上扬子地区震旦—寒武纪磷块岩岩石学特征及成因分析  

Characteristics and Phosphogenesis of Phosphorite of the Sinian-Cambrian,West Yangtze Area

作　　者：牟南[1] 吴朝东[1] 

机构地区：[1]北京大学地球与空间科学学院地质学系,北京100871

出　　处：《北京大学学报（自然科学版）》2005年第4期551-562,共12页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金(49802014);教育部重点项目(104004)资助项目

摘　　要：采用古地理、岩石学、有机地球化学、地球化学分析的方法,对上扬子区晚震旦陡山沱组和早寒武牛蹄塘组不同类型的磷块岩进行了研究。认为早寒武世早期古陆遭受风化,被剥蚀下来的产物成为潮坪型磷块岩的主要磷质来源,在碳酸盐岩台地发生的热点活动和上升洋流从盆底深部带来的磷质,共同作为台地型磷块岩的磷源,盆地型磷块岩的磷质同样是由热点活动和上升流携带至缺氧的沉积环境中,通过藻类或微生物的富集作用成岩,并保留了较高的有机碳含量。The late Sinian and early Cambrian are two most important age of phosphate formation in the west Yangtze area. Phosphate deposits are distributed along the margin, platform and basin in the west Yangtze area. The analysis methods include the paleogeography, petrology, organic geochemistry, geochemistry. The conclusions are drawn that the source of phosphate deposits distributed along the margin originate from the weathering production of continent, while phosphate deposits along the platform and basin gain phosphorus through hot spring on the bottom of the sea floor, which is brought to the sedimentary environment by rising sea-fluid, then accumulated by the organism and microorganism, meanwhile, basin phosphorite keep relatively higher organic carbon content.

关 键 词：磷块岩 上升洋流 热点活动 

分 类 号：P588.2[天文地球—岩石学] P581[天文地球—地质学]