秦岭东段金红石矿床成矿构造环境分析

通过对秦岭东段主要金红石矿床赋矿层位地质及地球化学特征的研究及对矿源层形成时的构造环境的分析 ,划分出 4种不同的成矿构造环境。中元古代以来 ,本区地壳处于强烈的陆 洋壳演化分异阶段 ,在北秦岭宽坪小洋盆、桐柏 大别古陆形成了与幔源成因有关的矿源层 ;在杨子地块北缘的被动陆缘拉张海盆形成了与沉积有关的矿源层。晚古生代以来 ,本区处于陆壳演化阶段 ,成矿构造环境为陆缘裂陷海槽环境 ,矿源层的形成与壳源岩浆有关

TECTONIC CONDITIONS NECESSARY FOR RUTILE MINERALIZATION IN THE EASTERN SEGMENT OF QINLING MOUNTAINS

Four different tectonic conditions necessary for the formation of major rutile deposits along the eastern segment of the Qinling mountains have been narrowed out mainly through investigating the geology and geochemistry of the ore bearing beds and analyzing the tectonic events related to source beds. Evolution of the crust in the study area has entered a stage of the intensive division form continental to oceanic crust since the middle Proterozoic time when mantle derived source beds got shaped in the kuanping oceanic basin north of the Qinling mountains and on the Tongbai dabie old land. In contrast, sedimentation related source beds were traceable to some basins caused by tensional events along the northern margin of the Yangtze massif. By the late Palaeozoic period, the crust of the study area proceeded with evolution from oceanic to continental crust, accompanying marginal rifting to lead crust-derived source beds.