident with the Oceanic-West Huasna, Santa Maria River-Little Pine, and Lompoc-Solvang fault zones. The volcanic rocks thin eastward and also vary in thickness along strike, the latter reflecting the undulation of `porpoising' highs and lows of basins. To account for the linear distribution of over 3000 km2 of bimodal volcanic rock types, it is proposed that they were intruded, extruded, and ejected into a continental submarine margin environment along a feature here named the San Luis Obispo transform (SLOT). The fault was near the mid-Miocene continental margin and evidently joined the early mid-Miocene Mendocino triple junction with the crest of the East Pacific Rise. Subduction of the Farallon Plate had stopped along the adjacent continental margin before Miocene magmatism in this region. The inferred position of the East Pacific Rise crest was too far to the south, and the inferred position of the Mendocino triple junction was too far to the north between 15 and 20 m.y. B.P. to have been directly related to the Miocene volcanic event near 35°N latitude at that time. A part of the western Transverse Ranges was transported northwestward immediately following Miocene volcanism. Earlier movement is possible, but evidence is inconclusive. Microplate transport was concurrent with the development of pull-apart structures and the ≃12- to ≃16-m.y.-old period of volcanism along the southern margin of the microplate within the Los Angeles basin. Variable paleomagnetic directions that display clockwise deflections in the Oligocene (e.g., Morro Rock-Islay Hill Complex) and Miocene igneous rocks (e.g., western Transverse Ranges) in the vicinity of SLOT can be accounted for by extension

  18. Gravity modeling reveals that the "Miocene Pyrenean peneplain" developed at high elevation

    NASA Astrophysics Data System (ADS)

    Bosch, Gemma V.; Van Den Driessche, Jean; Robert, Alexandra; Babault, Julien; Le Carlier, Christian

    2016-04-01

    Geodynamics that shaped the present morphology of the western Mediterranean are mostly linked to the African-Eurasia collision and the extension related to the Mediterranean opening. The Pyrenean chain formed by the collision between the Iberian microplate and the Eurasian plate from the Eocene to the late Oligocene. This resulted in lithosphere thickening especially below the Central Pyrenees that becomes thinner eastwards. Whether the later thinning of the lithosphere in the easternmost Pyrenees involves the removal of the lithospheric mantle or not is debated. This issue joins the problematics about the origin of the high-elevation of the "Miocene Pyrenean peneplain" remnants. Indeed the most striking feature of the Pyrenean morphology is the occurrence of high-elevation, low relief erosional surfaces that are interpreted as the remnants of a Miocene single planation surface, dissected and reworked by Quaternary fluvial and glacial erosion. Two end-member interpretations have proposed to explain the high elevation of this original surface. The first considers that the Miocene Pyrenean peneplain develops near sea-level and was later uplifted, the second claims that the planation surface developed at high elevation in response to the inhibition of erosion consecutively to the progressive rise of the base-level of the Pyrenean drainage network. The first interpretation implies the return to normal crustal thickness by erosion and later uplift by removal of the lithospheric mantle. The second interpretation considers that the mean elevation of the original planation surface matches the thickness of the lithosphere below the chain, taking into account some hundred meters of isostatic rebound due to Quaternary erosion. To test these interpretations, we first restore the Miocene original planation surface by mapping and interpolating the high-elevation, low relief surfaces across the Pyrenees. We then performed 1D and 2D gravity models that we compare with recent

  19. Orbitally paced phosphogenesis in Mediterranean shallow marine carbonates during the middle Miocene Monterey event

    PubMed Central

    Hauzenberger, Christoph A.; Reuter, Markus; Piller, Werner E.

    2016-01-01

    Abstract During the Oligo‐Miocene, major phases of phosphogenesis occurred in the Earth's oceans. However, most phosphate deposits represent condensed or allochthonous hemipelagic deposits, formed by complex physical and chemical enrichment processes, limiting their applicability for the study regarding the temporal pacing of Miocene phosphogenesis. The Oligo‐Miocene Decontra section located on the Maiella Platform (central Apennines, Italy) is a widely continuous carbonate succession deposited in a mostly middle to outer neritic setting. Of particular interest are the well‐winnowed grain to packstones of the middle Miocene Bryozoan Limestone, where occurrences of authigenic phosphate grains coincide with the prominent carbon isotope excursion of the Monterey event. This unique setting allows the analysis of orbital forcing on phosphogenesis, within a bio, chemo, and cyclostratigraphically constrained age‐model. LA‐ICP‐MS analyses revealed a significant enrichment of uranium in the studied authigenic phosphates compared to the surrounding carbonates, allowing natural gamma‐radiation (GR) to be used as a qualitative proxy for autochthonous phosphate content. Time series analyses indicate a strong 405 kyr eccentricity forcing of GR in the Bryozoan Limestone. These results link maxima in the GR record and thus phosphate content to orbitally paced increases in the burial of organic carbon, particularly during the carbon isotope maxima of the Monterey event. Thus, phosphogenesis during the middle Miocene in the Mediterranean was controlled by the 405 kyr eccentricity and its influence on large‐scale paleoproductivity patterns. Rare earth element data were used as a tool to reconstruct the formation conditions of the investigated phosphates, indicating generally oxic formation conditions, which are consistent with microbially mediated phosphogenesis. PMID:27570497

  20. A new age model for the early-middle Miocene in the North Alpine Foreland Basin

    NASA Astrophysics Data System (ADS)

    Reichenbacher, Bettina; Krijgsman, Wout; Pippèrr, Martina; Sant, Karin; Kirscher, Uwe

    2016-04-01

    The establishment of high-resolution age models for sedimentary successions is crucial for numerous research questions in the geosciences and related disciplines. Such models provide an absolute chronology that permits precise dating of depositional episodes and related processes such as mountain uplift or climate change. Recently, our work in the Miocene sediments of the North Alpine Foreland Basin (NAFB) has revealed a significantly younger age (16.6 Myr) for sediments that were thought to have been deposited 18 Myr ago. This implies that a fundamentally revised new age model is needed for the entire suite of lower-middle Miocene sedimentary rocks in the NAFB (20 to 15-Myr). Our new data also indicate that previously published reconstructions of early-middle Miocene palaeogeography, sedimentation dynamics, mountain uplift and climate change in the NAFB all require a critical review and revision. Further, the time-span addressed is of special interest, since it encompasses the onset of a global warming phase. However, it appears that a fundamentally revised new age model for the entire suite of lower-middle Miocene sedimentary rocks in the NAFB can only be achieved based on a 500 m deep drilling in the NAFB for which we currently seek collaboration partners to develop a grant application to the International Continental Deep Drilling Program (ICDP). Reference: Reichenbacher, B., W. Krijgsman, Y. Lataster, M. Pippèrr, C. G. C. Van Baak, L. Chang, D. Kälin, J. Jost, G. Doppler, D. Jung, J. Prieto, H. Abdul Aziz, M. Böhme, J. Garnish, U. Kirscher, and V. Bachtadse. 2013. A new magnetostratigraphic framework for the Lower Miocene (Burdigalian/Ottnangian, Karpatian) in the North Alpine Foreland Basin. Swiss Journal of Geosciences 106:309-334.

  1. The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru.

    PubMed

    Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; de Muizon, Christian; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle

    2010-07-01

    The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths. Lacking a functional upper dentition, it relies on suction for catching its prey; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as raptorial (versus suction) feeders, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12-13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding.

  2. Palynological evidence for late Miocene stepwise aridification on the northeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Li, Ji Jun; Song, Chun Hui; Yu, Hao; Jiang Peng, Ting; Chuang Hui, Zheng; Ye, Xi Yan

    2016-07-01

    Holding a climatically and geologically key position both regionally and globally, the northeastern Tibetan Plateau provides a natural laboratory for illustrating the interactions between tectonic activity and the evolution of the Asian interior aridification. Determining when and how the late Miocene climate evolved on the northeastern Tibetan Plateau may help us better understand the relationships among tectonic uplift, global cooling and ecosystem evolution. Previous paleoenvironmental research has focused on the western Longzhong Basin. Late Miocene aridification data derived from pollen now require corroborative evidence from the eastern Longzhong Basin. Here, we present a late Miocene pollen record from the Tianshui Basin in the eastern Longzhong Basin. Our results show that a general trend toward dry climate was superimposed by stepwise aridification: a temperate forest with a rather humid climate existed in the basin between 11.4 and 10.1 Ma, followed by a temperate open forest environment with a less humid climate between 10.1 and 7.4 Ma, then giving way to an open temperate forest-steppe environment with a relatively arid climate between 7.4 and 6.4 Ma. The vegetation succession demonstrates that the aridification of the Asian interior occurred after ˜ 7-8 Ma, which is confirmed by other evidence from Asia. Furthermore, the aridification trend on the northeastern Tibetan Plateau parallels the global cooling of the late Miocene; the stepwise vegetation succession is consistent with the major uplift of the northeastern Tibetan Plateau during this time. These integrated environmental proxies indicate that the long-term global cooling and the Tibetan Plateau uplift caused the late Miocene aridification of the Asian interior.

  3. Orbitally paced phosphogenesis in Mediterranean shallow marine carbonates during the middle Miocene Monterey event

    NASA Astrophysics Data System (ADS)

    Auer, Gerald; Hauzenberger, Christoph A.; Reuter, Markus; Piller, Werner E.

    2016-04-01

    During the Oligo-Miocene, major phases of phosphogenesis occurred in the Earth's oceans. However, most phosphate deposits represent condensed or allochthonous hemipelagic deposits, formed by complex physical and chemical enrichment processes, limiting their applicability for the study regarding the temporal pacing of Miocene phosphogenesis. The Oligo-Miocene Decontra section located on the Maiella Platform (central Apennines, Italy) is a widely continuous carbonate succession deposited in a mostly middle to outer neritic setting. Of particular interest are the well-winnowed grain to packstones of the middle Miocene Bryozoan Limestone, where occurrences of authigenic phosphate grains coincide with the prominent carbon isotope excursion of the Monterey event. This unique setting allows the analysis of orbital forcing on phosphogenesis, within a bio, chemo, and cyclostratigraphically constrained age-model. LA-ICP-MS analyses revealed a significant enrichment of uranium in the studied authigenic phosphates compared to the surrounding carbonates, allowing natural gamma-radiation (GR) to be used as a qualitative proxy for autochthonous phosphate content. Time series analyses indicate a strong 405 kyr eccentricity forcing of GR in the Bryozoan Limestone. These results link maxima in the GR record and thus phosphate content to orbitally paced increases in the burial of organic carbon, particularly during the carbon isotope maxima of the Monterey event. Thus, phosphogenesis during the middle Miocene in the Mediterranean was controlled by the 405 kyr eccentricity and its influence on large-scale paleoproductivity patterns. Rare earth element data were used as a tool to reconstruct the formation conditions of the investigated phosphates, indicating generally oxic formation conditions, which are consistent with microbially mediated phosphogenesis.

  4. Seawater osmium isotope evidence for a middle Miocene flood basalt event in ferromanganese crust records

    USGS Publications Warehouse

    Klemm, V.; Frank, M.; Levasseur, S.; Halliday, A.N.; Hein, J.R.

    2008-01-01

    Three ferromanganese crusts from the northeast, northwest and central Atlantic were re-dated using osmium (Os) isotope stratigraphy and yield ages from middle Miocene to the present. The three Os isotope records do not show evidence for growth hiatuses. The reconstructed Os isotope-based growth rates for the sections older than 10??Ma are higher than those determined previously by the combined beryllium isotope (10Be/9Be) and cobalt (Co) constant-flux methods, which results in a decrease in the maximum age of each crust. This re-dating does not lead to significant changes to the interpretation of previously determined radiogenic isotope neodymium, lead (Nd, Pb) time series because the variability of these isotopes was very small in the records of the three crusts prior to 10??Ma. The Os isotope record of the central Atlantic crust shows a pronounced minimum during the middle Miocene between 15 and 12??Ma, similar to a minimum previously observed in two ferromanganese crusts from the central Pacific. For the other two Atlantic crusts, the Os isotope records and their calibration to the global seawater curve for the middle Miocene are either more uncertain or too short and thus do not allow for a reliable identification of an isotopic minimum. Similar to pronounced minima reported previously for the Cretaceous/Tertiary and Eocene/Oligocene boundaries, possible interpretations for the newly identified middle Miocene Os isotope minimum include changes in weathering intensity and/or a meteorite impact coinciding with the formation of the No??rdlinger Ries Crater. It is suggested that the eruption and weathering of the Columbia River flood basalts provided a significant amount of the unradiogenic Os required to produce the middle Miocene minimum. ?? 2008 Elsevier B.V.

  5. The effect of a flexible hydrological discharge model on the climate of the Middle Miocene

    NASA Astrophysics Data System (ADS)

    Stärz, Michael; Ward, Andrew; Stepanek, Christian; Lohmann, Gerrit

    2016-04-01

    The Middle Miocene (~17‒14 Myrs ago) climate is characterized by much warmer temperatures and an amplified hydrological cycle with respect to present-day climate. Though it is well known that a change in the global freshwater distribution via the hydrological cycle can impact climate and large scale ocean circulation, most modelling studies encompassing tectonic time scales rather focus on the sensitivity of the climate to orography, ocean gateways, land surface, ice-sheets, and CO2 changes. Alternatively, here we study the effect of two different kinds of hydrological discharge models and their respective boundary conditions, that are fully implemented in the earth system model COSMOS, on the climate of the Middle Miocene. The standard hydrological discharge model (HD) of COSMOS requires the information of high spatial resolution orography for the Middle Miocene that is conventionally tuned to present-day conditions, to calculate river routing following the steepest slope of the terrain. Instead, the flexible hydrological discharge model (FHD) calculates river routing by using Middle Miocene orography at identical grid resolution as the atmosphere model and additionally taking the dynamic topography of continental water levels into account. We find that the anomaly between a climate simulation of the Middle Miocene with COSMOS and HD versus a comparable simulation based on COSMOS and FHD reveals strong differences in the redistribution of freshwater in form of continental discharge from land to the ocean. As a consequence, deep water formation and large scale ocean circulation significantly differ between both model versions, emphasizing the importance of representing a realistic freshwater redistribution from land towards the ocean. We therefore conclude that a more realistic representation of climate states at tectonic time scales necessitates geological constraints on the freshwater redistribution, and changes in the freshwater redistribution may have had a

  6. Paleogeographic and structural setting of Miocene strata in central western Nevada

    SciTech Connect

    Stewart, J.H. )

    1993-04-01

    Late Cenozoic sedimentary rocks as old as 19 Ma are widely distributed in central western Nevada. They are greatly more abundant than older Cenozoic strata and are commonly interpreted to have formed in fault-bounded basins that mark the onset of widespread extension in the Basin and Range Province. Miocene strata are largely coeval with a magmatic arc that extended south southeast near the boundary of the Basin and Range and Sierra Nevada Provinces. This arc produced voluminous andesitic flows and lahars that locally interfinger with the Miocene strata. Miocene depositional basins apparently varied greatly in size. The largest that can be defined clearly is the Esmeralda Basin that was at least 65 km long and 45 km wide. Other basins may have been larger but are difficult to reconstruct; still other basins may be small and isolated, particularly within the magmatic arc. Lacustrine deposits and minor interfingering deltaic and distal fluvial units predominate; near-source, coarse alluvial-fan and megabreccia landslide deposits are locally conspicuous. coarse near-source deposits, particularly landslide deposits, are interpreted to be adjacent to basin-bounding normal faults. The Esmeralda, Coal Valley, and Gabbs Valley-Stewart Valley-Tonopah Basins are interpreted to be related to large-scale Miocene extension. Other basins may be (1) pull-apart structures related to strike-slip faults, (2) downdropped blocks in areas of cross-cutting normal and/or strike-slip faults related to changes in the extension direction or (3) grabens or half-grabens related to uniform extension. Younger Cenozoic basins, including present-day basins, overprint and cut across the Miocene basins.

  7. Evidence for Repeated Early Miocene Glaciation and the Cutting of Upper Taylor Valley from the Friis Hills, Antarctica

    NASA Astrophysics Data System (ADS)

    Lewis, A.; Ashworth, A. C.; Marchant, D. R.; Hemming, S. R.

    2009-12-01

    preservation of the ash adjacent to Taylor Glacier suggests that cutting had already deepened the Taylor trough enough to protect the deposit from erosion during later glacier advances. The Friis Hills deposits are the first to show terrestrial evidence for Early Miocene-aged (or older) glacier cycles and the biota will provide novel constraints on paleoclimate. These tills may also help shed light on how Sirius Group deposits relate to the well-dated Middle Miocene-aged glacial record from the western Dry Valleys. Sirius Group tills occur on Table Mountain only 20 km to the south of the Friis Hills and at the same elevation. The lithology of these sediments is similar to that of the older tills in the Friis Hills and like them these sediments show ice flow into the Ferrar trough. One major difference is the degree of lithification. Tills in the Friis Hills are only weakly consolidated, whereas Sirius Group deposits are strongly lithified. This suggests that the Sirius Group in the southwestern Dry Valleys may be older than 19.76 Ma and could date to a period not long before deposition began on the Friis Hills. This research is supported by NSF OPP 0739693.

  8. Climatic variation along strike in the Himalayas since Mid-Miocene

    NASA Astrophysics Data System (ADS)

    Vögeli, N.; Van Der Beek, P.; Najman, Y.; Huyghe, P.; Wynn, P.

    2015-12-01

    The young Himalayan orogen is the perfect laboratory to study the interactions between tectonics, erosion and climate. The major force driving the evolution of this mountain belt is the India-Asia convergence. Whilst the Himalayas has a major influence on global and regional climate, it is suggested that the monsoonal climate plays a major role in the erosion and relief pattern. Understanding the past variations in monsoonal strength along strike is crucial to understand the role of climate in the evolution of the mountain belt. The Neogene sedimentary foreland basin of the Himalaya contains a record of tectonics and paleoclimate since Miocene times, within the so called molassic Siwalik Group. Therefore several sedimentary sections within the foreland basin along strike in the Himalayan range have previously been dated and studied with respect to determining hinterland exhumation rates, provenance and paleoclimatology. Lateral variations in hinterland exhumation rates have been observed but climate change in the past, especially the strengthening of the Asian summer monsoon along strike of the range, is still debated. In order to track vegetation as a marker of monsoon intensity and seasonality, we analyzed δ13C on soil carbonate and associated δ13C on bulk organic carbon from previously dated Siwalik Group sedimentary sections in the West and the East of the Himalayan foreland basin. Sedimentary records span from 20-1 Myr in the West and 13-1 Myr in the East. The presence of soil carbonate in the West, but its absence in the East is a first indication of lateral climatic variation. δ13C on soil carbonate shows a shift from around -10 ‰ to -2 ‰ at 6 Ma in the West. This is confirmed by δ13C analyses on bulk organic carbon which shows a shift from around -23 ‰ to -19 ‰ at the same time. Such a shift in isotopic value is likely to be associated with a change in vegetation type from C3 to C4. By contrast δ13C on bulk organic carbon remains at around -23

  9. Cementation in Oligo-Miocene non-tropical shelf limestones, Otway Basin, Australia

    NASA Astrophysics Data System (ADS)

    Nicolaides, Stelios

    1995-02-01

    The Oligocene to Miocene Heytesbury Group of the Otway Basin, southeastern Australia, is a non-tropical carbonate shelf succession. This subsurface stratigraphic succession consists of bioclastic grainstones to mudstones containing bryozoa, benthonic and planktonic foraminifera, echinoderms, brachiopods, and molluscs. The basal bryozoa-dominated Clifton Formation was deposited in relatively shallow waters. The overlying Gellibrand Marl, rich in planktonic foraminifera and bryozoa, formed under deep waters. The uppermost unit, benthonic foraminifera-dominated Port Campbell Limestone, was deposited in a moderately deep, middle shelf environment. Cementation is limited and includes: (1) scalenohedral calcite (non-luminescent to bright, Mn- and Fe-poor, in inter- and intraparticle porosity); (2) blocky equant calcite (dull, Mn- and Fe-rich, in interparticle porosity); (3) syntaxial calcite overgrowths on echinoderm particles (non/bright/dull-zoned); (4) euhedral dolomite (in the interparticle pore space of the Port Campbell Limestone); (5) bladed-prismatic calcite (ferroan, in planktonic foraminifera); (6) fibrous calcite (non-luminescent, in intraparticle porosity); and (7) glauconite and iron-oxides (only in intraparticle porosity). All CaCO 3 cements are low-Mg calcites (< 4 mol% MgCO 3). The cements observed in the Heytesbury Group appear to have formed in three successive diagenetic environments: (1) early shallow burial (early Fe- and Mn-poor, non-luminescent syntaxial overgrowths and non-luminescent scalenohedral calcite, under oxidising conditions); (2) late shallow burial (bright, more Mn-rich syntaxial overgrowth zone, i.e., more than the initial non-luminescent one, and bright scalenohedral calcite, under moderately reducing pore water conditions); and (3) moderate burial (ferroan, dull blocky calcite and dull syntaxial overgrowth zone, under reducing conditions). Pressure solution was the main cement-producing mechanism, although seawater and aragonite

  10. Simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves by RP-HPLC with ultraviolet photodiode array detection.

    PubMed

    Cheng, Shan; Qiu, Feng; Huang, Jia; He, Junqi

    2007-03-01

    RP-HPLC with UV photodiode array detection (UV-DAD) was developed and validated for the simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves. The analytes of interest were separated on a Diamonsil C18 column (250 x 4.6 mm id, 5 microm) with the mobile phase consisting of THF/ACN/methanol/ 0.05% phosphoric acid solution (pH 5.0) (18:1:1:80 v/vl/v). The flow rate was set at 1.0 mL/min and the eluent was detected at 340 nm for the four flavonoids. The method was linear over the studied range of 1.00-100 microg/mL for the four analytes of interest with the correlation coefficient for each analyte greater than 0.999. The LOD and LOQwere 0.03 and 0.10 microg/mL, 0.03 and 0.10 microg/mL, 0.05 and 0.15 pg/mL, 0.10 and 0.30 microg/mL for vitexin-2"-O-glucoside, vitexin-2"-0-rhamnoside, rutin, and hyperoside, respectively. The optimized method was successfully applied to the analysis of four important flavonoids in the extract of hawthorn leaves. The total amounts of the four flavonoids were 22.2, 62.3, 4.27, and 8.24 mg/g dry weight for vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn leaves, respectively.

