阿拉善右旗特拜金矿赋矿变沉积岩地球化学特征、源区属性及构造意义  

Geochemical characteristics,source area properties and tectonic significance of Ore bearing metasedimentary rocks from Tebai gold deposit in Alxa right banner area

作　　者：程先钰 田健 李以科[3] 董满华 曹侃 张天福 CHENG Xian-yu;TIAN Jian;LI Yi-ke;DONG Man-hua;CAO Kan;ZHANG Tian-fu(China Geological Survey Tianjin Geological Survey Center,Tianjin 300170,China;North China Center of Geoscience Innovation,Tianjin 300170,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037;Inner Mongolia Geology Limited Company,Hohhot 010010,China)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]中国地质调查局华北地质科技创新中心,天津300170 [3]中国地质科学院矿产资源研究所,北京100037 [4]内蒙古地质有限公司,呼和浩特010010

出　　处：《华北地质》2023年第1期42-49,60,共9页North China Geology

基　　金：中国地质调查局项目“渤海湾盆地地质结构与深层油气综合(DD20211339)”;“阴山成矿带小狐狸山和雅布赖地区地质矿产调查(DD20160039)”。

摘　　要：本次对阿拉善右旗特拜金矿赋矿变沉积岩进行地球化学分析,主要岩性为云母石英片岩、变质粉砂岩、变质岩屑石英砂岩等;主量元素SiO_(2)平均含量62.39%,Al_(2)O_(3)平均含量15.40%,Fe_(2)O_(3)平均含量6.57%,MgO平均含量3.84%,CaO平均含量2.31%,K_(2)O平均含量2.65%,Na_(2)O平均含量2.09%。ΣREE配分模式曲线一致,LREE/HREE=5.75~8.34,平均为7.18,(La/Yb)_(N)=5.39~8.38,平均6.83,Eu负异常明显,轻稀土元素相对重稀土元素明显富集;微量元素中相对稳定元素比值如La/Sc、Th/Sc、Cr/Zr显示出物源来自上地壳长英质;Rb-K_(2)O图解、Ni-TiO_(2)图解和La/Yb-ΣREE图解表明其母岩主要来源于花岗岩,结合古水流特征以及碎屑锆石年龄证据等推测物源可能来自北大山地区花岗岩。结合特拜赋矿变沉积岩岩石组合特征、构造特征和地球化学特征,认为其源岩形成于大陆岛弧构造环境。In this paper,geochemical analysis of the ore bearing metasedimentary rocks of the Tebai gold deposit in Alxa Right Banner is carried out,The main lithology is mica quartz schist,metamorphic siltstone,metamorphic lithic quartz sandstone,etc;The average content of SiO_(2) is 62.39%,the average content of Al_(2)O_(3) is 15.40%,the average content of Fe_(2)O_(3) is 6.57%,the average content of MgO is 3.84%,the average content of CaO is 2.31%,the average content of K_(2)O is 2.65%,the average content of Na_(2)O is 2.09%.The REE patterns of curves are consistent,LREE/HREE=5.75~8.34,the average value is 7.18,(La/Yb)_(N)=5.39~8.38,the average value is 6.83,Eu negative anomaly is obvious,LREE are obviously enriched relative to HREE;Rb-K_(2)O diagram、Ni-TiO_(2) diagram and La/Yb-ΣREE diagram show that the parent rocks may originate from granites;Combined with paleocurrent characteristics and detrital zircon age evidence,it is speculated that the provenance may come from granite in Beidashan area.Combined with the rock assemblage characteristics,tectonic combined characteristics and Geochemical characteristics of Ore bearing metasedimentary rocks in Tebai,it is considered that the source rocks were formed in a tectonic environment of continental island-arc.

关 键 词：阿拉善地块 特拜金矿 赋矿地层 变沉积岩 地球化学 大陆岛弧 

分 类 号：P588.2[天文地球—岩石学] P618.51[天文地球—地质学]