西藏措勤-申扎地层分区新建中—上侏罗统仁多组  

Ringtor Formation-a new Mid-Upper Jurassic lithostratigraphic unit in the Coqên-Xainza stratigraphic area, Tibet, China.

作　　者：赵兵[1] 刘登忠[1] 陶晓风[1] 马润则[1] 胡新伟[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059

出　　处：《地质通报》2005年第7期637-641,共5页Geological Bulletin of China

基　　金：中国地质调查局1:25万赛利普幅区域地质调查项目(编号:200313000020)成果。

摘　　要：在西藏措勤西部昂拉仁错南部新发现一套侏罗纪地层,其岩性和古生物组合特征均不同于邻区侏罗系。通过详细的层型剖面测制和对比研究,将其新建为组级岩石地层单位——仁多组。指定并详细描述了正层型剖面,讨论了仁多组的岩石组合特征、地层接触关系、基本层序和沉积环境。根据仁多组的生物化石组合及其地层分布建立了2个生物组合带,并确定仁多组下段与中—上段分属为中、上侏罗统。仁多组的建立为认识区域地层系统及地质演化提供了新资料。A sequence of Jurassic strata is found for the first time in southern Ngangla Ringco, western Coqên County, Tibet. Both the lithology and fossil assemblages of this Jurassic sequence are different from those in the neighboring areas. A new formal formation-rank lithostratigraphic unit-Ringtor Formation-has been established based on detailed measurements of a stratotype section and comparative study. The holostratotype section of the Ringtor Formation is designated and described in detail. Its rock association, stratigraphic contact relationships, essential sequences and sedimentary facies and environment are discussed. Two biostratigraphic assemblage zones have been established according to the fossil assemblages and their stratigraphic ranges in the Ringtor Formation. The Lower Member and the Mid-Upper Members of the Ringtor Formation are assigned to the Middle Jurassic and the Upper Jurassic respectively. The establishment of the Ringtor Formation provides new data for gaining a better knowledge of the regional stratigraphic system and geological evolution.

关 键 词：西藏 措勤西部 侏罗系 岩石地层 仁多组 

分 类 号：P534.52[天文地球—古生物学与地层学]