THE REFLECTION OF THE PHASES OF ALPINE TECTOGENESIS IN THE MESOZOIC-CENOZOIC ROCKS OF THE SOUTHERN TIEN-SHAN REGION

On the basis of an analysis of the sedimentary processes and consedimentational deformation in the development of the Mesozoic-Cenozoic basins of the southern Tien Shan region. it is established that they are relicts of depressions that developed from the beginning of the Mesozoic. Abrupt changes in the axis of subsidence in the Early and the Late Cretaceous and in the Neogene were found in these basins. The shift of the basin at the beginning of the Neogene was accompanied by buckling, uplift, and overthrusting of the region of maximal subsidence in the Mesozoic upon it. During the Neogene the margins were overthrust upon the basin, ultimately leading to a tectonic piling up of the Paleozoic basement above the chains of subsided basins. Thus, the process of transformation of the Mesozoic-Cenozoic basins into interlocking structures included a combination of sedimentational and deformational events. All the tectono-sedimentational transformations in the Mesozoic-Cenozoic cover of the southern Tien Shan region are cyclical in character and are echoed by tectonic events in the Alpine belt.