桂东南大瑶山地区南华纪-寒武纪砂岩地球化学特征及对沉积构造环境的指示  

Geochemical Characteristics of Nanhuan-Cambrian Sandstones in Dayaoshan Area of Southeastern Guangxi and Its Implication for Sedimentary Environment

作　　者：农军年 郭尚宇 孙明行 李昌明 石伟民 覃初礼 NONG Jun-Nian;GUO Shang-Yu;SUN Ming-Hang;LI Chang-Ming;SHI Wei-Min;QIN Chu-Li(China-ASEAN Geological Cooperation Center,Nanning 530023,Guangxi,China;Guangxi Institute of Geological Survey,Nanning 530023,Guangxi,China)

机构地区：[1]中国-东盟地学合作中心,南宁530023 [2]广西地质调查院,南宁530023

出　　处：《华南地质与矿产》2020年第2期93-103,共11页Geology and Mineral Resources of South China

基　　金：中国地质调查局项目“桂东-粤西成矿带地质矿产调查(DD20160035)”;“海南昌江-广东云浮地区区域地质调查(DD20190047)”联合资助。

摘　　要：桂东南大瑶山地区位于扬子陆块与华夏陆块拼合带的西南段,南华纪-寒武纪期间连续沉积了巨厚的类复理石,其沉积学与地球化学特征蕴含了华南大地构造演化的重要信息,因此,对该套地层进行研究,可为恢复华南大地构造演化提供新证据。本文对采集于大瑶山地区的21件砂岩样品进行了主量元素、微量元素测试和地球化学特征分析。结果显示,桂东南南华纪-寒武纪沉积岩的物源主要来自上地壳长英质、石英质岩石。结合区域地质资料分析,认为本区于南华纪-寒武纪时期并非大洋,而是被动大陆边缘环境的浅海盆地,因此,华南纪-寒武纪时期,华夏陆块和扬子陆块之间的沉积盆地并非洋盆,而是陆内裂谷(浅海)盆地。Dayaoshan area in Southeast Guangxi is located in the southwest section of the Yangtze and Cathaysian Block amalgamation belt.During the Nanhua-Cambrian period,huge flyschiod sequence were deposited continuously.Its sedimentological and geochemical characteristics contain important information of the tectonic evolution of South China.In this paper,21 sandstone samples collected in Dayaoshan area was tested for major and trace elements and analyzed for geochemical characteristics.The results show that the provenance of the Nanhua-Cambrian sedimentary rocks in Southeast Guangxi is mainly from the felsic and quartzitic rocks in the upper crust.Based on the analysis of the regional geological data,it is considered that this area was not an ocean in the South China Cambrian period,but a shallow sea basin in the passive continental margin environment.Therefore,in the Nanhua-Cambrian period,the sedimentary basin between the Cathaysian Block and the Yangtze Block was not an ocean basin,but an intracontinental rift(shallow sea)basin.

关 键 词：南华纪-寒武纪 砂岩 地球化学 构造背景 桂东南 华南 

分 类 号：P512.2[天文地球—地质学] P595