东昆仑拉陵灶火涛歌岩体地质特征及其与成矿作用关系

发布时间：2018-06-16 05:33

  本文选题：东昆仑 + 涛歌岩体　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：东昆仑拉陵灶火中游涛歌岩体周边成矿现象丰富,但是致矿侵入体至今不明。本文以涛歌岩体作为研究的出发点,对涛歌岩体及其周边的成矿现象进行了细致的研究。获得了涛歌岩体地质特征及其与成矿作用的联系,推断涛歌岩体为中游地区可能的致矿侵入体之一。对涛歌岩体及其周边进行了地质填图,发现涛歌岩体与片麻岩呈侵入接触关系,片麻岩的产状显示其大致为一个以涛歌岩体为枢纽的背斜,表明涛歌岩体在构造上符合致矿侵入体要求。涛歌岩体本身含金,富集铜,表明涛歌岩体在成矿物质来源上符合致矿侵入体要求。对涛歌岩体进行详细的矿物学研究。对金属矿物进行电子探针分析显示载金矿物为黄铁矿和磁铁矿。阴极发光研究表明斜长石普遍存在增生边。镜下使用卡钠复合双晶法测定了斜长石牌号,发现斜长石牌号分为两类。对斜长石成分进行了电子探针分析,发现斜长石分为基性斜长石和中性斜长石两类。这些表明岩石经历了两种不同的结晶过程。由CSD曲线的样式和SiO2、角闪石含量可以识别出两期流体活动。角闪石的方向优选显示中间样品的定向强度大于边缘样品的定向强度,这表明第二期流体活动强度大于第一期流体活动强度。对涛歌岩体进行了岩石地球化学分析,显示涛歌岩体冷却结晶过程中SiO2、Na2O、Fe2O3、P2O5、K2O的含量总体升高,而Al2O3、TiO2、CaO的含量总体降低。涛歌岩体稀土元素含量存在明显重稀土亏损,负Eu异常,显示岩石受到严重蚀变改造。Nb、Ta的负异常显示中游涛歌岩体应该为岛弧火山岩,这与区域内中三叠世是岛弧碰撞构造环境相吻合。涛歌岩体形成的时间在225~230Ma,而涛歌岩体下部的被活化的岩浆形成的时间是245~250Ma。涛歌岩体结晶温度存在两个区间:493℃~650℃和752℃~810℃;压力在2.81Kbar至1.54Kbar,前四个温度较低的样品的平均压力为2.68 Kbar,后六个温度较高的样品的平均压力为2.15 Kbar。表明岩体不同部位岩石经历了不同温压条件的结晶过程。涛歌岩体的形成过程是:第一期流体活动——岩体结晶粗化——第二期流体活动——岩体结晶粗化的波动过程。并且第二期流体活动活动的强度大于第一期流体活动的强度,在流体活动过程中由于下部岩浆的活化,导致下部近固结岩浆房中的锆石带入涛歌岩体。
[Abstract]:The ore-forming phenomena around the TAOGE rock body in the middle reaches of Laling Zaozao in East Kunlun are abundant, but the ore-forming intrusions are still unknown. Taking the TAOGE rock mass as the starting point, this paper makes a detailed study on the ore-forming phenomenon of the TAOGE rock mass and its surroundings. The geological characteristics of the TAOGE rock mass and its relation with mineralization are obtained, and it is inferred that the TAOGE rock body is one of the possible ore-forming intrusions in the middle reaches. The geological mapping of the TAOGE rock body and its surrounding area shows that the TAOGE rock body has an intrusive contact relationship with the gneiss, and the occurrence of the gneiss shows that it is approximately an anticline with the TAOGE rock body as its pivot. It shows that the TAOGE rock body meets the requirements of ore-forming intrusion in structure. The ore-forming source of the TAOGE rock body is in accordance with the requirements of ore-forming intrusive body. A detailed mineralogical study of the TAOGE rock mass is carried out. Electron probe analysis of metallic minerals shows that the gold bearing minerals are pyrite and magnetite. Cathodoluminescence studies show that plagioclase generally exists accretive edges. The plate number of plagioclase was determined by the method of sodium Carbonate and double crystal under the microscope, and it was found that the plate number of plagioclase can be divided into two categories. The composition of plagioclase is analyzed by electron probe. It is found that plagioclase can be divided into basic plagioclase and neutral plagioclase. These indicate that rocks undergo two different crystallization processes. Based on the CSD curve and Sio _ 2, amphibole content can be used to identify the two-stage fluid activity. The directional optimum selection of amphibole shows that the directional strength of the intermediate sample is higher than that of the edge sample, which indicates that the second phase of fluid activity is greater than the first phase. The geochemistry analysis of the TAOGE rock mass shows that the content of SiO2Na2O3Fe2O3Fe2O3P2O5K2O increases and the content of Al2O3TiO2CaO decreases during the cooling and crystallization of the TAOG rock body. The REE content in the Taoge rock body is obviously depleted in heavy rare earth elements and negative EU anomaly, which indicates that the rock is seriously altered. The negative anomaly of NbGTA indicates that the TAOGE rock body in the middle reaches should be island arc volcanic rock. This coincides with the tectonic environment of the island arc collision in the Middle Triassic in the region. The formation time of the TAOGE rock mass is 225 ~ 230 Ma, while the activated magma formation time of the lower part of the TAOGE rock body is 245 ~ 250 Ma. There are two ranges of crystallization temperature: 1: 493 鈩，

本文编号：2025561