青海省化隆县沙加含铜镍矿基性杂岩体地质特征及Re-Os同位素研究  

Geological Characteristics and Re-Os Isotopic Analysis of Shajia Cu-Ni Ore-Bearing Basic Complex in Hualong County, Qinghai Province

作　　者：李侃[1] 张照伟[1] 高永宝[1] 杜安道[2] 郭周平[1] 张江伟[1] 钱兵[1] 王亚磊[1] 张炳社 

机构地区：[1]西安地质矿产研究所,国土资源部岩浆作用成矿与找矿重点实验室,陕西西安710054 [2]国家地质实验测试中心,北京100037 [3]西安地质矿产勘查开发院,陕西西安710100

出　　处：《西北地质》2012年第4期314-320,共7页Northwestern Geology

基　　金：国家自然科学基金(41102050);中国地质调查局地质大调查项目(1212010911032;1212011220897;121201112088;1212011120183和1212011121092)

摘　　要：沙加岩体是化隆基性-超基性岩带中的一个含铜镍硫化物的基性杂岩体,其岩体规模较小,岩相分带弱,矿体呈透镜状产于岩体中,苏长岩为主要赋矿岩相。对其进行岩石地球化学及硫化物Re-Os同位素测试,结果表明:岩体属钙碱性、铁质系列,富集轻稀土元素,亏损Nb、Ta等高场强元素。硫化物187Os/188Os初始值为0.3469～0.4071,γOs为180～228,说明岩体遭受了显著的地壳混染作用,地壳物质加入比例大于30%。地壳混染可能在岩浆达到S饱和进而熔离出硫化物熔体的过程中起到了重要作用。Shajia Cu-Ni ore-bearing basic complex is one of the intrusive rocks in Hualong basic-ultrabasic rocks belt, it is small scale, weak lithological zoning. Orebody are lenticular in the intrusion, and norite is the main host rock for the Cu-Ni ores. The analysis on rock geochemistry indicate that the intrusive is calc- alkaline, iron series, rich in LREE, depleted in high field strength elements such as Nb, Ta. The analysis on the sulfide display that the initial 187 Os/188 Os ratios are from 0. 346 9 to 0.407 1, the γo, values are from 180 to 228, which suggest that abundant crustal material was mixed with the magma, and the content of crust-derived Os was estimated to 〉30%. The contamination by crustal material probably played an im- portant role in triggering the sulfide saturation and segregation.

关 键 词：基性杂岩体 铜镍硫化物矿床 RE-OS同位素 化隆 青海省 

分 类 号：P618.41[天文地球—矿床学] P618.63[天文地球—地质学]