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G. N. Sadovnikov 《Stratigraphy and Geological Correlation》2008,16(1):31-46
A unique succession of volcanogenic deposits with representative paleontological remains characterizing the Permian-Triassic boundary interval in the North Siberian platform and Taimyr is described. The succession is suitable for selecting a standard for the Triassic base in nonmarine deposits. Abundant and diverse fossils occurring in the succession evidence that volcanism responsible for origin of the plateau basalt province in Siberia was not a brief epoch of paroxysmal eruptions, which eliminated everything alive. Throughout the formation history of relevant plateau basalts, the organic world of the plateau and around existed and gradually evolved. 相似文献
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The new tribe Taimyralticini trib. nov., new genus Taimyraltica gen. nov. and new species Taimyraltica calcarata sp. nov. (Coleoptera: Chrysomelidae: Galerucinae) are described from Upper Cretaceous (Santonian) Taimyr amber of northern Siberia (Yantardakh locality). The new genus shares characters with genera of the tribe Alticini (small size, transverse antebasal groove on pronotum, regular punctate-striate elytra) and the Galerucini (narrow, non-swollen metafemora). A possible apomorphy of the new genus and tribe is a large and acute metatibial spur, erect and oriented transversely to the longitudinal axis of tibia. This character state is unknown in recent and fossil genera of Galerucinae. Early evolution and divergence of leaf beetles are discussed, and a Jurassic and Early Cretaceous subfamily radiation is proposed. Fossil galerucines are reviewed. The oldest Phyllotreta is recorded from the lower Miocene of Izarra (Spain). Our findings show an extreme rarity of Phytophaga in Taimyr amber from Yantardakh. Absence of Phytophaga was recorded earlier at Obeschayuschiy (Santonian-Campanian of the Magadan Region) and compared with their much larger share in Khetana (north of Khabarovsk Krai); we find nearly the same differences between Taimyr amber from Yantardakh and Canadian amber. In Obeschayuschiy this appears due to the Mesophytic character of the flora. It is assumed that the Santonian amber gymnosperm forest of the Khatanga Basin had the same character. 相似文献
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A new species of Glaesoconis Meinander (Neuroptera: Coniopterygidae) from the Santonian Taimyr amber
Glaesoconis popovi sp. nov. (Neuroptera: Coniopterygidae) is described from Upper Cretaceous (Santonian) Taimyr amber of northern Siberia (Yantardakh locality). The new species may be distinguished from others in the genus by much smaller eyes and the shape of the terminal segment of the maxillary palpus. The generic affinity of Glaesoconis baliopteryx Engel, 2004 from the mid-Cretaceous Burmese amber needs confirmation. 相似文献
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The structure and tectonic position of the Neoproterozoic Central Taimyr accretionary belt of northwestern Siberia is dominated by the Faddey and Mamont-Shrenk granite-gneiss terranes, ophiolites, and back-arc volcanic rocks. Granites in the granite-gneiss terranes are S-type and formed between 900 and 850 Ma from 1.9 to 1.8 Ga continental crust. U–Pb and Sm–Nd isotopic studies show that the plagiogranites of the Chelyuskin ophiolite belt formed between 850 and 740 Ma. The ophiolite complex was metamorphosed to garnet amphibolite grade around 600 Ma, which is considered to be when the accretionary belt was obducted onto the Siberian continent. Comparison of principal structures of the Central Taimyr accretionary belt with similar structures in Arctic countries permits definition of the principal stages of the Neoproterozoic destruction of the supercontinent Rodinia, in the Arctic region. 相似文献
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Prosisyrina sphinga sp. nov. (Neuroptera: Sisyridae) is described from Upper Cretaceous (Santonian) Taimyr amber of northern Siberia (Yantardakh locality). The new species is preliminary assigned to this Cretaceous genus, mainly based on character states of the maxillary palpus and the hind wing vein M and crossvein 1r-m, and the presumable absence of tibial false spurs. However, the structure of the costal space and the RP branching in the hind wing indicate that it may belong to a new, closely related genus. The discovery of this second species from the locality might suggest that sisyrids were usual members of the Santonian riparian biocenoses of northern Siberia. 相似文献
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This paper considers the potential of modern electrical prospecting methods for evaluating oil and gas occurrence on the northern margin of the Siberian Platform—a vast region from the Gydan Peninsula to the mouth of the Lena River. Results of regional electrical surveyes over the past 12 years in this region are generalized. The capabilities of electrical prospecting for solving the following four problems are defined: survey, in conjunction with seismics and drilling, in the Jurassic-Cretaceous part of the section; study of the structure of the Paleozoic sequence; study of the junction zones of large geoblocks and deep structure of the Earth’s crust and upper mantle; and study of the permafrost. © 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. 相似文献
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Late Precambrian and Palaeozoic platform sediments from the Central–South Taimyr Peninsula (Arctic Siberia) are all remagnetised. The remagnetisation is prefold and is related to thermal remagnetisation caused by Taimyr Trap magmatism. The remagnetisation age is estimated to 220–230 Ma and, hence, is considerably younger than the ca. 251 Ma age for the main body of Siberian Trap flood basalts. The folding that affected the Taimyr region platform sediments also included the Taimyr “Traps,” hence, relegating Taimyr deformation to post-Mid Triassic time, and most probably, to a Late Triassic age. This shows that whilst thrusting terminated in the Urals during the Permian, crustal shortening continued in Taimyr, Novaya–Zemlya and the South Barents Sea, well into the Mesozoic. 相似文献
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Changes in the diatom assemblages preserved in a sediment core taken from a small lake located north of arctic treeline on the western Taimyr Peninsula, Russia, were examined in order to investigate late Holocene (i.e., ca 5000 cal yr BP to present) climatic and environmental changes within the region. Early diatom assemblages were dominated by benthic Fragilaria taxa and indicate a transitional phase in the lake history, most likely reflecting lake development and environmental change associated with treeline retreat to the south of the study site. Concurrent with pollen and macrofossil evidence of a vegetation shift to shrub tundra in the catchment basin at ca 4200 cal yr BP, an increase in cold-water taxa, followed by little change in diatom assemblages until ca 2800 cal yr BP, suggests that conditions were relatively cool and stable at this time. The last 2000 years of the Middendorf Lake record have been marked by fluctuating limnological conditions, characterized by striking successional shifts between Fragilaria pinnata and Aulacoseira distans var. humilis. Recent conditions in Middendorf Lake indicate an increase in diatom taxa previously rare in the record, possibly associated with twentieth-century climatic warming. The Middendorf Lake record indicates that significant limnological change may occur in the absence of catchment vegetation shifts, suggesting late-Holocene decoupling of aquatic and terrestrial responses to climatic and hydrological change. Our study results represent one of the few paleoecological records currently available from northern Russia, and highlight the need for further development of calibration data sets from this region. 相似文献
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Ambaraphis baikurensis sp. nov. (Hemiptera: Palaeoaphididae) is described from the mid-Cretaceous (Albian–lower Cenomanian) of northern Siberia (Taimyr amber, Baikura locality) on the basis of wing morphology, which is most similar to that of aphids of the genus Ambaraphis Richards, 1966, previously reported only from Campanian Canadian amber. The new species primarily differs by pterostigma shape. The composition of the Baikura fauna supports assigning it to the Albian–lower Cenomanian Ognevka Formation. 相似文献
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