西藏类乌齐地区早、中侏罗世地层

The Early and Middle Jurassic strata in the Neiwugi area, Xizang(Tibet)

西藏类乌齐地区早、中侏罗世地层可划分为下部仁青卡群和上部雁石坪群两部分。仁青卡群系新创，代表早侏罗世海退沉积序列的杂色陆源碎屑岩建造，由隆再这组、去买组和埃买组组成，并首次发现Ｈｉａｔｅｌｌａａｒｅｎｉｃｏｌａ，Ｌｉｌｉｎｇｅｌｌａｃｕｎｅａｔａ等湘赣区的分子。该群下与三叠系，上与中侏罗统均为整合过渡。雁石坪群代表中侏罗世海进沉积序列的碳酸盐岩建造，由货乃组、结弄组、北腾组和日阿沙组组成。叙述和讨论了这些地层单位的岩石和生物特征及地质时代。

In this paper, the Early and Middle Jurassic strata in the Neiwugi area, Xizang are divided into the Renqingka Group below and the Yanshiping Group above. The Renqingka Group is established by the present author to represent the terrigeneous variegated elastic rock formations of the Early Jurassic regressive sequence and divided ascendingly into the Longzaida, Qumai and Aimal Formations. Hiatella arenicola and elements in the Hunan and Jiangxi area. This group conformably overlies the Triassic rocks and conformably underlies the Middle Jurassic rocks. The Yanshiping Group represents the carbonte rock formation of the Middle Jurassic transgressive sequence and is divided asscendingly into the Huonai, Jienong Beiteng and Riasba Formations. The lithological and biological characters of these stratigraphic units and their geologcal ages are described and discussed also in this paper in order to reflect the latest advance in study.