河南姚冲隐伏斑岩型钼矿床地质特征及地球动力学背景

GEOLOGY AND GEODYNAMIC SETTING OF THE CONCEALED PORPHYRY MOLYBDENUM DEPOSIT IN YAOCHONG, HENAN PROVINCE

对姚冲隐伏斑岩型钼矿床成矿背景、产出特征、成矿时代、成矿地球动力学背景等方面进行了综合分析、对比研究.姚冲钼矿床产于大别成矿带西段的斑岩型钼矿床.矿体赋存于花岗斑岩体(脉)外接触带的中元古界蚀变片麻岩中,主要受隐伏岩体和构造控制.矿床成矿方式以充填作用为主,辉钼矿化主要呈浸染状、细脉-网脉状、薄膜状、角砾状产出.通过姚冲钼矿床与邻近钼矿床及相关斑岩体、中生代花岗岩基同位素年龄的对比研究,结合前人在大别山北麓的研究成果,将姚冲钼矿床成矿年龄限定在140 Ma左右的峰期内,对应的地球动力学背景为中国东部岩石圈大规模快速减薄.

With comprehensive analysis and comparative study on the metallogenic setting, occurrence characteristics, metallogenic epoch and geodynamic setting of the Yaochong concealed porphyry Mo deposit, it is concluded that the Yaochong Mo deposit occurs in the western section of Dabie metallogenic belt, with the orebody hosted in the Mesoproterozoic altered gneiss at the exocontact of granite-porphyry body （dyke） and controlled by concealed porphyry and structures. The deposit is formed mainly by filling mineralization. The main molybdenite mineralization occurs in dissemination, veinlet-stockwork, thin film and breccia. With former researches on the northern foot of Dabie Mountains and the isotopic age contrast between Yaochong Mo deposit and neighboring Mo deposits, ore-bearing porphyry and Mesozoic granite batholiths, the authors suppose that the metallogenic age of the Yaochong Mo deposit is about 140 Ma and the corresponding geodynamic setting is the rapid lithospheric thinning on a large scale in Eastern China.