  11. Style and age of late Oligocene-early Miocene deformation in the southern Stillwater Range, west central Nevada: Paleomagnetism, geochronology, and field relations

    USGS Publications Warehouse

    Hudson, Mark R.; John, David A.; Conrad, James E.; McKee, Edwin H.

    2000-01-01

    Paleomagnetic and geochronologic data combined with geologic mapping tightly restrict the timing and character of a late Oligocene to early Miocene episode of large magnitude extension in the southern Stillwater Range and adjacent regions of west central Nevada. The southern Stillwater Range was the site of an Oligocene to early Miocene volcanic center comprising (1) 28.3 to 24.3 Ma intracaldera ash flow tuffs, lava flows, and subjacent plutons associated with three calderas, (2) 24.8 to 20.7 Ma postcaldera silicic dikes and domes, and (3) unconformably overlying 15.3 to 13.0 Ma dacite to basalt lava flows, plugs, and dikes. The caldera-related tuffs, lava flows, and plutons were tilted 60°-70° either west or east during the initial period of Cenozoic deformation that accommodated over 100% extension. Directions of remanent magnetization obtained from these extrusive and intrusive, caldera-related rocks are strongly deflected from an expected Miocene direction in senses appropriate for their tilt. A mean direction for these rocks after tilt correction, however, suggests that they were also affected by a moderate (33.4° ± 11.8°) component of counterclockwise vertical axis rotation. Paleomagnetic data indicate that the episode of large tilting occurred during emplacement of 24.8 to 20.7 Ma postcaldera dikes and domes. In detail, an apparent decrease in rotation with decreasing age of individual, isotopically dated bodies of the postcaldera group indicates that most tilting occurred between 24.4 and 24.2 Ma. The onset of tilting immediately following after the final caldera eruptions suggests that the magmatism and deformation were linked. Deformation was not driven by magma buoyancy, however, because tilting equally affected the caldera systems of different ages, including their plutonic roots. It is more likely that regional extension was focused in the southern Stillwater Range due to magmatic warming and reduction of tensile strength of the brittle crust

  12. Miocene to Recent geological evolution of the Lazufre segment in the Andean volcanic arc

    NASA Astrophysics Data System (ADS)

    Naranjo, J. A.; Villa, V.; Ramírez, C.; Pérez de Arce, C.

    2014-12-01

    The volcano-tectonic setting in which the InSAR-detected Lazufre deformation is developing is particularly relevant in the evolution of this Andean volcanic arc segment (25-26°S). Through regional mapping techniques, a comprehensive field control in addition to geochronological sampling, various volcanic units comprising stratovolcanoes, volcanic complexes, ignimbrites and caldera structures are distinguished. The Lazufre intumescence is located above the overlying block of the NE trending Middle Miocene, Pedernales-Arizaro overthrust. This area comprises an Upper Miocene (8-4 Ma) basal unit of andesitic-dacitic volcanoes and lava fields, upon which nine volcanic complexes of similar composition, including Caletones de Cori Ignimbrite and Escorial Volcano, Lastarria, Cordón del Azufre and Bayo volcanic complexes, were emplaced in several pulses between 3.5 Ma and Holocene times. Coalescing Lazufre structure, immediately to the SE, we have discovered the Miocene (9.8 Ma) Los Colorados caldera. This caldera is 30 km in diameter and sourced the homonymous dacitic ignimbrite of about 500 km3. The caldera scarp was formed in Paleozoic rocks, Miocene dacitic-rhyolitic ignimbrites and ~16 and 10 Ma volcanoes. A 6.9-6.8 Ma andesitic-dacitic volcano ridge formed by Abra Grande, Río Grande and Aguas Calientes stratovolcanoes, from NE to SW, is nested on the caldera floor. Lavas of early stages of Cordón del Azufre and Bayo complexes were shed into the NW part of the caldera. The coalescing structure formed by the Lazufre intumescence and Los Colorados caldera is conjugate at about 30° to the Pedernales-Arizaro overthrust, and has a NW-SE orientation, parallel to the Archibarca lineament. A SE to NW migration of volcanism is observed along this structure at least since the Middle Miocene. We proposed that, since Miocene, tectonic spaces with no surficial fault displacements and conjugated to the main compressive structures within the upper crust, have been created as a

  13. Orbitally paced phosphogenesis in Mediterranean shallow marine carbonates during the middle Miocene Monterey event

    NASA Astrophysics Data System (ADS)

    Auer, Gerald; Hauzenberger, Christoph A.; Reuter, Markus; Piller, Werner E.

    2015-04-01

    During the Oligo-Miocene major phases of phosphogenesis occurred in the Earth's oceans. Particularly in the Mediterranean region phosphate-rich sediments are well-known during this time. However, most phosphate-rich beds represent condensed or allochthonous hemipelagic deposits, formed by a complex interplay of physical and chemical enrichment processes. These underlying processes limit the application of these records for the study of a possible Milankovitch-scale climate control on Miocene phosphogenesis. In this regard the middle Miocene "Monterey event" is of particular interest, as it represents a documented phase of phosphogenesis coupled with a prominent carbon isotope excursion containing nine orbitally paced carbon isotope maxima (CM-events). The Oligo-Miocene shallow marine Decontra section located on the Maiella Platform (central Apennines, Italy), is a widely continuous carbonate succession in a mostly outer to middle neritic setting. Of particular interest are the well-winnowed grain- to packstones of the Middle Miocene Bryozoan Limestone, were occurrences of authigenic phosphate grains coincide with the Monterey event. The depositional setting of the Bryozoan Limestone allows to resolve the influence of orbital forcing on phosphogenesis, within a bio-, chemo- and cyclostratigraphically constrained stratigraphic model. LA-ICP-MS analyses revealed a significant enrichment of Uranium in the studied authigenic phosphate grains compared to the surrounding carbonate sediment. Notably, the Uranium enrichment allowed the use of natural gamma radiation (GR) as a proxy for the qualitative estimation of autochthonous phosphate content within the section, based on the absence of any other major gamma ray sources within the sediment. Time series analyses of high-resolution GR data indicate a strong influence of the 405kyr long-eccentricity cycle on natural gamma radiation in the Bryozoan Limestone. Our results link maxima in the GR record and thus phosphate

  14. Post-Miocene Tectonics from Black Sea to Mediterrenean Sea along Central Anatolian Plateau

    NASA Astrophysics Data System (ADS)

    Rojay, B.; Özsayın, E.; Çiner, A.

    2012-04-01

    The existences of the gross structures are crucial elements in the understanding of the Neogene evolution of the Anatolia. The structures, from north to south, are fairly documented extensional Black Sea coast structures, "N vergent tectonics" in Black Sea region, the cross cutting scar/shear zone -North Anatolian Fault- , S verging tectonics in central Anatolian overthrust belt (Cretaceous ophiolitic mélange belt), extensional Tuzgölü basin, basins like Cilicia, Mut situated to the back of the Cyprian arc and Cyprus locked subduction and accretionary tectonics (locked by approaching and colliding of the Eratosthenes and Hecatacus "seamount" obstacles). The closure of the northern Neotethys during post-Late Eocene- pre-Miocene end with the collision of the squeezed "Anatolian Block" from south with the Eurasian Continent. Consequently the linkage of the central Anatolian basins is lost with the Seas (Paratethys) in north by the evolution of Black Sea Mountains. However, the subduction in southern Neotethys continued with a complex array due to oblique subduction between "Anatolian Block" and downgoing African-Arabian plates. The growth of the accretionary wedge along southeast Anatolia resulted in retreat of the Miocene Seas towards Basra Bay (Iraq) and collision of the southeast Anatolian belt operated to the end of late Miocene where the marine realm in eastern Mediterrenean Sea continues. The rifting - sea-floor spreading in Red Sea, propagating of Dead Sea Transform to the north and oblique subduction in southern Tethys Ocean during different times in Miocene-Pliocene manifested a various different tectonic mechanism stories in the evolution of the Neogene basin in Anatolia. Consequently progressive closure of the Tethys Oceans resulted in the development Central Anatolian and Eastern Anatolian Plateaus. The growth of the Plateaus, in other words, the progressive shortening from north to south during Late Miocene, ended with the escape of the Anatolian Block

  15. The role of CO2 in modulating Miocene climate and ice volume (Invited)

    NASA Astrophysics Data System (ADS)

    Greenop, R.; Sosdian, S. M.; Lear, C. H.; Foster, G. L.; Wilson, P.

    2013-12-01

    The Neogene period is characterised by long term cooling interrupted by a number of prominent warming events, for example the Middle Miocene climate optimum (MCO), an interval of global warmth, that was followed by the Mid-Miocene climate transition (MMCT), a step cooling superimposed on the long-term climate trend. Several Antarctic climate records suggest that the East Antarctic ice sheet was dynamic during the early Miocene (Lewis et al., 2006, Passchier et al., 2011). However, the output from ice sheet modeling experiments suggest that once large ice sheets have grown on East Antarctica they are inherently stable and consequently relatively high levels of CO2 are needed in order to initiate a deglaciation (~1000 ppm; Pollard and DeConto 2005). Over the past 5 years or so an increasing number of studies have illustrated that atmospheric CO2 was much more variable during the Miocene than previously thought, although the magnitude of CO2 change remains much smaller than anticipated by the ice sheet models (Foster et al., 2012, Kurshner et al., 2008, Zhang et al., 2013). Here we will draw together δ11B-pCO2 records, both new published, to evaluate the role of CO2 in modulating Miocene climate. Calculated δ11B-CO2 spanning 5-23 Ma from ODP Sites 926 and 872 are in broad agreement with the other recently published alkenone CO2 records despite the limitations of δ11B based CO2 reconstruction over these long timescales (e.g. variable δ11B of seawater) (Sosdian et al. 2013). We will also present high-temporal resolution boron isotope records from ODP Site 761 across the MCO and ODP Site 926 across the Oligocene-Miocene boundary. We examine the role of CO2 in controlling the stability of the East Antarctic ice sheet during these short time intervals thought to be characterised by substantial retreat of the AIS (Feakins et al. 2012, Passchier et al. 2011, Warny et al. 2009). References: Feakins et al. (2012) Nat. Geoscience 5(8) 557-560, Foster et al., (2012) ESPL 341

  16. Quantitative analysis of phenolic compounds in Chinese hawthorn (Crataegus spp.) fruits by high performance liquid chromatography-electrospray ionisation mass spectrometry.

    PubMed

    Liu, Pengzhan; Kallio, Heikki; Lü, Deguo; Zhou, Chuansheng; Yang, Baoru

    2011-08-01

    Eleven major phenolic compounds (hyperoside, isoquercitrin, chlorogenic acid, ideain, epicatechin, two procyanidin (PA) dimers, three PA trimers and a PA dimer-hexoside) were quantified in the fruits of 22 cultivars/origins of three species of the Chinese hawthorn (Crataegus spp.) by HPLC-ESI-MS-SIR. Hyperoside (0.1-0.8mg/g dry mass [DM]), isoquercitrin (0.1-0.3mg/g DM), chlorogenic acid (0.2-1.6mg/g DM), epicatechin (0.9-11.7mg/g DM), PA B2 (0.7-12.4mg/g DM), PA dimer II (0.1-1.5mg/g DM), PA trimer I (0.1-2.7mg/g DM), PA trimer II (0.7-6.9mg/g DM), PA trimer III (0.01-1.2mg/g DM) and a PA dimer-hexoside (trace-1.1mg/g DM) were detected in all the samples. Ideain (0.0-0.7mg/g DM) was found in all the samples except Crataegus scabrifolia. Significant correlations between the contents of individual PA aglycons were observed (r>0.9, P<0.01). A strong correlation between flavonols was also shown (r=0.71, P<0.01). Fruits of Crataegus pinnatifida var. major had higher contents of PAs but lower contents of flavonols compared with Crataegus brettschneideri. The fruits of C. scabrifolia contained the highest level of PA dimer-hexoside, which was present in trace amounts in the fruits of C. pinnatifida.

  17. Highly extended terrains, lateral segmentation of the substratum, and basin development: The middle-late Miocene Radicondoli Basin (inner northern Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Brogi, Andrea; Liotta, Domenico

    2008-09-01

    This paper deals with the evolution of sedimentary basins not delimited by normal faults, with a substratum characterized by an upward concave shape and with infilling sediments synclinally deformed. We describe the middle-late Miocene Radicondoli Basin, representing an example of such bowl-shaped basins. Its tectonic origin is controversial, being related both to compression and extension; these opposite interpretations bear significant consequences on the geodynamic context in which the inner northern Apennines developed during the middle-late Miocene. The results of our structural studies, carried out in the substratum and infilling sediments, indicate that the Radicondoli Basin is an example of a hanging wall basin developed in an extensional setting. Extensional tectonics determined the lateral segmentation of the substratum competent levels (i.e., Tuscan Nappe and Verrucano Group) and the consequent collapse of overlying less competent levels (i.e., the Ligurian units) with the formation of a bowl-shaped tectonic depression. Here, the syntectonic sediments (Serravallian-late Messinian) are deformed in a large syncline, characterized by minor gravity-driven folds, with vergences toward the depocenter and traces of their axial planes parallel to the basin margins. This paper highlights the role of the competence contrast during the postcollisional tectonic evolution and the influence of substratum lateral segmentation for the accommodation of syntectonic sediments.

  18. The occurrence of an abdominal fauna in an articulated tapir (Tapirus polkensis) from the Late Miocene Gray Fossil Site, Northeastern Tennessee.

    PubMed

    McConnell, Shannon M; Zavada, Michael S

    2013-03-01

    The analysis of samples recovered from the abdominal area of an articulated tapir (Tapirus polkensis) from the Late Miocene (4.5-7 million BP) Gray Fossil Site (GFS) revealed a rich palyno-fauna comprised of about 94% egg/oocyst-like structures and 6% pollen and other palynomorphs. In addition, a group of 6 hickory nuts (Carya) was recovered from the same area suggesting that the samples represent the abdominal contents. The analysis of a sample from immediately outside the tapir produced a sample with 98% pollen and less than 0.5% egg/oocyst-like structures. The size, shape, and general morphology of egg/oocyst-like structures were analyzed with light and scanning electron microscopy and were compared to a variety of intestinal parasites found in extant ungulates, and the Perissodactyla in particular. We also compared fossil structures to the numbers and kind of intestinal parasites recovered from fecal samples from the Baird's tapir (T. bairdii) in Costa Rica and from samples collected from the lowland tapir (T. terrestris) from Ecuador to assess their similarity to our fossil sample. Based on these data, we discuss what role parasites may have played in the biology of T. polkensis during the Late Miocene-Early Pliocene.

  19. The antiquity of riverine adaptations in Iniidae (Cetacea, Odontoceti) documented by a humerus from the late Miocene of the Ituzaingó Formation, Argentina.

    PubMed

    Gutstein, Carolina Simon; Cozzuol, Mario Alberto; Pyenson, Nicholas D

    2014-06-01

    "River dolphins" are a paraphyletic group of toothed whales (Odontoceti) that represent independent secondary invasions of freshwater habitats. Different "river dolphin" lineages display suites of convergent morphological specializations that commonly reflect adaptations to riverine and freshwater environments, such as longirostry, reduced orbits, and wide, paddle-like flippers. One lineage, the Iniidae, is presently endemic to South America, and includes several extinct Neogene taxa along with their sole extant genus, Inia (the Amazon River dolphin). We report here a humerus recovered from the late Miocene deposits of the Ituzaingó Formation in the Paraná Basin of Argentina. The specimen exhibits diagnostic features of the family Iniidae, including a scapular-sternal joint of the humerus, which is a unique anatomical connection among mammals. This joint permits enhanced parasagittal adduction of the flipper as a control surface, relative to other odontocetes, providing Inia with a high degree of maneuverability in its structurally complex and heterogenous riverine habitat. This unique anatomical connection, here documented from the late Miocene (∼9 million years-6.5 million years old), not only provides the oldest diagnostic record for Iniidae, but it also indicates a similar habitat use for this lineage, a finding coincident with the current paleoenvironmental interpretation for the Ituzaingó Formation.

  20. Absolute Paleointensity Study of Miocene Tiva Canyon Tuff, Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Patiman, A.; Bowles, J.

    2014-12-01

    Unoriented samples from the ~12.7 Ma Tiva Canyon (TC) tuff from Yucca Mountain, Nevada are studied in terms of magnetic properties and geomagnetic paleointensity. The magnetic mineralogy and magnetic properties of the TC tuff have previously been well documented, and the remanence-carrier in ~15-m thick zones at the top and bottom of the unit is dominantly is single domain (SD) to superparamagnetic (SP) magnetite, which may be considered ideal for absolute paleointensity studies. Among one of the several episodic volcanic eruptions of the Southwestern Nevada Volcanic Field (SWNVF), the welded TC tuff belongs to the Paintbrush Group. Here we present magnetic properties from two previously unreported sections of the TC tuff, as well as Thellier-type absolute paleointensity estimates. Samples were collected from the lower ~7 m at the base of the flow. Magnetic properties studied include hysteresis, bulk magnetic susceptibility, frequency-dependent susceptibility, and anhysteretic remanent magnetization acquisition. Magnetic property results are consistent with earlier work, showing that the main magnetic mineral is magnetite. SP samples are dominant from the lower ~1 m to ~3.6 m basal unit while the middle unit of ~3.7 m to 7.0 m mainly consists of SD samples. The paleointensity results are closely tied to the stratigraphic height and magnetic properties linked to domain state. The SD samples have consistent absolute paleointensity values 32.40±0.22 uT, VADM 5.74*1022 A.m2 and behaved ideally during paleointensity experiments. The SP samples have consistently higher paleointensity and less ideal behavior, but would likely pass many traditional quality-control tests. Since the magnetite has been interpreted to form by precipitation out of the glass post-emplacement, but at temperatures higher than the Curie temperature, we tentatively interpret the SD remanence to be a primary thermal remanent magnetization and the paleointensity result to be a valid estimate of

  1. Late Miocene evolution of the Black Sea: insights from palynology and strontium isotope ratios

    NASA Astrophysics Data System (ADS)

    Grothe, Arjen; van Baak, Christiaan; Vasiliev, Iuliana; Sangiorgi, Francesca; Reichart, Gert-Jan; Stoica, Marius; Krijgsman, Wout

    2016-04-01

    During the late Miocene, the connection(s) between the Mediterranean Basin and the Atlantic Ocean deteriorated, which ultimately culminated in thick evaporite deposits and a water level drop in the Mediterranean Basin during the so-called Messinian Salinity Crisis (MSC, 5.97 - 5.33 Ma). It has been claimed that Black Sea, in response to the MSC, also desiccated but these claims have been proven incorrectly. Here we present palynological (dinoflagellate cysts and pollen) and strontium isotope ratios from two Black Sea records: the Zheleznyi Rog outcrop section and Deep Sea Drilling Project Hole 380A. Organic walled cyst-producing dinoflagellates are highly sensitive to even small changes in surface waters and strontium isotope ratios are excellent recorders of changing connectivity. Our records provide therefore more insights in the sensitivity of the Black Sea to Messinian Salinity Crisis and the general evolution of the late Miocene Black Sea.

  2. Sensitivity of climate and Atlantic overturning circulation to uncertain ocean gateway configurations for the late Miocene

    NASA Astrophysics Data System (ADS)

    Bradshaw, C.; Lunt, D. J.; Flecker, R.; Martinez-Mendez, G.

