机构地区:[1]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205 [2]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205 [3]湖南金水塘矿业有限责任公司,湖南祁东421613 [4]辽宁师范大学城市与环境学院,辽宁大连116029 [5]湖南省有色地质勘查局一总队,湖南郴州423000
出 处:《中国地质》2022年第6期1862-1874,共13页Geology in China
基 金:中国地质调查局花岗岩成岩成矿研究中心开放基金课题(PMGR2020009,PMGR202108);中国地质调查局项目(DD20190154,DD20221689)联合资助。
摘 要:【研究目的】为探讨衡阳盆地及周边地区铅锌矿床的成因问题,本文对研究程度较高的清水塘铅锌矿床开展工作。【研究方法】通过矿床地质调查,不同阶段石英、方解石及闪锌矿的流体包裹体研究及石英Rb-Sr测年工作,探讨其成矿流体地球化学特征、演化与成矿过程。【研究结果】根据矿物组合及矿脉之间的穿切关系,本文将清水塘铅锌矿床成矿作用划分为黄铁矿-石英(Ⅰ)、石英-方铅矿-闪锌矿(Ⅱ)和重晶石-方解石(Ⅲ)3个阶段。流体包裹体研究表明,Ⅱ阶段石英、闪锌矿中均发育L和VL两种类型原生、次生流体包裹体;Ⅰ阶段石英、Ⅲ阶段方解石主要发育VL型原生流体包裹体。测温结果显示:Ⅱ阶段石英原生包裹体根据均一温度、盐度可细分为258~296℃、8.55%~9.21%NaCl eqv,260~298℃、3.61%~4.18%NaCl eqv,120~160℃、12.73%~18.22%NaCl eqv及145~168℃、3.06%~3.87%NaCl eqv 4组,而闪锌矿均一温度、盐度主要集中于102~178℃、10.24%~19.45%NaCl eqv;成矿流体属中—低温、中盐度的NaCl-H_(2)O体系热液。结合包裹体产状和均一温度可知:Ⅱ阶段中盐度、低盐度流体具有不同的来源与演化过程,前者多成群分布,应为Ⅰ阶段中温(210~312℃)、中盐度(12.30%~19.30%NaCl eqv)流体演化而来;后者多沿矿物裂隙产出,可能为后期低盐度大气降水混合的结果。本文获得2组石英Rb-Sr等时线年龄分别为(88.8±2.4)Ma和(17.86±0.42)Ma,前者代表清水塘铅锌矿床的成矿时代,后者记录后期构造叠加的时代;二者均明显晚于矿区附近周家岭花岗岩((203.0±1.4)Ma)及邻区关帝庙岩体((223.4±1.9)Ma)的成岩时代。【结果】考虑到区内铅锌成矿流体与岩浆活动有关,结合清水塘、留书塘矿区硫化物S、Pb同位素组成特点推测矿区深部存在晚白垩世隐伏岩体,为铅锌成矿提供物质和能量来源。This paper is the result of the mineral exploration engineering.[Objective] In order to discuss the genesis of the lead-zinc deposits in Hengyang Basin and its surrounding areas, this paper has carried out work on the highly studied Qingshuitang lead-zinc deposit. [Methods] By means of geological survey, fluid inclusion study of quartz, calcite and sphalerite at different stages and Rb-Sr dating of quartz, we discuss the geochemical characteristics,evolution and mineralization processes of ore-forming fluid. [Results] Based on the mineral assemblages and the intercutting relationships between veins, this paper classifies the metallogenesis of the Qingshuitang lead-zinc deposit into three stages: pyritequartz stage(I), quartz-galena-sphalerite stage(II) and barite-calcite stage(III). The research of fluid inclusions show that both Land VL-type primary and secondary fluid inclusions occur in quartzs and sphalerites at stage II;VL-type primary fluid inclusions predominantly occurs in quartzs at stage I and calcites at stage III. The measured temperature results show that primary inclusions of quartz formed at stage II can be subdivided into four groups according to the homogeneous temperature and salinity, which are 258-296°C and 8.55%-9.21% NaCl eqv, 260-298°C and 3.61%-4.18% NaCl eqv, 120-160°C and 12.73%-18.22% NaCl eqv, 145-168° C and 3.06%-3.87% NaCl eqv, respectively. By comparison, the homogenization temperature and salinity of sphalerite are mainly concentrated in the range of 102-178℃ and 10.24%-19.45%NaCl eqv. The ore-forming fluid belongs to the NaCl-H_(2)O hydrothermal system of medium-low temperature and medium salinity. Based on occurrence and homogenization temperature of inclusions, the medium and low salinity fluids at stage II may have different sources and evolutionary processes. The former is mostly distributed in groups and might derive from medium temperature(210-312℃) and medium salinity(12.30-19.30% NaCl eqv) fluid at stage I. The latter mostly occurs along mineral fissures, which may
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...