青海它温查汉铁多金属矿床^(40)Ar-^(39)Ar年代学研究及意义  

^(40)Ar-^(39)Ar geochronology of Tawenchahan Fe-polymetallic deposit in Qimantag Mountain of Qinghai Province and its geological implications

作　　者：田承盛[1,2] 丰成友[3] 李军红 曹德智 

机构地区：[1]中国地质大学,北京100083 [2]青海省地质调查局,青海西宁810001 [3]中国地质科学院矿产资源研究所,北京100037 [4]青海省第四地质矿产勘查院,青海西宁810008

出　　处：《矿床地质》2013年第1期169-176,共8页Mineral Deposits

基　　金：中国地质调查局地质调查项目(1212011085528;1212011120135);中国地质调查局青年地质英才计划(201112);国家自然科学基金项目(批准号:41172076)的联合资助

摘　　要：它温查汉铁多金属矿床是新近发现于柴达木盆地和祁漫塔格山结合部位靠近盆地覆盖区一侧、风成沙覆盖严重、成矿元素组合复杂的矽卡岩型多金属矿床。文章主要探讨了其地质特征和成矿年代学,利用云母Ar-Ar法同位素定年技术,获得该矿床钻孔岩芯矽卡岩磁铁矿矿石中白云母40Ar-39Ar坪年龄和等时线年龄分别为(230·7±2·0)Ma和(229·9±3·5)Ma(MSWD=1·8),等时线年龄与坪年龄在误差范围内完全一致,厘定了该矿床成矿年龄为中三叠世晚期。结合区域多金属矿床最新成岩成矿年代学数据,认为该矿床形成于碰撞向后碰撞转换的地质构造环境,构成本区十分重要的与印支期碰撞造山有关的铁铜铅锌金多金属矿床成矿系列。Located in the basin overburden area between the Qaidam Basin and the Qimantag Mountain,the Tawenchahan deposit is a typical skarn Fe-polymetallic deposit characterized by heavy sand overburden and various mine-ralization elements.The detailed geological features and he ore-forming age of the Tawenchahan deposit were studied in this paper.In order to obtain the ore-forming age,the authors measured the muscovite separated from skarn magnetite ore in the Tawenchahan Fe-polymetallic deposit by the 40Ar-39Ar incremental heating method,and the results yield a 40Ar-39Ar plateau age of（230.7±2.0） Ma and an isochron age of（229.9±3.5） Ma with MSWD being 1.8.It is shown that the Tawenchahan Fe-polymetallic deposit was formed during Indosinian period.These new age data,combined with the available petrogenetic and metallogenic chronological data obtained by SHRIMP zircon U-Pb,zircon LA-ICP-MS U-Pb,molybdenite Re-Os isochron and Ar-Ar methods in Qimantag area of Qinghai Province,indicate that this deposit was formed from the collisional to post-collisional environment,and belonged to the metallogenic series of Fe-Cu-Pb-Zn-Au polymetallic deposits related to Indosinian collision orogeny in eastern Kunlun.

关 键 词：地球化学 矽卡岩型矿床 40Ar-39Ar同位素年龄 印支期 它温查汉 青海 祁漫塔格 东昆仑 

分 类 号：P618.31[天文地球—矿床学]