    2013-12-01

    The palaeorecord documents late Miocene (11.6-5.3 Ma) climate to be much warmer and wetter than today yet CO2 reconstructions are similar to modern levels. Given the apparent decoupling between CO2 and warmth for this period we investigate here the role of the oceans. The late Miocene experienced significant tectonic change including the restriction of some of the last ocean gateways to close (Panama Gateway and Indonesian Seaway) and open (Bering Strait and Barents/Kara Sea). However, the timing and configuration of these tectonic changes is uncertain. The final closure of the Panama Gateway is dated to the Pliocene, but continental mammal exchange suggests the existence of a Central American archipelago from the mid-late Miocene. The Bering Strait is typically assumed to have opened at the very end of the late Miocene/early Pliocene based on diatom exchange, but other marine and terrestrial evidence points to a much earlier, perhaps intermittent, opening. The timing of the restriction of the Indonesian Seaway is very poorly constrained at middle Miocene to Pliocene. The Barents Sea and Kara Sea shelves are documented as having being subject to extensive glacial erosion and post-glacial uplift since the Pliocene and throughout the Quaternary but records of uplift and erosion during the earlier Cenozoic are limited. However, the presence of significant preglacial sediments suggests that this region underwent tectonic uplift, volcanism and subsequent erosion during the Eocene-Miocene period although the age assignment of the data remains controversial. The Panama Gateway has been suggested to influence North Atlantic Deep Water (NADW) production through numerous modelling studies, the Bering Strait has been suggested to greatly impact NADW during the Quaternary, and the strength of Indonesian Throughflow is hypothesised to influence Agulhas Leakage, which, in turn, has been speculated to influence Atlantic meridional overturning and thus NADW production. Here, we

  3. Lower Miocene stratigraphy of the Gebel Shabrawet area, north Eastern desert Egypt

    NASA Astrophysics Data System (ADS)

    Abdelghany, Osman

    2002-05-01

    The Lower Miocene carbonate/siliciclastic sequence of the Shabrawet area, comprises a complex alternation of autochthonous and allogenic sediments. The sequence can be subdivided into two lithostratigraphic units. The lower unit (unit I) is equivalent to the Gharra Formation. It is mainly clastic and composed of sandstones, siltstones and shales with minor limestone intercalations. These sediments are rich in Clypeaster spp., Scutella spp., Miogypsina intermedia, Operculina complanata, and smaller foraminifera. The upper unit (unit II) was considered by previous workers as being equivalent to the Marmarica Formation. It consists mainly of non-clastic rocks, dominated by sandy and chalky limestones rich in larger foraminifera (miogypsinids and nummulitids). This unit is topped by a highly fossiliferous ( Heterostegina, Operculina and Planostegina) sandy limestone. The present study places both units in the Gharra Formation and reports for the first time M. intermedia from the Miocene sequence of the Shabrawet area.

  4. Basal Adare volcanics, Robertson Bay, North Victoria Land, Antarctica: Late Miocene intraplate basalts of subaqueous origin

    USGS Publications Warehouse

    Mortimer, N.; Dunlap, W.J.; Isaac, M.J.; Sutherland, R.P.; Faure, K.

    2007-01-01

    Late Cenozoic lavas and associated hyaloclastite breccias of the Adare volcanics (Hallett volcanic province) in Robertson Bay, North Victoria Land rest unconformably on Paleozoic greywackes. Abundant hyaloclastite breccias are confined to a paleovalley; their primary geological features, and the stable isotope ratios of secondary minerals, are consistent with eruption in a subaqueous environment with calcite formation probably involving seawater. In contrast, the lavas which stratigraphically overlie the hyaloclastites on Mayr Spur probably were erupted subaerially. K-Ar dating of eight samples from this basal sequence confirms the known older age limit (Late Miocene) of the Hallett volcanic province. Geochemical data reveal an ocean island basalt-like affinity, similar to other Cenozoic igneous rocks of the Hallett volcanic province. If a submarine eruptive paleoenvironment is accepted then there has been net tectonic or isostatic post-Late Miocene uplift of a few hundred metres in the Robertson Bay-Adare Peninsula area

  5. Late Miocene hominin teeth from the Gona Paleoanthropological Research Project area, Afar, Ethiopia.

    PubMed

    Simpson, Scott W; Kleinsasser, Lynnette; Quade, Jay; Levin, Naomi E; McIntosh, William C; Dunbar, Nelia; Semaw, Sileshi; Rogers, Michael J

    2015-04-01

    Since 2000, significant collections of Latest Miocene hominin fossils have been recovered from Chad, Kenya, and Ethiopia. These fossils have provided a better understanding of earliest hominin biology and context. Here, we describe five hominin teeth from two periods (ca. 5.4 Million-years-ago and ca. 6.3 Ma) that were recovered from the Adu-Asa Formation in the Gona Paleoanthropological Research Project area in the Afar, Ethiopia that we assign to either Hominina, gen. et sp. indet. or Ardipithecus kadabba. These specimens are compared with extant African ape and other Latest Miocene and Early Pliocene hominin teeth. The derived morphology of the large, non-sectorial maxillary canine and mandibular third premolar links them with later hominins and they are phenetically distinguishable and thus phyletically distinct from extant apes.

  6. Terpenoids Preserved in Fossils from Miocene-aged Japanese Conifer Wood.

    PubMed

    Ludwiczuk, Agnieszka; Asakawa, Yoshinori

    2015-06-01

    The compositions of terpenoids from the solvent extracts of two silicified wood samples were analyzed using a GC/MS method. Chromatographic analysis showed that several biomolecules were preserved unaltered in the Miocene-aged Japanese wood. These were α-terpineol, α-cedrene, thujopsene, widdrol and ferruginol, among others. In addition to the bioterpenoids, the fossil woods contained a series of geoterpenoids that were generated from their biological precursors before and after burial. These were cadalene, daucalene, pseudowiddrene and cuparene. The chemical composition of both analyzed fossil samples suggest that the silicified woods collected in the Noto Peninsula belong to the Cupressaceae family; this was confirmed by morphological analysis. Both samples were identified as Taxodioxylon cunninghamioides, which is the most common Miocene wood in Japan.

  7. The femur of Orrorin tugenensis exhibits morphometric affinities with both Miocene apes and later hominins.

    PubMed

    Almécija, Sergio; Tallman, Melissa; Alba, David M; Pina, Marta; Moyà-Solà, Salvador; Jungers, William L

    2013-01-01

    Orrorin tugenensis (Kenya, ca. 6 Ma) is one of the earliest putative hominins. Its proximal femur, BAR 1002'00, was originally described as being very human-like, although later multivariate analyses showed an australopith pattern. However, some of its traits (for example, laterally protruding greater trochanter, medially oriented lesser trochanter and presence of third trochanter) are also present in earlier Miocene apes. Here, we use geometric morphometrics to reassess the morphological affinities of BAR 1002'00 within a large sample of anthropoids (including fossil apes and hominins) and reconstruct hominoid proximal femur evolution using squared-change parsimony. Our results indicate that both hominin and modern great ape femora evolved in different directions from a primitive morphology represented by some fossil apes. Orrorin appears intermediate between Miocene apes and australopiths in shape space. This evidence is consistent with femoral shape similarities in extant great apes being derived and homoplastic and has profound implications for understanding the origins of human bipedalism.

  8. A Toba-scale eruption in the Early Miocene: The Semilir eruption, East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Smyth, Helen R.; Crowley, Quentin G.; Hall, Robert; Kinny, Peter D.; Hamilton, P. Joseph; Schmidt, Daniela N.

    2011-10-01

    The Indonesian archipelago is well-known for volcanic activity and has been the location of three catastrophic eruptions in the last million years: Krakatau, Tambora and Toba. However, there are no reports of large magnitude eruptions during the earlier Cenozoic despite a long volcanic record in Indonesia during subduction of Indian Ocean lithosphere since the Eocene. Here we report an Early Miocene major eruption, the Semilir eruption, in south Java, the main phase of which occurred at 20.7 ± 0.02 Ma. This major volcanic eruption appears similar in scale, but not in type, to the 74 ka Toba event. Its products can be identified elsewhere in Java and are likely to have been distributed widely in SE Asia and adjacent oceans. The Semilir eruption could have triggered a climate response, but cannot yet be linked with certainty to Early Miocene climatic events such as glaciations.

  9. Sr-isotopic, paleomagnetic, and biostratigraphic calibration of horse evolution: Evidence from the Miocene of Florida

    SciTech Connect

    MacFadden, B.J.; Bryant, J.D.; Mueller, P.A. )

    1991-03-01

    During the middle Miocene an explosive adaptive radiation resulted in the advent of grazing horses with high-crowned teeth in North America. New Sr isotopic, paleomagnetic, and biostratigrahic evidence from the Miocene marine and nonmarine sequence of the Florida panhandle calibrates the base of this adaptive radiation. The transition from the primitive outgroup species 'Parahippus' leonensis to the most primitive high-crowned horse, 'Merychippus' gunteri occured after about 17.7 Ma. After this event, the lowest known stratigraphic level at which diversification (i.e., presence of two or more sympatric species) of grazing merychippine horses occurs is about 16.2 Ma, or within the early part of Chron C5BR. Although this currently is the only sequence where the parahippine-merychippine transition is directly calibrated, biochronologic evidence from other important, contemporaneous localities in Texas, Nebraska, and California indicate that diversification occured rapidly throughout North America between 15 and 16 Ma.

  10. Geopressured geothermal resource potential of Miocene Bayou Hebert Prospect, Vermilion and Iberia parishes, Louisiana

    SciTech Connect

    McCulloh, R.P.; Pino, M.A.; Bebout, D.G.; Bachman, A.L.

    1981-01-01

    The Bayou Hebert prospect is a fault-bounded block of lower Miocene shale and sandstone which covers a 75-square-mile area in southeastern Vermilion and southwestern Iberia parishes, southwestern Louisiana. The average depth to the top of the geopressured zone is 12,500 feet. Detailed correlation of shale resistivity patterns on well logs from this area has delineated faults, local unconformities, and changes in thickness and facies of lithologic units. Most faults revealed by this method are associated with the boundary fault zones, but the few delineated in the interior of the prospect could reduce the volume of potential reservoir units. Cross sections show that the lower Miocene section thickens across growth faults by addition of new units as well as by expansion. Of the parameters of reservoir volume, salinity, temperature, and permeability, reservoir volume shows the most significant variation and indicates that the eastern fourth of the prospect has the most geopressured geothermal potential.

  11. Chemical composition and palaeobotanical origin of Miocene resins from Kerala-Konkan Coast, western India

    NASA Astrophysics Data System (ADS)

    Dutta, Suryendu; Mallick, Monalisa; Mathews, Runcie Paul; Mann, Ulrich; Greenwood, Paul F.; Saxena, Rakesh

    2010-10-01

    The terpenoid composition of resins from the Miocene lignite horizons from the Kerala-Konkan Coast, western India was analyzed by Curie-point pyrolysis-gas chromatography-mass spectrometry (Cupy-GC-MS). The major pyrolysates were cadalene-based bicyclic sesquiterpenoids including some C30-C31 bicadinenes and bicadinanes typical of dammar resin from angiosperm plants of Dipterocarpaceae family. These plants are typically supported by tropical climates which the western Indian region was known to have experienced during early Tertiary period. The present study suggests that these palaeoclimatic conditions persisted until at least the Miocene epoch. These sesquiterpenoids which are commonly detected in many SE Asian crude oils may be utilised as useful biomarkers for petroleum exploration in the western Indian region.

  12. The Miocene Cyprideis species flock (Ostracoda; Crustacea) of western Amazonia (Solimões Formation)

    NASA Astrophysics Data System (ADS)

    Gross, Martin; Ramos, Maria Ines F.; Piller, Werner E.

    2015-04-01

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic aquatic invertebrate fauna (e.g., molluscs, ostracods). Among ostracods, the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400-m-long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. Ostracod index species enabled a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones (late middle to early late Miocene age). The current study underlines once more Cyprideis' remarkable capability to produce species flocks and western Amazonian Cyprideis comply with the criteria of a species flock: i) endemicity: up to now not a single species is recorded in adjacent areas; ii) monophyly: although hardly verifiable to date and probably Amazonian Cyprideis is not monophyletic s.str., several closely related, quite rapidly evolving species are proved; iii) speciosity: due to the present study, 30 formally described species exist; several further species, left in open nomenclature, are recorded in the literature, which strongly hints to a much higher, still unrecorded species richness; iv) ecological diversity: based on rare sedimentologic cross-references, ecological diversity within a highly structured wetland is possible; the current results demonstrate the sympatric occurrence of up to 12 Cyprideis species, which may indicate adaptations to different microhabitats; v) habitat dominance: regularly Cyprideis holds more than >90 % in western Amazonian ostracod assemblages during the early and middle Miocene. Explanations for this extreme habitat monopolisation are still arguable and touch the highly disputed question about the nature of western Amazonia's environments during the Miocene. It seems, however, evident that a strictly actualistic approach to endemic Neogene Amazonian biota is highly

  13. Miocene to Recent structural evolution of the Nevado de Toluca volcano region, Central Mexico

    NASA Astrophysics Data System (ADS)

    García-Palomo, A.; Macías, J. L.; Garduño, V. H.

    2000-03-01

    Based on aerial photography, satellite imagery, and detailed field work, a geological and structural model of Nevado de Toluca and its surroundings is presented. The Nevado de Toluca volcano is built upon the intersection of three complex fault systems of different age, orientation, and kinematics. These systems from the older to the younger are: (a) The Taxco-Querétaro Fault System (NNW-SSE) with clear expression south of the volcano; (b) The San Antonio Fault System (NE-SW) that runs between the San Antonio and Nevado de Toluca volcanoes; and (c) The Tenango Fault System (E-W) located to the east of Nevado de Toluca volcano. Our field data, supported by previous studies, suggest that these systems have coexisted since the late Miocene. In addition, the stratigraphy, chronology, and kinematics of fault planes point to the existence of at least three main deformation events that have affected the region since the late Miocene. During the early Miocene, an extensional phase with the same deformation style as the Basin and Range tectonics of northern Mexico caused the formation of horsts and grabens south of Nevado de Toluca and allowed the intrusion of sub-vertical dikes oriented NW-SE and NNW-SSE. During the middle Miocene, a transcurrent episode generated NE-SW faults that presented two main motions: the first movement was left-lateral with a σ3 oriented NW-SE and later turned into normal through a counter-clockwise rotation of σ3 up to a N-S position. The latest deformation phase started during the late Pliocene and produced oblique extension ( σ3 oriented NE-SW) along E-W-trending faults that later changed to pure extension by shifting of σ3 to a N-S orientation. These faults appear to control the late Pleistocene to Holocene monogenetic volcanism, the flank collapses of Nevado de Toluca volcano and the seismic activity of the region.

  14. Rapid middle Miocene extension and unroofing of the southern Ruby Mountains, Nevada

    USGS Publications Warehouse

    Colgan, Joseph P.; Howard, Keith A.; Fleck, Robert J.; Wooden, Joseph L.

    2010-01-01

    Paleozoic rocks in the northern Ruby Mountains were metamorphosed during Mesozoic crustal shortening and Cenozoic magmatism, but equivalent strata in the southern Ruby Mountains were never buried deeper than stratigraphic depths prior to exhumation in the footwall of a west dipping brittle normal fault. In the southern Ruby Mountains, Miocene sedimentary rocks in the hanging wall of this fault date from 15.2 to 11.6 Ma and contain abundant detritus from the Paleozoic section. Apatite fission track and (U-Th)/He samples of the Eocene Harrison Pass pluton record rapid cooling that peaked ca. 17–15 Ma, while apatite fission track data from Jurassic plutons east and west of the southern Ruby Mountains indicate near-surface temperatures (<60°C) since the Cretaceous. We interpret these data to record rapid unroofing of the southern Ruby Mountains during slip on the west dipping brittle detachment between 17–16 and 10–12 Ma, followed by minor high-angle faulting. We interpret published Oligocene to early Miocene K-Ar biotite and zircon fission track dates from the Harrison Pass pluton to be partially reset rather than to directly record fault slip. Our new data, together with published data on the distribution and composition of Miocene basin fill, suggest that rapid middle Miocene slip took place on the west dipping brittle detachment that bounds the Ruby Mountains and East Humboldt Range for 150 km along strike. This fault was thus active during a period of rapid extension (ca. 17–15 to 12–10 Ma) documented widely across the northern Basin and Range Province.

  15. Role of Marine Gateways in the Paleoceanography of the Miocene Mediterranean Sea; A Model Study

    NASA Astrophysics Data System (ADS)

    de la Vara, A.; Meijer, P. T.

    2015-12-01

    During the Miocene, due to the convergence of the African plate and the Eurasian plate, the Mediterranean region was subject to profound paleogeographic changes. The evolving coastline and bathymetry of the Mediterranean Sea and, in particular, the opening and closure of the marine connections between the Mediterranean and the outside oceans, triggered important changes in Mediterranean circulation and, indirectly, also affected the global-scale ocean circulation. Until about the Middle Miocene the proto-Mediterranean Sea was open to the Indo-Pacific Ocean through the so-called Indian Gateway. Although the exact age of closure of this gateway is still debated, it is accepted that it substantially affected the paleoceanography of the Mediterranean Sea. Later in time, during the Late Miocene, the Mediterranean was only connected to the Atlantic Ocean but by two marine corridors: the Betic and Rifian corridors. Closure of these narrow passages resulted in the Messinian Salinity Crisis, during which a sequence of evaporites was deposited throughout the Mediterranean basin. In this work we use a regional-scale ocean general circulation model (the Princeton Ocean Model) to gain insight into the role of the evolving gateways. The analysis focuses on large-scale (overturning) circulation, patterns of exchange in the gateways and properties of the Mediterranean water. By comparing our model results to geological data we are able to propose new scenarios or rule out previously proposed ones, and determine the conditions evidenced by the geological observations. More specifically we investigate two different topics: (i) the effects of shoaling and closure of the Indian Gateway and (ii) the functioning of the Late Miocene double gateway to the Atlantic.

  16. 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

  17. Antarctic Ice Sheet Sensitivity to Atmospheric CO2 Variations During the Early to Mid-Miocene

    NASA Astrophysics Data System (ADS)

    Levy, R. H.; Harwood, D. M.; Florindo, F.; Sangiorgi, F.; Eagle, R.; von Eynatten, H.; Gasson, E.; Kuhn, G.; Tripati, A.; Deconto, R. M.; Fielding, C. R.; Field, B.; Golledge, N. R.; Mckay, R. M.; Naish, T.; Olney, M.; Pollard, D.; Schouten, S.; Talarico, F. M.; Warny, S.; Willmott, V.

    2015-12-01

    The Early to mid-Miocene (23 to 14 million years ago) is a compelling interval to study Antarctic ice sheet sensitivity to changes in atmospheric CO2 as oceanic and atmospheric circulation patterns in the southern hemisphere were broadly similar to present and reconstructed atmospheric CO2 concentrations were analogous to those projected for the next several decades. This time interval includes the Miocene Climatic Optimum (MCO), a period of global warmth during which average surface temperatures were 3 to 4°C higher than today. Miocene sediments in the AND-2A drill core from the Western Ross Sea, Antarctica provide direct information regarding ice sheet variability through this key time interval and offer insight into the potential Antarctic contribution to future sea level rise. A multi-proxy dataset derived from AND-2A identifies four distinct environmental "motifs" based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major disconformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of marine-based ice across the Ross Sea. They all correlate with major positive shifts in benthic oxygen isotope records and episodes of sea-level fall, and generally coincide with intervals when atmospheric CO2 concentrations were below current levels (~400 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for significant ice mass loss during episodes of high (>400 ppm) atmospheric CO2. These results suggest that polar climate and the Antarctic Ice Sheet (AIS) were highly sensitive to relatively small changes in CO2 during the early to mid-Miocene, which is supported by numerical ice sheet and climate modelling.

  18. Plate kinematics of the central Atlantic during the Oligocene and early Miocene

    NASA Astrophysics Data System (ADS)

    Schettino, Antonio; Macchiavelli, Chiara

    2016-04-01

    A new plate motions model for the northwest Africa-North America Plate pair during the Oligocene and early Miocene is presented. The model is accompanied by a high-resolution isochron map for the central Atlantic region, resulting from a re-examination of 423 ship tracks from the NGDC data base for the area between the 15°20' FZ and the Azores triple junction. A new digital model of fracture zones for this region and a set of 309 magnetic profiles crossing the Oligocene to recent oceanic crust within the study area allowed to determine accurate finite reconstruction poles for the North America-northwest Africa conjugate plate pair between the early Miocene (Chron 6) and the early Oligocene (Chron 13). For times older than Chron 7 (˜25 Ma), the finite reconstruction poles were calculated using a reliable data set coming exclusively from the region south of the Canary Islands FZ (˜32°N), which allowed to test the rigidity of the northwest African oceanic lithosphere during the Oligocene-early Miocene phase of Atlas orogeny. A comparison of theoretical magnetic isochrons with observed magnetic lineations systematically shows that anomalously high spreading rates occurred in the area north of the Canary Islands FZ before Chron 7, thereby suggesting that the formation of the Atlas mountain, rather than being a localized intracontinental process, was logically linked to the central Atlantic spreading history. Thus, an independent Moroccan Plate could have existed during the Oligocene-early Miocene time interval, which included both the oceanic lithosphere north of the Canary Islands FZ and the northern Maghrebian areas of Morocco, Algeria and Tunisia. In this eventuality, the Atlas mountain belt should be reinterpreted as a giant flower structure associated with dextral transpression.

  19. A Miocene termite nest from southern Argentina and its paleoclimatological implications

    USGS Publications Warehouse

    Bown, T.M.; Laza, J.H.

