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1.
A new concept concerning the structure and stages of evolution of the Kas Block of the West Siberian Plate is stated in this paper. The Kas Block is traditionally considered to be a subsided western margin of the Siberian Platform. The new concept is based on the results of the interpretation of the geophysical data recently obtained along the reference and regional profiles in this territory. The geological interpretation of the deep dynamic sections obtained by reprocessing of the CDP seismic reflection records has been performed for the first time. The structural features of the Kas Block, as well as the character of its junction with the Siberian Platform and the Paleozoic framework, are discussed. The tectonic scheme of the territory and the scheme of the pre-Late Devonian surface of the Kas Block have been compiled. The Baikalian age of the basement of the Kas Block is substantiated. The Salairian allochthonous ophiolite-basalt tectonic nappe is localized for the first time within the sedimentary cover of the Kas Block. The available information allowed us to reconstruct the development of the western margin of the Siberian continent in the Riphean and Early Paleozoic before and after the Baikalian Orogeny, respectively. The informational background of the geological and geophysical interpretation involves the results of the CDP seismic reflection profiling, including the deep dynamic seismic sections and parameters of the P-wave velocities along the reference 1-SB seismic line and the regional Vostok 10, 12, 15, and 16 seismic lines; the results of the deep seismic and magnetotelluric soundings; the gravity measurements; the magnetic exploration; and the new coherent physical geological models.  相似文献   

2.
The tectonic structure of the junction of the eastern Central Asian Fold Belt and the Siberian Platform, along with the deep structure of the Earth's crust and lithosphere in this region, has been described on the basis of new geological and geophysical data (seismic, geoelectric, and space-structural studies as well as new-generation geological maps), combined with new interpretation techniques (processing of the previous data by special software). The data suggest the existence of oblique collision during the convergence of the tectonic plates and, correspondingly, tectonic units composing these plates, when the Mongol–Okhotsk paleobasin closed. Such a scenario within the Aldan–Stanovoi Shield is evidenced by areas of syn- and postcollisional magmatism, with their deep-level and geochemical characteristics, and by the presence of a Late Mesozoic fold–thrust zone. Deep “traces” of these tectonomagmatic events, detected in the course of geological and geophysical modeling, are manifested in inclined deep boundaries between the crustal and lithospheric blocks. On the Earth's surface, they correspond to large fault systems: the Dzheltulak, North and South Tukuringra, Gulyui, and Stanovoi. It has been found that the influence of collision decreases northward with distance from the junction of the eastern Central Asian Fold Belt and the Siberian Platform (Dzheltulak and North Tukuringra transcrustal faults).  相似文献   

3.
A method for processing of a digital terrain model using a gradient module and the Laplace operator of a Gaussian surface is described, and the results of applying it to small-scale geological-structural demarcation are presented. The studied area (52–61° N, 120–133° E) covers the southern portion of the Siberian Platform (the Aldan-Stanovoi Shield), the southeastern flank of the Early Paleozoic Selenga-Stanovoi orogenic belt, and the western portion of the Mesozoic Mongol-Okhotsk orogenic belt. It has been demonstrated that the interpretation of modified digital terrain models allows confident determinations of the sizes of and relationships between geological features and zones of different types and the identification of faults and tectonic blocks transformed to different extents.  相似文献   

4.
The data on typomorphism of placer gold and its localization in the eastern Siberian Platform have been integrated for the first time. The alluvial, pseudolode, and eolian morphology of gold determines the origin of placers, which is explained not only by hydrodynamic but also by eolian processes. The recent and older alluvial (Au-bearing reservoir rocks in the second case), as well as eolian (unconventional type), genetic types of placers are recognized in the given territory. Precambrian and Mesozoic stages of ore formation are distinguished by the set of typomorphic attributes of placer gold (chemical composition, microinclusions, internal structure, etc.). On the basis of distinguishing features of placer gold, Precambrian lode deposits of great depth spatially related to outcrops of the basement have been forecasted for the first time and classified into low-sulfide gold-quartz, Au-bearing banded iron formation, Au-Cu porphyry, and Au-PGE types. The inferred shallow-seated gold-silver and gold-sulfide-quartz disseminated deposits occur locally and are related to the Mesozoic tectonomagmatic reactivation. The elaborated methods and approaches to the study of placer gold typomorphism in the eastern Siberian Platform also could be helpful in providing insights into placer origin, and forecasting and prospecting gold deposits on the East European Platform, which is close to the Siberian Platform in geological evolution.  相似文献   

