甘肃辉铜山铜矿床燕山期钾长花岗岩的发现及其地质意义  

Discovery of Yanshanian K-feldspar Granite in Huitongshan Copper Deposit, Gansu Province, and Its Implication

作　　者：江思宏[1] 聂凤军[1] 陈文[2] 刘妍[1] 白大明[1] 刘新宇[2] 张思红[2] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质科学院地质研究所

出　　处：《矿床地质》2003年第2期185-190,128,共7页Mineral Deposits

基　　金：国家自然科学基金 ( 4 0 0 73 0 15 );国土资源大调查项目 (K1.3 .3 2 )的联合资助

摘　　要：文章对辉铜山铜矿床内的钾长花岗岩进行了岩石化学分析、钕同位素测量和高精度的40 Ar/ 3 9Ar法年龄测定。结果表明 ,钾长花岗岩的形成时代为 (192± 3)Ma ,相当于燕山早期 ,它们具有A型花岗岩的特征 ;成岩物质来自地幔 ,并遭受了地壳物质的混染。Located in the southern part of the Beishan Mountain, the Huitongshan deposit is an important skarn type copper deposit in this region. The orebodies occur in the contact zone between the K_feldspar granite and the marble of the Middle_Lower Ordovician Huaniushan Group. The ore_forming age of the deposit has not been determined since its discovery in 1956. According to the 40 Ar/ 39 Ar isotopic dating of the K_feldspar from the K_feldspar granite, the plateau age is (192±3) Ma. It indicates that the Huitongshan copper deposit was formed at 190 Ma or so. The petro_chemical data of the K_feldspar granites in Huitongshan and Huaniushan areas show that these K_feldspar granites belong to A type granites. The Nd isotopic data further demonstrate that these K_feldspar granites were derived from the mixture of the mantle and crust_derived materials. The emplacement of these K_feldspar granites was related to the intracontinental extension during early Yanshanian tectonic movement. As the Au, Pb, Zn, Cu and Mo deposits are associated with the K_feldspar granites in the region, a detailed study of the K_feldspar granites is helpful not only to understanding the tectonic evolution but also to guiding the evaluation and exploration of regional mineral resources.

关 键 词：甘肃 铜矿床 钾长花岗岩 燕山期 岩石化学分析 钕同位素 ^40Ar/^39Ar法年龄 形成时代 

分 类 号：P618.41[天文地球—矿床学] P588.121.1[天文地球—地质学]