    1990-01-01

    A Miocene termitarium attributable to the extant termite Syntermes (Isoptera: Termitidae, Nasutitermitinae) is the first fossil termite nest reported from South America and possibly the oldest record of the Isoptera from that continent. A new ichnogenus and ichnospecies, Syntermesichnus fontanae, is proposed for this distinctive trace fossil. It differs from nests constructed by other members of the Nasutitermitinae in its architectural organization and its large size. -from Authors

  20. A new Middle Miocene Niveria Jousseaume, 1884 (Mollusca: Gastropoda: Trivioidea) from Hungary

    NASA Astrophysics Data System (ADS)

    Fehse, Dirk

    2011-02-01

    A new species of Niveria from the Middle Miocene (Badenian) of the Paratethys of Borsodbóta, Hungary is described. This species is characterized by its callused dorsum and dorsal depression. Niveria jozefgregoi sp. nov. is discussed with comparative species from the Badenian of Hungary, the Pliocene of the Mediterranean region, Florida and Recent species from Madeira and the Islas Galápagos.

  1. Antarctic ice sheet sensitivity to atmospheric CO2 variations in the early to mid-Miocene

    PubMed Central

    Levy, Richard; Harwood, David; Florindo, Fabio; Sangiorgi, Francesca; Tripati, Robert; von Eynatten, Hilmar; Tripati, Aradhna; DeConto, Robert; Fielding, Christopher; Field, Brad; Golledge, Nicholas; McKay, Robert; Naish, Timothy; Olney, Matthew; Pollard, David; Schouten, Stefan; Talarico, Franco; Warny, Sophie; Willmott, Veronica; Acton, Gary; Panter, Kurt; Paulsen, Timothy; Taviani, Marco

    2016-01-01

    Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23–14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3–4 °C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major disconformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (∼280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (∼500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene. PMID:26903644

  2. Functional anatomy of the limbs of erethizontidae (Rodentia, Caviomorpha): Indicators of locomotor behavior in Miocene porcupines.

    PubMed

    Candela, Adriana M; Picasso, Mariana B J

    2008-05-01

    Functional analysis of the limb bones of the erethizontid Steiromys duplicatus, one of the most abundant Miocene porcupines from Patagonia, provides evidence to infer their locomotor behavior. Remains of the giant Neosteiromys pattoni (Late Miocene of Northeast Argentina) are also analyzed. Osteological and myological features of extant porcupines were evaluated and used as a model to interpret the functional significance of Miocene species' limbs. Several features in erethizontids are compatible with the ability to climb: the low humeral tuberosities indicate a mobile gleno-humeral joint; the prominent and distally extended deltopectoral crest indicates a powerful pectoral muscle, which is particularly active when climbing; the humero-ulnar and humero-radial joints are indicative of pronation-supination movements; the well-developed lateral epicondylar ridge and the medially protruding entepicondyle are in agreement with an important development of the brachioradialis, supinator, flexor digitorum profundus, and pronator teres muscles, acting in climbing and grasping functions; the mechanical advantage of the biceps brachii would be emphasized because of its distal attachment on the bicipital tuberosity. As with extant porcupines, in Miocene species, the large femoral head would have permitted a broad range of abduction of the femur, and the medially protruding lesser trochanter would have emphasized the abduction and outward rotation of the femur by the action of the ilio-psoas complex. In S. duplicatus, the shape of the hip, knee, and cruro-astragalar, calcaneo-astragalar, and astragalo-navicular joints would have allowed lateral and rotational movements, although probably to a lesser degree than in extant porcupines. Foot features of S. duplicatus (e.g., great medial sesamoid bone, medial astragalar head, complete hallux) indicate that this species would have had grasping ability, but would not have achieved the high degree of specialization of Coendou

  3. Etisus evamuellerae, a new xanthid crab (Decapoda, Brachyura) from the Middle Miocene of Austria and Hungary

    PubMed Central

    Hyžný, M.; van Bakel, B.W.M.; Guinot, D.

    2015-01-01

    On the basis of several carapaces, a new species of xanthid crab, Etisus evamuellerae, is described from the Middle Miocene of the Vienna (Austria) and Great Hungarian basins. It differs from the coeval xanthids, Xantho moldavicus and Pilodius vulgaris, in having a distinctly protruding front and comparatively longer carapace. Contrary to those two species, the new one makes up for just a small percentage in the decapod crustacean assemblages studied. PMID:25983383

  4. A new Late Miocene hominoid from Kenya: Samburupithecus kiptalami gen. et sp. nov.

    NASA Astrophysics Data System (ADS)

    Ishida, Hidemi; Pickford, Martin

    1997-11-01

    A new genus and species of hominoid, Samburupithecus kiptalami, is erected on the basis of a maxillary specimen with complete post canine dentition. Its age is established as upper Miocene (9.5 Ma) on the basis of radioisotopic dating and associated mammalian fauna. The new genus is more closely related to the African ape —human clade (AAH) than is any other known extinct hominoid and it may well be on the line leading to hominids.

  5. First joint record of Mesopithecus and cf. Macaca in the Miocene of Europe.

    PubMed

    Alba, David M; Delson, Eric; Carnevale, Giorgio; Colombero, Simone; Delfino, Massimo; Giuntelli, Piero; Pavia, Marco; Pavia, Giulio

    2014-02-01

    Cercopithecid fossil remains from the post-evaporitic Messinian (5.40-5.33 Ma, MN13, latest Turolian, latest Miocene) locality of Moncucco Torinese (Tertiary Piedmont Basin, NW Italy) are described. A talus is assigned to the fossil colobine Mesopithecus pentelicus, while a proximal fragment of ulna and a male lower canine are attributed to cf. Me. pentelicus. An isolated I(2) and M3 are assigned to the papionin cf. Macaca sp., and two cercopithecid phalanges are left unassigned even to the subfamily level. The record of Mesopithecus at Moncucco Torinese agrees well with the previously-known range of this species in Italy and elsewhere in Europe, whereas that of cf. Macaca constitutes only the second occurrence of macaques in the Miocene of Eurasia. Although the co-occurrence of these two genera in a single locality had been previously reported in the Pliocene, this is the first instance in which macaques are associated with the Late Miocene M. pentelicus instead of Mesopithecus monspessulanus. The record of cf. Macaca and Mesopithecus-and especially the latter's talar morphology, similar to that of extant arboreal colobines-fits well with paleoenvironmental reconstructions of Moncucco Torinese based on the associated fauna, which indicate a humid and densely-forested environment, probably with more open and drier habitats nearby. From a paleobiogeographic viewpoint, the record of Macaca at Moncucco Torinese, together with the previously reported occurrence at Almenara-Casablanca M (Spain), supports the contention that macaques dispersed from Africa into Europe during the latest Miocene (ca. 5.9-5.3 Ma) at the same time as the sea level drop associated with the Messinian Salinity Crisis.

  6. Middle Miocene hiatus in volcanic activity in the Great Basin area of the Western United States

    USGS Publications Warehouse

    McKee, E.H.; Noble, D.C.; Silberman, M.L.

    1970-01-01

    A summary of potassium-argon dates shows that a high level of igneous activity in the Great Basin and adjacent regions during middle Tertiary time (40 to 20 my ago) was followed by a period of relative quiescence in middle Miocene time that lasted for several million years (from 20 to 17 my ago). Volcanism resumed 16 my ago mainly at the margins of the region and has continued to the present. ?? 1970.

  7. Origin and structure of the fossil resin from an Indonesian Miocene coal

    NASA Astrophysics Data System (ADS)

    Brackman, W.; Spaargaren, K.; van Dongen, J. P. C. M.; Couperus, P. A.; Bakker, F.

    1984-12-01

    The structure of a fossil resin from Miocene coal outcrops of the Bukit Asam region (Sumatra) has been studied. The fossil material has been formed from sesqui- and tri-terpenes from trees of the Dipterocarp family. The original terpenes have lost virtually all oxygen-containing functions and the resulting mono- and di-olefins have polymerized to a mainly non-crosslinked resin whose components have molecular weights of up to 300,000.

  8. Planktonic foraminiferal biostratigraphy of the Miocene sequence in the area between Wadi El-Tayiba and Wadi Sidri, west central Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Phillip, G.; Imam, M. M.; Abdel Gawad, G. I.

    1997-10-01

    The present work deals with the study of lithostratigraphy and the planktonic foraminiferal biostratigraphy of the Early-Middle Miocene sequence in six measured stratigraphical surface sections in west central Sinai. They are namely, from north to south: Wadi El-Tayiba, Gabal Sarbut El-Gamal, Wadi Nukhul, Wadi Baba, Gabal Abu Alaqa and Wadi Sidri. The Miocene sequence, exposed in the study area, is represented lithostratigraphically by four rock units, arranged from base to top as follows: the Nukhul and Rudeis Formations (Early Miocene), the Sarbut El-Gamal Formation and the Hammam Faraun Member of the Belayim Formation (Middle Miocene). The planktonic foraminiferal biostratigraphical studies led to the recognition of 51 planktonic foraminiferal species. They are illustrated with the scanning electron microscope. Five planktonic foraminiferal biozones and one large benthonic foraminiferal zone have been recognised. They are arranged from top to bottom as follows: Orbulina suturalis/Globorotalia siakensis Zone (Middle Miocene); Borelis melo Zone (larger foraminiferal zone) (Middle Miocene); Globigerinoides sicanus Zone (Early Miocene); Globigerinoides trilobus Zone (Early Miocene); Globigerinoides altiaperturus-Catapsydrax dissimifis Zone (Early Miocene); Globigerinoides primordius Zone (Early Miocene). Correlation of these biozones with others from Egypt and the world is also attempted.

  9. Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China.

    PubMed

    Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

    2016-02-01

    Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7-6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids.

  10. Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China

    PubMed Central

    Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A.; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

    2016-01-01

    Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids. PMID:26829756

  11. Slowing extrusion tectonics: Lowered estimate of post-Early Miocene slip rate for the Altyn Tagh fault

    USGS Publications Warehouse

    Yue, Y.; Ritts, B.D.; Graham, S.A.; Wooden, J.L.; Gehrels, G.E.; Zhang, Z.

    2004-01-01

    Determination of long-term slip rate for the Altyn Tagh fault is essential for testing whether Asian tectonics is dominated by lateral extrusion or distributed crustal shortening. Previous slip-history studies focused on either Quaternary slip-rate measurements or pre-Early Miocene total-offset estimates and do not allow a clear distinction between rates based on the two. The magmatic and metamorphic history revealed by SHRIMP zircon dating of clasts from Miocene conglomerate in the Xorkol basin north of the Altyn Tagh fault strikingly matches that of basement in the southern Qilian Shan and northern Qaidam regions south of the fault. This match requires that the post-Early Miocene long-term slip rate along the Altyn Tagh fault cannot exceed 10 mm/year, supporting the hypothesis of distributed crustal thickening for post-Early Miocene times. This low long-term slip rate and recently documented large pre-Early Miocene cumulative offset across the fault support a two-stage evolution, wherein Asian tectonics was dominated by lateral extrusion before the end of Early Miocene, and since then has been dominated by distributed crustal thickening and rapid plateau uplift. ?? 2003 Elsevier B.V. All rights reserved.

  12. Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China

    NASA Astrophysics Data System (ADS)

    Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A.; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

    2016-02-01

    Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids.

  13. C4 plant expansion since the late Miocene and the evolution of Asian summer monsoon

    NASA Astrophysics Data System (ADS)

    Wu, H.; Guo, Z.; Guiot, J.; Yu, Y.; Ge, J.; Zhang, Y.; Peng, S.

    2015-12-01

    A dramatic expansion of C4 plant distribution occurred in the South Asia during the late Miocene and in the East Asia during the Pliocene period, with broad spatial and temporal variations. Although the event is well documented, whether subsequent expansions were caused by a decreased atmospheric CO2 concentration or climate change is a contentious issue. In this study, we used an improved inverse vegetation modeling approach that accounts for the physiological responses of C3 and C4 plants to quantitatively reconstruct the paleoclimate in the Siwalik of South Asia and in the Loess Plateau of East Asia, based on pollen and carbon isotope data. We also studied the sensitivity of the C3 and C4 plants to changes in the climate and the atmospheric CO2 concentration. We suggest that the expansion of the C4 plant distribution since the late Miocene was unlikely caused by reduced CO2 levels alone. The expansion may have been primarily triggered by regional aridification, and seasonal analysis revealed that this climate shift mainly attributed to the summer rainfall decrease. Our findings suggest that this abrupt ecological shift mainly resulted from the weakening of the Asian summer monsoon, which may related to the decrease of SST in the tropic since the late Miocene.

  14. Late Eocene-Middle Miocene paleoclimates of the south-west Pacific: oxygen isotopic evidence

    SciTech Connect

    Kennett, J.P.; Murphy, M.G.

    1985-01-01

    High resolution oxygen isotopic stratigraphy is presented for Late Eocene-Middle Miocene sequences in a traverse of 6 DSDP sites from the southwest Pacific at water depths ranging from 1300 to 2000 m and from the warm subtropics to the cool temperature water masses. The data record the progressive increase of latitudinal temperature gradients from the late Eocene. A pattern of increasing isotopic offset between the latitudinally distributed sites is linked to the establishment and strengthening of the circum-Antarctic Current. The intensification of this current system progressively decoupled the warm subtropical gyres from cool polar circulation, in turn leading to Antarctic glaciation. Enriched oxygen isotopic values clustering in the middle Oligocene, are interpreted to represent accumulations of Antarctic ice, although this must have been temporary and of relatively low volume. This Antarctic ice must have disappeared by the Early Miocene when delta/sup 18/O values were relatively depleted, reaching minimum values during the late Early Miocene (19.5 to 16.5), the climax of Neogene warmth. This climatic optimum was immediately followed by a major enrichment in benthic delta/sup 18/O values between approx. 16.5 and 13.5 Ma, which is interpreted to represent major, permanent accumulation of the East Antarctic ice sheet and cooling of bottom waters.

  15. Miocene honey bees from the Randeck Maar of southwestern Germany (Hymenoptera, Apidae)

    PubMed Central

    Kotthoff, Ulrich; Wappler, Torsten; Engel, Michael S.

    2011-01-01

    Abstract The Miocene Randeck Maar (southwestern Germany) is one of the only sites with abundant material of fossil honey bees. The fauna has been the focus of much scrutiny by early authors who recognized multiple species or subspecies within the fauna. The history of work on the Randeck Maar is briefly reviewed and these fossils placed into context with other Tertiary and living species of the genus Apis Linnaeus (Apinae: Apini). Previously unrecorded specimens from Randeck Maar were compared with earlier series in an attempt to evaluate the observed variation. A morphometric analysis of forewing venation angles across representative Recent and Tertiary species of Apis as well as various non-Apini controls was undertaken to evaluate the distribution of variation in fossil honey bees. The resulting dendrogram shows considerable variation concerning the wing venation of Miocene Apini, but intergradation of other morphological characters reveals no clear pattern of separate species. This suggests that a single, highly variable species was present in Europe during the Miocene. The pattern also supports the notion that the multiple species and subspecies proposed by earlier authors for the Randeck Maar honey bee fauna are not valid, and all are accordingly recognized as Apis armbrusteri Zeuner. PMID:21594072

  16. Seastacks buried beneath newly reported Lower Miocene sandstone, northern Santa Barbara County, California

    SciTech Connect

    Fritsche, A.E.; Hanna, F.M.

    1985-04-01

    Three large, isolated exposures of a light-gray, coarse-grained, thick-bedded sandstone unit occur in the northern San Rafael Mountains of Santa Barbara County, California. These rocks are moderately fossiliferous and contain Vertipecten bowersi, Amussiopecten vanvlecki, Aequipecten andersoni, Otrea howelli, shark teeth, whale bones, and regular echinoid spines. The fossils indicate that the sandstone unit, although previously reported as upper(.) Miocene, correlates best with the lower Miocene Vaqueros Formation. This unit was deposited in angular unconformity on a Cretaceous, greenish-gray turbidite sequence of interbedded sandstone and shale, and onlaps the unconformity erosion surface from west to east, the unit being thicker in the west and older at its base. The underlying Cretaceous sandstone beds are well indurated, and during the eastward transgression of the early Miocene sea, they resisted wave erosion and stood as seastacks offshore of the advancing coastline, thus creating a very irregular topographic surface upon which the Vaqueros Formation was deposited. Some seastacks were as much as 4 m tall, as indicated by inliers of Cretaceous rock surrounded by 4-m thick sections of the Vaqueros Formation.

  17. On Mesopithecus habitat: Insights from late Miocene fossil vertebrate localities of Bulgaria.

    PubMed

    Clavel, Julien; Merceron, Gildas; Hristova, Latinka; Spassov, Nikolaï; Kovachev, Dimitar; Escarguel, Gilles

    2012-07-01

    The aim of this study is to describe the environments where the cercopithecid Mesopithecus was found during latest Miocene in Europe. For this purpose, we investigate the paleoecology of the herbivorous ungulate mesofauna of three very rich late Miocene fossil localities from southwestern Bulgaria: Hadjidimovo, Kalimantsi and Strumyani. While Mesopithecus has been found in the two first localities, no primate remains have yet been identified in Strumyani. Comparison between localities with and without primates using the herbivore mesofauna allows the cross-corroboration of paleoenvironmental conditions where this primate did and did not live. A multi-parameter statistical approach involving 117 equid and 345 bovid fossil dental and postcranial (phalanges, metapodia, astragali) remains from these three localities provides species to generic-level diet and locomotor habit information in order to characterize the environment in which Mesopithecus evolved. The analysis of dental mesowear indicates that the bovids were mainly mixed feeders, while coeval equids were more engaged in grazing. Meanwhile, postcranial remains show that the ungulate species from Hadjidimovo and Kalimantsi evolved in dry environments with a continuum of habitats ranging from slightly wooded areas to relatively open landscapes, whereas the Mesopithecus-free Strumyani locality was in comparison reflecting a rather contrasted mosaic of environments with predominant open and some more closed and wet areas. Environments in which Mesopithecus is known during the late Miocene were not contrasted landscapes combining open grassy areas and dense forested patches, but instead rather restricted to slightly wooded and homogeneous landscapes including a developed grassy herbaceous layer.

  18. Miocene Fossils Reveal Ancient Roots for New Zealand's Endemic Mystacina (Chiroptera) and Its Rainforest Habitat.

    PubMed

    Hand, Suzanne J; Lee, Daphne E; Worthy, Trevor H; Archer, Michael; Worthy, Jennifer P; Tennyson, Alan J D; Salisbury, Steven W; Scofield, R Paul; Mildenhall, Dallas C; Kennedy, Elizabeth M; Lindqvist, Jon K

    2015-01-01

    The New Zealand endemic bat family Mystacinidae comprises just two Recent species referred to a single genus, Mystacina. The family was once more diverse and widespread, with an additional six extinct taxa recorded from Australia and New Zealand. Here, a new mystacinid is described from the early Miocene (19-16 Ma) St Bathans Fauna of Central Otago, South Island, New Zealand. It is the first pre-Pleistocene record of the modern genus and it extends the evolutionary history of Mystacina back at least 16 million years. Extant Mystacina species occupy old-growth rainforest and are semi-terrestrial with an exceptionally broad omnivorous diet. The majority of the plants inhabited, pollinated, dispersed or eaten by modern Mystacina were well-established in southern New Zealand in the early Miocene, based on the fossil record from sites at or near where the bat fossils are found. Similarly, many of the arthropod prey of living Mystacina are recorded as fossils in the same area. Although none of the Miocene plant and arthropod species is extant, most are closely related to modern taxa, demonstrating potentially long-standing ecological associations with Mystacina.

  19. Late Miocene remagnetization within the internal sector of the Northern Apennines, Italy

    USGS Publications Warehouse

    Aiello, I.W.; Hagstrum, J.T.; Principi, G.

    2004-01-01

    Paleomagnetic and geologic evidence indicates that Upper Jurassic radiolarian cherts of both the Tuscan Cherts Formation (continental margin, Tuscan Units) and the Monte Alpe Cherts Formation (oceanic crust, Ligurian Units) were remagnetized during Miocene orogenesis of the Northern Apennines of Italy. Characteristic overprint magnetizations with reversed polarities have been found over a large area within the internal sector of the Northern Apennines, including eastern Liguria, Elba Island and the Thyrrenian margin, and west of the Middle Tuscan Ridge. The reversed-polarity overprint (average direction: D=177??, I=-52??, ??95=15??) was most likely acquired during Late Miocene uplift and denudation of the orogenic chain, and thermochemical remagnetization was a probable consequence of increased circulation of orogenic fluids. Similarly, mostly reversed-polarity directions of magnetization have been found by other workers in overlying post-orogenic Messinian sediments (D=177??, I=-57??, ??95=3??), which show little counterclockwise (CCW) vertical-axis rotation with respect to stable Europe (-8??5??). The Monte Alpe Cherts sampled at sites in the external sector of the Northern Apennines, close to major tectonic features, have normal- polarity overprint directions with in situ W-SW declinations. Since the overlying post-orogenic Messinian sediments have not been substantially rotated about vertical axes, the evidence points to an earlier,pre-Late Miocene remagnetization in the external parts of the orogenic chain. ?? 2004 Elsevier B.V. All rights reserved.