5.
The formation of the western margin of the Siberian craton in the Neoproterozoic is considered, with a focus on its transformation from a passive continental margin into an active one, accretion and collision processes, formation of island arcs and ophiolites, orogeny, and continent-marginal rifting. The evolution and correlation of sedimentary basins within fold-thrust belts of the Siberian Platform framing are considered. New structural and kinematic data on the Yenisei fault zone are discussed. On the basis of paleomagnetic data obtained for the structures in the zone of junction of the Siberian Platform and the West Siberian Plate, new models are proposed for the location of the Siberian craton relative to other paleocontinents and microcontinents in the Neoproterzoic. All these data provide a consistent evolution scheme for the western margin of the Siberian paleocontinent in the Neoproterozoic and constrain the position of the Siberian craton margin in Late Neoproterozoic (pre-Vendian) time.  相似文献   

6.
The formation history of dispersion halos of kimberlite indicator minerals in the Siberian Platform is described beginning from the main Middle Paleozoic productive epoch of kimberlite magmatism. The history and formation conditions of the halos are reconstructed from the ontogeny and typomorphism of indicator mineral assemblages with involvement of the geological history of the Siberian Platform. The general trend characterizing the development of indicator mineral halos is discussed. The data obtained allow adequate estimation of of the character and geological setting of indicator mineral halos for forecasting purposes.  相似文献   

7.
In this paper we consider the results of geological interpretation of 3DV (Tommot–Skovorodino segment) and Tynda–Amurzet geophysical transects crosscutting the Aldan Shield and the Stanovoi Granite–Greenstone Domain of the Siberian Platform; the Selengino–Stanovoi, Mongolia–Okhotsk, and Gobi–Hinggang foldbelts; and the Argun and Mamyn microcontinents with a total extent of sections of about 1000 km and depth of about 40 km. The data of previous studies and follow-up electric conductivity information have been used. The data of geological mapping, subject studies, and insights into the deep-seated structure of the considered territory obtained with a complex of geophysical methods are discussed. It is shown that Mesozoic strike-slip and thrust faults play the leading role in the present-day structure of the territory and in control rifting and mantle diapirism. It is suggested that Californian-type metamorphic nuclei, which are of structure-forming significance for adjacent territories in the west, have also developed in the studied region.  相似文献   

8.
《International Geology Review》2012,54(12):1568-1575
Sixteen geologically definable areas within the Irkutsk amphitheater (maps), with the total of about 100 dispersion halos and indications of mercury in waters, alluvium, and rocks of various origin and age, may contain blind ores of cinnabar, particularly in the zones of fractures on the margins of the Siberian Platform and within the platform itself. --IGR Staff.  相似文献   

9.
《Gondwana Research》2002,5(1):35-39
The Siberian-West Laurentian connection is a postulated reconstruction of a Proterozoic craton that formed between 1800 Ma and 1500 Ma. Correlation of geological trends and of rift facies between the Siberian platform and western Laurentia indicates that, although the two cratons underwent significant intracontinental rifting in Mesoproterozoic and Neoproterozoic times, they did not undergo complete separation until early Cambrian, ca. 530 Ma. Although this interpretation does not support the hypothetical Columbia supercontinent model of Rogers (2000) and Rogers and Santosh (2002), some elements of it are compatible with that model.  相似文献   

