川西里伍式铜矿床成矿物质来源:电气石元素地球化学及硼同位素制约

发布时间：2018-06-16 21:45

  本文选题：松潘-甘孜造山带 + 里伍群　； 参考：《地质学报》2017年09期

【摘要】：川西江浪穹隆在大地构造上位于松潘-甘孜造山带东南缘。环穹窿腰部分布着一系列产状、矿床特征相似的铜多金属矿床——里伍式铜矿床,包括里伍、中咀、笋叶林、柏香林、挖金钩、黑牛洞等矿床。这些矿床的矿体主要呈似层状产出于中元古代里伍群中,其成因模式目前尚不明确。本研究选择里伍和黑牛洞铜矿中的含矿石英-电气石脉作为重点研究对象,对其中的代表性电气石单矿物进行了电子探针分析及LA-MC-ICPMS原位硼同位素测试,据此制约矿床的成矿物质来源。背散射及显微图像特征揭示两矿床的含矿电气石具有单一的流体来源;电子探针分析结果表明这些电气石在类型上均属镁电气石;硼同位素测试结果显示两矿床的电气石δ11 B值分别为-15.47‰±0.83‰~-13.06‰±0.77‰(n=10)及-13.19‰±0.57‰~-5.91‰±0.67‰(n=16),与花岗岩的δ11B值区间非常一致,表明这两个矿床属(区内燕山期)岩浆期后热液矿床。通过对比研究,本文进一步提出在松潘-甘孜造山带内很可能存在一条NE-SW向的铜多金属成矿带,即松潘-甘孜铜多金属构造成矿带。本次研究不仅可以丰富层状型矿床成矿理论,而且对指导该造山带中其他穹窿体的找矿具有较为重要的实际意义。
[Abstract]:The Jianglang dome in western Sichuan is located in the southeast margin of Songpan-Ganzi orogenic belt. At the waist of the ring dome, there are a series of copper-polymetallic deposits with similar characteristics, such as Liwu, Zhongzui, bamboo shoot Ye Lin, cypress, gold-gouging, HeiNiudong and so on. The ore bodies of these deposits are mainly stratiform occurring in the Middle Proterozoic Liwu Group, and its genetic model is unclear. In this study, the ore-bearing tourmaline veins in Liwu and Heiniodong copper mines were selected as the main research objects, and the typical tourmaline monoliths were analyzed by electron probe and in situ boron isotopic measurements by LA-MC-ICPMS. Therefore, the source of ore-forming material is restricted. The characteristics of backscattering and microscopic images reveal that the mineralized tourmalines of the two deposits have a single fluid source, and the results of electron probe analysis show that these tourmalines are of magnesium tourmaline type. The results of boron isotope test show that the 未 11B values of tourmaline in the two deposits are -15.47 卤0.83 鈥，

本文编号：2028211