STRATIGRAPHY AND LITHOLOGY OF THE PALEOZOIC DEPOSITS IN THE TASBULAK GRABEN, SHU-SARYSU BASIN

Abstract

Despite of more than 40-year history of prospecting work, the degree of geological and geophysical knowledge of the Shu-Sarysu basin is still very low. Current comprehensive study is based on the geological, geophysical, well and geochemical data from published literature and reports of the state institutions. The Shu-Sarysu sedimentary basin evolved at the western margin of the Kazakhstan microcontinental plate in the beginning of Devonian. Subduction of oceanic crust under the microcontinent raised to magmatic and volcanic processes in the south and east territories of the basin. Afterwards, throughout the late Paleozoic, these areas became a source of the clastic sediments of the basin. Territory of the Shu-Sarysu basin was uplifted in the Triassic and Jurassic. This confirmed by the absence or very thin sediments of the Cretaceous and Tertiary in the territory of the basin. The basement of the Shu-Sarysu basin is represented by the Precambrian and partially the Lower Paleozoic formations. They are dislocated, metamorphosed, and intruded by intrusions of various compositions and ages.The lithology and stratigraphy of the Paleozoic sediments in the north and west parts of the Shu-Sarysu basin are have the similar construction. This statement well confirmed by the well data from the parametric and prospecting wells drilled within the Tasbulak and Kokpansor grabens. Based on this data, the next lithological-stratigraphic layers are established within the Paleozoic sediments of the Tasbulak graben: carbonate-terrigenous-halogen Upper Devonian; terrigenous-carbonate Lower Carboniferous; continental terrigenous of the Middle-Upper Carboniferous, terrigenous-halogenous of the Lower Permian and terrigenous-carbonate of the Upper Permian.