中国地质2013，Vol.40Issue(3)：767-779,13.
内蒙古东乌旗索纳嘎铅锌银矿区花岗岩地球化学特征及其构造与成矿意义
Geochemical characteristics of granites in the Suonaga Pb-Zn-Ag deposit of Dong Ujimqin Banner, Inner Mongolia, and their tectonic and ore-forming implications
摘要
Abstract
The ore-bearing pluton in the Suonaga Pb-Zn-Ag deposit is composed of medium-coarse-grained granite,fine-grained biotite granite and pseudoporphyritic K-feldspar granite.The zircon U-Pb dating results show that the medium-coarse-grained granite was formed at 319.6±4.1 Ma,the fine-grained biotite granite was formed at 172.5 ±1.4 Ma,and the pseudoporphyritic K-feldspar granite was formed at 165.5 ±1.8 Ma.The petrogeochemistry of the three rock bodies is characterized by high K,rich alkali and poor magnesium,so they all belong to calcium-basic,quasi-aluminous to weakly peraluminous and highly-differentiated rocks.All of the granites have high REE and negative Eu anomalies,exhibiting relative enrichment of LREE.These rock bodies belong to S-type granites,because they are enriched in U and Th and their Rb/Sr ratios are higher than those of the crustal source.Regional geology and granite geochemistry indicate that the medium-coarse-gained granite was formed in a post-collisional extensional environment in Late Carboniferous； the Middle Jurassic fine-grained biotite granite and pseudoporphyritic K-feldspar granite were formed in an intraplate extensional environment,and they were products of different evolutionary stages of a comagmatic region.The pseudoporphyritic Kfeldspar granite was probably the ore-forming parent rock,because its diagenetic age is consistent with the molybdenite Re-Os ages (163.4±2.4Ma to 166.6±2.4Ma) and the rocks are enriched in metallogenic elements Pb and Zn.关键词
花岗岩/岩石年龄/地球化学/构造背景/金属成矿/内蒙古东乌旗Key words
granite/ age of the rock/ geochemistry/ tectonic setting/ mineralization /Dong Ujimqin Banner in Inner Mongolia分类
天文与地球科学引用本文复制引用
梁玉伟,余存林,沈国珍,孙庆茹,李进文,杨郧城,佘宏全,张斌,谭刚..内蒙古东乌旗索纳嘎铅锌银矿区花岗岩地球化学特征及其构造与成矿意义[J].中国地质,2013,40(3):767-779,13.基金项目
中国地质调查局地质调查项目(1212011085260)、科技支撑计划(2006BAB01A10)和内蒙古地质矿产勘查开发局综合研究项目(ND2007004)联合资助. （1212011085260）
