黔北地区合山组硅质沉积物地球化学特征及其地质意义  

Geochemistry Data of Siliceous Deposits in Heshan Formation,Northern Guizhou Province

作　　者：何碧 辛欢 赵飞 陶刚 张文斌 王宁祖 李生喜 孙平原 张志玺 HE Bi;XIN Huan;ZHAO Fei;TAO Gang;ZHANG Wen-bin;WANG Ning-zu;LI Sheng-xi;SUN Ping-yuan;ZHANG Zhi-xi(The Second Institute of Geology and Minerals Exploration Team,Gansu Provincial Bureau of Geology and Minerals Exploration and Development,Lanzhou 730020,China;School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]甘肃省地质矿产勘查开发局第二地质矿产勘查院,兰州730020 [2]西南科技大学环境与资源学院,绵阳621010

出　　处：《科学技术与工程》2022年第26期11321-11333,共13页Science Technology and Engineering

基　　金：中国地质调查局地质调查项目(DD20160019)。

摘　　要：为明确黔北官坝—革木地区上二叠统合山组硅质沉积物(硅质岩、硅质灰岩)特征及其成因,对硅质沉积物样品进行主量元素、稀土元素和微量元素测试分析。其地球化学结果表明:官坝剖面硅质岩SiO_(2)含量在90.95%~93.98%,Al_(2)O_(3)含量在0.46%~0.94%;申家寨剖面硅质灰岩SiO_(2)含量在39.18%~63.55%,Al_(2)O_(3)含量在0.49%~0.82%,CaO含量在18.44%~29.81%;硅质沉积物常量元素Al/(Al+Fe+Mn)在0.18~0.43,Al/(Al+Fe)在0.18~0.44,U/Th在0.76~1.34、平均为1.07,ΣREE为7.70×10^(-6)~35.25×10^(-6),均指示硅质沉积物为热水沉积成因;硅质沉积物Ce/Ce^(*)为0.72~0.87,呈负Ce异常,Eu/Eu^(*)为1.10~1.41(PM315-DH1为0.98),呈正Eu异常,(La/Yb)_(N)为1.02~5.45,平均为3.07,(La/Ce)_(N)为1.25~1.60,平均为1.48,指示其形成于受陆源影响输入不明显的大陆边缘环境。结合区域岩相古地理演化特征,在黔北官坝-革木地区晚二叠世长兴期硅质沉积物为热水成因,沉积环境为大陆边缘环境。In order to clarify the characteristics and genesis of the siliceous sediments(siliceous rocks and siliceous limestones)of the Upper Permian Heshan Formation in Guanba-Gemu area,northern Guizhou Province,the main elements,rare earth elements and trace elements of the siliceous sediments were tested and analyzed.The geochemical results show that the SiO_(2) content of the siliceous rocks in Guanba section is 90.95%~93.98%and the Al_(2)O_(3) content is 0.46%~0.94%.The contents of SiO_(2),Al_(2)O_(3) and CaO in the Siliceous limestone of Shenjiazhai section range from 39.18%to 63.55%,0.49%to 0.82%and 18.44%to 29.81%.The values of Al/(Al+Fe+Mn),Al/(Al+Fe)and U/Th in siliceous sediments range from 0.18 to 0.43,0.18 to 0.44,and 0.76 to 1.34,with an average of 1.07.ΣREE values of 7.70×10^(-6)~35.25×10^(-6) indicate that the siliceous sediments are caused by hydrothermal deposition.In siliceous sediments,Ce/Ce^(*)ranges from 0.72 to 0.87,showing negative Ce anomaly.Eu/Eu^(*)ranges from 1.10 to 1.41(PM315-DH1 is 0.98),and showing positive Eu anomaly.(La/Yb)_(N) values range from 1.02 to 5.45,with an average of 3.07.(La/Ce)_(N) values range from 1.25 to 1.60,with an average of 1.48,indicating that it was formed in a continental margin environment with no obvious terrigenous input.Combined with the evolution characteristics of regional lithofacies and paleogeography,the Changsingian Siliceous sediments of late Permian in Guanba-Gemu area of northern Guizhou Province are of hydrothermal origin and the sedimentary environment is continental margin environment.

关 键 词：合山组 硅质沉积物 热水成因 上二叠统 

分 类 号：P618.13[天文地球—矿床学]