西藏札达盆地上新统—早更新统河湖相地层多重地层划分与对比

Division and Correlation of Pliocene and Early Pleistocene Fluvio-lacustrine Strata in the Zhada Basin, Tibet, China

根据札达盆地河湖相地层实测剖面中的接触关系、沉积旋回、沉积体系、岩相、岩性、古生物特征和ESR、古地磁测年结果,笔者对札达盆地上新统—早更新统河湖相地层进行了重新划分和时代确定。结合该套河湖相沉积的岩石地层、生物地层、年代地层、磁性地层、层序地层和地质构造事件,对札达盆地上新统—早更新统河湖相地层进行了多重地层的划分与对比。将札达盆地河湖相地层划分为3个组、4个沉积相、7个沉积亚相、11个岩性段。由新到老划分为:早更新统香孜组(Qp1-1x)、上新统古格组(N22g)和上新统托林组(N21t)。

Based on the contact relationship, the sedimentary cycle, the sedimentary system, lithofacies, lithology, palaeontologic features, and the results of the ESR and paleomagnetic dating in the measured geologic section, the authors redivided the Pliocene-Early Pleistocene fluvio-lacustrine facies strata in Zanda basin of Tibet, with the age redefined. The division and correlation of the multiple strata were made for the Pliocene and Early Pleistocene fluvio-lacustrine strata in Zanda basin, in combination with such factors as rock stratigraphy, biostratigraphy, chronohorizon, magnetostratigraphy, sequence stratigraphy, and event geological structure of the fluvio-lacustrine facies sediments. The fluvio-lacustrine strata in Zanda basin are divided into 3 groups, 4 sedimentary facies, 7 sedimentary subfacies and 11 lithologic members. The strata of the fluvial and lacustrine sediments have been divided from top to bottom into Early Plestocene Qangzê Formation ( Qp1-1x ), Neogene Pliocene Guge Formation ( N22g ) and Neogene Pliocene Tuolin Formation (N12t).