(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室,長(zhǎng)沙 410083;
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院,長(zhǎng)沙 410083)
摘 要: 粵北曲仁碳酸鹽巖盆地北緣聚集的鉛鋅硫化物礦床地質(zhì)礦化特征相比于其他MVT礦床,具有成礦特殊性。為了確定該類礦床成礦流體和物質(zhì)的來(lái)源以及成礦作用過(guò)程,對(duì)研究區(qū)礦床地層、斷裂構(gòu)造地球化學(xué)特征、稀土元素、硫鉛同位素和流體包裹體特征進(jìn)行系統(tǒng)研究。結(jié)果表明:地層、構(gòu)造以及稀土元素研究結(jié)果顯示該類鉛鋅硫化物礦床經(jīng)歷了黃鐵礦礦化與鉛鋅礦化兩個(gè)成礦作用過(guò)程,前者與賦礦層灰?guī)r的物源聯(lián)系更緊密,后者的成礦金屬物質(zhì)并非直接來(lái)自賦礦層灰?guī)r,而是由通過(guò)北東、北西向斷裂向上運(yùn)移的盆地深部流體提供,且局部受到中基性巖漿侵入活動(dòng)輕微改造;礦石及相關(guān)地質(zhì)體同位素地球化學(xué)特征顯示鉛主要來(lái)自盆地基底碎屑巖層,部分來(lái)自盆地深部殼源重熔型花崗質(zhì)巖漿,少部分來(lái)自盆地碳酸鹽巖層,而硫主要為地層硫,小部分為殼源巖漿硫;閃鋅礦流體包裹體氣液相成分、鹽度和溫度結(jié)果顯示鉛鋅熱液成礦期古地?zé)岣弋惓#璧鼗姿樾紟r含水系統(tǒng)及燕山期巖漿熱液參與鉛鋅成礦。綜合礦床地球化學(xué)特征可知,粵北曲仁盆地北緣凡口式MVT鉛鋅礦床屬于兩期熱液疊加-改造熱液型鉛鋅礦床。
關(guān)鍵字: 凡口式MVT鉛鋅礦床;地球化學(xué)特征;成礦流體;成礦物質(zhì)來(lái)源;成礦作用過(guò)程
(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geoscience and Info-Physics, Central South University, Changsha 410083, China)
Abstract:Compared with other MVT deposits, the lead-zinc sulfide deposits gathering in the north margin of Quren carbonate basin, Guangdong Province, China, have mineralization particularity. The deposit strata and fault structure geochemistry, rare earth elements (REE), sulphur isotope, lead isotope and fluid inclusion geochemistry were discussed for understanding the source of the ore-forming metal, fluids and the mineralization processes in Fankou-type lead-zinc deposit. The strata, fault structure and REE results show that this type deposit experiences pyrite and lead-zinc mineralization processes, the former gets closer provenance contact with limestone, while ore metal of the latter does not come directly from ore-hosting carbonate rocks, but gets from basin deep fluid transferred up by NE, NW faults, and is slightly modified by intermediate-basic magmatism. Lead and sulphur isotope geochemistry of ores and related geological samples shows that lead comes mainly from basement clastic formation, partly from crust remelting type granitic magma, little from carbonate rocks; sulphur is mainly from carbonate rocks, only a litter from crustal magma. Sphalerite fluid inclusions components, salinity and temperature results reveal that lead-zinc hydrothermal mineralization exists ancient geothermal anomaly, and basement clastic aquifer and Yanshanian granite are involved in lead-zinc mineralization. Fankou-type MVT lead-zinc deposit in this research area can be classified as two-hydrothermal superimposition-transformation lead-zinc deposit after geochemical characteristics of ore deposits being analyzed synthetically.
Key words: Fankou-type MVT lead-zinc deposit; geochemistry; ore-forming fluid? ore-metal source; metallogenesis