  20. Middle Miocene to present sediment transport and deposits in the Southeastern Weddell Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Huang, Xiaoxia; Jokat, Wilfried

    2016-04-01

    Understanding the transport and deposition of sediments along the Antarctic continental shelves helps to provide constraints on past ice sheet dynamics. Seismic stratigraphic and scientific drilling data from the Antarctic continental margins have provided much direct evidence concerning ice sheet evolution and sedimentation history. In this study, we describe a series of sedimentary features along the continental margin of the southeastern Weddell Sea to constrain glacial-influenced sedimentation processes from the Middle Miocene to the present. The Crary Trough Mouth Fan (CTMF), channel systems, Mix-system turbidity-contourites are investigated by using seismic reflection, sub-bottom profiler, and results from ODP Site 693. The sinuous, NE-SW-oriented turbidity-contourites are characterized by bathymetric highs that are more than 150 km wide, 700 km long, and have a sediment thickness of up to 2 km. The unique sedimentation environment of the southeastern Weddell Sea is controlled by a large catchment area and its fast (paleo-)ice streams feeding the Filchner Ronne Ice Shelf, turbidity/bottom currents as well as sea level changes. A remarkable increase in mass transport deposits (MTDs) in the Late Miocene and Early Pliocene strata has been related to, ice sheet loading, eustatic sea level fall, earthquakes, and overpressure of rapid sediment accumulation. Our seismic records also imply that fluctuations of East Antarctic ice sheet similar to those that occurred during the last glacial cycle might have been typical for southeastern Weddell Sea during glacial periods since the Late Miocene or even earlier.

  1. New magnetochronology of Late Miocene mammal fauna, NE Tibetan Plateau, China: Mammal migration and paleoenvironments

    NASA Astrophysics Data System (ADS)

    Ao, Hong; Zhang, Peng; Dekkers, Mark J.; Roberts, Andrew P.; An, Zhisheng; Li, Yongxiang; Lu, Fengyan; Lin, Shan; Li, Xingwen

    2016-01-01

    Lanzhou Basin lies on the northeastern margin of the Tibetan Plateau in western China and is a rich source of Oligocene-Miocene mammalian fossils. Obtaining precise age determinations for these fossils is important to address key questions concerning mammalian and environmental evolution in Asia associated with stepwise Tibetan Plateau uplift. Here we report a new magnetostratigraphic record for the Xingjiawan fluvio-lacustrine section from the northwestern margin of Lanzhou Basin that can be correlated to the geomagnetic polarity timescale with two options. The Late Miocene Xingjiawan Fauna is located either at the boundary between reversed polarity chron C4r.1r and normal polarity chron C4n.2n or at the boundary between subchrons C5r.1r and C5n.2n, with an estimated age of at least ∼8 Ma or perhaps as early as ∼11 Ma. Both age estimations imply that the fossil Stegodon in the Lanzhou Basin is the oldest known record of Stegodon worldwide; it predates the formerly oldest Stegodon find from Africa by at least one million years and perhaps by as many as four million years. This provides new evidence for an Asian origin of Stegodon. Together with other faunal components, a mixed woodland/grassland setting existed in the Lanzhou Basin during the Late Miocene, in contrast to its modern arid environment.

  2. First hominoid from the Miocene of Ethiopia and the evolution of the catarrhine elbow.

    PubMed

    Richmond, B G; Fleagle, J G; Kappelman, J; Swisher, C C

    1998-03-01

    The first known fossil ape from the early-middle Miocene of Fejej, Ethiopia, is described here. The specimen, FJ-18SB-68, is a partial ulna from a locality dated by 40Ar/39Ar and paleomagnetic methods to a minimum age of 16.18 MYA. Compared to a variety of extant and fossil ulnae, FJ-18SB-68 is most similar to Turkanapithecus, Proconsul, and Pliopithecus, and appears to have been an arboreal quadruped with substantial forearm rotational mobility. Among the extant ulnae, canonical variates analysis successfully discriminates platyrrhines from catarrhines and within the latter, cercopithecoids from hominoids. Basal catarrhines (e.g., Aegyptopithecus) are platyrrhine-like in their morphology. Two basic trends appear to evolve from this generalized template: one with less mobile and more habitually pronated forearms, as seen in living and fossil cercopithecoids (including Victoriapithecus and Paracolobus), and another with greater forearm rotational mobility in fossil and modern hominoids. Primitive Miocene apes, including Proconsul, Turkanapithecus, and FJ-18SB-68, share with extant hominoids a more laterally positioned and laterally facing radial notch and an incipient trochlear keel. This morphology, along with a large insertion area for m. brachialis, suggests a departure from the more habitually pronated hand posture of monkeys and may indicate greater climbing abilities in these arboreally quadrupedal apes. Later Miocene apes, such as Oreopithecus and Dryopithecus share additional morphological features with hominoids, indicating considerable suspensory and climbing capabilities.

  3. Late Miocene sedimentary environments in south-western Amazonia (Solimões Formation; Brazil)

    PubMed Central

    Gross, Martin; Piller, Werner E.; Ramos, Maria Ines; Douglas da Silva Paz, Jackson

    2011-01-01

    In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ18O and δ13C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake (“Lake Pebas”) or any influx of marine waters can be excluded for that region during the Late Miocene. PMID:26523089

  4. Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.

    PubMed

    Reuter, Markus; Kern, Andrea K; Harzhauser, Mathias; Kroh, Andreas; Piller, Werner E

    2013-04-01

    Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.

  5. Late Miocene sedimentary environments in south-western Amazonia (Solimões Formation; Brazil).

    PubMed

    Gross, Martin; Piller, Werner E; Ramos, Maria Ines; Douglas da Silva Paz, Jackson

    2011-08-01

    In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ(18)O and δ(13)C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake ("Lake Pebas") or any influx of marine waters can be excluded for that region during the Late Miocene.

  6. Terpenoid Compositions and Botanical Origins of Late Cretaceous and Miocene Amber from China

    PubMed Central

    Shi, Gongle; Dutta, Suryendu; Paul, Swagata; Wang, Bo; Jacques, Frédéric M. B.

    2014-01-01

    The terpenoid compositions of the Late Cretaceous Xixia amber from Central China and the middle Miocene Zhangpu amber from Southeast China were analyzed by gas chromatography-mass spectrometry (GC-MS) to elucidate their botanical origins. The Xixia amber is characterized by sesquiterpenoids, abietane and phyllocladane type diterpenoids, but lacks phenolic abietanes and labdane derivatives. The molecular compositions indicate that the Xixia amber is most likely contributed by the conifer family Araucariaceae, which is today distributed primarily in the Southern Hemisphere, but widely occurred in the Northern Hemisphere during the Mesozoic according to paleobotanical evidence. The middle Miocene Zhangpu amber is characterized by amyrin and amyrone-based triterpenoids and cadalene-based sesquiterpenoids. It is considered derived from the tropical angiosperm family Dipterocarpaceae based on these compounds and the co-occurring fossil winged fruits of the family in Zhangpu. This provides new evidence for the occurrence of a dipterocarp forest in the middle Miocene of Southeast China. It is the first detailed biomarker study for amber from East Asia. PMID:25354364

  7. Global warming and South Indian monsoon rainfall—lessons from the Mid-Miocene

    PubMed Central

    Reuter, Markus; Kern, Andrea K.; Harzhauser, Mathias; Kroh, Andreas; Piller, Werner E.

    2013-01-01

    Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3–4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall. PMID:27087778

  8. First occurrence of Platycladus from the upper Miocene of Southwest China and its phytogeographic implications.

    PubMed

    Wu, Jing-Yu; Ding, Su-Ting; Li, Qi-Jia; Zhao, Zhen-Rui; Sun, Bai-Nian

    2014-01-01

    Platycladus Spach is native to Central China, but its natural occurrences are very difficult to establish. According to molecular phylogenetic data, this genus might have originated since the Oligocene, but no fossil record has been reported. Here, we describe eight foliage branches from the upper Miocene in western Yunnan, Southwest China as a new species, P. yunnanensis sp. nov., which is characterized by foliage branches spread in flattened sprays, and leaves decussate, imbricate, scale-like and dimorphic. The leaves are amphistomatic, and the stomata are elliptical or oblong, haplocheilic, and monocyclic type. Based on a detailed comparison with the extant genera of Cupressaceae sensu lato, our fossils are classified into the genus Platycladus. The occurrence of P. yunnanensis sp. nov. indicates that this genus had a more southernly natural distribution in the late Miocene than at present. Molecular phylogeny and fossil records support a pre-Oligocene common ancestor for the genera Platycladus, Microbiota and Calocedrus. The separation of the three taxa was most likely caused by the arid belt across Central China during the Oligocene. In addition, the cooling down of the global temperature and the strengthening of Asian monsoon since the Miocene will further promote the migration of these genera.

  9. Badenian (Middle Miocene) echinoids and starfish from western Ukraine, and their biogeographic and stratigraphic significance

    NASA Astrophysics Data System (ADS)

    Radwański, Andrzej; Górka, Marcin; Wysocka, Anna

    2014-06-01

    Echinoderms from the Badenian (Middle Miocene) of the Fore-Carpathian Basin of western Ukraine are facies restricted. The Mykolaiv Beds, stratigraphically older, yielded the starfish Astropecten forbesi (complete skeletons), two genera of sand dollars (Parascutella, Parmulechinus), and numerous other echinoids of the genera Psammechinus , Echinocyamus, Spatangus, Hemipatagus, Echinocardium, Clypeaster, Echinolampas, and Conolampas. The stratigraphically younger, calcareous Ternopil Beds yielded Eucidaris (complete coronae, isolated spines), Arbacina , Brissus, and Rhabdobrissus. Sixteen species of echinoids are distinguished and/or commented. A new brissid, Rhabdobrissus tarnopolensis sp. nov., is established. A mass occurrence of some species (Psammechinus dubius and Hemipatagus ocellatus) contrasts with that of mass aggregations (sand dollars and Echinocardium leopolitanum) by dynamic events in selected layers of proximal tempestites. Of special note is the occurrence of very small specimens, interpreted as juveniles (`babies') having been swept out of their restricted biotopes (`nurseries'). Some species hitherto regarded as of Early Miocene age, and the problem of their persistence beyond the Fore-Carpathian Basin and/or migration into that basin during the Middle Miocene transgression are discussed.

  10. First Occurrence of Platycladus from the Upper Miocene of Southwest China and Its Phytogeographic Implications

    PubMed Central

    Li, Qi-Jia; Zhao, Zhen-Rui; Sun, Bai-Nian

    2014-01-01

    Platycladus Spach is native to Central China, but its natural occurrences are very difficult to establish. According to molecular phylogenetic data, this genus might have originated since the Oligocene, but no fossil record has been reported. Here, we describe eight foliage branches from the upper Miocene in western Yunnan, Southwest China as a new species, P. yunnanensis sp. nov., which is characterized by foliage branches spread in flattened sprays, and leaves decussate, imbricate, scale-like and dimorphic. The leaves are amphistomatic, and the stomata are elliptical or oblong, haplocheilic, and monocyclic type. Based on a detailed comparison with the extant genera of Cupressaceae sensu lato, our fossils are classified into the genus Platycladus. The occurrence of P. yunnanensis sp. nov. indicates that this genus had a more southernly natural distribution in the late Miocene than at present. Molecular phylogeny and fossil records support a pre-Oligocene common ancestor for the genera Platycladus, Microbiota and Calocedrus. The separation of the three taxa was most likely caused by the arid belt across Central China during the Oligocene. In addition, the cooling down of the global temperature and the strengthening of Asian monsoon since the Miocene will further promote the migration of these genera. PMID:25517767

  11. Thermochronologic constraints on the Miocene slip history of the South Tibetan detachment system in the Everest region, central Himalaya

    NASA Astrophysics Data System (ADS)

    Schultz, M.; Hodges, K. V.; Van Soest, M. C.; Wartho, J. A.

    2014-12-01

    North-dipping, low-angle normal faults of the South Tibetan detachment system (STDS) can be traced for a distance of more than 2000 km along strike and represent an important tectonic characteristic of the Miocene Himalayan-Tibetan orogenic system. Nowhere is the STDS better exposed than the N-S-trending Rongbuk Valley in southern Tibet, where it can be traced down dip from the summit of Everest for a distance of over 30 km before disappearing beneath the valley floor. This places a minimum constraint on Miocene displacement on the feature in this area, but some research groups have suggested ~200 km of displacement based on the difference in metamorphic pressures across the STDS and the very low (< 15˚) primary dip of the structure. We are exploring this issue further using developing (U-Th)/He and 40Ar/39Ar datasets from deformed footwall sillimanite gneisses and leucogranites. Data obtained thus far indicate relatively rapid cooling of the footwall after the intrusion of deformed leucogranites at ca. 16.7 Ma to muscovite 40Ar/39Ar closure temperatures (ca. 15.5-14.2 Ma) and zircon (U-Th)/He closure temperatures (ca. 14.5-11 Ma). We attribute this cooling to tectonic denudation related to ca. 16 Ma STDS slip. Although the (U-Th)/He systematics of apatites from these rocks is complex, our current interpretation of available data places cooling through the ca. 75˚C closure isotherm at ca. 8-9 Ma, which would suggest a significant reduction in cooling rate that is observed in our inverse model runs of the 1D program, HeFTy. Ongoing analyses of footwall samples from ~8 km to the north of our Rongbuk sample localities in the Ra Chu river valley will greatly strengthen our datasets. With the Ra Chu analyses, our datasets will constrain the cooling history of the footwall for more than 20 km perpendicular to the strike of the detachment. Our presentation will also incorporate results from the program Pecube that will contribute to our calculation of the slip rate by

  12. Interim report on the ground-water resources of Manatee County, Florida

    USGS Publications Warehouse

    Peek, Harry M.; Anders, Robert B.

    1955-01-01

    Manatee County comprises an area of about 800 square miles adjacent to the Gulf of Mexico in the southwestern part of the Florida peninsula. The county is underlain at depths ranging from about 200 to 350 feet by a series of limestone formations of Tertiary age having a total thickness of several thousand feet. The upper part of the limestone section consists of the Ocala group of Eocene age, the Suwannee limestone of Oligocene age, and the Tampa formation of early Miocene age. These limestone formations are overlain by the Hawthorn formation of middle Miocene age which consists of interbedded clay, limestone, and sand. The Hawthorn is overlain by undifferentiated deposits of sand, limestone, and shell of Pliocene(?) and Pleistocene age that range in thickness from a few feet to about 75 feet.

  13. Palynology, paleoclimatology and correlation of middle Miocene beds from Porcupine River (locality 90-1), Alaska

    USGS Publications Warehouse

    White, J.M.; Ager, T.A.

    1994-01-01

    Beds in the Upper Ramparts Canyon of the Porcupine River, Alaska (67?? 20' N, 141?? 20' W), yielded a flora rich in pollen of hardwood genera now found in the temperate climates of North America and Asia. The beds are overlain or enclosed by two basalt flows which were dated to 15.2 ?? 0.1 Ma by the 40Ar 39Ar method, fixing the period of the greatest abundance of warm-loving genera to the early part of the middle Miocene. The assemblage is the most northern middle Miocene flora known in Alaska. Organic bed 1 underlies the basalt and is older than 15.2 Ma, but is of early to middle Miocene age. The pollen assemblage from organic bed 1 is dominated by conifer pollen from the pine and redwood-cypress-yew families with rare occurrences of temperate hardwoods. Organic bed 2 is a forest floor containing redwood trees in life position, engulfed by the lowest basalt flow. A pine log has growth rings up to 1 cm thick. Organic beds 3 and 4 comprise lacustrine sediment and peat between the two basalt flows. Their palynoflora contain conifers and hardwood genera, of which about 40% have modern temperate climatic affinities. Hickory, katsura, walnut, sweet gum, wingnut, basswood and elm pollen are consistently present, and beech and oak alone make up about 20% of the pollen assemblage. A warm high latitude climate is indicated for all of the organic beds, but organic bed 3 was deposited under a time of peak warmth. Climate data derived by comparison with modern east Asian vegetation suggest that, at the time of deposition of organic bed 3, the Mean Annual Temperature (MAT) was ca. 9??C, the Warm Month Mean Temperature (WMMT) was ??? 20??C and the Cold Month Mean Temperature (CMMT) was ca. -2??C. In contrast, the modern MAT for the region is -8.6??C, WMMT is 12.6??C and CMMT is -28??C. Organic beds 3 and 4 correlate to rocks of the middle Miocene-late Seldovian Stage of Cook Inlet and also probably correlate to, and more precisely date, the lower third of the Suntrana Formation

  14. An objective statistical test for eccentricity forcing of Oligo-Miocene climate

    NASA Astrophysics Data System (ADS)

    Proistosescu, C.; Huybers, P.; Maloof, A. C.

    2008-12-01

    We seek a maximally objective test for the presence of orbital features in Oligocene and Miocene δ18O records from marine sediments. Changes in Earth's orbital eccentricity are thought to be an important control on the long term variability of climate during the Oligocene and Miocene Epochs. However, such an important control from eccentricity is surprising because eccentricity has relatively little influence on Earth's annual average insolation budget. Nevertheless, if significant eccentricity variability is present, it would provide important insight into the operation of the climate system at long timescales. Here we use previously published data, but using a chronology which is initially independent of orbital assumptions, to test for the presence of eccentricity period variability in the Oligocene/Miocene sediment records. In contrast to the sawtooth climate record of the Pleistocene, the Oligocene and Miocene climate record appears smooth and symmetric and does not reset itself every hundred thousand years. This smooth variation, as well as the time interval spanning many eccentricity periods makes Oligocene and Miocene paleorecords very suitable for evaluating the importance of eccentricity forcing. First, we construct time scales depending only upon the ages of geomagnetic reversals with intervening ages linearly interpolated with depth. Such a single age-depth relationship is, however, too uncertain to assess whether orbital features are present. Thus, we construct a second depth-derived age-model by averaging ages across multiple sediment cores which have, at least partly, independent accumulation rate histories. But ages are still too uncertain to permit unambiguous detection of orbital variability. Thus we employ limited tuning assumptions and measure the degree by orbital period variability increases using spectral power estimates. By tuning we know that we are biasing the record toward showing orbital variations, but we account for this bias in our

  15. The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system

    NASA Astrophysics Data System (ADS)

    Latrubesse, Edgardo M.; Cozzuol, Mario; da Silva-Caminha, Silane A. F.; Rigsby, Catherine A.; Absy, Maria Lucia; Jaramillo, Carlos

    2010-05-01

    On the basis of paleontological content (vertebrates and palynology) and facies analysis from river banks, road cuts, and three wells, we have assigned the uppermost levels of the Solimões Formation in western Amazonia, Brazil, to the Late Miocene. The vertebrate fossil record from outcropping sediments is assigned to the Huayquerian-Mesopotamian mammalian biozones, spanning 9-6.5 Ma. Additionally, we present results that demonstrate that deposits in Peruvian Amazonia attributed to Miocene tidal environments are actually fluvial sediments that have been misinterpreted (both environmentally and chronologically) by several authors. The entire Late Miocene sequence was deposited in a continental environment within a subsiding basin. The facies analysis, fossil fauna content, and palynological record indicate that the environment of deposition was dominated by avulsive rivers associated with megafan systems, and avulsive rivers in flood basins (swamps, lakes, internal deltas, and splays). Soils developed on the flatter, drier areas, which were dominated by grasslands and gallery forest in a tropical to subtropical climate. These Late Miocene sediments were deposited from westward of the Purus arch up to the border of Brazil with Peru (Divisor Ranges) and Bolivia (Pando block). Eastward of the Iquitos structural high, however, more detailed studies, including vertebrate paleontology, need to be performed to calibrate with more precision the ages of the uppermost levels of the Solimões Formation. The evolution of the basin during the late Miocene is mainly related to the tectonic behavior of the Central Andes (˜ 3°-15°S). At approximately 5 Ma, a segment of low angle of subduction was well developed in the Nazca Plate, and the deformation in the Subandean foreland produced the inland reactivation of the Divisor/Contamana Ranges and tectonic arrangements in the Eastern Andes. During the Pliocene southwestern Brazilian Amazonia ceased to be an effective sedimentary

  16. The Cenozoic Diversity of Agglutinated Foraminifera - Evidence for a late Oligocene to early Miocene diversification event

    NASA Astrophysics Data System (ADS)

    Kaminski, Michael; Setoyama, Eiichi; Kender, Sev; Cetean, Claudia

    2014-05-01

    The agglutinated foraminifera are among the most abundant micro-organisms in the deep marine environment and have a diversity record extending back to the late Precambrian. We present an updated diversity curve for agglutinated foraminiferal genera based on the stratigraphic ranges of all the agglutinated genera recognized as valid in the classification of Kaminski (2014). The data set for this analysis is based on the stratigraphic ranges of agglutinated genera published in Foraminiferal Genera and their Classification, which has been subsequently updated based on published studies and our new observations. The mean standing diversity of agglutinated foraminiferal genera was compiled by counting the number of boundary crossers rather than the number of genera in each stage. In this study, we report the stratigraphic and geographical occurrence of a benthic foraminiferal diversification event that has previously received little attention. In the latest Oligocene to earliest Miocene a number of trochospiral agglutinated genera with alveolar or canaliculate walls first appeared in the fossil record. Our studies of late Oligocene of the Congo fan, offshore Angola (Kender et al., 2008; Cetean and Kaminski, 2011) have revealed a diverse assemblage that includes new taxa of deep-water agglutinated foraminifera. In a biostratigraphic study of the Miocene foraminiferal assemblages Kender et al. (2008) noted steadily increasing diversity and proportions of infaunal agglutinated foraminiferal morphotypes over the lower Miocene interval. The proportion of infaunal agglutinated foraminifera assigned to the order Textularida increased dramatically in the lower mid-Miocene, suggesting expansion of the oxygen minimum zone into deeper waters. In addition to the trochospiral alveolar genera, several species of Reticulophragmium and Cyclammina display rapid diversification into numerous separate lineages that are at present not reflected in our generic diversity record owing to

  17. Palinspastic reconstruction of southeastern California and southwestern Arizona for the middle Miocene

    NASA Astrophysics Data System (ADS)

    Richard, Stephen M.

