广西油麻坡矽卡岩型钨钼矿床矿床成因初步研究

发布时间：2018-04-27 09:32

  本文选题：地球化学 + 钨钼矿　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：广西博白-岑溪断裂带位于钦杭成矿带南段,即是一条长期活动的地体边界断裂带,也是一条岩浆活动频繁的W-Mo-Sn-Pb-Zn-Sb-Au-Ag多金属成矿带。文章以该带中的广西博白县油麻坡矽卡岩型钨钼矿床为研究对象,主要研究了油麻坡钨钼矿床矿床地质特征、矿床地球化学、成岩成矿年代等方面内容,探讨了油麻坡钨钼矿床的矿床成因,主要取得如下几个方面的认识:1)油麻坡矽卡岩型钨钼矿床主要由矽卡岩型白钨矿矿体组成。围岩蚀变主要有矽卡岩化、硅化、大理岩化等。2)油麻坡矿床主成矿期原生流体包裹体主要有气-液两相、CO2三相包裹体、纯液相包裹体这三种类型。流体形成温度在157.9~444.5℃之间,峰值主要集中在300.0~325.0℃,平均温度为318.9℃;流体盐度范围为5.11%~13.51%,峰值集中在7.0%~10.0%;矿床的流体密度平均密度为0.87g/cm3,表明油麻坡矿床成矿流体属于中高温中低盐度体系。3)H、O同位素分析显示,样品的投影点均落在岩浆水范围,表明油麻坡矽卡岩钨钼矿床的成矿流体主要来源于岩浆水。硫同位素研究结果表明,硫化物δ34S值显示塔式分布特点,δ34SV-CDT值分布范围为0.5‰~4.1‰,平均值为2.45‰。推测油麻坡矽卡岩型钨钼矿体中硫化物的硫主要为深部岩浆来源。4)LA-ICP-MS锆石U-Pb测年结果表明,油麻坡矿区深灰色花岗斑岩的等时线年龄为(479.7±3.9)Ma,灰色黑云母花岗闪长岩为(109.7±1.1)Ma,浅灰色细粒白云母花岗岩为(103.3±1.2)Ma。辉钼矿Re-Os测年获得加权平均年龄为(97.4±1.9)Ma。由此可知,油麻坡岩体为一个复式岩体,存在两期岩浆热液活动,由早奥陶世(加里东期)的花岗斑岩、早白垩世(燕山晚期)的黑云母花岗闪长岩和细粒白云母花岗岩组成,其中早白垩世的黑云母花岗闪长岩是岩体的主体部分,细粒白云母花岗岩应该是补体。钨钼矿形成于早白垩世晚期(即燕山晚期),与黑云母花岗闪长岩和细粒白云母花岗岩密切相关。
[Abstract]:The Bobb-Cenxi fault zone in Guangxi is located in the southern section of Qinghang metallogenic belt, which is a long-active terrane boundary fault zone and a W-Mo-Sn-Pb-Zn-Sb-Au-Ag polymetallic metallogenic belt with frequent magmatic activity. Taking the oil-mapo skarn type tungsten and molybdenum deposit in Bobai County, Guangxi, as the research object, this paper mainly studies the geological characteristics, deposit geochemistry, diagenesis and metallogenic age of the oil-mapo tungsten and molybdenum deposit. In this paper, the genesis of the Yunmapo tungsten and molybdenum deposit is discussed. The main understanding is as follows: 1) the skarn type tungsten molybdenum deposit is mainly composed of skarn type scheelite ore bodies. The alteration of surrounding rock mainly includes skarnization, silicification, marble, etc.) the primary fluid inclusions in the main metallogenic period of the Youmapo deposit are mainly gas-liquid two-phase CO _ 2 three-phase inclusions and pure liquid fluid inclusions. The formation temperature of the fluid is between 157.9 鈩，

本文编号：1810184