Late Mesozoic tectonics of Central Asia based on paleomagnetic evidence (original) (raw)
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Russian Geology and Geophysics, 2012
In this paper we present the results of a generalization of paleomagnetic data for the territory of the Siberian craton and its folded framing that were obtained during the last fifteen years. We propose a new version of the apparent polar wander path for the Siberian continental plate, including the interval from the Mesoproterozoic-Neoproterozoic boundary up to the end of the Mesozoic. The constructed path forms the basis for new concepts on the tectonics of the Siberian paleocontinent and the paleooceans that surrounded it. We present a series of paleotectonic reconstructions based on paleomagnetic data, which not only displays the paleogeographic position of the Siberian continent, but also reveals the features of the tectonic evolution of its margins during the last billion years. In particular it has been established that large-scale strike-slip motions played an important role in the tectonic regime of the continental plate at all stages of its development.
Russian Geology and Geophysics, 2009
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.
The Mongol-Okhotsk Ocean was an embayment of the Palaeo-Pacific, which existed in Late Paleozoic - Early Mesozoic between the Siberian continent and Amurian continental block. The scenario of the Mongol-Okhotsk Ocean development, characteristics of subduction of its crust beneath the Siberian continent and the age of subduction-related complexes are still under debate. We represent review of geological, geochronological and geochemical data on the Late Paleozoic - Mesozoic magmatic complexes of the Siberian continent, which are located north of the Mongol-Okhotsk suture. We assume that the formation of these complexes was related to the subduction of the oceanic crust of the Mongol-Okhotsk Ocean under the Siberian continent, which started in the Devonian, prior to the main peaks of magmatic activity. The magmatic complexes demonstrate variable compositions, which were possible controlled by a changing of the subduction regime. We noted that the Late Permian - Middle Triassic as well...
Tectonophysics, 1995
This paper presents the first palaeostress results obtained for the basement of the Baikal rift system, in southern Siberi (Russia). Large-scale structural analysis and palaeostress reconstructions show that the Palaeozoic-Mesozoic kinemati. history, precursor of the Baikal Cenozoic rifting, is characterized by the succession of six regional palaeostress stages. Stres inversion of fault-slip data and earthquake focal mechanisms is performed using an improved right-dieder method, followe by rotational optimization (D. Delvaux, TENSOR program). The results are interpreted in the light of recent developments il the investigation of regional intraplate stress field, and used as additional constraints for palaeogeodynamic reconstruction 0 Central Asia.
Russian Journal of Earth Sciences, 2002
This paper describes the Late Precambrian geologic complexes from the southern margin of the Siberian Craton, associated with the extension epochs. Analysis of the data available suggests that there were two episodes of intracontinental breakup, which resulted in the opening of the ocean (1300-900 and 850-550 million years ago). The time sequence of the "rift-related volcanic rocks and terrigenous deposits → basic dike swarms → carbonate-terrigenous rocks → ophiolites and island-arc rocks reflects the successive change of geodynamic environments in the marginal part of the craton. The stage of intracontinental rifting was superseded by the stage of advanced rifting which preceded the continent break and the formation of oceanic crust. This period was followed by two phases of oceanic evolution: a passive phase (sedimentary rocks of the passive margins) and an active phase (island arcs, backarc seas, and the like). Several different versions are offered and discussed for the extension processes in the southwestern and southeastern parts of the Siberian Craton is association with the breakup of the Rodinia Continent.
Tectonophysics, 2003
The east margin of the Siberian craton is a typical passive margin with a thick succession of sedimentary rocks ranging in age from Mesoproterozoic to Tertiary. Several zones with distinct structural styles are recognized and reflect an eastwardmigrating depocenter. Mesozoic orogeny was preceded by several Mesoproterozoic to Paleozoic tectonic events. In the South Verkhoyansk, the most intense pre-Mesozoic event, 1000-950 Ma rifting, affected the margin of the Siberian craton and formed half-graben basins, bounded by listric normal faults. Neoproterozoic compressional structures occurred locally, whereas extensional structures, related to latest Neoproterozoic-early Paleozoic rifting events, have yet to be identified. Devonian rifting is recognized throughout the eastern margin of the Siberian craton and is represented by numerous normal faults and local half-graben basins. Estimated shortening associated with Mesozoic compression shows that the inner parts of ancient rifts are now hidden beneath late Paleozoic-Mesozoic siliciclastics of the Verkhoyansk Complex and that only the outer parts are exposed in frontal ranges of the Verkhoyansk thrust-and-fold belt. Mesoproterozoic to Paleozoic structures had various impacts on the Mesozoic compressional structures. Rifting at 1000-950 Ma formed extensional detachment and normal faults that were reactivated as thrusts characteristic of the Verkhoyansk foreland. Younger Neoproterozoic compressional structures do not display any evidence for Mesozoic reactivation. Several initially east-dipping Late Devonian normal faults were passively rotated during Mesozoic orogenesis and are now recognized as west-dipping thrusts, but without significant reactivation displacement along fault surfaces.
