摘要
摘要：安徽巢湖地区孤峰组地层为一套层状硅质岩与泥质岩交互沉积岩系，对其成因一直存在不同的认识。本文通过详细的野外地质调查和岩相学研究，以及常量元素和稀土元素等地球化学研究表明，该区硅质岩在Al-Fe-Mn三角图和SiO2—Al2O3，SiO2-MgO双变量图解中都落到生物成因的硅质岩范围内。δCe具有正异常，轻稀土富集，这些特征表明本区硅质岩属海水生物沉积成因。硅质岩的EREE值在22．62～209．03μg／g之间，平均值为88．58μg／g；Ceanom值的范围在0．20～2．78，平均值为1．70；（La／Yb）N值在0．39～2．80之间，平均值为1．01，这些地球化学指标揭示了本区硅质岩形成于深水缺氧环境。
Gufeng Formation is a set of sedimentary rocks composed of bedded siliceous rocks and argil- laceous rocks in Chaohu region, Anhui Province. The origin for the siliceous rocks has been debated for a long time. In this paper, we report the details of field and petrographic research, data of major ele- ments, rare earth elements compositions of these rocks. Our results suggest that in the A1-Fe-Mn terna- ry, and the SiO2-Al2O3, SiO2-MgO binary discriminant diagrams, these rocks fall in the biochemically- deposited area. These siliceous rocks show positive Ce anomaly, and a comparatively enrichment of LREE, which indicate a biochemically-deposited origin for these rocks. The siliceous rocks have the total REE contents of 22. 62-209. 03 μg/g, with an average of 88. 58μg/g; the Ceanom values are 0. 20-2.78, with an av- erage of 1.70; the （La/Yb）N values are 0. 39-2. 80, with an average of 1.01. All these geochemical character- istics suggest that these siliceous rocks were deposited in a deep-water and anoxic condition.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2014年第4期78-85,99,共9页
Periodical of Ocean University of China
基金
国家自然科学基金项目(41376053)资助
关键词
安徽
巢湖
二叠系
孤峰组
硅质岩
地球化学
沉积环境
Anhui
Chaohu
Permian strata
Gufeng Formation
silicalite
geochemistry
sedimentary en-vironment
