贵州清镇陡山沱组帽白云岩地球化学特征以及其中藻类化石Beltanelliodes podolicus发现  

Geochemical Characteristics of Doushantuo Cap Carbonate (Dolostone) and Discovery of Beltanelliodes Podolicus Fossil in Qingzhen County,Guizhou Province,China

作　　者：杨瑞东[1] 魏怀瑞[1] 陈吉艳[1] 

机构地区：[1]贵州大学喀斯特环境与地质灾害防治教育部重点实验室,贵阳550025

出　　处：《沉积学报》2009年第6期1050-1056,共7页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(批准号:40462001);贵州大学博士点基金联合资助

摘　　要：贵州清镇陡山沱组为浅海白云岩、泥质白云岩,在陡山沱组底部泥质白云岩中产大量的圆盘状炭质化石,个体直径为2～15 mm。由于以前发现类似的化石主要保存在泥岩中,而碳酸盐岩中这类化石只有俄罗斯地台上发现过,从化石保存的结构分析,其应该归属藻类中的Chuarid。通过对陡山沱组帽白云岩的碳同位素分析,其具有典型的帽碳酸盐岩碳同位素负异常的特征,这表明在冰后浅海滨岸泻湖环境,球形藻类已经繁盛。同时,研究发现浅海滨岸泻湖环境冰后碳酸盐沉积是一个钙质(白云质)逐渐增加的渐变过程,而非Hoffman等认为的非常快速沉积。The basal Doushantuo Formation in Qingzhen County, Guizhou Province, China, consists of mudstones, rnud-dolostones, dolo-sandstones, thin dolostones and thick dolostones. The preserved-well and abundant carbon discform fossils, 2 -15 mm in diameter, the carbon disc-form fossil was first discovered in dolostone in China. According to shape and feature of fossil, it may belong to algae fossil Chuarid. The cap dolostone of Doushantuo Formation in Qingzhen County, Guizhou Province, China, shows typical negative carbon isotopic composition of Marinoan Cap carbonate. Therefore, it reflects that abundant algae live in shallow lagoon after glaciation. Additionally, carbonate content rise gradually from glaciation-end to carbonate （or dolostone） deposit in shallow lagoon, the feature shows that form of cap dolostone is gradually after glaciation, more than Hoffman et al .（1998） suggested that the cap dolostone is formed suddenly after glaciation.

关 键 词：藻类化石 帽碳酸盐岩 Marinoan冰期 陡山沱组 贵州 

分 类 号：P588.245[天文地球—岩石学] Q924.82[天文地球—地质学]