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1.
The first results on current movements are presented for the western part of the Dzhugdzhur–Stanovoi Terrane based on GPS geodesy of a geodynamic survey area of the Upper Amur region. Processing of the GPS data resulted in a vector field of the displacement rates of points of the geodynamic survey area with zones of intense deformations. It was concluded from a comprehensive analysis of geological–geophysical data and estimates of the displacement rates that the terrane is characterized by kinematic integrity and was subjected to a complex of tectonic factors related to the evolution of the eastern segment of Baikal Rift Zone in the area of transpression interaction of the Eurasian and Amur plates. 相似文献
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A. M. Mazukabzov A. B. Kotov T. M. Skovitina E. V. Sklyarov A. M. Larin 《Doklady Earth Sciences》2016,467(1):224-227
Structural studies showed that the Elikanskii granite–gneiss swell is similar to the Late Mesozoic Cordilleran-type metamorphic core complexes distinguished in the southern part of the Eravninskii terrane and in the northeastern part of the Argun–Idermeg superterrane of this belt. 相似文献
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I.V. Buchko A.A. Sorokin E.B. Sal'nikova A.B. Kotov S.D. Velikoslavinskii A.M. Larin A.E. Izokh S.Z. Yakovleva 《Russian Geology and Geophysics》2010,51(11):1157-1166
With U-Pb zircon dating, the ages of the Ul'degit (228 ± 1 Ma) and Chek-Chikan (203 ± 1 Ma) mafic massifs were determined. These massifs were earlier considered to form at the Early Precambrian stage of the geologic evolution of the Dzhugdzhur–Stanovoi superterrane. In geochemical features the igneous rocks of the massifs show relation with a within-plate source, on the one hand, and are similar to igneous rocks of subduction zones, on the other. They might have formed after subduction, which caused the intrusion of gabbroids of the Lucha massif (248 ± 1 Ma) and diorites of the Tok-Algoma complex (238 ± 2 Ma), followed by the fracturing of the subducted plate. 相似文献
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I. V. Buchko A. A. Sorokin A. A. Rodionov N. M. Kudryashov 《Doklady Earth Sciences》2018,479(2):448-451
U–Pb ID–TIMS zircon analyses of the Dzhigda gabbro–gabbrodiorite Massif (Ilikan block in the southwestern part of the Dzhugdzhur–Stanovoi superterrane) have been carried out. The results demonstrate that the formation of the massif at 244 ± 5 Ma corresponds to one of the stages of formation of the Selenga–Vitim volcano–plutonic belt. The latter stretches along the southeastern margin of the North Asian Craton along its border with the Mongol–Okhotsk fold belt. This indicates that the Selenga–Vitim volcano–plutonic belt along with granitoids and volcanics comprises Permian–Triassic massifs and that this belt is superimposed onto structures of not only the Selenga–Stanovoi terrane but also the Dzhugdzhur–Stanovoi terrane. 相似文献
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S. D. Velikoslavinskii A. B. Kotov E. B. Salnikova A. M. Larin A. A. Sorokin A. P. Sorokin V. P. Kovach E. V. Tolmacheva S. Z. Yakovleva I. V. Anisimova 《Doklady Earth Sciences》2012,444(2):661-665
According to the results of U-Pb geochronological investigations, the age of the amphibolite protoliths (metabasalts) in the Ust??-Gilyui sequence within the Stanovoi Complex of the Amazar-Gilyui structural and formational zone in the Selenga-Stanovoi Superterrain of the Central Asian fold belt can be estimated at 193 ± 1 Ma. The Nd model age of the Ust??-Gilyui metasedimentary rocks is in the interval of t Nd(DM) = 1.1?C3.1 Ga. This information along with the previously obtained geochronological data are indicative of the fact that the Ust??-Gilyui sequence consists of metasedimentary and metavolcanic rocks of various ages: (1) volcanic rocks with the age of 193 ± 1 Ma; (2) metasedimentary and metavolcanic rocks broken through by the Paleozoic granitoids dated to 370 Ma and characterized by minimum estimations of t Nd(DM) = 1.1 Ga, i.e., rocks with an age of 1.1?C0.4 Ga. In addition, it is quite possible that this sequence also includes more ancient rocks. The SSS Amazar-Gilyui structural and formational zone is likely to be a tectonic mélange composed of the metasedimentary and metavolcanic rocks of the Mesozoic and, probably, Paleozoic and Early Precambrian ages. The studied zone was formed in the Mesozoic, most likely, in the course of the collision processes initiated by the closing up of the Mongol-Okhotsk Ocean. 相似文献
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V. E. Kirillov 《Russian Journal of Pacific Geology》2010,4(1):41-55
The available stored, published, and original materials on the ore-bearing mesomatites developed in the eastern Aldan—Stanovoy Shield are systematized with their classification according to their formation and facies affiliation. Data on the age, structural localization, mineral composition, metallogenic specialization, and genesis of the ore–bearing formations are disc ussed with consideration for their spatial distribution patterns. 相似文献
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Doklady Earth Sciences - Numerical modeling of the dynamics of the block structure and the resulting seismicity of the Altai–Sayan–Baikal region has been carried out. The earthquake... 相似文献
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Doklady Earth Sciences - New data on the minerals of the Fe–Ni–Co–Cu–S system in the differentiated intrusions of the Southern Urals are presented. Based on a detailed study... 相似文献
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S. D. Velikoslavinskii A. B. Kotov E. B. Sal’nikova A. B. Kuznetsov V. P. Kovach N. V. Popov E. V. Tolmacheva I. V. Anisimova Yu. V. Plotkina 《Doklady Earth Sciences》2018,482(2):1265-1269
