青海省南祁连盆地砂岩铜矿成矿地质特征与控矿因素分析

南祁连盆地广泛分布的二叠纪地层中近年来发现了多处砂岩铜矿化点,笔者在总结含铜砂岩出露区地质特征、分析典型的矿化点特征的基础上,认为铜矿化发生在上二叠统忠什公组灰绿或灰白色砂岩与灰紫色砂岩交互带,受岩性、岩相控制明显,而铜质的来源为晚奥陶世隆起的北祁连造山带的风化产物,在盆地内三角洲沉积相中还原条件下,铜质富集沉淀,形成矿源层,在成岩过程中改造富集矿化。这些有利的成矿条件应该引起重视。

Analysis of geological characteristics of ore-forming and ore-controlling factors of sandstone type copper deposits in South Qilian Basin of Qinghai Province

Sandstone type copper mineralized points were found in the Permian strata which widely distributed in the South Qilian Basin in recent years. On the basis of summarized the characteristics of the cupriferous sandstone ＇s outcropped area,and of analyzed the characteristics of the typical mineralized points. The copper mineralization occurred on the mutual contact zone of grey green or gray sandstone interaction with grey purple sandstone in the Zhongshengong group of upper Permian series,and controlled by lithology and lithofacies. The sources of the copper were weathering products of North Qilian Orogenic belt which uplifted in Late Ordovician. Under the reducing condition of delta facies sediments in the basin,the copper enriched and deposited,formed the source bed. The enrichment of mineralization occurred in the process of diagenetic transformation. These favorable metallogenic conditions should be taken seriously.