藏东北巴青县江绵乡上三叠统东达村组和“甲丕拉组”沉积特征及其意义

Sedimentary characteristics of the Upper Triassic Dongdacun Formation and "Jiapila Formation" in the Jiangmianxiang area, Baqên County, northern Tibet, and their significance.

在藏北巴青县江绵乡一带发现与滇西他念他翁山、藏东昌都地区相似的上三叠统东达村组和“甲丕拉组”。东达村组自下而上为冲积扇泥石流沉积、无障壁碎屑滨岸沉积和浅水碳酸盐台地潮坪沉积。“甲丕拉组”为干热环境下的碳酸盐台地潮坪(包括潮汐水道砂)沉积、障壁砂坝沉积和滨外粉砂、泥沉积,其中有地震事件记录。两组总体上构成一套向上变深的海侵序列。两组沉积特征新资料为认识藏东北地区印支运动阶段本区“构造域”的转换提供了重要信息。

The Upper Triassic Dongdacun Formation and 'Jiapila Formation' similar to those in the Taniantaweng Mountains, western Yunnan, and the Qamdo area, eastern Tibet, have been found for the first time in the Jiangmianxiang area, Baqên County, northern Tibet. The Dongdacun Formation consists in ascending order of alluvial fan debris flow deposits, barrier-free clastic littoral deposits and shallow-water carbonate platform tidal-flat deposits. The 'Jiapila Formation' consists of carbonate platform tidal-flat (including tidal channel sand) deposits, barrier bar deposits and mud deposits formed in a hot environment, which contain records of seismic events. The two formations make up an upward-deepening transgressive sequence. The new data of the sedimentary characteristics of the two formations provide important information for the rarely known tectonic-paleogeographic environment occurring in the Indosinian movement in northern Tibet.