藏北查桑上三叠统复理石沉积大地构造背景的初步探讨

藏北羌塘地块的构造性质和构造局是中国地学界长期争论的重要问题。这里人迹罕至,研究程度很低,基础地质资料缺乏。这是有关地质问题得不到解决的根本原因之一。本项研究的首要目的也是为该地区的地质研究提供一份基础资料,羌塘地块腹地查桑地区的上三叠统肖茶上涨且,下部为细碧岩、中基性火山岩、玄武质角砾岩来灰岩和大理岩,上部主要为碎屑岩（复理石）和灰岩,我们在肖茶卡组上部的复理石中采集砂岩、粉砂岩样品,进行主量元

A preliminary study on the tectonic setting of Upper Triassic flysch at Chasang, North Tibet

Is Qiangtang block in North Tibet an ancient continental block or fold belt? And how is its composition (tectonic framework)? These are the geological topics still in debate. Qiangtang is far from human society. It is one of the places in the world with lowest geological working degree. The lacking of basic geological data is an important reason, which makes the related geological problems difficult to get clear and correct interpretation. Chasang is located at the inner part of Qiangtang. The Upper Triassic Xiaochaka Formation there is composed of spillite, basalt, medium-basic volcanic rocks, basaltic breccia, intercalated with limestone and marble at the lower part, clastic rocks (flysch) and limestone at the upper part. Sandstone and siltstone samples were collected from the flysch of the upper part of Xiaochaka to do major element geochemical analysis for tectonic-setting discrimination. The result of this research indicates that the tectonic setting of Xiaochaka flysch is oceanic island arc of an active continental margin, and its sedimentary provenance is mainly intermediate volcanic rocks.