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Gennady G. Boeskorov Peter A. Lazarev Andrei V. Sher Sergei P. Davydov Nadezhda T. Bakulina Marina V. Shchelchkova Jonas Binladen Eske Willerslev Bernard Buigues Alexey N. Tikhonov 《Quaternary Science Reviews》2011,30(17-18):2262-2272
A nearly complete frozen mummy of a woolly rhinoceros (Coelodonta antiquitatis Blum., 1799) was discovered in a gold mine on the lower reaches of the Kolyma River, north–eastern Siberia. This is the first find of the whole body of woolly rhino in permafrost. A large part of the mummified body was preserved, including the left part of the body, covered by skin, including skin of the head and ear, fore and hind legs. The skull with 2 horns and the lower jaw were also preserved. Most of the internal organs were lost, except the intestines, stomach, and their contents. A rib fragment from this individual was dated by AMS-radiocarbon method to 39,140 ± 390 years BP (OxA-18755). Spore and pollen analyses of the stomach contents indicate that grasses and sagebrushes formed the main part of the diet of C. antiquitatis in this region of Arctic Siberia. 相似文献
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Svetlana A. Kuzmina Andrei V. Sher Mary E. Edwards James Haile Evgeny V. Yan Anatoly V. Kotov Eske Willerslev 《Quaternary Science Reviews》2011,30(17-18):2091-2106
Chukotka is a key region for understanding both Quaternary environmental history and transcontinental migrations of flora and fauna during the Pleistocene as it lies at the far eastern edge of Asia bordering the Bering Sea. The now submerged land bridge is the least understood region of Beringia yet the most critical to understanding migrations between the Old and New Worlds. The insect fauna of the Main River Ledovy Obryv (Ice Bluff) section, which is late Pleistocene in age (MIS 3-2), is markedly different from coeval faunas of areas further to the west, as it is characterized by very few thermophilous steppe elements. From the fauna we reconstruct a steppe-tundra environment and relatively cold conditions; the reconstructed environment was moister than that of typical steppe-tundra described from further west. The data from this locality, if typical of the Chukotka Peninsula as a whole, may indicate that a barrier associated with the environments of the land bridge restricted trans-Beringian migrations, particularly the more thermophilous and xeric-adapted elements of the Beringian biota, supporting the hypothesis of a cool but moist land-bridge filter inferred from evidence from several other studies. 相似文献
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Coupled trace element mobilisation and strain softening in quartz during retrograde fluid infiltration in dry granulite protoliths 总被引:1,自引:0,他引:1
This study focuses on the retrograde rheological and chemical evolution of quartz and the behaviour of quartzites during retrograde
metamorphism following dry high grade metamorphism at 750°C, 7 kbar. SEM-CL and LA-HR-ICP-MS are applied to document quartz
texture and chemistry, respectively. Four generations of quartz were distinguished by SEM-CL; Qz1, Qz2, Qz3 and Qz4. Qz1,
brecciated and partly dissolved old grains, is enriched in B, Al and Ti when compared with the other types. Qz2, formed during
brecciation and partial dissolution of Qz1, has low Al contents (<50 ppm) but, due to rutile inclusions, variable Ti contents
when occurring in amphibolite (210–10 ppm) but more consistent values when occurring in quartzites (peak value 32 ppm). Qz3,
dark grey luminescent quartz forming fluid migration channels (fluid pathways), has Ti < 5 ppm and Al contents below 10 ppm
and B < 1 ppm. Qz4, comprises are group of quartz later than Qz3 filling micron thick cracks and pods with very low luminescent
quartz, i.e. darker than Qz3. The textural and chemical evolution of quartz in our study is explained by two major influxes
of aqueous fluids during regional uplift and retrogression. They facilitated rehydration and recrystallisation in the otherwise
dry high grade quartzites. The first introduction of aqueous fluids was associated with brecciation of the high grade quartz
(Qz1) and dissolution/precipitation of quartz (Qz2). Ti in quartz geothermometry (Wark and Watson, Contrib Mineral Petrol
152(6):637–652) gives 626°C in agreement with the retrograde PT-path deduced from phase diagrams. Later fluid influx associated
with scapolitisation of amphibolite caused localised recrystallisation (Qz3) and alteration of biotite to muscovite along
mm-wide fluid migration channels. During subsequent deformation, Qz3 deformed plastically and recovered by subgrain rotation
recrystallisation (SGR), resulting in a reduction of grain size, whereas Qz1 quartz formed micro faults. Qz2 was plastic but
did not experience SGR to the same degree as Qz3 quartz. Increased plasticity and recovery rates most likely relate to an
increased H2O fugacity and the depletion in trace elements of the quartz lattice by promoting strain softening processes dislocation climb
and recovery.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Jaco Weinstock Beth Shapiro Alfredo Prieto Juan Carlos Marín Benito A. González M. Thomas P. Gilbert Eske Willerslev 《Quaternary Science Reviews》2009,28(15-16):1369-1373
We present the results of a palaeogenetic analysis of two Late Pleistocene camelids originating in southern Chile. Our analysis of two mitochondrial DNA fragments (control region and cytochrome b gene) reveals that these specimens do not belong to an extinct taxon, but rather to extant vicuña (Vicugna vicugna), whose modern distribution is restricted to the extreme elevations of the Andes, more than 3500 km to the north of where these specimens originated. Our results also suggest fossil specimens from Patagonia that are currently assigned to the extinct taxon Lama gracilis, may actually belong to V. vicugna, implying a continuous distribution of the latter from the southern tip of South America to the Andes during the Final Pleistocene. The haplotypes of both specimens are not present in modern populations, suggesting a loss of genetic diversity concomitant with the contraction of the vicuña geographical distribution during the Final Pleistocene or early Holocene. 相似文献
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