    1992-12-01

    A paleogeographic reconstruction of southeastern California and southwestern Arizona at 10 Ma was made based on available geologic and geophysical data. Clockwise rotation of 39 deg was reconstructed in the eastern Transverse Ranges, consistent with paleomagnetic data from late Miocene volcanic rocks, and with slip estimates for left-lateral faults within the eastern Transverse Ranges and NW-trending right lateral faults in the Mojave Desert. This domain of rotated rocks is bounded by the Pinto Mountain fault on the north. In the absence of evidence for rotation of the San Bernardino Mountains or for significant right slip faults within the San Bernardino Mountains, the model requires that the late Miocene Pinto Mountain fault become a thrust fault gaining displacement to the west. The Squaw Peak thrust system of Meisling and Weldon may be a western continuation of this fault system. The Sheep Hole fault bounds the rotating domain on the east. East of this fault an array of NW-trending right slip faults and south-trending extensional transfer zones has produced a basin and range physiography while accumulating up to 14 km of right slip. This maximum is significantly less than the 37.5 km of right slip required in this region by a recent reconstruction of the central Mojave Desert. Geologic relations along the southern boundary of the rotating domain are poorly known, but this boundary is interpreted to involve a series of curved strike slip faults and non-coaxial extension, bounded on the southeast by the Mammoth Wash and related faults in the eastern Chocolate Mountains. Available constraints on timing suggest that Quaternary movement on the Pinto Mountain and nearby faults is unrelated to the rotation of the eastern Transverse Ranges, and was preceded by a hiatus during part of Pliocene time which followed the deformation producing the rotation. The reconstructed Clemens Well fault in the Orocopia Mountains, proposed as a major early Miocene strand of the San

  18. Palinspastic reconstruction of southeastern California and southwestern Arizona for the middle Miocene

    NASA Technical Reports Server (NTRS)

    Richard, Stephen M.

    1992-01-01

    A paleogeographic reconstruction of southeastern California and southwestern Arizona at 10 Ma was made based on available geologic and geophysical data. Clockwise rotation of 39 deg was reconstructed in the eastern Transverse Ranges, consistent with paleomagnetic data from late Miocene volcanic rocks, and with slip estimates for left-lateral faults within the eastern Transverse Ranges and NW-trending right lateral faults in the Mojave Desert. This domain of rotated rocks is bounded by the Pinto Mountain fault on the north. In the absence of evidence for rotation of the San Bernardino Mountains or for significant right slip faults within the San Bernardino Mountains, the model requires that the late Miocene Pinto Mountain fault become a thrust fault gaining displacement to the west. The Squaw Peak thrust system of Meisling and Weldon may be a western continuation of this fault system. The Sheep Hole fault bounds the rotating domain on the east. East of this fault an array of NW-trending right slip faults and south-trending extensional transfer zones has produced a basin and range physiography while accumulating up to 14 km of right slip. This maximum is significantly less than the 37.5 km of right slip required in this region by a recent reconstruction of the central Mojave Desert. Geologic relations along the southern boundary of the rotating domain are poorly known, but this boundary is interpreted to involve a series of curved strike slip faults and non-coaxial extension, bounded on the southeast by the Mammoth Wash and related faults in the eastern Chocolate Mountains. Available constraints on timing suggest that Quaternary movement on the Pinto Mountain and nearby faults is unrelated to the rotation of the eastern Transverse Ranges, and was preceded by a hiatus during part of Pliocene time which followed the deformation producing the rotation. The reconstructed Clemens Well fault in the Orocopia Mountains, proposed as a major early Miocene strand of the San

  19. Paleomagnetic quantification of upper-plate deformation during Miocene detachment faulting in the Mohave Mountains, Arizona

    USGS Publications Warehouse

    Pease, V.; Hillhouse, J.W.; Wells, R.E.

    2005-01-01

    Paleomagnetic data from Miocene (???20 Ma) volcanic rocks and dikes of west central Arizona reveal the tilt history of Proterozoic crystalline rocks in the hanging wall of the Chemehuevi-Whipple Mountains detachment fault. We obtained magnetization data from dikes and flows in two structural blocks encompassing Crossman Peak and Standard Wash in the Mohave Mountains. In the Crossman block the dike swarm records two components of primary magnetization: (1) CNH, a normal polarity, high-unblocking-temperature or high-coercivity component (inclination, I = 48.5??, declination, D = 6.4??), and (2) CRHm, a reversed polarity, high-temperature or high-coercivity component (I = -33.6??, D = 197.5??). Argon age spectra imply that the dikes have not been reheated above 300??C since their emplacement, and a baked-contact test suggests that the magnetization is likely to be Miocene in age. CRHm deviates from the expected direction of the Miocene axial dipole field and is best explained as a result of progressive tilting about the strike of the overlying andesite flows. These data suggest that the Crossman block was tilted 60?? to the southwest prior to intrusion of the vertical dike swarm, and the block continued to tilt during a magnetic field reversal to normal polarity (CNH). Miocene dikes in the Crossman block are roughly coplanar, so the younger dikes with normal polarity magnetization intruded along planes of weakness parallel to the earlier reversed polarity swarm. An alternative explanation involves CNH magnetization being acquired later during hydrothermal alteration associated with the final stages of dike emplacement. In the Standard Wash block, the primary component of magnetization is a dual-polarity, high-temperature or high-coercivity component (SWHl, I = 7.2??,D= 0.7??). To produce agreement between the expected Miocene magnetic direction and the SWH component requires (1) correcting for a 56?? tilt about the strike of flow bedding and (2) removing a

  20. The strontium isotope seawater curve during the early Middle Miocene and its relation to paleoceanographic events

    SciTech Connect

    Hodell, D.A. . Dept. of Geology); Woodruff, F. . Dept. Geological Sciences)

    1992-01-01

    Breaks in slope of the strontium isotope seawater curve signal fundamental changes in either rates of continental weathering, seafloor spreading (i.e., tectonic reorganizations), or submarine dissolution of marine carbonates. The authors conducted a detailed study of the change in slope of the strontium isotopic seawater curve that occurred during the early middle Miocene in three Pacific DSDP sites (289, 574, and 588). The change in slope from the rapid rise in Sr-87/Sr-86 of the early Miocene (60 ppm/Ma) to the less rapid increase of the mid- and late Miocene (22 ppm/Ma) occurred between two periods of maximum [delta]C-13 values dated between 15.5 and 15.2 Ma. This internal was followed by relatively constant Sr-87/Sr-86 values (averaging 0.70878) between 15.2 and 14.2 Ma. Sr-87/Sr-86 ratios began to increase again after 14.2 Ma, but at a reduced rate compared to the early Miocene. The break in slope in Sr-87/Sr-86 preceded the mid-Miocene increase in [delta]O-18 that represents ice growth on Antarctica, which began at 14.9 Ma and increased rapidly after 14.2 Ma. In 2 out of 3 of the sites, the break in Sr-slope between 15.5 and 15.2 Ma is accompanied by a small, but significant, decrease in Sr-87/Sr-86 values. They speculate, that this decrease in Sr-87/Sr-86 may have been related to massive dissolution of older carbonate on the sea floor associated with NH2B (Neogene Hiatus 2 of Keller and Barron, 1983). This event may have important implications for changes in carbonate chemistry of the oceans. Numerical modeling of the strontium isotope budget will be used to test the feasibility of this mechanism and to estimate the volume and age of dissolved carbonate needed to produce the observed decrease in Sr-87/Sr-86.

  1. Dated molecular phylogenies indicate a Miocene origin for Arabidopsis thaliana

    PubMed Central

    Beilstein, Mark A.; Nagalingum, Nathalie S.; Clements, Mark D.; Manchester, Steven R.; Mathews, Sarah

    2010-01-01

    Dated molecular phylogenies are the basis for understanding species diversity and for linking changes in rates of diversification with historical events such as restructuring in developmental pathways, genome doubling, or dispersal onto a new continent. Valid fossil calibration points are essential to the accurate estimation of divergence dates, but for many groups of flowering plants fossil evidence is unavailable or limited. Arabidopsis thaliana, the primary genetic model in plant biology and the first plant to have its entire genome sequenced, belongs to one such group, the plant family Brassicaceae. Thus, the timing of A. thaliana evolution and the history of its genome have been controversial. We bring previously overlooked fossil evidence to bear on these questions and find the split between A. thaliana and Arabidopsis lyrata occurred about 13 Mya, and that the split between Arabidopsis and the Brassica complex (broccoli, cabbage, canola) occurred about 43 Mya. These estimates, which are two- to threefold older than previous estimates, indicate that gene, genomic, and developmental evolution occurred much more slowly than previously hypothesized and that Arabidopsis evolved during a period of warming rather than of cooling. We detected a 2- to 10-fold shift in species diversification rates on the branch uniting Brassicaceae with its sister families. The timing of this shift suggests a possible impact of the Cretaceous–Paleogene mass extinction on their radiation and that Brassicales codiversified with pierid butterflies that specialize on mustard-oil–producing plants. PMID:20921408

  2. Episodic exhumation of the Greater Himalayan Sequence since the Miocene constrained by fission track thermochronology in Nyalam, central Himalaya

    NASA Astrophysics Data System (ADS)

    Wang, An; Garver, John I.; Wang, Guocan; Smith, Jacqueline A.; Zhang, Kexin

    2010-12-01

    The Greater Himalayan Sequence (GHS), which makes up the core of the Himalayan orogen, has an uppermost tectonic contact defined by the South Tibetan Detachment System (STDS) and a lower tectonic contact defined by the Main Central Thrust (MCT). The GHS occurs as one of the most important tectostratigraphic units for deciphering processes related to tectonic and climatic exhumation across the orogen. Zircon and apatite fission track (ZFT, AFT) dating were carried out along a transect in Nyalam, central Himalaya in southern Tibet to constrain cooling driven by orogenic process since the middle Miocene. The hanging wall of the STDS yields an essentially unreset Jurassic ZFT age in the Jurassic strata. However, below the STDS within the GHS there is a clear and distinct thermal signal of cooling related to exhumation. In the footwall and within the GHS, the rocks have ZFT ages of middle Miocene to Pliocene, and AFT ages of late Miocene to Quaternary that get younger downward and away from the STDS. In combination with thermal structure modeling, a two-part episodic model, which is widely compatible with existing thermochronological data, is proposed for cooling and exhumation of the GHS since the middle Miocene: [1] middle Miocene; and [2] Pliocene to Quaternary (Recent). The middle Miocene cooling is suggested to have resulted from a rapid tectonic unroofing by down-to-the-north slip on the STDS. The tectonic exhumation was also recorded by several other thermochronological systems (e.g. biotite 40Ar/ 39Ar) with concordant middle Miocene cooling ages in different structural positions across the GHS. Post middle Miocene ZFT and AFT cooling ages in the lower part of the GHS suggest accelerated cooling by climate-enhanced erosional exhumation, which was initiated in the late Miocene to Pliocene and was dramatic in the Quaternary to Recent. Thermochronological data and modeling further imply that the present Himalayan topographic front may have been shaped essentially by

  3. Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates.

    PubMed

    Bibi, Faysal; Kraatz, Brian; Craig, Nathan; Beech, Mark; Schuster, Mathieu; Hill, Andrew

    2012-08-23

    Many living vertebrates exhibit complex social structures, evidence for the antiquity of which is limited to rare and exceptional fossil finds. Living elephants possess a characteristic social structure that is sex-segregated and multi-tiered, centred around a matriarchal family and solitary or loosely associated groups of adult males. Although the fossil record of Proboscidea is extensive, the origin and evolution of social structure in this clade is virtually unknown. Here, we present imagery and analyses of an extensive late Miocene fossil trackway site from the United Arab Emirates. The site of Mleisa 1 preserves exceptionally long trackways of a herd of at least 13 individuals of varying size transected by that of a single large individual, indicating the presence of both herding and solitary social modes. Trackway stride lengths and resulting body mass estimates indicate that the solitary individual was also the largest and therefore most likely a male. Sexual determination for the herd is equivocal, but the body size profile and number of individuals are commensurate with those of a modern elephant family unit. The Mleisa 1 trackways provide direct evidence for the antiquity of characteristic and complex social structure in Proboscidea.

  4. From Problem Taxa to Problem Solver: A New Miocene Family, Tranatocetidae, Brings Perspective on Baleen Whale Evolution

    PubMed Central

    Gol’din, Pavel; Steeman, Mette Elstrup

    2015-01-01

    Miocene baleen whales were highly diverse and included tens of genera. However, their taxonomy and phylogeny, as well as relationships with living whales, are still a subject of controversy. Here, “Mesocetus” argillarius, a poorly known specimen from Denmark, is redescribed with a focus on the cranial anatomy. It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae. The whales of this family have the rostral bones either overriding or dividing the frontals; the rostral bones are contacting the parietals and nasals dividing the maxillae on the vertex; the occipital shield is dorsoventrally bent. The tympanic bulla is particularly characteristic of this family featuring a short, narrow anterior portion with a rounded or squared anterior end and a wider and higher posterior portion that is swollen in the posteroventral area. A phylogenetic analysis including 51 taxa supports a monophyletic group comprising most Neogene and modern whales, with Tranatocetidae being possibly closer related to Balaenopteridae (rorquals) than to Cetotheriidae. Tranatocetidae exhibit a charahteristic bulla shape. In fact, all Neogene and modern mysticete families examined have a unique shape of the tympanic bulla that is diagnostic at family-level. Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits. This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years. PMID:26331471

  5. Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates

    PubMed Central

    Bibi, Faysal; Kraatz, Brian; Craig, Nathan; Beech, Mark; Schuster, Mathieu; Hill, Andrew

    2012-01-01

    Many living vertebrates exhibit complex social structures, evidence for the antiquity of which is limited to rare and exceptional fossil finds. Living elephants possess a characteristic social structure that is sex-segregated and multi-tiered, centred around a matriarchal family and solitary or loosely associated groups of adult males. Although the fossil record of Proboscidea is extensive, the origin and evolution of social structure in this clade is virtually unknown. Here, we present imagery and analyses of an extensive late Miocene fossil trackway site from the United Arab Emirates. The site of Mleisa 1 preserves exceptionally long trackways of a herd of at least 13 individuals of varying size transected by that of a single large individual, indicating the presence of both herding and solitary social modes. Trackway stride lengths and resulting body mass estimates indicate that the solitary individual was also the largest and therefore most likely a male. Sexual determination for the herd is equivocal, but the body size profile and number of individuals are commensurate with those of a modern elephant family unit. The Mleisa 1 trackways provide direct evidence for the antiquity of characteristic and complex social structure in Proboscidea. PMID:22357934

  6. Evolution of Miocene footwall-derived coarse-grained deltas, Gulf of Suez, Egypt: Implications for exploration

    SciTech Connect

    Gawthorpe, R.L. ); Hurst, J.M.; Sladen, C.P. )

    1990-07-01

    The Miocene Abu Alaqa Group, exposed on the eastern side of the Gulf of Suez, contains a series of coarse-grained delta deposits located in the hanging wall of the northwest-trending East Margin fault zone. Seven major fan sequences have been identified. The first three fan sequences are aggradational and cover an area of less than 2 km{sup 2}. The sequences are dominated by pebble/boulder conglomerates, with predominantly sigmoidal, high-angle clinoforms (between 15 and 25{degree}) as much as 150 m high. These fan sequences represent talus cones and fan deltas, which were probably deposited during activity on the fault zone and are situated at transfer segments. The other four fan sequences are predominantly progradational, consisting of mixed carbonate-siliciclastic braid deltas with local reefs. They are less than 30 m high, have low-angle clinoforms (< 15{degree}), and cover an area as large as 30 km{sup 2}. These fan sequences were deposited during a phase of tectonic quiescence when sedimentary and eustatic mechanisms determined sand-body geometry. These fan deltas and braid deltas may form hydrocarbon traps in the subsurface and create localized reservoirs. The rapid facies change into basinal fines creates an excellent lateral stratigraphic seal, but vertical and lateral seals across the fault zone generally are not well developed. 8 figs.

  7. Chewing through the Miocene: an examination of the feeding musculature in the ground sloth Hapalops from South America (Mammalia: Pilosa).

    PubMed

    Naples, Virginia L; McAfee, Robert K

    2014-01-01

    Hapalops, a smaller-sized and early sloth of the Megatheroidea, appeared in the middle Miocene Santa Cruz formation of Argentina. This genus is part of the group from which later, larger megatheroids arose, i.e., Nothrotheriops and Megatherium. Many cranial characters support this idea; however Hapalops is not merely a smaller antecedent of the later forms. Specifically, Hapalops retains short anterior caniniform teeth, and a temporomandibular joint elevated above the cheek tooth row; a combination distinct among sloths. An elevated temporomandibular joint occurs in Bradypus, a tree sloth with anterior chisel-shaped teeth instead of caniniforms, and the tree sloth Choloepus, which is aligned with the megalonychids, has anterior caniniforms. Hapalops has an elongated zygomatic ascending process that is reminiscent of that in Bradypus; however, the Bradypus skull is extremely foreshortened while that of Hapalops is elongated, as in nothrotheres, but not deepened as in megatheres. Previous work identified many sloth cranial character complexes, and functional limitations on skull feature combinations. The unique Hapalops character patterns indicate a selective feeder with a mediolaterally oriented grinding stroke during mastication.

  8. From Problem Taxa to Problem Solver: A New Miocene Family, Tranatocetidae, Brings Perspective on Baleen Whale Evolution.

    PubMed

    Gol'din, Pavel; Steeman, Mette Elstrup

    2015-01-01

    Miocene baleen whales were highly diverse and included tens of genera. However, their taxonomy and phylogeny, as well as relationships with living whales, are still a subject of controversy. Here, "Mesocetus" argillarius, a poorly known specimen from Denmark, is redescribed with a focus on the cranial anatomy. It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae. The whales of this family have the rostral bones either overriding or dividing the frontals; the rostral bones are contacting the parietals and nasals dividing the maxillae on the vertex; the occipital shield is dorsoventrally bent. The tympanic bulla is particularly characteristic of this family featuring a short, narrow anterior portion with a rounded or squared anterior end and a wider and higher posterior portion that is swollen in the posteroventral area. A phylogenetic analysis including 51 taxa supports a monophyletic group comprising most Neogene and modern whales, with Tranatocetidae being possibly closer related to Balaenopteridae (rorquals) than to Cetotheriidae. Tranatocetidae exhibit a charahteristic bulla shape. In fact, all Neogene and modern mysticete families examined have a unique shape of the tympanic bulla that is diagnostic at family-level. Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits. This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.

  9. Chewing through the Miocene: an examination of the feeding musculature in the ground sloth Hapalops from South America (Mammalia: Pilosa)

    PubMed Central

    Naples, Virginia L.; McAfee, Robert K.

    2014-01-01

    Hapalops, a smaller-sized and early sloth of the Megatheroidea, appeared in the middle Miocene Santa Cruz formation of Argentina. This genus is part of the group from which later, larger megatheroids arose, i.e., Nothrotheriops and Megatherium. Many cranial characters support this idea; however Hapalops is not merely a smaller antecedent of the later forms. Specifically, Hapalops retains short anterior caniniform teeth, and a temporomandibular joint elevated above the cheek tooth row; a combination distinct among sloths. An elevated temporomandibular joint occurs in Bradypus, a tree sloth with anterior chisel-shaped teeth instead of caniniforms, and the tree sloth Choloepus, which is aligned with the megalonychids, has anterior caniniforms. Hapalops has an elongated zygomatic ascending process that is reminiscent of that in Bradypus; however, the Bradypus skull is extremely foreshortened while that of Hapalops is elongated, as in nothrotheres, but not deepened as in megatheres. Previous work identified many sloth cranial character complexes, and functional limitations on skull feature combinations. The unique Hapalops character patterns indicate a selective feeder with a mediolaterally oriented grinding stroke during mastication. PMID:25075299

  10. A multi-gene dataset reveals a tropical New World origin and Early Miocene diversification of croakers (Perciformes: Sciaenidae).