10.
The Early Cambrian history of the development of the Siberian Platform was marked by events of global significance. In the Early Cambrian the Siberian Platform was the centre of appearance of the first shelly fossils. For this reason, paleobiogeographical features of the distribution of fossils are of interest for scientists as a tool for paleogeographic and paleogeodynamic reconstructions. An analysis of changes in the Early Cambrian biota taxonomic diversity allowed us to reveal two major stages in its development: (1) Late Vendian (Tommotian and Atdabanian Stages): spreading of the Siberian biota worldwide; (2) Late Botomian-Toyonian Stages: an increase in the degree of endemism, extinction of archeocyaths, reduction in organogenic structures, deposition of black shales, and flourishing of trilobites. A permanent increase in the degree of biota endemism, which reached its maximum in the Botomian Stage, and the first appearance of migrants at the generic and species level at the same time, coincided with the first major transgressive phases. The study of the geographic distribution of diverse groups of the Early Cambrian fauna and calcareous algae of the Siberian basin allowed us to identify a number of biofacies of different age, whose boundaries do not coincide. The evolution and change in the taxonomic composition of the Siberian basin biota were affected by events of the first (Salair) phase of the Caledonian orogeny, manifested in the Altai-Sayan region much earlier than in other parts of the world and influencing the geological history of the Siberian Platform. These events resulted in the extinction and appearance of some specific groups of the Tommotian fauna in the Siberian Platform.  相似文献   

11.
The U-Pb dating of detrital zircons from Carboniferous rocks in the northern frontal zone of the Verkhoyansk Fold-and-Thrust Belt (Kharaulakh Anticlinorium) at the boundary with the Siberian Platform is carried out for the first time. The age distribution of detrital zircons from the four dated samples has much in common, indicating that the same sources of clastic material were predominant. All of the samples are dominated by Precambrian zircons; the majority of them are Paleo- and Neoproterozoic grains. Early Ordovician and Late Devonian-Early Carboniferous detrital zircons are also numerous. The igneous rocks of the Taimyr-Severnaya Zemlya and/or Central Asian foldbelts extending along the northern, western, and southwestern margins of the Siberian continent probably were the main source areas of the studied sedimentary successions. The clastic material was transferred at a great distance by large river systems similar to the present-day Mississippi River and deposited in submarine fans at the passive margin of the Siberian continent. The occurrence of the detrital zircons whose age is synchronous to the time of sedimentation of the Carboniferous successions in the northern Verkhoyansk region (320–340 Ma) allows us to suggest that they were derived from the Taimyr-Severnaya Zemlya Foldbelt and that collision of the Kara Block with the Siberian continent began in the Early Carboniferous. The performed study shows the dating of detrital zircons is very helpful for the paleogeographic and tectonic reconstructions.  相似文献   

12.
New data on the geochemistry and isotopic composition of chloride brines of the Siberian Platform are presented. The distribution of stable isotopes (2H, 18O, and 37Cl) in brines of the Tunguska, Angara-Lena, western part of the Yakutian and Olenek artesian basins and 87Sr/86Sr in brines of the western part of the Olenek artesian basin was studied in the context of the problem of genesis of highly mineralized groundwaters. Results of the study and comparative analysis of the geochemical and isotopic peculiarities of the Siberian Platform brines conform to the theory of brine formation through the interaction of connate waters with enclosing rocks.  相似文献   

13.
The particularities of the current tectonic structure of the Russian part of the Arctic region are discussed with the division into the Barents–Kara and Laptev–Chukchi continental margins. We demonstrate new geological data for the key structures of the Arctic, which are analyzed with consideration of new geophysical data (gravitational and magnetic), including first seismic tomography models for the Arctic. Special attention is given to the New Siberian Islands block, which includes the De Long Islands, where field work took place in 2011. Based on the analysis of the tectonic structure of key units, of new geological and geophysical information and our paleomagnetic data for these units, we considered a series of paleogeodynamic reconstructions for the arctic structures from Late Precambrian to Late Paleozoic. This paper develops the ideas of L.P. Zonenshain and L.M. Natapov on the Precambrian Arctida paleocontinent. We consider its evolution during the Late Precambrian and the entire Paleozoic and conclude that the blocks that parted in the Late Precambrian (Svalbard, Kara, New Siberian, etc.) formed a Late Paleozoic subcontinent, Arctida II, which again “sutured” the continental masses of Laurentia, Siberia, and Baltica, this time, within Pangea.  相似文献   

