柴达木盆地北缘锡铁山-长山梁古近纪沉积演化

Palaeogene sedimentary evolution in the Xitieshan-Changshanliang region,northern Qaidam Basin

柴达木盆地北缘大柴旦镇锡铁山-长山梁古近系—新近系实测剖面沉积相研究显示:锡铁山剖面古近系路乐河组沉积相自下而上为辨状河-辨状河三角洲-滨浅湖-洪积扇,总体上表现为进积-退积-进积的沉积旋回;长山梁剖面古近系干柴沟组沉积相自下而上为由辫状河三角洲-滨浅湖相构成的三个进积-退积旋回,岩性总体上为由粗到细的退积型序列。锡铁山剖面路乐河组古水流方向为NNW向,其东南方向的锡铁山为物源区;长山梁剖面路乐河组和干柴沟组古水流方向为SSE向,其物源为北侧的南祁连山脉。

Sedimentary facies in the Palaeogene Lulehe Formation in the Xitieshan section consist, from the base upwards, of the braided stream, braided delta, littoral-shallow lake, pluvial fan facies, dislaying an overall progradation-regradation-progradation depositional cycle. The palaeocurrents are oriented to NNW, and the sediments are derived from the Xitie Mountains in the southeastern part. Sedimentary facies in the Palaeogene Ganchaigou Formation in the Changshanliang section are assembled, from the base upwards, by the braided delta and littoral-shallow lake, constituting three progradation-regradation depositional cycles. The palaeocurrents are oriented to SSE, and the sediments are derived from the South Qilian Mountains in the northern part.