新疆东天山金滩金矿区安山岩岩石学、地球化学及地质意义

发布时间：2018-03-14 04:38

本文选题：晚石炭世　切入点：安山岩　出处：《中南大学学报(自然科学版)》2017年10期 　论文类型：期刊论文

【摘要】：新疆金滩金矿发育一套与成矿密切相关的安山岩,对该安山岩元素质量分数和相关性进行分析。研究结果表明:安山岩中锆石结构以及Th和U的质量分数之比ω(Th)/ω(U)(0.30~1.02)均显示其为岩浆成因,锆石LA-ICP-MS U-Pb年龄为(303.65±4.8)Ma,代表安山岩形成时代;安山岩ω(Si O_2)为54.29%~69.05%,ω(Al_2O_3)为11.27%~19.46%,全碱ω(K_2O+Na_2O)为2.46%~6.81%,ω(Mg O)为3.60%~10.45%,Mg指数为46~66。安山岩轻稀土元素(LREE)富集、轻重稀土元素分异作用明显,绝大多数样品具中等Eu负异常(δω(Eu)=0.44~0.77)和轻微Ce负异常(δω(Ce)=0.93~0.98),富集K,Rb,Ba,Th和U等大离子亲石元素,相对亏损Nb和Ti等高场强元素;岩浆经历了分离结晶作用,且发生部分熔融;安山岩可能是康古尔塔格洋向南俯冲,洋壳脱水进入地幔楔,被俯冲流体交代的地幔楔部分熔融,同时产生结晶分异作用而形成,而且遭受明显的陆壳物质混染;东天山地区在晚石炭世依旧存在康古尔洋的俯冲消减作用。
[Abstract]:The Jintan gold deposit in Xinjiang has a set of andesite closely related to mineralization. The results show that the zircon structure in the andesite and the ratio of Th and U mass fraction 蠅 _ (Th) / 蠅 ~ (U) (0.30U ~ (1.02)) are magmatic origin, and the zircon LA-ICP-MS U-Pb age is 303.65 卤4.8 Ma, which represents the age of formation of the andesite, and the results show that the zircon is of magmatic origin, and that the zircon U-Pb age is 303.65 卤4.8 Ma.The results show that the zircon structure and the ratio of Th and U mass fraction are magmatic origin. The number of Al2O3 in the andesite is 11.27 and 19.46, and the total alkali 蠅 -K _ 2O _ O _ 2O _ Na _ 2O _ 2 is 2.46 ~ 6.81, and 蠅 _ (mg _ O) is 3.60 ~ 10.45 mg ~ (6) ~ (66. 6). The LREE of the andesite is enriched, and the difference between the light rare earth elements and the light rare earth elements is obvious, and the difference between the light rare earth elements (LREE) and the light rare earth elements (LREE) in the andesite is obvious, the difference between the light rare earth elements and the light rare earth elements in the andesite is obvious. Most of the samples have moderate EU negative anomaly (未蠅 -OE EU + 0.44 + 0.77) and slight ce negative anomaly (未蠅 Ce) (未蠅 -Ce) 0.93 ~ (0.98), which are rich in large ion lithophile elements such as K _ (Rb), Ba _ (Th) and U, and are relatively depleted of high field strength elements such as NB and Ti. The magma has undergone separation and crystallization and partial melting. The andesite may be subducted southward in the Kangurtag ocean, the oceanic crust dehydrated into the mantle wedge, partially melted in the mantle wedge replaced by the subduction fluid, and formed by crystallization differentiation at the same time, and suffered from obvious continental crust material mixing. In the late Carboniferous, the subduction and subduction of the Kanggur Ocean still exist in the East Tianshan area.
【作者单位】：中南大学有色金属成矿预测教育部重点实验室;中南大学地球科学与信息物理学院;西南科技大学环境与资源学院;湖南工程职业技术学院资源工程系;马来西亚大学理学院;中国科学院地球化学研究所矿床地球化学国家重点实验室;
【基金】：国家重点基础研究发展计划(973计划)项目(2014CB440901)~~
【分类号】：P588.144;P618.51

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