14.
The Verkhoyansk–Kolyma belt (VK) forms the western part of the Verkhoyansk–Chukotka Mesozoic orogen (NE Asia) and lies between the Siberian craton on the western side, the Mesozoic–Cenozoic Koryak–Kamchatka accretionary orogen on the eastern side, and the Arctic Alaskan craton to the north. The VK results from the collision of the Siberian craton and the Kolyma–Omolon composite terrane (KO), which acted as an indentor resulting the Kolyma orocline. The KO is made up of ophiolite and olistostromal and schistose units that were amalgamated during the Middle–Late Jurassic by thrust and nappe tectonics under greenschist facies metamorphism. This was followed in Latest Jurassic by thrusting and strike-slip faulting related to the collision of the KO composite terrane with the Siberian craton. This collision also produced the Verkhoyansk fold-and-thrust belt in the Siberian continental margin. In the earliest Cretaceous, collision of the Alaskan and Siberian margins resulted in further thrust and strike-slip tectonism.  相似文献   

15.
As a result of regional seismic research by the method of isolated seismic sounding with waves of different types, the peculiarities of the wave field and main features of abyssal structures of the earth's crust are ascertained throughout the line: western Siberia lowland, the Yenisey mountain range, and the western part of the Siberian Platform. – Authors.  相似文献   

16.
The paper presents the results of paleomagnetic and geochronological studies of the Late Paleozoic granites of the Angara-Vitim batholith as well as Vendian-Early Cambrian sedimentary rocks and Late Devonian subvolcanic rocks of the Patom margin of the Siberian Platform. Primary and metachronous magnetization in the rocks of the study region was used to calculate an Early Permian (~ 290 Ma) paleomagnetic pole, which is proposed as a reference pole for the Siberian Platform in paleomagnetic reconstructions, plotting of the apparent polar-wander path curve, and other magnetotectonic studies. The published and obtained paleomagnetic data and analysis of the geological data confirm the Late Paleozoic age of the final folding in the Baikal-Patom area. Possible causes of Late Paleozoic deformations and large-scale granite formation in the Baikal-Patom area and Transbaikalia in the Late Paleozoic are discussed.  相似文献   

17.
An integrated geological and geophysical study was performed to investigate the region of junction of the eastern part of the Central Asian Fold Belt and the Siberian Platform in the Skovorodino–Tommot 3-DV reference profile line (52°–60° N, 122°–129° E), where the belt is separated from the Aldan–Stanovoi Shield of the Platform by a series of deep faults. The main results are as follows: Seismic, density, and geoelectric characteristics of rocks were obtained and used to determine (refine) the intracrustal boundaries of tectonic structures; large-block structure of the Earth’s crust, caused by mantle faults, and the difference between the layered structure of the crust for the shield and fold regions were established; and available paleomagnetic data were used to perform palinspastic reconstructions for 180 and 140 million years, the most productive metallogenic epoch in the region, coeval with collision processes at the closure of the Mongol-Okhotsk paleobasin.  相似文献   

