西藏革吉县赛利普地区捷嘎组地层古生物及沉积环境

在西藏革吉县赛利普地区测制了多条捷嘎组剖面,详细描述了阿母弄勒捷嘎组剖面,首次将区内捷嘎组细分为两个岩性段,讨论了捷嘎组的岩性组合特征及横向变化规律.在捷嘎组内建立了一个圆笠虫生物组合带和一个腹足类生物组合带,确定捷嘎组的时代为早白垩世阿普特晚期至阿尔布期.认为赛利普地区捷嘎组从早到晚空间上由北向南火山活动趋于强烈,出现了偶发火山碳酸盐台地→间歇火山碳酸盐台地→火山爆发-溢流相的空间变化规律.

Stratigraphy and sedimentary environment of the Jiega Formation in Sailipu, Geiji County, Tibet, China

Several sections of the Jiega Formation were measured in the Sailipu area of Geiji County in Tibet.The Jiega Formation section located at Amulongle is described in detail.The Jiega Formation is first divided into two members in this area.The characteristics and transverse variation of lithologic associations of the Jiega Formation are discussed in this paper.An orbitolina biozone and a gastropoda biozone in the Jiega Formation are established.They belong to the Aptian to Albian stage of Early Cretaceous Epoch.The volcanic activity became more violent from north to south during the Aptian -Albian stage in the Sailipu area.The sedimentary facies of low Jiega Formation is carbonate plateform with occasional volcanic eruptions and that of upper Jiega Formation is mostly composed of carbonate plateform with interval to volcanic overflow from north to south.