Palaeozoic orogeneses around the Siberian craton: Structure and evolution of the Patom belt and foredeep

Abstract

This paper sheds light on the evolution of the Patom belt. This mountain range draws an arc along the southeastern edge of the Siberian craton. It is supposed to be of Caledonian age and to result from the accretion of microcontinents against the craton, but up to now, its detailed stratigraphic and tectonic history was unclear. A field study allows us to clarify it. The sedimentary record is marked by a slow evolution with stable periods of more than 250 Ma. The observed sedimentary succession confirms the existence of a passive margin setting in the late Riphean (900 Ma), followed during the Vendian (650–600 Ma) by the obduction of the Baikal‐Muya ophiolites belt and a foredeep inversion. After that, a Late Cambrian extension occurred, which is first described in this paper. The second collision stage occurred after 385 Ma, in the Late Devonian–Early Carboniferous. Sedimentary and tectonic data are interpreted in the light of the geodynamic evolution of Siberia, which is dominated by continental collages against the Siberian craton. Field data reveal a homogeneous direction of compression from the inner areas to the foreland. Whereas the inner range displays metamorphosed units deformed in the ductile domain, deformation is weaker in the foreland, which developed above the cratonic crust. We relate this high deformation gradient to the presence of the stiff craton which impeded strain propagation. The irregular shape of the craton as well as preexistent basement topography can explain the different tectonic styles observed along the belt.

Structural constraints on the evolution of the Central Asian Orogenic Belt in SW Mongolia

“…18B). This major shortening corroborates the NW-SE oriented collisional event in the area of the Patom belt in southern Siberia as shown in structural studies of Delvaux andothers (1995) andde Boisgrollier andothers (2009). NW-SE collision between Siberia and the northern part of the Tuva-Mongol continental block was coeval with E-W compressive deformation in the south, implying westward drift of the Tuva-Mongol ribbon (fig.…”

How old is the Baikal Rift Zone? Insight from apatite fission track thermochronology

“…By that time (circa 360–350 Ma) sample BA10 collected well inside the platform is covered by about 3 km of sediments whereas sample BA09 located closer to the Baikal and Patom ranges is covered by about 4 km of sediments (Figure 6). This ∼100 Ma subsidence episode is coeval with the beginning of accretion of the remote Tuva‐Mongolia (Late Cambrian–Early Ordovician) and Khamar‐Daban blocks (Late Silurian–Early Devonian) [ Fedorovskii et al , 1993; Zorin et al , 1993; Gibsher et al , 1993; Delvaux et al , 1995a; Gusev and Khain , 1996] and predates the onset of compressional deformation in the outer Patom region [ de Boisgrollier et al , 2009].…”

Controls of lithospheric structure and plate kinematics on rift architecture and evolution: An experimental modeling of the Baikal rift

“…The thickness of Cenozoic sediments reaches maximum values of 8–9 km in the South‐Centre Baikal and decreases northward up to ∼4.5 km in the North Baikal (Figure 1) [ Hutchinson et al , 1992; Petit and Déverchère , 2006]. To the northeast of Lake Baikal, the northern rift domain develops farther from the preexisting suture trace on map, within the Sayan‐Baikal fold belt [ de Boisgrollier et al , 2009]. Deformation in this area is distributed over a larger area characterized by the presence of shorter, still largely asymmetric en echelon basins developed within the Sayan‐Baikal mobile belt [ Logatchev and Florensov , 1978; Logatchev and Zorin , 1992].…”