上扬子区早寒武世黑色页岩磷结核特征及生化淀磷机制  

THE CHARACTERISTICS OF BLACK SHALE-HOSTED CONCRETIONARY PHOSPHATES AND THE MECHANISMS OF MICROBES MEDIATED PHOSPHORUS PRECIPITATION IN CAMBRIAN HORIZON ON YANGTZE PLATFORM

作　　者：雷加锦[1] 李任伟[1] 曹杰[1] 

机构地区：[1]中国科学院地质研究所,北京100029

出　　处：《地质科学》2000年第3期277-287,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金!资助项目 ( 4950 2 0 32 )

摘　　要：通过野外观察、室内化学分析、矿物学分析、硫同位素分析、光学显微镜和扫描电镜观察 ,发现磷结核内所观察到的许多现象均与微生物的活动有关 ,微生物是使磷淀积的重要营力 ,这为磷结核的生物成矿作用提供了有力的证据。沉积物孔隙水物理化学条件的变化直接影响着磷结核的生长过程。With the methods of chemical analysis, mineralogical analysis, isotopic analysis and observation under microscope and scan electric microscope (SEM) in combination with knowledge of field work, black shale-hosted concretionary phosphates were investigated so as to get the detailed information of their structure and composition, and then to reveal formation mechanisms. The results showed that the evident microbic activities were characteristic of the concretions, and indicated microbes played an important role in phosphate precipitation. From these results we concluded that biomineralization was the essential power for formation of concretionary phosphates in black shale. According to these phenomena we could also infer that the growth of concretionary phosphates were initiated by microbic activities which created neutral or weak alkaline microenvironments favoring phosphate precipitation. In the mean time the growing process of concretionary phosphate were influenced by evolution development of physic-chemical condition of sedimentary porous medium.

关 键 词：磷结核 黑色页岩 微生物成矿 早寒武世 上扬子区 

分 类 号：P536[天文地球—古生物学与地层学]