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文摘
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阿斯喀尔特铍钼矿床位于中亚成矿域阿尔泰成矿省哈龙-青河成矿带的东南部。7件辉钼矿样品Re-Os同位素年龄介于(224.6±3.1) Ma与(235.7±3.4) Ma之间,加权平均年龄为(229.0±3.0) Ma,等时线年龄为(228.7±7.1) Ma,表明成矿作用发生于印支期。辉钼矿样品Re含量为38.26~56.45 μg/g,指示成矿元素Re 具有壳幔混合来源特征。由于阿斯喀尔特铍-钼矿床成矿时代晚于古亚洲洋闭合时间(约250 Ma),并且花岗岩-伟晶岩体系中的晚期伟晶岩以低的锆石Hf同位素组成(-1.50~+1.69)为特征,相似于区域中侵入的三叠纪伟晶岩中锆石Hf同位素组成,如可可托海3号脉、柯鲁木特112号脉,因此,推测与阿斯喀尔特铍钼矿床具有成因联系的花岗岩-伟晶岩体系,其成因与哈萨克斯坦-西伯利亚板块在晚古生代发生陆-陆碰撞造山作用,在三叠纪构造体系由挤压转为伸展背景下,先期存在幔源物质的古老地壳物质发生减压部分熔融有关。 |
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其他语种文摘
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The Asikaerte Be-Mo deposit is located in the southeast of the Halong-Qinghe metallogenic belt of the Altai metallogenic province in Central Asian metallogenic domain. Seven molybdenite samples from the deposit were collected and analyzed, which yield Re-Os isotope ages ranging from (224.6±3.1) Ma to (235.7±3.4) Ma,with an isochron age of (228.7±7.1) Ma, and a weighted mean age of (229.0±3.0) Ma, indicating that Be and Mo mineralization occurs in the Triassic period. The Re contents of the seven molybdenite samples range from 38.26 μg/g to 56.45 μg/g, suggesting that the ore-forming metals are originated from crust-mantle mixed sources. As the minerogenetic epoch of Asikaerte Be-Mo deposit postdates the closure time of Paleo-Asia ocean (~250 Ma), and zircons from the late pegmatite show Hf isotope characteristics similar to those from the Triassic pegmatites in the Chinese Altay (such as Koktokay No. 3 pegmatite, and Kelumute No. 112 pegmatite), it can be speculated that the granite-pegmatite system, to which the Be-Mo deposit shows a genetic relationship, is derived from partial melting (crust thickening and decompression melting) of ancient crust with mantle-derived residual materials under a post-collision extensional setting in the Triassic, after the Kazakhstan block collides with the Siberian block in late Paleozoic. |
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来源
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地球化学
,2015,44(2):145-154 【核心库】
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关键词
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印支成矿作用
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Re-Os同位素
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辉钼矿
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铍钼矿床
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阿斯喀尔特
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地址
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中国科学院地球化学研究所, 贵州, 贵阳, 550002
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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0379-1726 |
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学科
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地质学 |
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基金
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新疆有色金属工业集团地质科研项目
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国家自然科学基金
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文献收藏号
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CSCD:5392589
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