18.
古亚洲洋不是西伯利亚陆台和华北地台间的一个简单洋盆,而是在不同时间、不同地区打开和封闭的多个大小不一的洋盆复杂活动(包括远距离运移)的综合体.其北部洋盆起始于新元古代末-寒武纪初(573~522Ma)冈瓦纳古陆裂解形成的寒武纪洋盆.寒武纪末-奥陶纪初(510~480Ma),冈瓦纳古陆裂解的碎块、寒武纪洋壳碎块和陆缘过渡壳碎块相互碰撞、联合形成原中亚-蒙古古陆.奥陶纪时,原中亚-蒙古古陆南边形成活动陆缘,志留纪形成稳定大陆.泥盆纪初原中亚-蒙古古陆裂解,裂解的碎块在新形成的泥盆纪洋内沿左旋断裂向北运动,于晚泥盆世末到达西伯利亚陆台南缘,重新联合形成现在的中亚-蒙古古陆.晚古生代时,在现在的中亚-蒙古古陆内发生晚石炭世(318~316Ma)和早二叠世(295~285Ma)裂谷岩浆活动,形成双峰式火山岩和碱性花岗岩类.蒙古-鄂霍次克带是西伯利亚古陆和中亚-蒙古古陆之间的泥盆纪洋盆,向东与古太平洋连通,洋盆发展到中晚侏罗世,与古太平洋同时结束,其洋壳移动到西伯利亚陆台边缘受阻而向陆台下俯冲,在陆台南缘形成广泛的陆缘岩浆岩带,从中泥盆世到晚侏罗世都非常活跃.古亚洲洋的南部洋盆始于晚寒武世.此时,华北古陆从冈瓦纳古陆裂解出来,在其北缘形成晚寒武世-早奥陶世的被动陆缘和中奥陶世-早志留世的沟弧盆系.志留纪腕足类生物群的分布表明,华北地台北缘洋盆与塔里木地台北缘、以及川西、云南、东澳大利亚有联系,而与上述的古亚洲洋北部洋盆没有关连,两洋盆之间有松嫩-图兰地块间隔.晚志留世-早泥盆世,华北地台北部发生弧-陆碰撞运动,泥盆纪时,在松嫩地块南缘形成陆缘火山岩带,晚二叠世-早三叠世华北地台与松嫩地块碰撞,至此古亚洲洋盆封闭.古亚洲洋的南、北洋盆最后的褶皱构造,以及与塔里木地台之间发生的直接关系,很可能是后期的构造运动所造成的.  相似文献   

19.
The Siberian Platform, covering a vast area of East Siberia (Russian Federation), represents one of the largest underexplored regions in Asia. Previous expeditions and regional surveys in the twentieth century, however, suggest that the Siberian Platform and adjacent orogenic belts hold significant potential for large undiscovered gold, copper, diamond and industrial mineral deposits, along with extensive oil and gas fields. The remoteness of the region, its inhospitable winter climate, and a major lack of modern infrastructure and mining methods have long hampered exploration in this area. These factors, along with the additional investment required and political uncertainties involved with operating in Russia, have deterred many international mining companies from considering the Siberian Platform as a viable region for exploration and mining. However, as mining industry paradigms change into a green, battery metals‐driven commodity sector, and modern mining methods are developed, increasing efficiency at a lower cost, the significant undiscovered mineral potential of the Siberian Platform could elevate the region to the forefront of mineral exploration and mining in the future.  相似文献   

20.
The geological, structural and tectonic evolutions of the Yenisey Ridge fold-and-thrust belt are discussed in the context of the western margin of the Siberian craton during the Neoproterozoic. Previous work in the Yenisey Ridge had led to the interpretation that the fold belt is composed of high-grade metamorphic and igneous rocks comprising an Archean and Paleoproterozoic basement with an unconformably overlying Mesoproterozoic–Neoproterozoic cover, which was mainly metamorphosed under greenschist-facies conditions. Based on the existing data and new geological and zircon U–Pb data, we recognize several terranes of different age and composition that were assembled during Neoproterozoic collisional–accretional processes on the western margin of the Siberian craton. We suggest that there were three main Neoproterozoic tectonic events involved in the formation of the Yenisey Ridge fold-and-thrust belt at 880–860 Ma, 760–720 Ma and 700–630 Ma. On the basis of new geochronological and petrological data, we propose that the Yeruda and Teya granites (880–860 Ma) were formed as a result of the first event, which could have occurred in the Central Angara terrane before it collided with Siberia. We also propose that the Cherimba, Ayakhta, Garevka and Glushikha granites (760–720 Ma) were formed as a result of this collision. The third event (700–630 Ma) is fixed by the age of island-arc and ophiolite complexes and their obduction onto the Siberian craton margin. We conclude by discussing correlation of these complexes with those in other belts on the margin of the Siberian craton.  相似文献   

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