부산대학교 도서관

During the Paleocene and Eocene the extratropical Central Eurasia was the main seaway link of the contiguous south to north seaway system connecting the Tethys and Arctic oceans. The seaway extended from North Pakistan and India to North Siberia through a system of inland seas and straits and acted as a kind of heat transfer to the Arctic during this time. Before the emergence of the latitudinal Alpine-Himalayan orogenic belt, the Tethys and its marginal seas to the north formed a continuous shelf area. The closest linkage of the water masses and exchange of biota between the Tethys and the Arctic ocean existed during the Thanetian and Ypresian. Latest Paleocene - Early Eocene heat transfer developed both by water- and atmospheric currents at the mid- latitudes of Central and Eastern Eurasia. From the end of the Paleocene or earliest Eocene onwards this system was complicated by latitudinally oriented straits that ensured the connection of the Northern Peri-Tethys with the Atlantic through the North Sea basin. The combination of two sea systems controlled the climatic history of the Central Asia regions from the Late Paleocene until the Late Eocene. During the Bartonian and Priabonian the West Siberian inland sea was isolated completely from the Arctic Basin during the last phase of marine sedimentation. It was connected with the Turan sea through the Turgai strait. Azolla beds accumulated periodically during eustatic sea level lowstands in fresh-water surface waters, and in dysoxic bottom waters inhabited stunted benthos during the Bartonian - earliest Late Eocene. During the Late Eocene eustatic rise of sea level the input of saline water from the Peri- Tethys increased and the West Siberian basin became normally marine again. The monsoonal subtropical climate during Ypresian - Early Lutetian was transformed to subtropical seasonal with semi-arid features during the Late Lutetian - Early Priabonian, up to subtropical to warm-temperate with alternations of humid and arid phases in the Late Priabonian. [ABSTRACT FROM AUTHOR]