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引用本文:杜晓东1,2 邹和平1,2 苏章歆1 劳妙姬1 陈诗艾1 丁汝鑫1,2. 广西大瑶山—大明山地区寒武纪砂岩-泥岩的地球化学特征及沉积-构造环境分析[J]. 中国地质, 2013, 40(4): 1112-1128.
DU Xiao-dong1,2, ZOU He-ping1,2, SU Zhang-xin1, LAO Miao-ji1, CHEN Shi-ai1, DING Ru-xing1,2. Geochemical characteristics and sedimentary-tectonic setting of the Cambrian sandstones and mudstones in Dayaoshan-Damingshan area,Guangxi[J]. Geology in China, 2013, 40(4): 1112-1128(in Chinese with English abstract).
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广西大瑶山—大明山地区寒武纪砂岩-泥岩的地球化学特征及沉积-构造环境分析
杜晓东1,2 邹和平1,2 苏章歆1 劳妙姬1 陈诗艾1 丁汝鑫1,2
作者单位
杜晓东1,2 邹和平1,2 苏章歆1 劳妙姬1 陈诗艾1 丁汝鑫1,2 1.中山大学地球科学系,广东 广州 5102752.广东省地质过程与矿产资源探查重点实验室广东 广州 510275 
摘要:
提要:大瑶山—大明山地区位于钦杭结合带西南段,是研究华南大地构造问题的关键部位。对区内寒武纪地层中采集的27件砂岩、泥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。结果表明,样品普遍具有较高的Al2O3/TiO2(11.95~36.26,平均20.81)、低Rb/Cs(13.02~68.27,平均32.21,接近上地壳值)和低Cr/Zr(0.14~1.15,平均0.59)比值。在砂岩-泥岩物源判别函数和Ni-TiO2、Th/Sc-La/Sc、La/Th-Hf图解中,投点特征均显示大瑶山—大明山寒武纪沉积岩的物源以上地壳长英质、石英质岩石为主,含有少量的火成物源及古老再循环沉积物。通过微量元素蛛网图、稀土元素配分图和La-Th-Sc、K2O/Na2O-SiO2等图解判别,再根据大部分样品的δEu值(变化于0.47~0.68,平均0.58);δCe(0.61~1.10,平均0.89);Tb/Yb(0.21~0.41,平均0.34);La/Sc(1.45~7.66,平均3.97);Th/U(3.37~11.18,平均5.80)等特征,及其与不同构造环境参数进行对比,并结合浅水沉积标志、沉积古地理及区域地质和地球化学资料分析,认为研究区寒武纪碎屑岩成分主要代表了被动大陆边缘浅海环境物源,早古生代岩石中不存在反映“华南洋”洋壳成分的地球化学证据。
关键词:  沉积岩  物源  构造环境  寒武纪  大瑶山—大明山
DOI:
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基金项目:中国地质调查局地质大调查项目(1212011121064)资助。
Geochemical characteristics and sedimentary-tectonic setting of the Cambrian sandstones and mudstones in Dayaoshan-Damingshan area,Guangxi
DU Xiao-dong1,2, ZOU He-ping1,2, SU Zhang-xin1, LAO Miao-ji1, CHEN Shi-ai1, DING Ru-xing1,2
Abstract:
Abstract:The Daoyaoshan-Damingshan area is located in the southwestern section of the Qinzhou-Hangzhou juncture between the Yangtze Block and the Cathayian Block.The study of the early Paleaozoic sedimentary environment and tectonic setting of this area is a key to understanding the geotectonic problems in South China. Major and trace elements of 27 pieces of samples from Cambrian sandstones and mudstones in this area were analyzed and discussed. The samples generally have high ratios of Al2O3/TiO2 ( in the range of 11.95~36.26,20.81 on average) and lower ratios of Rb/Cs(in the range of 13.02~68.27, 32.21 on average) and Cr/Zr(ranging 0.14~1.15,averagely 0.59). Geochemical characteristics, such as the plots of Ni-TiO2,Th/Sc-La/Sc and La/Th-Hf , indicate that the Cambrian sediments in the Daoyaoshan-Damingshan area were mainly sourced from the upper crustal felsic quartz rocks,with the addition of a small amount of igneous sources and ancient recirculation sediments.The distribution of trace and rare-earth elements and the data of La-Th-Sc,K2O/Na2O-SiO2, δCe,δEu,Tb/Yb,La/Sc,La/Th,Th/U as well as the comparison with different tectonic settings show that the study area belonged to a passive continent-marginal setting. In addition, such evidence as the marks of shallow-sea deposits,the data of sedimentary palaeogeography,regional geology and geochemistry suggests that during the Early Paleozoic there existed no geochemical evidence for the so called “ancient ocean in South China”.
Key words:  sedimentary rock  sources  tectonic settings  Cambrian  Dayaoshan-Damingshan area