    PubMed

    Lo, Pei-Chun; Liu, Shu-Hui; Chao, Ning Labbish; Nunoo, Francis K E; Mok, Hin-Kiu; Chen, Wei-Jen

    2015-07-01

    Widely distributed groups of living animals, such as the predominantly marine fish family Sciaenidae, have always attracted the attention of biogeographers to document the origins and patterns of diversification in time and space. In this study, the historical biogeography of the global Sciaenidae is reconstructed within a molecular phylogenetic framework to investigate their origin and to test the hypotheses explaining the present-day biogeographic patterns. Our data matrix comprises six mitochondrial and nuclear genes in 93 globally sampled sciaenid species from 52 genera. Within the inferred phylogenetic tree of the Sciaenidae, we identify 15 main and well-supported lineages; some of which have not been recognized previously. Reconstruction of habitat preferences shows repeated habitat transitions between marine and euryhaline environments. This implies that sciaenids can easily adapt to some variations in salinity, possibly as the consequence of their nearshore habitats and migratory life history. Conversely, complete marine/euryhaline to freshwater transitions occurred only three times, in South America, North America and South Asia. Ancestral range reconstruction analysis concomitant with fossil evidence indicates that sciaenids first originated and diversified in the tropical America during the Oligocene to Early Miocene before undergoing two range expansions, to Eastern Atlantic and to the Indo-West Pacific where a maximum species richness is observed. The uncommon biogeographic pattern identified is discussed in relation to current knowledge on origin of gradients of marine biodiversity toward the center of origin hypothesis in the Indo-West Pacific.

  11. Relating Major Surface Processes to the Deep Earth — The Importance of the Miocene

    NASA Astrophysics Data System (ADS)

    Potter, P. E.; Szatmari, P.

    2012-12-01

    Many global scale tectonic, oceanic and climate changes began in the Tertiary with global tectonics as the underlying driving force and changed the world. In full flower by the beginning of the Middle Miocene around 16 Ma, these changes continued through the Late Miocene into the present so we can firmly say that most of our modern world, continental glaciations excepted, began in the Middle and Late Miocene. We summarize in a flow diagram how the major earth surface processes active in the Miocene are related to the Deep Earth as understood by recent advances in seismic tomography. This 11 Ma interval had two global orogenic zones, the Alpine-Tethyan orogen from Gibraltar across southern Asia into Vietnam and around the Pacific Rim, both crustal expressions of downwellings taking place, especially in the upper mantle. These downwellings are balanced by upwellings in the lower mantle in and on the rim of the African and Pacific superplumes, which are large, low-shear velocity provinces; part of the rising plumes originated from the most extensively melted regions of the core-mantle boundary layer, D", where heat flow from the outer core is highest. Together these up-and downwellings indicate that mantle convection extended, at least periodically, through the whole mantle and reflected lateral variations in convection and heat flow in the cooling and slowly crystallizing outer core. Correlation of mantle convection with surface features is most evident in the uppermost mantle whose dynamic topography is readily reflected by the subsidence and tilting of continents moving toward the downwelling zones. Because they are closely synchronous, these two orogenic belts had enormous consequences for the earth's surface, and because they are close to us in time, they are easy to study and sample. Thus the Miocene is ideal to study for both its many global intra connections and for their link to the Deep Earth. As these two orogenies developed, they changed a global warm

  12. Post-Miocene Right Separation on the San Gabriel and Vasquez Creek Faults, with Supporting Chronostratigraphy, Western San Gabriel Mountains, California

    USGS Publications Warehouse

    Beyer, Larry A.; McCulloh, Thane H.; Denison, Rodger E.; Morin, Ronald W.; Enrico, Roy J.; Barron, John A.; Fleck, Robert J.

    2009-01-01

    on the Vasquez Creek Fault adds to the generally accepted 22-23 km of middle-late Miocene right separation established for the San Gabriel Fault east of the bifurcation, resulting in total right separation of 34-35 km northwest of the bifurcation. Clast sizes and lithologies in Saugus Formation deformed alluvial fan deposits in the Gold and Little Tujunga Canyons area indicate that alluvial stream flow was from the north or north-northeast. The alluvial fan complex is beheaded at the San Gabriel Fault Zone, and no correlative deposits have been found north of the fault zone. Likely sources of several distinctive clast types are east of the bifurcation and north of the Vasquez Creek Fault. Combining these data with right slip caused by the 34 deg +-6 deg of clockwise local block rotation suggests that post-Saugus Formation (<2.6 to 0.78 Ma) right separation along the fault zone is 4+-2 km. The fossils, lithology, and age of the Gold Canyon beds correlate with the basal Pico Formation. The beds presumably connected southward or southwestward to a more open marine setting. A search for correlative strata to the south and southwest found that some strata previously mapped as Towsley Formation correlate with the Modelo Formation. Oyster spat in some Modelo Formation beds are the first recorded fossil occurrences and are especially remarkable because of associations with Miocene bathyal benthic foraminifers, planktonic calcareous nannofossils, and diatoms. Topanga Group basalt resting on basement rocks between Little and Big Tujunga Canyons gives an age of 16.14+-0.05 Ma from 40Ar/39Ar analysis. Improved understanding of the upper Miocene stratigraphy indicates large early movement on the eastern Santa Susana Fault at about 7-6 Ma.

  13. Phylogeny and historical biogeography of ancient assassin spiders (Araneae: Archaeidae) in the Australian mesic zone: evidence for Miocene speciation within Tertiary refugia.

    PubMed

    Rix, Michael G; Harvey, Mark S

    2012-01-01

    years ago), with tropical and subtropical taxa diverging in the early-mid Miocene, prior to southern and temperate taxa in the mid-late Miocene. Area cladograms reconciled with Bayesian chronograms for all known Archaeidae in southern and south-eastern Australia revealed seven potentially vicariant biogeographic barriers in eastern Queensland, New South Wales and southern Australia, each proposed and discussed in relation to other mesic zone taxa. Five of these barriers were inferred as being of early Miocene age, and implicated in the initial vicariant separation of endemic regional clades. Phylogeographic results for Australian Archaeidae are congruent with a model of sequential allopatric speciation in Tertiary refugia, as driven by the contraction and fragmentation of Australia's mesic biomes during the Miocene. Assassin spiders clearly offer great potential for further testing historical biogeographic processes in temperate and eastern Australia, and are a useful group for better understanding the biology and biogeography of the Australian mesic zone.

  14. Early to middle Miocene vegetation history of Antarctica supports eccentricity-paced warming intervals during the Antarctic icehouse phase

    NASA Astrophysics Data System (ADS)

    Griener, Kathryn W.; Warny, Sophie; Askin, Rosemary; Acton, Gary

    2015-04-01

    Recent palynological evidence from the upper section (< 664 mbsf) of the Miocene ANDRILL 2A (AND-2A) core in the Ross Sea indicated a brief warm period during the Mid Miocene Climatic Optimum (MMCO), during Antarctica's icehouse phase. The nature of other Miocene climate fluctuations in Antarctica remains poorly resolved. Here, we present new palynological data from the lower section of the AND-2A core (> 664 mbsf) that reveal additional intervals of increased palynomorph abundance and diversity during the Antarctic early to middle Miocene. This evidence is consistent with a relatively dynamic early Miocene Antarctic icehouse climate with intervals of increased temperature and moisture, prior to the MMCO. Comparison with previous AND-2A studies indicates that periods of increased palynomorph abundance in the lower stratigraphic section largely coincide with ice sheet minima, distal ice conditions, and the presence of freshwater (i.e. increased precipitation, meltwater run-off, and freshwater ponds). Decreases in plant productivity mostly coincide with increased glaciation, decreased freshwater, and ice-proximal conditions during the Antarctic Miocene. Comparing the palynological data with other AND-2A data and global climate proxies (e.g., pCO2, δ18O, relative sea level, Milankovitch cycles) helps to resolve questions regarding the driving forces behind climate and vegetation change. We found that palynomorph assemblages reflecting generally warmer conditions are largely associated with 400-kyr eccentricity maxima, while assemblages indicative of colder conditions coincide with 400-kyr eccentricity minima. These data are consistent with other findings that indicate the early to middle Miocene climate was eccentricity-paced.

  15. Miocene and Pliocene lacustrine and fluvial sequences, Upper Ramparts and Canyon village, Porcupine river, east-central Alaska

    USGS Publications Warehouse

    Fouch, T.D.; Carter, L.D.; Kunk, M.J.; Smith, C.A.S.; White, J.M.

    1994-01-01

    Cenozoic strata exposed along the Porcupine River between the Upper Ramparts and Canyon Village, Alaska, can be divided into five unconformity-bounded units (sequences) which are: lower and middle Miocene unit A, the white sandy fluvial sequence with peat beds; middle Miocene unit B, the basalt sequence-part B1 is basalt, and part B2 is organic-rich sedimentary beds; upper Miocene unit C, mudrock-dominated lake sequence; late Miocene or Pliocene to Pleistocene unit D, terrace gravels, detrital organic matter and associated sediments, and Holocene unit E, mixed sand and gravel-rich sediment and other sedimentary material including peat and eolian silt. The sequence (unit A) of lower and middle Miocene fluvial deposits formed in streams and on flood plains, just before the inception of local volanism. Fossil pollen from unit A suggests conifer-dominated regional forests and cool temperate climates. Peat beds and lake deposits from unit B contain pollen that indicates a warmer temperate climate coinciding with the middle Miocene thermal maximum. The lake deposits (unit C) downstream from the basalts accumulated in a small basin which resulted from a hydrologic system that was dammed in the late Miocene but breached soon thereafter. The lower part of the terrace gravels (unit D) expresses breaching of the dammed hydrologic system (of unit C). The Porcupine River became a major tributary of the Yukon River in late Pleistocene time when Laurentide ice blocked drainage from the Yukon interior basins causing meltwater to spill over the low divide separating it from the Porcupine River drainage initiating erosion and capture of the Yukon interior basins. ?? 1994.

  16. Miocene squat lobsters (Decapoda, Anomura, Galatheoidea) of the Central Paratethys – a review, with description of a new species of Munidopsis

    PubMed Central

    Hyžný, M.; Gašparič, R.; Robins, C.M.; Schlögl, J.

    2015-01-01

    All squat lobsters of the families Galatheidae, Munididae and Munidopsidae from the Miocene of the Central Paratethys are reviewed taxonomically. Based on additional observations emended diagnoses are provided for Agononida cerovensis and Galathea weinfurteri, from the Lower and Middle Miocene, respectively. Munidopsis is represented by two species in the study area; additional data for M. lieskovensis from the Lower Miocene of Slovakia are presented and a new species, M. palmuelleri, from the Middle Miocene of Slovenia is erected. Implications for palaeoenvironmental reconstructions are briefly discussed for each taxon. PMID:26005283

  17. CONTROLS OF EXTENSION ON MIOCENE ARC MAGMATISM IN THE CENTRAL SIERRA NEVADA (CA)

    NASA Astrophysics Data System (ADS)

    Busby, C.; Putirka, K. D.; Hagan, J. C.; Koerner, A.; Melosh, B. L.

    2009-12-01

    Ancestral Cascades arc volcanism in the central Sierra Nevada occurred in three Miocene pulses, at about 16-13 Ma, 11-9 Ma, and 7-6 Ma. Our work in the Carson Pass to Sonora Pass areas shows that range-front faults clearly controlled the positions of volcanic centers during the second and third magmatic pulses. Voluminous high-K volcanic rocks of the 11-9 Ma Stanislaus Group record the onset of transtensional calving of the Sierra Nevada microplate off the western edge of the Nevadaplano. The Little Walker Caldera or Center formed at a releasing stepover in range-front faults at Sonora Pass, and erupted widesperad trachydacite ignimbrite in three distinct phases (Eureka Valley Tuff). Interstratified with these ignimbrites are widespread trachyandesite (latite), basaltic-trachyandesite (shoshonite) and trachydacite lava flows, in sections up to 500 m thick, whose vents have never been discovered (e.g. Table Mountain Latite). Although some of these lavas may have erupted from vents buried beneath the Little Walker Center, we recognize intrusions and vent facies for them along Sierran range-front and range-crest faults that emanate northwestward from the Little Walker Center between Sonora Pass and Ebbetts Pass. The biggest volcanic centers of the third magmatic pulse also include silicic volcanic rocks, and are sited along normal faults; they include the Markleeville Center southeast of Carson Pass, and the Ebbetts Pass Center. The 8 km diameter Markleeville Center consists of andesites and dacites that formed within the Hope Valley graben. The next fault to the east of the Hope Valley graben, which we name the Grover Hot Springs fault, extends southward to Ebbetts Pass, where it forms an overlapping right (releasing) step with the Noble Canyon fault to the west. The Ebbetts Pass Center lies above this releasing step along the Sierran crest. The base of the Ebbetts Pass Center is 10 km in diameter and is formed of radially-dipping basaltic andesite lava flows and

  18. The palaeoclimatic significance of Eurasian Giant Salamanders (Cryptobranchidae: Zaissanurus, Andrias) - indications for elevated humidity in Central Asia during global warm periods (Eocene, late Oligocene warming, Miocene Climate Optimum)

    NASA Astrophysics Data System (ADS)

    Vasilyan, Davit; Böhme, Madelaine; Winklhofer, Michael

    2010-05-01

    Cryptobranchids represent a group of large sized (up to 1.8 m) tailed amphibians known since the Middle Jurassic (Gao & Shubin 2003). Two species are living today in eastern Eurasia: Andrias davidianus (China) and A. japonicus (Japan). Cenozoic Eurasian fossil giant salamanders are known with two genera and two or three species from over 30 localities, ranging from the Late Eocene to the Early Pliocene (Böhme & Ilg 2003). The Late Eocene species Zaissanurus beliajevae is restricted to the Central Asian Zaissan Basin (SE-Kazakhstan, 50°N, 85°E), whereas the Late Oligocene to Early Pliocene species Andrias scheuchzeri is distributed from Central Europe to the Zaissan Basin. In the latter basin the species occur during two periods; the latest Oligocene and the late Early to early Middle Miocene (Chkhikvadse 1982). Andrias scheuchzeri is osteological indistinguishable from both recent species, indicating a similar ecology (Westfahl 1958). To investigate the palaeoclimatic significance of giant salamanders we analyzed the climate within the present-day distribution area and at selected fossil localities with independent palaeoclimate record. Our results indicate that fossil and recent Andrias species occur in humid areas where the mean annual precipitation reach over 900 mm (900 - 1.300 mm). As a working hypothesis (assuming a similar ecology of Andrias and Zaissanurus) we interpret occurrences of both fossil Eurasian giant salamanders as indicative for humid palaeoclimatic conditions. Based on this assumption the Late Eocene, the latest Oligocene (late Oligocene warming) and the late Early to early Middle Miocene (Miocene Climatic Optimum) of Central Asia (Zaissan Basin) are periods of elevated humidity, suggesting a direct (positive) relationship between global climate and Central Asian humidity evolution. Böhme M., Ilg A. 2003: fosFARbase, www.wahre-staerke.com/ Chkhikvadze V.M. 1982. On the finding of fossil Cryptobranchidae in the USSR and Mongolia. Vertebrata

  19. Plate tectonic significance of Late Oligocene/Early Miocene deep sea sedimentation at Maewo, Vanuatu (New Hebrides)

    NASA Astrophysics Data System (ADS)

    Neef, G.

    1982-08-01

    Eight lithofacies representing a westward trending, deep sea fan, dominantly deposited from mass flow mechanisms, are recognised in geologic sections in the lower part of the Sarava Formation, of Late Oligocene/Early Miocene age, on Maewo Island, Vanuatu, New Hebrides. Also present representing the floor on which the deep sea fan prograded are non-calcareous, red siltstone and minor green siltstone which indicate deposition beyond the calcareous compensation depth, i.e. a depth greater than 4.25 km, and rare thin airfall ash. Previous workers proposed that rifting occurred in the area now occupied by Maewo during the Mid Miocene. However, the great depth at which the Late Oligocene/Early Miocene strata were deposited suggests that rifting occurred prior to the Late Oligocene. Rifting may have occurred even earlier because Pentecost Island, which lies south of Maewo, has a dismembered ophiolite suite which ranges in age from 35-28 Ma (Oligocene). The ophiolite suite may have formed in an interarc environment. The writer's reconstruction of the Oligocene arc system of the New Hebrides is an analogue of the present day Mariana Arc System. Interarc rifting ceased by the Early Miocene and during the Mid-Late Miocene the subduction of zone may have migrated westwards to lie along the Maewo-Pentecost axis.

  20. The Superimposed Paleocene-Miocene Tectonics of the middle part of the Nallihan Wedge (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Şahin, Murat; Yaltirak, Cenk

    2015-04-01

    In the NW Turkey, the area between the suture zones of the Rhodope-Pontide Ocean and Izmir-Ankara Ocean, and North Anatolian Fault Zone (NAFZ) and Thrace-Eskişehir Fault Zone (TEFZ) is known as the Nallıhan Wedge. The shape of Nallıhan Wedge is a 90 degree counter-clockwise rotated isosceles triangle. The northwestern boundary is a part of NAFZ and the southwestern boundary is a part of TEFZ. The 160 km-long eastern boundary is located at around Beypazarı and western corner is on the Bursa Plain. Nallıhan is situated at the centre of this isosceles triangle. While all the thrusts and folds shrink towards to the west and show an imbricate-like structure, the characteristics of the folds turn into to the open folds. Thrusts faults are locally observed as blind and almost perpendicular thrusts at the fold limbs towards to the east. The rocks of the study area show different characteristics according to their types and basins of formation. On the other hand the structural properties of these rocks display the effects of the closure of the Intra-Pontide and Izmir-Ankara Oceans in between Paleocene and Early Oligocene. During Miocene, the thrust faults reactivated and a deformation formed the NEE-SWW left lateral strike-slip faults parallel to these thrust faults. Whereas the first events are related to the closure of the branches of Neo-Tethys, the Miocene deformation is probably based on the Miocene tectonics of the Western Anatolia by the reason of equivalent age of the TEFZ. In this framework, the deformation of the Nallıhan Wedge presents significant information about the period between the evolution of Paleotectonic and Neotectonic of Turkey.

  1. Late Miocene decoupling of oceanic warmth and atmospheric carbon dioxide forcing.

    PubMed

    LaRiviere, Jonathan P; Ravelo, A Christina; Crimmins, Allison; Dekens, Petra S; Ford, Heather L; Lyle, Mitch; Wara, Michael W

    2012-06-06

    Deep-time palaeoclimate studies are vitally important for developing a complete understanding of climate responses to changes in the atmospheric carbon dioxide concentration (that is, the atmospheric partial pressure of CO(2), p(co(2))). Although past studies have explored these responses during portions of the Cenozoic era (the most recent 65.5 million years (Myr) of Earth history), comparatively little is known about the climate of the late Miocene (∼12-5 Myr ago), an interval with p(co(2)) values of only 200-350 parts per million by volume but nearly ice-free conditions in the Northern Hemisphere and warmer-than-modern temperatures on the continents. Here we present quantitative geochemical sea surface temperature estimates from the Miocene mid-latitude North Pacific Ocean, and show that oceanic warmth persisted throughout the interval of low p(co(2)) ∼12-5 Myr ago. We also present new stable isotope measurements from the western equatorial Pacific that, in conjunction with previously published data, reveal a long-term trend of thermocline shoaling in the equatorial Pacific since ∼13 Myr ago. We propose that a relatively deep global thermocline, reductions in low-latitude gradients in sea surface temperature, and cloud and water vapour feedbacks may help to explain the warmth of the late Miocene. Additional shoaling of the thermocline after 5 Myr ago probably explains the stronger coupling between p(co(2)), sea surface temperatures and climate that is characteristic of the more recent Pliocene and Pleistocene epochs.

  2. Miocene-Pleistocene Paleoclimate and Paleoenvironment in the Meade Basin, Kansas

    NASA Astrophysics Data System (ADS)

    Snell, K. E.; Uno, K. T.; Fetrow, A. C.; Burgess, C.; Lukens, W. E.; Fox, D. L.; Fox-Dobbs, K.; Polissar, P. J.

    2015-12-01

    The Meade Basin in southwestern Kansas preserves a unique record of paleovegetation and small mammal faunal change from the Miocene to the Pleistocene. Many of the paleosols preserved in this basin contain paleosol carbonate nodules, thick calcretes and abundant organic-rich horizons, which makes it ideally suited for a multiproxy study that explores the role of paleoenvironmental change in driving floral and faunal change. Here we focus on the carbonate samples where we measured carbon and oxygen isotopes (δ13Cc and δ18Oc, respectively); used clumped isotope thermometry (Δ47) to estimate soil temperature and soil water δ18O; and assessed the preservation state and additional paleoenvironmental features of the samples using optical and cathodoluminescence (CL) microscopy. The carbon isotope record matches previous studies from the region and shows an increase in the relative abundance of C4 biomass on the landscape since the late Miocene. The Δ47 temperatures and the δ18O of soil water, while variable, show no significant change in average values through time. The textural and luminescenece characteristics suggest some samples have undergone moderate to extensive diagenetic alteration from groundwater fluids, perhaps causing some of the variability in the geochemical records. Soil depth may also account for some of the variability. Overall, these data suggest that temperature is unlikely to be the dominant factor driving paleovegetation and faunal change in this region from the Miocene to Pleistocene. In addition, these data highlight the importance of assessing preservation for all carbonate samples, regardless of whether or not the samples have been deeply buried.

