| 东天山土屋和延东斑岩铜矿床时代讨论 |
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| 引用本文：.2002.Discussion on Meallogenic Epoch of Town and Yandong Porphyry Copper Deposits in Eastern Tianshan Mountains, Xinjiang[J].Mineral Deposits,21(1):16~22 |
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| 基金项目:中国地质调查局项目（编号0499165192） |
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| 中文摘要:关于东天山土屋和延东斑岩铜矿的时代问题，前人是根据距矿区1 km左右的沉积岩夹层中生物化石和矿区附近的花岗质岩体的同位素年龄确定为早石炭世-二叠纪的，并推测其成矿的构造环境属于哈萨克斯坦板块的活动陆缘——石炭纪火山岛弧。文章通过对矿区各类地质体的同位素年代学研究??获得了许多新认识，归纳为：① 含矿斑岩（斜长花岗斑岩）的同位素年龄为369~356 Ma（Rb-Sr等时线法和单颗粒锆石U-Pb法），属于泥盆纪末期产物；② 辉钼矿的同位素年龄为（323±2）Ma（Rb-Sr等时线法），属于早石炭世产物；③ 含矿火山岩（原定名为闪长玢岩）的同位素年龄变化于416~360 Ma（Sm-Nd等时线法和单颗粒锆石U-Pb法），可归为泥盆纪；④ 东天山斑岩铜矿的成矿构造环境应属于塔里木板块的活动陆缘，是泥盆纪岛弧火山-深成作用的产物。 |
| 中文关键词:同位素年代学 土屋铜矿 延东铜矿 东天山 |
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| Discussion on Meallogenic Epoch of Town and Yandong Porphyry Copper Deposits in Eastern Tianshan Mountains, Xinjiang |
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| Abstract:With regard to the metallogenic epoch of the Tuwu and Yang dong porphyry copper deposits in Eastern Tianshan Mountains, the previous researchers held that they were of early Carboniferousr-Permian according to the fossil organism discovered in the sedimentary rocks about 1 km away from the ore district and the isotope ages of the granitoids adjacent to the ore district. In addition, the tectonic setting of the copper mineralization was inferred to be of the active continental margin of Kazakhstan plate- the Carboniferous volcanic island arc. However, the suggestions mentioned above need to be reconsidered according to the ne w evidence of isotope chronology obtained in this study: ( 1 ) the age of the plagiogranite porphyry ( ore- bari ng porphyry) is about 369 -356 Ma (Rb-Sr isochron dating and single-zircon U-Pb dating), indicating that the porphyry occurred at the end of Devonian ; ( 2) the age of molybdenite is ( 323±2) Ma ( Re-Os isochron dating), suggesting its for mation in early Carboniferous; ( 3 ) the age of the altered rock is about 341-310 Ma ( K-Ar dating), implying that the alteration must have taken place in early Carboniferous; ( 4) the ages of ore-bearing volcanic rocks ( naeddiorite porphyrite before) range fro m 416 Ma to 360 Ma , which should be assigne d to Devonian ; and (5)：etectonic setting of porphyry copper deposits in Eastern Tianshan Mountains belongs to the active continental margin of the Tarim Plate, and hence the deposits are likely to be products of the island arc volcanism- plutonic activity . |
| keywords:isotope chronology , Tuwu copper deposit, Yandong copper deposit , Eastern Tianshan Mountalns |
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