CAJ | 학술논문

应用锆石SHRIMP U-Pb法和辉钼矿Re-Os同位素测年法对斑岩的形成时代进行精确定年.结果表明:成矿花岗斑岩体的形成年龄为44.6±1.1Ma;辉钼矿Re-Os等时线年龄为43.78±0.78Ma;成岩成矿期与滇西新生代岩浆-成矿作用高峰期吻合.结合区域地质条件和岩浆的可能源岩年龄(126.7±3.5Ma～529.3±13Ma)等资料分析,提出花岗斑岩在成因上与印支地块与滇缅泰地块陆内俯冲碰撞引发的地幔上涌及地壳重熔作用有关,岩浆来源具壳-幔混合特征.研究还证实滇西地区喜山期存在与隐伏花岗斑岩有关的大规模成矿作用.
응용고석SHRIMP U-Pb법화휘목광Re-Os동위소측년법대반암적형성시대진행정학정년.결과표명:성광화강반암체적형성년령위44.6±1.1Ma;휘목광Re-Os등시선년령위43.78±0.78Ma;성암성광기여전서신생대암장-성광작용고봉기문합.결합구역지질조건화암장적가능원암년령(126.7±3.5Ma～529.3±13Ma)등자료분석,제출화강반암재성인상여인지지괴여전면태지괴륙내부충팽당인발적지만상용급지각중용작용유관,암장래원구각-만혼합특정.연구환증실전서지구희산기존재여은복화강반암유관적대규모성광작용.
The Laochang polymetallic deposit, situated in the south part of the late Palaeozoic Changning-Menglian continental rift belt in western Yunnan, is one of the areas with significant breakthrough for a new discovery of great thick porphyry molybdenum ore bodies in the depths since 2008. This paper provides precise rock-forming ages of the granite-porphyry by the SHRIMP zircon U-Pb and molybdenite Re-Os dating methods. The results show that the forming age of the granite-porphyry is 44.6±1.1Ma, and the Re-Os isochron age of molybdenites 43.78±0.78Ma. The rock- and ore-forming ages are in consistent with the peak phase of Cenozoic magmatism-mineralization of western Yunnan. For this reason, combining dating with regional geological conditions and the ages (126.7±3.5Ma～529.3±13Ma) of possible source rocks of the magma, it is suggested that the genesis of the concealed granite-porphyry may be related to mantle upwelling and crustal anatexis, and its origin exhibits the mixing features coming from crust-derived and mantle-derived magmas caused by intracontinental collision and subduction between the Indo-Chinese block and Yunnan-Burma block. It has also demonstrated that a large-scale Mo(Cu)-mineralization related to Himalayan concealed granite-porphyries exists in western Yunnan.