新疆圪塔山口含铜镍岩体锆石SHRIMPU-Pb年龄、岩石地球化学特征及其地质意义

发布时间：2018-01-12 05:04

本文关键词：新疆圪塔山口含铜镍岩体锆石SHRIMPU-Pb年龄、岩石地球化学特征及其地质意义　出处：《大地构造与成矿学》2016年06期 　论文类型：期刊论文

【摘要】：圪塔山口含铜镍镁铁-超镁铁质岩体位于东天山黄山镜儿泉图拉尔根铜镍矿带东段。岩体由I-1,I-2,I-3,I-4四个小岩体组成,主要岩石类型为辉石橄榄岩、橄榄辉石岩、辉长岩和闪长岩,主要赋矿岩相为辉石橄榄岩。I-2号含矿岩体锆石SHRIMP U-Pb年龄为275.0±3.6 Ma,与东天山地区含铜镍矿镁铁超镁铁岩体形成时代相近,I-4号不含矿岩体锆石SHRIMP U-Pb年龄为364.2±3.9 Ma,明显早于含矿岩体。样品的主量元素组成显示岩浆演化过程主要发生了橄榄石和少量辉石的分离结晶/堆晶作用;稀土元素球粒陨石标准化配分曲线呈轻稀土略富集的右倾型,Eu异常不明显;微量元素特征显示相对富集大离子亲石元素(Cs、Sr、Ba),适度亏损高场强元素(Nb、Ta、Ti)。岩石地球化学特征表明岩浆演化过程中遭受了较弱的中下地壳物质混染。U/Th-Th/Zr、Ba/Th-Th/Yb图解,La/Nb、La/Ba和Ba/Nb比值表明岩浆源区遭受了明显的俯冲流体交代作用。综合含矿岩体年代学、岩石地球化学特征及区域演化历史,认为圪塔山口含矿岩体形成于碰撞后伸展背景,可能同时叠加了塔里木地幔柱活动的影响。
[Abstract]:The Getashankou copper-nickel magnesium-ultramafic rock body is located in the eastern section of the Huangshan Jingerquan Tulargen Cu-Ni ore belt in the East Tianshan Mountains. The main rock types are pyroxene peridotite, olivine pyroxenite, gabbro and diorite. The main ore-bearing facies are pyroxene peridotite. I-2 ore-bearing body. The SHRIMP U-Pb age of zircon is 275.0 卤3.6 Ma. The SHRIMP U-Pb age of zircon from the I-4 non-ore body is 364.2 卤3.9 Ma, similar to the age of formation of the Mg-Fe ultramafic body in the East Tianshan area. The main element composition of the sample shows that the separation crystallization / stacking of olivine and a small amount of pyroxene occurred during the magmatic evolution. The normalized partition curve of chondrites of rare earth elements is slightly enriched with light rare earth elements, and the anomaly of EU is not obvious. The characteristics of trace elements show that they are relatively enriched in the large ion lithophile elements, Csn, Sr-Baan, and moderate depletion of high field strength elements. The petrogeochemical characteristics of the magma indicate that the magmatic evolution suffered from a relatively weak mixing of medium and lower crust materials. U- / Th-Th-Thr / ZrBa- / Th-Th-Yb diagram shows La / Nb. The ratios of La/Ba and Ba/Nb indicate that the magmatic source has suffered obvious subduction fluid metasomatism. It is considered that the ore-bearing body in Geta Mountain pass was formed in the post-collision extensional setting and may have superimposed the influence of mantle plume activity in Tarim at the same time.
【作者单位】：中国地质调查局西安地质调查中心国土资源部岩浆作用成矿与找矿重点实验室;
【基金】：地质调查项目(1212011121092) 国家自然科学基金项目(41302052)联合资助
【分类号】：P597.3;P618.41;P618.63
【正文快照】： 新疆东天山黄山镜儿泉图拉尔根铜镍矿带是国内第三大铜镍矿带,该带已发现的铜镍矿床主要有黄山东、黄山、图拉尔根、香山和葫芦等矿床,已有研究表明这些铜镍矿床均形成于晚石炭世早二叠世(韩宝福等,2004;孙涛等,2010;三金柱等,2010;肖庆华等,2010;Qin et al.,2011;肖凡

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