Resumen de Upper Cretaceous–Cenozoic Lacustrine Deposits of the Zaysan Basin, Eastern Kazakhstan

Spencer G. Lucas, Robert J. Emry, Viacheslav Chkhikvadze, Bolat U. Bayshashov, Lyubov A. Tyutkova, Pyruza A. Tleuberdina, Ayzhan Zhamangara

• The Zaysan Basin of northeastern Kazakhstannorthwestern China (Figure 1) is a collisional successor basin that formed during the Late Cretaceous (Grahamet al., 1993;Allen et al., 1995). Beginning during the late Campanian-Maastrichtian, a lake basin developed in the Zaysan depression and has been there until the present. Lake Zaysan is now one of the large fresh water lakes of central Asia. Located between the Altai and Tarbagatay ranges at an altitude of 386 m, it is fed by the Cherny Irtysh River to the east and historically was about 100km long, 32 km wide, and 8 m deep. Its original surface area of 3200 km", however, was enlarged,and the lake was deepened (to 14 m) in the 1980s when Lake Zaysan became part of Bukhtarma Reservoir to the west. The new water body is 440km long and has a total area of 5504 km". Here, we present a brief overview of the lithostratigraphy, paleontology, and depositional335history of the Zaysan lacustrine basin, the majority of which is located in eastern Kazakhstan (Figure 1).