摘要
马头山组是滇中红色盆地中最重要的赋矿层位,其岩性特征主要为泥岩、砂岩、砾岩等碎屑岩。碎屑岩的化学成分可以反映源区沉积岩的构造背景和物源属性,基于马头山组非矿化岩石主量元素、微量元素和稀土元素地球化学特征分析,揭示组成马头山组的岩石具有:①SiO2含量高;②Ag、Pb、Bi、Ni等亲铜元素富集,Be、Ga、Rb、Y、Nb、Ta、Hf、Sr、Sn等亲石元素亏损;③轻稀土富集、重稀土亏损、弱负Eu异常等特征。利用判别图解得出原岩大地构造背景为被动大陆边缘和活动大陆边缘环境,原岩的原始物质组成应以来自上地壳的长英质岩石为主。结合岩相古地理条件,可知马头山组岩石的物源区主要为康滇古陆和哀牢山造山带。
The Matoushan Formation,one of the most important ore-bearing stratum,is located in the Red-bed basin of central Yunnan Province,China.Its lithology is mainly clastic rocks,including mudstone,sandstone,as well as conglomerate.The geochemical compositions of sandstones and argillaceous rocks could discriminate the tectonic setting and provenance of source rock area.Based on the geochemical signatures of major elements,trace elements,and rare earth elements of the non-mineral rocks,which picked from Matoushan Formation of Mouding,reveal that the sandstones and argillaceous rocks of Matoushan Formation,which are characterized by： ①high contents of SiO2;②Enrichment some chalcophile elements such as Ag,Pb,Bi and Ni,loss of some lithophile elements for example Be,Ga,Rb,Y,Nb,Ta,Hf,Sr and Sn;③LREE enrichment,HREE depletion and slightly negative Eu anomaly.The differentiate diagrams refer that the provenance of Matoushan Formation belong to passive continental margin and active continental margin tectonic setting.The primary materials of sedimentary rocks should come from the upper continental crust,and are mainly composed by felsic rocks.Combined with the data of sedimentary facies and palaeogeography,we know that the principal source rock area of Matoushan Formation are Kangdian ancient land and Ailaoshan orogenic belt.
出处
《沉积学报》
CAS
CSCD
北大核心
2011年第2期303-311,共9页
Acta Sedimentologica Sinica
基金
国家危机矿山专项(编号:NO.200653098
NO.20089943)资助
关键词
地球化学
构造背景
物源属性
马头山组
牟定
geochemistry
tectonic setting
provenance of source rock
Matoushan Formation
Mouding
