摘要
晚三叠世北羌塘前陆盆地为处于金沙江缝合带南缘的周缘前陆盆地 ,其中充填了厚度大于 2 5 0 0m的晚三叠世肖茶卡群 ,自南向北可分出 4个沉积相带 ,显示为北厚南薄的楔形沉积体 ,具双物源、双古流向以及沉降中心和沉积中心不一致性等特点 ,以不整合面为界可将其分为 2个构造层序 ,下部构造层序以诺利期复理石建造为特征 。
The Late Triassic Northern Qiangtang Foreland Basin is a peripheral one situated to the south of the Jinshajiang suture zone, to the south of the basin is a forebulge (center uplift). The basin was filled with Late Triassic Xiaochaka group, in thickness more than 2 500 m, which could be divided into two tectonic sequences bounded by unconformities. In a transverse section there is a wedge\|shaped sedimentary body with thicker in the north and thinner in the south with double paleocurrents and double provenances: the Hoh Xil thrust belt in the north and the forebulge in the south. The depocenter was located in north part of the basin . The sedimentary and tectonic evolution of the basin can be divided into two phases by stratigraphic signatures. The early one was flysch phase, characterized with the carbonate ramp developing along the north slope of the forebulge and the turbidite occurring along the south margin of the Hoh Xil thrust belt respectively. This phase should be coincident with subduction of the Jinshajiang Ocean and initial collision. The second one was molasse phase, during which the delta system developed along the north slope of the forebulge and the molasse deposits (alluvial apron as well as delta system) developed along the south margin of the Hoh Xil thrust belt respectively. This phase should be coincident with the collision followed the Jinshajiang ocean's closure.
出处
《地质科学》
CAS
CSCD
北大核心
2002年第1期27-37,共11页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
青藏高原 1:2 5万温泉兵站幅区域地质调查项目
国家重点基础研究 (973 )项目 (G1 990 40 80 1 5 )资助
关键词
北羌塘前陆盆地
充填样式
构造层序
晚三叠世
金沙江缝合带
西藏
The Northern Qiangtang Foreland Basin, Fill models, Tectonic sequences, Late Triassic, Jinshajiang suture
