青海南部赤布张错地区中侏罗世沉积环境及双壳类化石

Middle Jurassic depositional environments and bivalve fossils in the Chibuzhang Lake area,southern Qinghai

摘要: 赤布张错地区中侏罗统十分发育,最大沉积厚度达6311m,包括雀莫错组、布曲组、夏里组、索瓦组和雪山组等5个岩石地层单元。根据所含丰富的双壳类、菊石、腕足类等化石,将它们划归中侏罗统(巴柔阶至卡洛夫阶)。沉积盆地的性质、早期的地貌格局和同沉积断裂活动可能是导致该地区中侏罗统厚度巨大、横向变化大的主要原因。

Abstract: The Middle Jurassic strata with a maximum sediments thickness up to 6311 m in the Chibuzhang Lake area,southern Qinghai are well developed and divisible into Qoimaco,Biqu,Gyari,Sogwa and Xueshan Formations on the basis of the fossils of bivalves,ammonites and brachiopods.The tremendous thickness and horizontal variations of the Middle Jurassic strata in this area may result from the nature of the basin,early geomorphic framework and syn-sedimentary faulting.