New U–Pb zircon (TIMS) results allow dating of protoliths of tonalite–trondhjemite orthogneisses of the Olekma Complex in the central part of the Chara–Olekma Geoblock (Aldan Shield) to 2825 ± 3 Ma and 2994 ± 3 Ma. Together with the results of previous geochronological studies, this proves that the Olekma Complex comprises heterochronous igneous rocks intensively reworked under amphibolite facies conditions and formed during different stages of geological evolution of the Aldan Shield. 相似文献
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In order to examine the precursory seismic quiescence of upcoming hazardous earthquakes, the seismicity data available in the vicinity of the Thailand–Laos–Myanmar borders was analyzed using the Region–Time–Length (RTL) algorithm based statistical technique. The utilized earthquake data were obtained from the International Seismological Centre. Thereafter, the homogeneity and completeness of the catalogue were improved. After performing iterative tests with different values of the \(r_{0}\) and \(t_{0}\) parameters, those of \(r_{0}\) = 120 km and \(t_{0}\) = 2 yr yielded reasonable estimates of the anomalous RTL scores, in both temporal variation and spatial distribution, of a few years prior to five out of eight strong-to-major recognized earthquakes. Statistical evaluation of both the correlation coefficient and stochastic process for the RTL were checked and revealed that the RTL score obtained here excluded artificial or random phenomena. Therefore, the prospective earthquake sources mentioned here should be recognized and effective mitigation plans should be provided. 相似文献
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Koroteev V. A. Chervyakovskiy V. S. Zaitseva M. V. Volchek E. N. Necheukhin V. M. 《Doklady Earth Sciences》2019,487(1):756-760
Doklady Earth Sciences - This paper reports on the first U–Pb dating of zircons from dacites of the volcanic paleo-edifice of the andesite–dacite complex of the Eastern Zone of the... 相似文献
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A. S. Ivleva V. N. Podkovyrov V. B. Ershova O. A. Anfinson A. K. Khudoley P. V. Fedorov A. V. Maslov D. Yu. Zdobin 《Doklady Earth Sciences》2016,468(2):593-597
Here we present the results of U–Pb LA–ICP–MS dating of detrital zircons from the Ediacaran–Early Cambrian deposits of the eastern part of the Baltic monoclise (Leningrad Region). The obtained age spectra of the detrital zircons suggest that, in the Ediacaran–Early Cambrian, the main clastic material source to the northwest of the Russian Platform was the Baltic Shield. Then in the Early Cambrian along with the Baltic Shield provenance, a clastic source from the Timanian margin of Baltica (northeast in modern coordinates) contributed to the deposits. The obtained data either somewhat set limits of the Timanian orogen formation as older than the previously suggested Middle Cambrian (about 510 Ma), based on the “absence of a Proto–Uralian–Timanian provenance signal” in the Sablino Formation rocks in the south Ladoga, or suggest another rearrangement of detritus transportation paths at the end of Stage 3 (Atdabanian). 相似文献
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Ivanov K. S. Berzin S. V. Erokhin Yu. V. Ronkin Yu. L. Khiller V. V. 《Doklady Earth Sciences》2019,484(1):97-100
Doklady Earth Sciences - Dolerites of the parallel dikes formed in a back-arc spreading setting have been dated by Sm–Nd to the Silurian (426 ± 34 Ma) for Mount Azov in the Central... 相似文献
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Doklady Earth Sciences - In the Precambrian sequence, namely, in the Proterozoic, Archean calcium and ferruginous carbonate rocks changed to magnesian carbonate ones. This correlates with the... 相似文献
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The reflectance of sediments (gray level) were measured on 11 sediment cores from the Norwegian–Greenland–Iceland Sea (Nordic
seas). The analyzed time interval covers the past five glacial–interglacial cycles. Although the results demonstrate that
the gray-level method has a potential for stratigraphic purposes, it is indicated that gray-level changes in the Nordic seas
are not necessarily driven by variations in the content of biogenic calcite. A detailed comparison of gray-level values with
contents of total CaCO3 (carbonate) and total organic carbon (TOC) reveals no overall causal link between these proxies. However, specific glacial
core sections with layers containing organic-rich sediment clasts as a consequence of iceberg-rafting seem to correlate well
with law gray-level values. Of those cores which show relatively high and comparable carbonate values in the last three main
interglacial intervals (stages 11, 5.5, and 1), stage 11 is always marked by the highest gray-level values. A close inspection
of the surface structure of the foraminiferal tests as well as the conduction of reflectance measurements on these tests leads
to the conclusion that enhanced carbonate corrosion occurred during stage 11. The test corrosion not only affected the reflectance
of the tests by making them appear whiter, it also seems responsible for the comparatively high gray-level values of the total
sediment in stage 11. In contrast, the relatively low gray-level values found in stages 5.5, and 1 are not associated with
enhanced test corrosion. This observation implies that variable degrees of carbonate corrosion can have a profound effect
on total sediment reflectance.
Received: 6 September 1998 / Accepted: 4 April 1999 相似文献
20.
The carbonate sediments from the Vendian–Cambrian shelf of the Tuva-Mongolian microcontinent were dated by Sr and C isotope chemostratigraphy. Analysis of the Sr-isotopic characteristics (0.70725–0.70873) and δ13C variations (+ 10.5 to –3.5‰), as well as their comparison with the data on the key sections of Siberia, Africa, Central Asia, Australia, South America, and Spitsbergen, showed that the carbonate sedimentary cover of the Tuva-Mongolian microcontinent accumulated at 600–520 Ma and the carbonate sediments of the Muren Formation and the basal beds of the Bokson Group near the Ukha-Gol River are the oldest. Their sedimentation followed the Marinoan global glaciation. 相似文献