Neocomian paleogeography, gas hydrate cementation of sediments, and abnormal sequences of the Bazhenov Formation (West Siberia)

Abnormal zones of the Bazhenov Formation originated in the Neocomian as a result of protobazhenite reworking by submarine slide and slump waste wedgings, which eroded and deformed slope toe protobazhenite. But gas hydrate (GH) cementation might restrict the rock ability for plastic deformation. The conditions for GH thermodynamic stability in protobazhenites are inferred from reconstructions of paleogeographic and paleo-oceanic evironments. Joint analysis of Neocomian marine paleodepths and deep water paleotemperatures provides an explanation of the Bazhenov abnormal-zone extension.