  3. A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia.

    PubMed

    Rybczynski, Natalia; Dawson, Mary R; Tedford, Richard H

    2009-04-23

    Modern pinnipeds (seals, sea lions and the walrus) are semi-aquatic, generally marine carnivores the limbs of which have been modified into flippers. Recent phylogenetic studies using morphological and molecular evidence support pinniped monophyly, and suggest a sister relationship with ursoids (for example bears) or musteloids (the clade that includes skunks, badgers, weasels and otters). Although the position of pinnipeds within modern carnivores appears moderately well resolved, fossil evidence of the morphological steps leading from a terrestrial ancestor to the modern marine forms has been weak or contentious. The earliest well-represented fossil pinniped is Enaliarctos, a marine form with flippers, which had appeared on the northwestern shores of North America by the early Miocene epoch. Here we report the discovery of a nearly complete skeleton of a new semi-aquatic carnivore from an early Miocene lake deposit in Nunavut, Canada, that represents a morphological link in early pinniped evolution. The new taxon retains a long tail and the proportions of its fore- and hindlimbs are more similar to those of modern terrestrial carnivores than to modern pinnipeds. Morphological traits indicative of semi-aquatic adaptation include a forelimb with a prominent deltopectoral ridge on the humerus, a posterodorsally expanded scapula, a pelvis with relatively short ilium, a shortened femur and flattened phalanges, suggestive of webbing. The new fossil shows evidence of pinniped affinities and similarities to the early Oligocene Amphicticeps from Asia and the late Oligocene and Miocene Potamotherium from Europe. The discovery suggests that the evolution of pinnipeds included a freshwater transitional phase, and may support the hypothesis that the Arctic was an early centre of pinniped evolution.

  4. Dynamic Antarctic ice sheet during the early to mid-Miocene.

    PubMed

    Gasson, Edward; DeConto, Robert M; Pollard, David; Levy, Richard H

    2016-03-29

    Geological data indicate that there were major variations in Antarctic ice sheet volume and extent during the early to mid-Miocene. Simulating such large-scale changes is problematic because of a strong hysteresis effect, which results in stability once the ice sheets have reached continental size. A relatively narrow range of atmospheric CO2 concentrations indicated by proxy records exacerbates this problem. Here, we are able to simulate large-scale variability of the early to mid-Miocene Antarctic ice sheet because of three developments in our modeling approach. (i) We use a climate-ice sheet coupling method utilizing a high-resolution atmospheric component to account for ice sheet-climate feedbacks. (ii) The ice sheet model includes recently proposed mechanisms for retreat into deep subglacial basins caused by ice-cliff failure and ice-shelf hydrofracture. (iii) We account for changes in the oxygen isotopic composition of the ice sheet by using isotope-enabled climate and ice sheet models. We compare our modeling results with ice-proximal records emerging from a sedimentological drill core from the Ross Sea (Andrill-2A) that is presented in a companion article. The variability in Antarctic ice volume that we simulate is equivalent to a seawater oxygen isotope signal of 0.52-0.66‰, or a sea level equivalent change of 30-36 m, for a range of atmospheric CO2 between 280 and 500 ppm and a changing astronomical configuration. This result represents a substantial advance in resolving the long-standing model data conflict of Miocene Antarctic ice sheet and sea level variability.

  5. Steps in the intensification of Benguela upwelling over the Walvis Ridge during Miocene and Pliocene

    NASA Astrophysics Data System (ADS)

    Hoetzel, Sebastian; Dupont, Lydie M.; Marret, Fabienne; Jung, Gerlinde; Wefer, Gerold

    2017-01-01

    Upwelling is a significant part of the ocean circulation controlling largely the transport of nutrient-rich cold waters to the surface and therefore influencing ocean productivity and global climate. The Benguela upwelling system (BUS) is one of the major upwelling areas in the world. Previous reconstructions of the BUS mainly focused on the onset and intensification in southern and central parts, but changes of the northern part have been rarely investigated in detail. Using the Late Miocene to Pliocene organic-walled dinoflagellate cyst record of ODP Site 1081, we reconstruct and discuss the early upwelling history over the Walvis Ridge with a special focus on the movement of the Angola-Benguela Front (ABF). We suggest that during the Late Miocene the Angola Current flowed southwards over the Walvis Ridge more frequently than today because the ABF was probably located further south as a result of a weaker meridional temperature gradient. A possible strengthening of the meridional gradient during the latest Miocene to early Pliocene in combination with uplift of south-western Africa intensified the upwelling along the coast and increased the upwelling's filaments over the Walvis Ridge. An intermediate period from 6.2 to 5.5 Ma is shown by the dominance of Habibacysta tectata, cysts of a cool-tolerant dinoflagellate known from the northern Atlantic, indicating changing oceanic conditions contemporaneous with the Messinian Salinity Crisis. From 4.3 Ma on, the upwelling signal got stronger again and waters were well-mixed and nutrient-rich. Our results indicate a northward migration of the ABF as early as 7 Ma and the initial stepwise intensification of the BUS.

  6. Late Oligocene to Late Miocene Antarctic Climate Reconstructions Using Molecular and Isotopic Biomarker Proxies

    NASA Astrophysics Data System (ADS)

    Duncan, B.; Mckay, R. M.; Bendle, J. A.; Naish, T.; Levy, R. H.; Ventura, G. T.; Moossen, H. M.; Krishnan, S.; Pagani, M.

    2015-12-01

    Major climate and environmental changes occurred during late Oligocene to the late Miocene when atmospheric CO2 ranged between 500 and 300ppm, indicating threshold response of Antarctic ice sheets and climate to relatively modest CO2 variations. This implies that the southern high latitudes are highly sensitive to feedbacks associated with changes in global ice sheet and sea-ice extent, as well as terrestrial and marine ecosystems. This study focuses on two key intervals during the evolution of the Antarctic Ice Sheet: (1) The Late Oligocene and the Oligocene/Miocene boundary, when the East Antarctic Ice Sheet expanded close to present day volume following an extended period of inferred warmth. (2) The Mid-Miocene Climate Optimum (MMCO ~17-15 Ma), a period of global warmth and moderately elevated CO2 (350->500 ppm) which was subsequently followed by rapid cooling at 14-13.5 Ma. Reconstructions of climate and ice sheet variability, and thus an understanding of the various feedbacks that occurred during these intervals, are hampered by a lack of temperature and hydroclimate proxy data from the southern high latitudes. We present proxy climate reconstructions using terrestrial and marine organic biomarkers that provide new insights into Antarctica's climate evolution, using Antarctic drill cores and outcrop samples from a range of depositional settings. Bacterial ether-lipids have been analysed to determine terrestrial mean annual temperatures and soil pH (via the methylation and cyclisation indexes of branched tetraethers - MBT and CBT, respectively). Tetraether-lipids of crenarchaeota found in marine sediments sampled from continental shelves around Antarctica have been used to derive sea surface temperatures using the TEX86 index. Compound specific stable isotopes on n-alkanes sourced from terrestrial plants have been analysed to investigate changes in the hydrological and carbon cycles.

  7. Late Miocene Global Ocean Cooling Linked to Terrestrial Aridification and Evolutionary Events

    NASA Astrophysics Data System (ADS)

    Herbert, T.; Lawrence, K. T.; Tzanova, A.; Kelly, C. S.; Peterson, L.

    2015-12-01

    The path of global temperatures between the permanent establishment of the East Antarctic ice sheet at ~13.9 Ma and the onset of cyclical northern hemisphere glaciation at circa 2.7 Ma is poorly known. Enormous changes to terrestrial environments and ecosystems occurred approximately halfway between these polar glaciation milestones. What is perplexing is that this environmental upheaval on land occurred without any substantial evidence for late Miocene temperature change. Our single best marine index of the global climate state, the marine oxygen isotope record derived from benthic foraminifera is singularly devoid of a strong trend that would suggest notable climatic change during this time period. We present a globally distributed data set of estimated marine sea surface temperatures (SST) for the past 12 Ma reconstructed via the alkenone unsaturation method. Our reconstruction reveals what may be the strongest directional cooling of the Neogene, which occurred broadly synchronously in both hemispheres and culminated with ocean temperatures dipping to values close to the present between ~7 and 5.8 Ma before rebounding to warmer conditions in the Pliocene. The cold interval from circa 7-5.8 Ma that we reconstruct coincides very closely in time with previously enigmatic evidence of late Miocene glaciations of southeast Greenland, southeastern Alaska, and South America, with pulses of ice rafted detritus off Wilkes Land and Adelie Land and, perhaps the formation of an ice sheet on West Antarctica. A large scale forcing mechanism, such as a previously hypothesized decline in atmospheric CO2 levels from 8-6 Ma [T.E. Cerling and colleagues] seems required to coordinate the increase in late Miocene Equator-Pole temperature gradients with evidence for a contemporaneous increase in aridity on land, restructuring of terrestrial plant and animal communities, and a pronounced shift in the marine carbon cycle.

  8. Antarctic Ice Sheet dynamics in the Ross Sea during the Early to Middle Miocene

    NASA Astrophysics Data System (ADS)

    Levy, Richard; Harwood, David; Florindo, Fabio; DeConto, Robert; Golledge, Nicholas; Hoffmann, Stefan; Kuhn, Gerhard; McKay, Robert; Naish, Timothy; Pollard, David; Sangiorgi, Francesca; von Eynatten, Hilmar

    2015-04-01

    A 1138-meter sediment core (AND-2A) recovered from the Southern McMurdo Sound sector of the Ross Sea comprises a near-continuous record of Antarctic climate and ice sheet variability through the Early to early Middle Miocene (20.2 to 14.5 million years ago), including an interval of inferred sustained global warmth known as the Miocene Climatic Optimum (MCO). The record preserves 55 sedimentary sequences that reflect cycles of glacial advance and retreat. A new analysis of proxy environmental data from the AND-2A core, and synthesis with regional geological information, show that the early to middle Miocene Antarctic climate ranged from cold polar conditions, similar to Antarctica during the Holocene, to those that characterise modern sub-polar environments. Four disconformities that punctuate the sedimentary sequence coincide with regionally mapped seismic discontinuities and reflect transient expansion of marine-based ice across the Ross Sea. The timing of these major marine-based ice sheet advances correlates with shifts in highly-resolved deep sea isotope records and major drops in eustatic sea-level indicating the global nature of these events. In contrast, three distinct intervals in the core indicate that this high latitude site was periodically influenced by an ice sheet margin that had retreated beyond the coastline. These relatively large-scale changes in climate and ice sheet extent occurred under atmospheric carbon dioxide concentrations that generally varied between 300 to 500 ppm. Therefore, our reconstructions suggest that Antarctica's climate and ice sheets were sensitive to modest changes in greenhouse gas forcing and support previous studies, which indicate that marine-based portions of the WAIS and EAIS can retreat under climatic conditions that were similar to those projected for our future under current levels of atmospheric CO2.

  9. Miocene carbonate reservoirs related to tectonic and thermal evolution of southeast Asian marginal basins

    SciTech Connect

    Fulthorpe, C.S.; Brodholt, J.P.; Jurdy, D.M.; Schlanger, S.O.

    1986-05-01

    The early Miocene global sea level rise and oceanic warming period allowed the tropical reef growth belt to expand and fostered the development of major carbonate buildups throughout southeast Asia. A regional paleogeographic reconstruction for 18 m.y. places reefal, shelf, and basinal facies in a tectonic setting of island arcs, subduction zones, and marginal basins. For typical basins, such as the Sulu, Celebes, and South China Sea basins, basin formation and sedimentation models have been developed based on ages inferred from identified marine magnetic anomalies and heat flow data. These basins have many of the attributes needed for hydrocarbon development and maturation. They accumulated sediment from pelagic sources and surrounding island arcs and landmasses fringed by reefs. During the early Miocene, limited water circulation in restricted basins, such as the Sulu and Celebes basins, may have induced dysaerobic conditions that enhanced organic carbon preservation. Models of marginal basin formation provide the basis for studying the time-dependent thermal histories of their sediment sequences. The authors models show that, for example, lower Miocene sediments deposited at a rate of 100 m/m.y. on 20-m.y.-old crust in a typical basin have just entered the oil-generation window. Lower sedimentation rates require deposition on younger crust in order for the sediments to reach an equivalent maturation stage. Estimates of the hydrocarbon potential of such marginal basins should be based on a sequential time-slice analysis of each basin in terms of sediment type, sedimentation rate, sea floor age and thermal regime, and the presence of reservoirs.

  10. Dynamic Antarctic ice sheet during the early to mid-Miocene

    NASA Astrophysics Data System (ADS)

    Gasson, Edward; DeConto, Robert M.; Pollard, David; Levy, Richard H.

    2016-03-01

    Geological data indicate that there were major variations in Antarctic ice sheet volume and extent during the early to mid-Miocene. Simulating such large-scale changes is problematic because of a strong hysteresis effect, which results in stability once the ice sheets have reached continental size. A relatively narrow range of atmospheric CO2 concentrations indicated by proxy records exacerbates this problem. Here, we are able to simulate large-scale variability of the early to mid-Miocene Antarctic ice sheet because of three developments in our modeling approach. (i) We use a climate-ice sheet coupling method utilizing a high-resolution atmospheric component to account for ice sheet-climate feedbacks. (ii) The ice sheet model includes recently proposed mechanisms for retreat into deep subglacial basins caused by ice-cliff failure and ice-shelf hydrofracture. (iii) We account for changes in the oxygen isotopic composition of the ice sheet by using isotope-enabled climate and ice sheet models. We compare our modeling results with ice-proximal records emerging from a sedimentological drill core from the Ross Sea (Andrill-2A) that is presented in a companion article. The variability in Antarctic ice volume that we simulate is equivalent to a seawater oxygen isotope signal of 0.52-0.66‰, or a sea level equivalent change of 30-36 m, for a range of atmospheric CO2 between 280 and 500 ppm and a changing astronomical configuration. This result represents a substantial advance in resolving the long-standing model data conflict of Miocene Antarctic ice sheet and sea level variability.

  11. Miocene fossil hydrothermal system associated with a volcanic complex in the Andes of central Chile

    NASA Astrophysics Data System (ADS)

    Fuentes, Francisco; Aguirre, Luis; Vergara, Mario; Valdebenito, Leticia; Fonseca, Eugenia

    2004-11-01

    Cenozoic deposits in the Andes of central Chile have been affected by very low-grade burial metamorphism. At about 33°S in the Cuesta de Chacabuco area, approximately 53 km north of Santiago, two Oligocene and Miocene volcanic units form a ca. 1300-m-thick rock pile. The Miocene unit corresponds to a volcanic complex composed of two eroded stratovolcanoes. Secondary mineral assemblages in both units were studied petrographically and using X-ray diffraction and electron microprobe analyses. Most of the igneous minerals are wholly or partially preserved, and the ubiquitous secondary minerals are zeolites and mafic phyllosilicates. The alteration pattern observed is characterized by a lateral zonation in secondary mineralogy related to a lateral increase in temperature but not to stratigraphic depth. The following three zones were established, mainly based on the distribution of zeolites: zone I comprises heulandite, thomsonite, mesolite, stilbite and tri-smectite; zone II contains laumontite, yugawaralite, prehnite, epidote and chlorite; and zone III comprises wairakite, epidote, chlorite, diopside, biotite and titanite. For each zone, the following temperature ranges were estimated: zone I, 100-180 °C; zone II, 180-270 °C; and zone III, 245-310 °C. The alteration episode was characterized by a high Pfluid/ Ptotal ratio (ca. 1.0), although slightly variable, a high geothermal gradient of ca. 160 °C km -1 and fluid pressures below 500 bars. Although temperature was the main control on the mineral zonation, several interrelated parameters, mainly fluid composition, porosity and permeability, were also important. Hot, near neutral to slightly alkaline pH, alkali chloride hydrothermal fluids with very low dissolved CO 2 contents deposited the secondary minerals. The alteration pattern is the result of depositing fluids in outflow regions from a hydrothermal system developed inside a volcanic complex during the Miocene. The hydrothermal system has been eroded to a

  12. Correlating Mediterranean shallow water deposits with global Oligocene-Miocene stratigraphy and oceanic events.

    PubMed

    Reuter, Markus; Piller, Werner E; Brandano, Marco; Harzhauser, Mathias

    2013-12-01

    Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene-Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene-Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene-late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale.

  13. Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama

    PubMed Central

    Pimiento, Catalina; Ehret, Dana J.; MacFadden, Bruce J.; Hubbell, Gordon

    2010-01-01

    Background As we know from modern species, nursery areas are essential shark habitats for vulnerable young. Nurseries are typically highly productive, shallow-water habitats that are characterized by the presence of juveniles and neonates. It has been suggested that in these areas, sharks can find ample food resources and protection from predators. Based on the fossil record, we know that the extinct Carcharocles megalodon was the biggest shark that ever lived. Previous proposed paleo-nursery areas for this species were based on the anecdotal presence of juvenile fossil teeth accompanied by fossil marine mammals. We now present the first definitive evidence of ancient nurseries for C. megalodon from the late Miocene of Panama, about 10 million years ago. Methodology/Principal Findings We collected and measured fossil shark teeth of C. megalodon, within the highly productive, shallow marine Gatun Formation from the Miocene of Panama. Surprisingly, and in contrast to other fossil accumulations, the majority of the teeth from Gatun are very small. Here we compare the tooth sizes from the Gatun with specimens from different, but analogous localities. In addition we calculate the total length of the individuals found in Gatun. These comparisons and estimates suggest that the small size of Gatun's C. megalodon is neither related to a small population of this species nor the tooth position within the jaw. Thus, the individuals from Gatun were mostly juveniles and neonates, with estimated body lengths between 2 and 10.5 meters. Conclusions/Significance We propose that the Miocene Gatun Formation represents the first documented paleo-nursery area for C. megalodon from the Neotropics, and one of the few recorded in the fossil record for an extinct selachian. We therefore show that sharks have used nursery areas at least for 10 millions of years as an adaptive strategy during their life histories. PMID:20479893

  14. Correlating Mediterranean shallow water deposits with global Oligocene–Miocene stratigraphy and oceanic events☆

    PubMed Central

    Reuter, Markus; Piller, Werner E.; Brandano, Marco; Harzhauser, Mathias

    2013-01-01

    Shallow-marine sediment records have the strong potential to display sensitive environmental changes in sedimentary geometries and skeletal content. However, the time resolution of most neritic carbonate records is not high enough to be compared with climatic events as recorded in the deep-sea sediment archives. In order to resolve the paleoceanographic and paleoclimatic changes during the Oligocene–Miocene transition in the Mediterranean shallow water carbonate systems with the best possible time resolution, we re-evaluated the Decontra section on the Maiella Platform (central Apennines, Italy), which acts as a reference for the correlation of Oligocene–Miocene shallow water deposits in the Mediterranean region. The 120-m-thick late Oligocene–late Miocene carbonate succession is composed of larger foraminiferal, bryozoan and corallinacean limestones interlayered with distinct planktonic foraminiferal carbonates representing a mostly outer neritic setting. Integrated multi-proxy and facies analyses indicate that CaCO3 and total organic carbon contents as well as gamma-ray display only local to regional processes on the carbonate platform and are not suited for stratigraphic correlation on a wider scale. In contrast, new biostratigraphic data correlate the Decontra stable carbon isotope record to the global deep-sea carbon isotope record. This links relative sea level fluctuations, which are reflected by facies and magnetic susceptibility changes, to third-order eustatic cycles. The new integrated bio-, chemo-, and sequence stratigraphic framework enables a more precise timing of environmental changes within the studied time interval and identifies Decontra as an important locality for correlating not only shallow and deep water sediments of the Mediterranean region but also on a global scale. PMID:25844021

  15. Dynamic Antarctic ice sheet during the early to mid-Miocene

    PubMed Central

    DeConto, Robert M.; Pollard, David; Levy, Richard H.

    2016-01-01

    Geological data indicate that there were major variations in Antarctic ice sheet volume and extent during the early to mid-Miocene. Simulating such large-scale changes is problematic because of a strong hysteresis effect, which results in stability once the ice sheets have reached continental size. A relatively narrow range of atmospheric CO2 concentrations indicated by proxy records exacerbates this problem. Here, we are able to simulate large-scale variability of the early to mid-Miocene Antarctic ice sheet because of three developments in our modeling approach. (i) We use a climate–ice sheet coupling method utilizing a high-resolution atmospheric component to account for ice sheet–climate feedbacks. (ii) The ice sheet model includes recently proposed mechanisms for retreat into deep subglacial basins caused by ice-cliff failure and ice-shelf hydrofracture. (iii) We account for changes in the oxygen isotopic composition of the ice sheet by using isotope-enabled climate and ice sheet models. We compare our modeling results with ice-proximal records emerging from a sedimentological drill core from the Ross Sea (Andrill-2A) that is presented in a companion article. The variability in Antarctic ice volume that we simulate is equivalent to a seawater oxygen isotope signal of 0.52–0.66‰, or a sea level equivalent change of 30–36 m, for a range of atmospheric CO2 between 280 and 500 ppm and a changing astronomical configuration. This result represents a substantial advance in resolving the long-standing model data conflict of Miocene Antarctic ice sheet and sea level variability. PMID:26903645

  16. Combination of hand mapping and automatic mapping to reveal the Miocene h