Structure and evolution of the Baikal rift: A synthesis

摘要: Active continental rifts are spectacular manifestations of the deformation continents but not very numerous at surface Earth. Among them, Baikal rift has been extensively studied during last decades. Yet no simple scenario explains its origin and development because style rifting changed throughout ∼30 Myr history. In this paper, we use forward inverse models gravity data to map Moho lithosphere-asthenosphere boundary in three dimensions. We then integrate these new results with existing geophysical geological on structure dynamics, propose a evolution. Earthquake depths, mantle xenoliths, heat flow, seismic advocate for normal moderately thinned lithosphere crust, except beneath Siberian craton, which exhibits >100-km-thick lithosphere. Relatively thin (70–80 km) is found east south system spatial connection Hangai-Hovsgol region anomalous Mongolia. From top bottom, asymmetric appears strongly controlled by geometry suture zone bounding craton. Moreover, mode topography support changes significantly along length rift: mountain ranges north underlain negative Bouguer anomalies, suggesting deep crustal roots and/or mantle; shoulders center seem result from flexural uplift. The commonly assumed “two-stage” evolution corroborated all stratigraphic data; however, it seems clear that Oligocene, an “early stage,” might be dominated strike-slip tectonics instead pure extension, created primitive basins much different present ones. Most “true” have initiated later, Late Miocene or Pliocene. This kinematic change extensional part more general reorganization Asia can associated rapid growth Tibetan plateau end marginal opening Pacific boundary.