Russian Journal of Earth Sciences, 2002
The Paleozoic fold-and-thrust belt, confined between the European, Siberian, Tarim, and North China Precambrian continents, results from a complex evolution of the Paleo-Asian Ocean. At the end of the Ordovician, the Kazakhstan-Kyrghyz continent, originating from the accretion of island arcs and Gondwanan continental fragments, divided the Paleo-Asian Ocean into four oceanic basins, Uralian, Turkestan, Junggar-Balkhash, and Ob-Zaisan. The Middle to Late Paleozoic history of these oceanic basins, which closed completely in the terminal Carboniferous to Permian, is portrayed in eight detailed, 1:10,000,000 scale, palinspastic reconstructions for the Early Silurian (430 Ma), Early Devonian (Emsian, 390 Ma), Middle Devonian (Givetian, 380 Ma), Late Devonian (Famennian, 360 Ma), Early Carboniferous (late Visean to Serpukhovian, 330 Ma), early Late Carboniferous (305 Ma), Early Permian (280 Ma), and Late Permian (255 Ma) time slices. These reconstructions draw on 1:2,500,000 scale sedimentologic-paleogeographic maps and paleomagnetic measurements from ancient continents and Variscan orogenic zones of the Urals, Kazakhstan, Tien Shan, Junggaria, and Altay. The shrinking and collision-induced closure of the oceans were ensured by the three large and long-lived (100-130 m.y.) Urals-Tien Shan, Junggar, and Siberian subduction belts, spanning thousands of kilometers, whose polarities remained stable. The belts were represented by systems of roughly parallel and branching subduction zones, each with a 10-30 m.y. lifespan, plunging beneath the Kazakhstan-Kyrghyz and Siberian continents. Taken together, they constituted a system that diverged in a southwesterly direction and ensured differential rotations of the European, Siberian, and Kazakhstan-Kyrghyz continents. The Urals-Turkestan belt began to form at the beginning of the Silurian, and the Siberian and Junggar belts, at the beginning of the Devonian. The subduction belts ceased to exist as they were crushed between continents during a general collision that set on in the second half of the Devonian and in which the Junggar belt became involved prior to the beginning of the Permian. Geologic and paleomagnetic evidence points to oblique motions of oceanic plates being consumed in the subduction belts and, accordingly, to an oblique collision in the Urals and South Tien Shan foldbelts that propagated through time and space to finally give rise to large-scale post-collisional lengthwise strike slips. We believe the subduction belts to be surface manifestations of descending mantle convection flows that drove the long-lasting sinking of oceanic plates into the mantle.
American Journal of Science, 2010
Available geochronological data substantiate the existence of an apparent ca. one billion year gap in geological activity in the southern part of the Siberian craton. The duration of the gap is about 0.8 to 1.1 Ga in the Sayan Uplift and at least 0.9 Ga in the Baikal Uplift. We suggest that the absence of major geological activity in this interval might be due to the southern margin of Siberia occupying an internal position within a Transproterozoic supercontinent, that is, a fragment of Nuna that did not disperse until the late Neoproterozoic breakup of Rodinia. The absence of Mesoproterozoic-early Neoproterozoic sedimentary successions in southern Siberia could possibly be explained by their removal by erosion. Ediacaran subsidence following the breakup of Rodinia may reflect the solidification of magma chambers that fed Neoproterozoic mafic dike swarms. We suggest that a combination of these factors (dike emplacement and erosion) has a significant influence on global tectonics, controlling the uplift and subsidence of ancient cratons.
The geodynamic evolution of the eastern Eurasian margin in Mesozoic times
Tectonophysics, 1992
. The ge~dynamic evolution of the eastern Eurasian margin in Mesozoic times. Teetonophysics, 208: 397-411 s The Cenozoic features of Eurasia, such as marginal seas and intracontinental deformation, are unraveled using available paleomagnetic and field data. The Late Cretaceous shape of Eurasia is then reconstructed. From the examples of SW Japan and South Russian Far East, the major features OF the Mesozoic Eurasian margin-suture zones marked by ophiolites or high-pre~ure metamorphic rocks, otistostromes characterized by the ~~tholo~ of the o~istoi~ths, talc-alkaline magmatism and strike-&p fat&s-are outiined. Correlations of the opbiolitic belts and the ohstostromes along the eastern Eurasian margin from Borneo to Siberia aliow the defjnition of four mj~r~ont~nents~ the West Fhi~~p~ines, South Japan, and the Anuy and Okhotsk Sea microblocks from south to north. The Mesozoic structure of the Eurasian margin is due to three processes: (1) oceanic subduction and the accretion of subduction complexes; (2) the collision of these microcontinents with Eurasia between the Late Jurassic and the Late Cretaceous; and (3) the reactivation of the ophiolitic sutures by left-lateral wrench faulting.