Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kin...Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite （magnetite）, showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit.展开更多
基金supported by the National Natural Science Foundation of China (Grants No. 40473027 and 40773031)the Foundation of Doctoral Supported by the Ministry of Education (20105122110010 and 20115122110005)+1 种基金the Foundation of Open Subjects of State Key Laboratory for Mineral Deposits Research,Nanjing University (14-08-3)the Project of the State Key(Preparation Support) Disciplines of Mineralogy,Petrology and Mineral Deposit Geology of Sichuan Province (SZD0407)
文摘Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite （magnetite）, showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit.
