鄂西宣恩娄山关组顶部燧石结核成因及沉积环境

摘要

Through the samples of the chert nodules developed in upper Loushanguan Formation in Xuan’en County, Western Hubei,the authors manly use the petrology and geochemistry methods to discuss the petrogenesis and sedimenta-ry environment of the chert nodules. The major element characteristics show that the chert nodules belong to non-hydro-thermal origin. Trace elements,U/Th,V/( V+Ni) and Ceanom etc. ,index that the weak oxidation and poor oxygen sedi-mentary environment;the major elements,trace elements and rare earth element( REE) comprehensively make sure that the chert nodules in this area deposited in continental shelf.%通过对鄂西宣恩娄山关组顶部发育的燧石结核进行采样分析，利用岩石学和地球化学分析方法，探讨娄山关组顶部燧石结核的成因和沉积环境。主量元素特征表明：燧石结核属于非热水成因。微量元素U/Th、 V/( V+Ni)、 Ceanom值等显示了沉积时弱氧化的贫氧环境，主量、微量、稀土元素特征很好地指示了该区硅质结核沉积于大陆边缘。