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石鸡河一带是近年新发现的北祁连山多金属成矿带,气侯和自然条件恶劣,研究程度很低.该区地层岩性为阳起石岩、角岩和细碧岩;岩石地球化学和Nd同位素数据显示岩石来源于亏损地幔,具有N-MORB洋脊玄武岩特征;Sr同位素特征显示地层Sr同位素组成的改变是蚀变引起,而不是由地壳物质加入引起的.Sm-Nd等时线年龄为481±20Ma.提出了石鸡河地区地层形成于早奥陶世,成岩环境为北祁连洋扩张环境,而非区域资料上显示的残留海盆封闭、大陆碰撞造山环境.
The Shiji River area is a newly discovered North Qilian Mountains polymetallic metallogenic belt in recent years with poor climate and natural conditions and a low degree of research.The lithology of this area is Yangzidan, Angular and Bijinbi; lithogeochemistry And Nd isotopic data show that the rocks originated from the depleted mantle and have N-MORB ridges. The Sr isotopic characteristics show that the change of Sr isotope composition is caused by alteration but not by the addition of crustal material. The age is 481 ± 20Ma. It is proposed that the strata in Shijijian area formed in the Early Ordovician, the diagenetic environment is the North Qilian ocean expansion environment, while the non-regional data show that the remaining basin is closed and the continental collision orogenic environment.