摘要
大坂山“铬矿物”产出于灰绿色中细粒石英闪长岩中,笔者从区域地质特征、岩石学、岩石化学、地球化学、同位素等方面对石英闪长岩进行了较全面的研究后认为,该套岩石成因为壳幔混合型,构造环境为北祁连加里东洋盆收缩阶段板块俯冲作用下形成的火山弧,岩石成岩时代为早奥陶世,铬矿物形成深度约30km,受区域性岩石圈断裂带控制。
The chromium mineral is produced in a gray middle-fine grain quartz-diorite inDabanshan. Based on a comprehensive studies on regional geology, petrology,petrochemistry, geochemistry, isotope, and so on, the kind of rock was identified as a mixedtype of crust and mantle. The tectonic environment is a volcano arc formed in EarlyOrdovician when North Qilian Caledonian ocean basin contracted and plate subducted. Thechromium mineral formed in the depth of 300 Km and controlled by regional lithosphericfault.
出处
《青海地质》
2001年第2期26-31,42,共7页
