安徽马头矿区热液成矿边界的地球化学标志  

Geochemical identification marks of hydrothermal metallogenic system boundary of Matou mining area,Anhui Province

作　　者：马生明[1] 朱立新[2] 席明杰[1] 唐世新[1] 苏磊[1] 

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [2]中国地质科学院,北京100037

出　　处：《地学前缘》2015年第4期131-140,共10页Earth Science Frontiers

基　　金：国家科技支撑计划项目(2014BAB05B00);国土资源部公益性行业专项(201111008)

摘　　要：成矿系统具有时间和空间边界,确定热液成矿边界不仅具有重要的理论研究意义,而且对指明找矿方向、指导矿产勘查具有重要实用价值。但是,目前热液成矿边界如何确定尚缺乏研究。文章在地球化学勘查长期实践和理论方法探讨的基础上,在安徽马头热液成因金属矿区开展试验,提出了确定和判断热液成矿边界的地球化学标志。在勘探剖面上,斑岩型Mo、Cu矿分布在由带出作用形成的Na2O等元素负异常之内,含矿地段粉砂岩和花岗闪长斑岩中Na2O带出量大于80%,稀土元素Eu表现出明显的负异常;在地表条件下,矿化带产出在Na2O含量为0.1%-0.2%的负异常之内,δ34S值小于3.2‰,显著低于矿区外围花岗岩的δ34S值。由此认为,Na2O带出量大于80%,稀土元素Eu的负异常是确定马头斑岩型钼铜矿深部成矿边界的地球化学标志;Na2O含量为0.1%-0.2%的负异常、δ34S值小于3.2‰,是确定该矿床外围成矿边界的地球化学标志。本研究不仅为马头勘查区深部、外围找矿和成矿前景评价提供了成功案例,而且对其他勘查区热液成矿边界的研究和确定具有借鉴作用。The identification of temporal and spatial boundary of metallogenic system is not only of great significance in theoretic research, but also can guide the mineral exploration and provide direct information for deep and periphery prospecting of known deposits. However, at present that how to determine hydrothermal mineralization boundary is still a lack of research. On the basis of long-term practice and theory and method of geochemical exploration, this paper, taking Matou porphyry molybdenum copper mine of Anhui Province for an example, proposes some geochemical identification marks to determine and judge the boundary of hydrothermal ore-forming. The experimental results show that orebody is located in the negative anomalies system of some elements such as Na2O. In ore output area the out put amount of Na2O of powder sandstone and granite diorite porphyry is more than 80% and rare earth element Eu shows obvious negative anomaly. In the earth＇s surface, mineralized belt is located in the Na2O negative anomaly, the content of Na2O ranges from 0. 1 % to 0.2%, and the δ^34S value being less than 3.2‰ is significantly lower than that of granite in mining area periphery. Therefore, we infer that the output amount of Na20 being more than 80% with the negative anomaly of rare earth element Eu, is the geochemistry identification mark of deep metallogenic boundary of Matou porphyry mine. Na2O negative anomaly with content ranging from 0.1% to 0. 2 % and δ^34 S value being less than 3.2‰ are the geochemical marks of the peripheral metallogenic boundary. Our test results provide a reference for deep and periphery prospecting of Matou deposit and have a broad application prospect in delineating temporal and spatial boundary of exploration area.

关 键 词：马头矿区 斑岩型钼铜矿 热液成矿边界 地球化学标志 

分 类 号：P591[天文地球—地球化学]