Abstract:The Hogeqi deposit is a Cu-Pb-Zn polymetallic deposit located in the Nei Monggol Autonomous Region. An analysis of its ore-forming conditions and sedimentation environment rules out the possibility of forming such a large deposit during syndeposition. The correlation of near-ore and distant wall rocks of this deposit with the conesponding rocks at the rest of the world in ore-forming elements shows that Pt1L2 was a source bed. It is presumed that under the metamorphic environments of greenschist facies and amphibolite facies, chalcophile elements separated from lithophile elements, migrated with metamorphic fluids and finally concentrated into ores. This accounts for the fact that galena has the same age as the regional metamorphism. Ore occurrence is closely related to banded quartzite, diopside-tremolife rocks, arid mica-quartz schist. Such phenomena of ore bodies as widening or narrowing, ramification, convergence, and their cutting into or penetrating the underlying or overlying strata can sometimes be observed within the ore-bearing bed. Silicification, chloritization, sericitization and phlogopitization are common alterations accompanying mineralization. The ores assume mainlybanded, veinlet- network and taxitic structures, apparently having replacement character from place to place. Solid solution textures are well-developed. δS34 values vary in the range from +4.0 to 21.4‰, showing no noticeable peaks. According to solid solution textures, geological thermometer of marmatite, inclusion temperatures and metamorphic facies, ore-forming temperatures are estimated to be have been between 300℃ and 600℃. Mineralization was obviously controlled by the superimposed structure. All this indicates unequivocally that mineralization had much to do with post-mineral transformation and bore the characteristic of multiple ore-forming processes. Of all factors, regional metamorphism played the dominant role in ore formation. This deposit, therefore, is of stratabound metamorphic type. Metallogenic elements were derived predominantly from terrestrial sources. The source bed formed during sedimentation provided material basis for the subsequent economic ore deposit. Hot brine of the post-sedimentation phase or the diagenesis and post-diagenesis phase began to concentrate the ore material. Later, the metamorphic fluids formed the economic deposit during regional metamorphism. Magmatic activity and supergene diagenesis modified the deposit to some extent but did not change fundamentally its genetic character.
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蒋心明.1983.内蒙霍各乞铜铅锌矿床成因及成矿机理[J].矿床地质,2(4):1~10.1983.A Discussion On The Genesis And Ore-Forming Mechanism Of The Hogeqi Cu-Pb-Zn Deposit .[J].Mineral Deposits2(4):1~10
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