Sedimentary Characteristics and Distribution of Neogene Quaternary Gravel Layers in the Middle of Kuqa Depression, Tarim Basin

Key words: 
•   /
• Kuqa Depression /
• alluvial fan /
• gravel layers /
• sedimentary characteristics /
• controlling factors

Abstract:  Based on the outcrop investigation and core borings identification, we systematically studied the cycle of development, the sedimentary and distribution characteristics of NeogeneQuaternary gravel layers of Kuqa Depression in Tarim Basin, to solve the problems of velocity changes and engineering decision. We analysed the thicknes, lithology, structures, tectonic and gravel composition of different outcrops and rock debris, and we also correlate gravel layers of all period. We believe  that  there were four periods which developed thick gravel layers, and the sedimentary origins of gravel layers could be alluvial fan, fan delta and fluvial plain. All gravels had four provenance systems, in which there developed different gravel composition. The gravel layers of Kuqa depression continuously developed in different periods vertically, and had different facies which changed fast laterally. The tectonic evolution, tectonic style, and the northsouth faults were the main factors which influenced the sedimentary characteristics, distribution of the gravel layers.