【摘要】 在对老柞山矿床地质特征系统研究的基础上,对与成矿有关的岩石开展了进一步的主、微量元素地球化学测试分析。结果显示与成矿有关的花岗岩具富Sr、低Ti的高钾钙碱性火山弧花岗岩的特征,闪长玢岩具偏铝质钙碱性岩系列特征。岩石样品均呈现出富集轻稀土元素和大离子亲石元素(LILEs)、相对亏损重稀土元素和Nb、Ta、Ti等高场强元素(HFES)的特征,显示了与岛弧或活动大陆边缘岩浆岩相似的属性。流体包裹体特征显示,成矿流体主要来自岩浆水,矿床具中低温(125.6℃~324.5℃)、中浅成(1.0~7.1 km)成矿的特点。与成矿有关岩浆岩显示幔源岩浆特征,可能是地幔交代作用部分熔融所形成的。结合区域上同时期的火成岩时空展布认为,老柞山金矿床成矿可能分别与晚古生代古亚洲洋板块北向俯冲作用和中生代太平洋板块俯冲作用密切相关。更多还原

【Abstract】 On the basis of systematical studies of Laozuoshan gold deposit,the geochemical analyses( including major and trace elements) were further undertaken for the ore-related rocks. The results show that the ore-related granites are low Ti and high Sr in content,belonging to High-K calc-alkaline volcanic arc granites,while the diorite porphyrite appears the feature of metaluminous calc-alkaline rock series. All the rock samples are characterized by enrichment in light rare earth elements( LREEs) and large ion lithophile elements( LILEs),and relative depletion in heavy rare earth elements( HREEs) and high field strength elements( HFSEs),such as Nb,Ta and Ti,with affinities to the igneous rocks formed in island arc or active continental margin settings. The features of fluid inclusions indicate that the ore-forming fluid mainly came from magmatic water,and the deposit was characterized by formation in the low-medium depth( 1. 0- 7. 1 km) under low-medium temperature( 125. 6℃-324. 5℃). Notably,the ore-related magmatic rocks show the characteristics of mantle-derived magma,suggestingthat they were likely produced by partial melting of mantle experienced in metasomatism. According to the distribution of the coeval igneous rocks in the area,it is proposed that the formation of Laozuoshan gold deposit may be closely related to the Late Paleozoic northward subduction of the Paleo-Asian oceanic plate and the Mesozoic westward subduction of the Pacific oceanic plate,respectively.更多还原