湘南粤北铅锌矿床闪锌矿的标型特征及指示意义  

Typomorphic characteristics and indicative significance of sphalerite in Pb-Zn deposits in southern Hunan-northern Guangdong area

作　　者：徐接标 张术根[1,2] 左亚飞 冯雨周 卢敏晨 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083 [3]江西省聚拓矿业投资有限公司,江西南昌330000

出　　处：《岩石矿物学杂志》2016年第2期283-296,共14页Acta Petrologica et Mineralogica

基　　金：国家"十一五"科技支撑计划资助项目(2009BAB43B00)~~

摘　　要：湘南粤北位于南岭成矿带中段,是我国最重要的铅锌矿集区之一。本文选取湘南粤北地区MVT和岩浆热液型两类铅锌矿床的闪锌矿样品,对闪锌矿的形态、结构、化学成分、硫同位素组成、流体包裹体成分等进行系统研究,分析其成矿温度、硫的来源和成矿流体特征,为揭示成矿作用提供可靠依据。研究结果表明：MVT铅锌矿床成矿作用发生在中低温、氧化-弱还原、较低压力环境,硫主要来源于容矿地层,成矿流体主要来自于热卤水和沉积物变质脱水;岩浆热液型铅锌矿床成矿作用发生在中高温、弱还原、较高压力条件下,硫源主要以岩浆硫为主,成矿流体早期以岩浆热液为主,晚期为混合流体。结合矿体与岩体的形成时间、空间分布、大地构造背景,认为岩浆热液型铅锌矿床由燕山早期（180～150 Ma）古太平洋向大陆俯冲、岩石圈加厚,爆发大规模花岗质岩浆岩侵位,导致铅锌成矿;MVT铅锌矿床由燕山晚期（130～90 Ma）欧亚大陆岩石圈伸展减薄产生的岩浆热液叠加改造泥盆系的原始矿源层形成。As one of the most important Pb-Zn ore concentration areas in China,southern Hunan-northern Guangdong area is located in the middle part of the Nanling metallogenic belt. Morphology,texture,composition,δ34S and composition of fluid inclusions of sphalerite from MVT and magmatic hydrothermal Pb-Zn deposits were investigated to discuss the ore-forming temperature,the source of sulfur and the ore-forming fluid,which can provide valid constraints on the mineralization. It is suggested that lead-zinc sulfides in the MVT PbZn deposit were formed in the medium-low temperature,oxidative-weak reductive and lower stress environment. The sulfur was mainly derived from the ore-bearing strata,the ore-forming fluid was composed of hot brine and metamorphic dehydration of the sediments. Magmatic hydrothermal Pb-Zn deposits were formed under the medium-high temperature,weak reductive and higher stress condition. The sulfur was mainly derived from the magma,the ore-forming fluid was composed of magmatic hydrothermal solution in the early stage and mixed fluid in the late stage. Based on the formation time,spatial distribution and tectonic background of the orebodies and the rocks,it is held that magmatic hydrothermal Pb-Zn deposits were formed by the emplacement of the large-scale granitic magmatite which was caused by subduction of the Paleo-Pacific plate to the mainland,thus the lithosphere was thickened in the Early Yanshanian period（ 180 ～ 150 Ma）,and that MVT PbZn deposits were formed after the superimposed reformation of the original Devonian source bed by the magmatic hydrothermal solution formed by the Eurasian lithospheric extension-thinning in the Late Yanshanian period（130 ～90 Ma）.

关 键 词：湘南粤北 闪锌矿 标型特征 铅锌矿床 成矿作用 

分 类 号：P618.4[天文地球—矿床学] P575[天文地球—地质学]