Magmatic hydrothermal overprinting in the
Mesoproterozoic Dongshengmiao deposit, Inner Mongolia: geological and fluid inclusion evidences
- 出版年：2007
- 作者：PENG RunMinh；ZHAI YuSheng；HAN XueFeng；WANG JianPing；WANG ZhiGang；QIN JunWeng
- 单位1：State Key laboratory of Geological rocesses and Mineral Resources,China University of Geosciences
- 语种：英文
- 作者关键词：Fissure vein-shaped chalcopyrite and sphalerite ore；Decrepitation temperature；Superimposed magmato-hydrothermal mineralization；Dongshengmiao super-large deposit；Inner Mongolia
- 起始页：145
- 总页数：8
- 刊名：岩石学报
- 是否内版：否
- 刊频：月刊
- 创刊时间：1985
- 主办单位：中国矿物岩石地球化学学会；中国科学院地质与地球物理研究所
- 电子信箱：Ihzd@ public.tpt.tj.cn
- 卷：23
- 期：1
- 期刊索取号：P350.66357
摘要
The Dongshengmiao Pb-Zn deposit located in the Mesoproterozoic aulacogen in a passive continental margin in the north-west margin of the North-China Craton is widely considered to be a untypical SEDEX deposit. Recently, new types of mineralizationsuch as chalcopyrite veins and re-crystallized sphalerite ores with visible hydrothermal alteration have been found in the deposit atdepth. In this paper we report the decrepitation temperatures of fluid inclusions in chalcopyrite, sphalerite and quartz from these newtypes of ores. The decrepitation temperatures of fluid inclusions in chalcopyrite (4samples), sphalerite (2samples) and quartz(5samples) are303～456℃,97～497℃,146～350℃ and 350～556℃,respectively. The decrepitation temperatures of fluid inclusionsin the vein-type chalcopyrite are similar to the decrepitation temperatures of fluid inclusions in chalcopyrite from the HercynianOubulage porphyry Cu-Au deposit (313～514℃) and the Chehugou porphyry Cu-Mo deposit (277～485℃),supporting ourinterpretation that the Dongshengmiao deposit was overprinted by magmatic hydrothermal mineralization. The decrepitation temperaturesof fluid inclusions in re-crystallized sphalerite from the Dongshengmiao deposit are characterized by two peaks, 97～358℃ and 358～497℃. The decrepitation temperatures of fluid inclusions in quartz in chalcopyrite veins from the Dongshengmiao deposit are alsocharacterized by two peaks, 146～350℃ and 350～556℃. The lower and higher temperature peaks in both cases are considered torepresent two separate mineralization events, original SEDEX mineralization and magmatic hydrothermal overprinting, respectively. Thehigher decrepitation temperatures of fluid inclusions in quartz and sphalerite from the Dongshengmiao deposit are similar to thedecrepitation temperatures (340～526℃) of fluid inclusions in sphalerite from the Baiyinnuoer skam-type Pb-Zn deposit in the region.Replacement of pyrite by sphalerite and overgrowth of chalcopyrite on pyrite in the Dongshengmiao support our interpretation that theoriginal SEDEX mineralization was overprinted by magmatic hydrothermal activity in the deposit. Our results suggest that there may beseparate porphyry and skam-type deposits related to Hercynian magmatism and associated hydrothermal activities in the Langshan area,which are potential exploration targets in the future.