In the past two decades,great progress in exploration of large porphyry metal deposits has been made in the South Gobi metallogenic belt of Mongolia where large porphyry deposits,such as Oyu Tolgoi Cu-Au and Tsagaan Suvarga Cu-Mo deposit,which were formed in a Late Devonian arc associated with the Paleo-Asian Ocean have been discovered.Study shows:①the Oyu Tolgoi-Tsagaan Suvarga area was uplifted and denudated after the Famennian arc magmatism and mineralization,shortly followed by the deposition of the Carboniferous volcanic-sedimentary rocks and the two deposits are below the Famennian-Tournaisian unconformity;②deposits occur currently in the windows surrounded by the Carboniferous-Permian rocks so the preservation of ore body strongly depends upon the denudation degree of overlying rocks;③the EW-trending of South Gobi metallogenic belt of Mongolia extends eastwards to the Dongwuqi of Chin in spite of its turning NE locally in the Oyu Tolgoi-Tsagaan Suvarga area due to the influence of the left-lateral Zuunbayan faulting during the Triassic-Early Cretaceous.Therefore,prospec ting for large porphyry metal deposits in the Dongwuqi should mainly focu on Late Devonian intrusions and their country rocks below the Famennian-Tournaisian unconformity with help of structural analyses in potential areas.%近二十年来,蒙古南戈壁成矿带在寻找大宗金属矿产方面取得丰硕成果,发现了欧玉陶勒盖和查干苏布尔加等与古亚洲洋晚泥盆世岛弧演化有关的大型斑岩型矿床.研究表明:1)欧玉陶勒盖—查干苏布尔加地区在法门期弧岩浆与矿化作用之后,经历了短暂的抬升和剥蚀过程,随后被石炭纪火山-沉积岩所覆盖.两个矿床皆被埋藏于法门期(D3)—杜内期(C1)不整合面之下;2)矿床现今出露于石炭纪—二叠纪岩体包围的“天窗”中,矿体能否保存与其上覆岩层遭受的剥蚀程度有关;3)近EW向展布的蒙古南戈壁成矿带在欧玉陶勒盖—查于苏布尔加地区受三叠纪—早白垩世准巴彦断裂左旋走滑运动的影响,局部转变为NE走向,向东可延伸至中国境内东乌旗一带.因此,在中国内蒙古东乌旗地区开展的找矿勘查工作应重点关注法门期(D3)—杜内期(C1)不整合之下的晚泥盆世侵入体及其围岩,并在成矿远景区进行相应的区域构造解析研究.
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