广西大瑶山地区寒武系沉积环境及其演化

Evolution of sedimentary environments through the Cambrian in the Dayaoshan area,Guangxi Province

通过综合分析岩性、古生物、沉积构造以及地球化学特征等,探讨了广西大瑶山地区寒武系沉积环境。研究认为研究区寒武系沉积环境主要是深水盆地至斜坡环境,发育深水原地沉积和浊流沉积,在早寒武世和中寒武世出现过2次大规模海进。对比桂东大瑶山地区和桂北、湘南、湘中等地区寒武系岩性特征、古生物特征、沉积物来源以及砂岩的地球化学特征,发现桂东等地区存在明显不同,因此推测在扬子板块和华夏板块在寒武纪期间存在一个地质界线,界线可能位于桂东和桂北地区之间。

Comprehensive facies indicators,e.g.lithologic characters,fossils and sedimentary structures are applied to to analyze sedimentary environments of the Cambrian in Dayaoshan of Guangxi.Results show that the studied area was a deep-water basin to slope environment during the Cambrian.Deep-water in situ deposits and turbidites are developed.The area experienced two transgressive events during the Early Cambrian and the Middle Cambrian respectively.By comparing lithological,paleontologic,sedimentary source,and geochemic data of Cambrian sandstonewith other regions such as,Northern Guangxi,Southern Hunan,Central Hunan,the Dayaoshan area is distinctive in many aspects.Thus it can be inferred that there existed a geological boundary between Eastern and Northern Guangxi during the Cambrian.