喬夏哈拉式鐵銅金礦成礦模式及其找礦意義-預(yù)覽頁
【正文】 inerogenetic model of Qiaoxiahalatype FeCuAu depositsThe Qiaoxiahala FeCuAu deposit in Xinjiang is the typical one as Qiaoxiahalatype FeCuAu deposit. Taking it as an example, the main contents of this type can be concluded as following. Describing patternThe Qiaoxiahala FeCuAu deposit mainly produces magnetite and chalcopyrite hosted by basic marine volcanic rocks and the responding pyroclastic rocks with TFe at % and Cu at % at average and up to %. The No. III orebody in the eastern mining sector is with Cu at % at average and Au at , whereas No. I with Cu at .055% and Au at (Xinjiang Uygur Autonomous Region Geological Bureau, 1978). Magnetite orebodies mainly occurred in the western mining sector as the stratiformlike, phacoidal, lenticular, whereas chalcopyrite orebodies concentrated in the eastern mining sector labelled I~VII as stratiform and/or lenticular (Li Longqian, 2003). Ores included massive magnetite and chalcopyrite, banded epidote+magnetite, and disseminated pyrite+chalcopyrite+magnetite and chalcopyrite+magnetite. Ore structures appeared euhedral and subhedral granular, polygonal cleavage, anhdral granular and sheet texture.The Qiaoxiahala FeCuAu deposit located at the south side of the Ertix Fault at the margin of Altay Mountains hosted by Middle Devonian Beitashan Formation (D2b). The footwall rocks were basic volcanic rocks and pyroclastic rocks, whereas volcanic lava and the pyroclastic rocks were the hanging wall. Orebodies occurred as Fe174。pact massive chalcopyrite ore. Alterations in the wall rocks developed well including epidotization, chloritization, carbonatization, sericitization, quartz, pyrite, tremolite et al (Ni Liang, 2004). Minerogenetic patternThe Qiaxiahala FeCuAu deposit was supposed to be formed by marine volcanicsedimentary mineralization enriched by later hydrothermal activity. The ArAr plateau age of hornblende in diorite from the western mining sector as almost vertically cutting the iron bed was 177。 4)Junggar openclose system between continents→North Junggar Pz openclose belt→QiaoxiahalaA’ermantai ?O ocean crust relic (Chen Zhefu et al., 1997). Its present geotectonic location was in the transitional belt between Altay south margin and Junggar north margin, and also the southern side of Ertix Fault, but not the inside of Altay orogin belt. As far as the minerogenetic material concerned, Fe came from the same magmatic source as the basic volcanic lava related to the marine volcanism, Cu mainly sourced from later hydrotherm and a little from the basic volcanic lava, whereas Au was mainly provided by the later hydrotherm related to the diorite intrusion.On geochemistry of sulfur isotopes, d34S of pyrite changed from +‰ to +‰, +‰ at average。 ②written records: it was recorded in the regional report of Fuyun at scale of 1:200 000 in 1978 as a smallscale Fe deposit and Cu occurrence. In recent years, Fe ore resources have reached 4620 000 t, Cu 31200 t and Au 1051 kg.(3) Geophysical criteria:①gravity: the gravity anomaly in Qiaoxiahala was lineary consist with the tectonic striking as the high value of gravit
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鄂ICP備17016276號-1