柴达木盆地北缘滩间山金矿区斜长花岗斑岩锆石LA-MC-ICPMS测年及其岩石地球化学特征  

Zircon LA-MC-ICPMS U-Pb Dating and Geochemical Characteristics of the Plagiogranite Porphyry from Tanjianshan Gold Ore District in North Margin of Qaidam Basin

作　　者：贾群子[1] 杜玉良[1] 赵子基[2] 宋忠宝[1] 全守村[1] 陈博[1] 孔会磊[1] 栗亚芝[1] 李金超[1] 陈向阳[1] 张雨莲[1] 

机构地区：[1]中国地质调查局西安地质调查中心,西安710054 [2]青海省国土资源厅,西宁810001

出　　处：《地质科技情报》2013年第1期87-93,共7页Geological Science and Technology Information

基　　金：青藏高原地质矿产调查与评价专项"青海省地质调查综合研究"(1212010918044);国土资源大调查项目"祁连成矿带重大找矿疑难问题研究"(200420190002)

摘　　要：滩间山金矿区斜长花岗斑岩出露于柴达木盆地北缘构造带,是区内出露较大的斑岩体。利用LA-MC-ICPMS锆石定年方法,测得斜长花岗斑岩锆石的年龄为2 416～336Ma,可分为3组:2 416～2 365,1 797～1 602,358～336Ma。对锆石矿物成因研究表明,第一组和第二组年龄为继承性锆石的年龄,反映其源岩有前寒武纪变质岩或同期岩浆岩的物质;第三组为斜长花岗斑岩的结晶年龄,表明岩体形成于早石炭世,为华力西中期斜长花岗斑岩。岩石地球化学特征表明,岩石属钙碱性系列偏铝质岩石,为I型花岗岩,形成于后碰撞环境。结合锆石的年龄测定数据,认为斜长花岗斑岩物质具有多来源的特点,华力西中期是本区金矿形成的一个重要成矿期。The plagiogranite porphyry from Tanjianshan gold ore district is a large porphyry body in north margin of Qaidam basin. The U-Pb ages of zircon from plagiogranite porphyry are determined by LA-MC- ICPMS. The U-Pb ages of zircon ranged from 2 416 Ma to 336 Ma are divided into three groups. 2 416- 2 365 Ma, 1 797-1 602 Ma and 358--336 Ma. The ages of group 1 and group 2 from Precambrian inheri- ted zircon show that the source of the plagiogranite porphyry contains materials from Precambrian meta- morphic rocks or cotemporary igneous rocks. The ages of group 3 indicate the Early Carboniferous forma- tion of the plagiogranite porphyry, which can thus be termed Middle Variscan plagiogranite porphyry. Lithogeochemical characteristics shows that the plagiogranite porphyry belongs to calc-alkaline series and I-type granite, and is formed post-collisional tectonic setting. Based on the geochemical characteristics and zircon dating data, it is considered that the plagiogranite porphyry comes from multiple sources, and that the Middle Variscan is one of the most important mineralized period of the Tanjianshan gold ore deposit.

关 键 词：斜长花岗斑岩 锆石LA-MC-ICPMS U-PB定年 地球化学 滩间山 柴达木盆地北缘 

分 类 号：P588.12[天文地球—岩石学]