纳如松多矿集区电性结构特征及对成矿作用的约束

Electrical Structure of Narusongduo Ore Concentration District and Its Constraints on Mineralization

为了研究西藏纳如松多矿集区的电性结构特征和对成矿作用的约束,对覆盖矿集区的大地电磁测深数据进行全面的数据处理分析,得到了可靠的二维电性结构模型.研究结果表明,分别在深度为40~50 km,20~30 km和10 km处见高导体,推测这些高导体可能为部分熔融和水流体共同所致.由于纳如松多矿集区内矿床为岩浆-热液型,深部岩浆的上涌在成矿作用中起到关键作用,所以壳内高导体可能为与成矿有关岩浆房的电性痕迹,将这些高导体连起来可能代表着深部热液向上运移的古通道.电性结构主要体现了壳内高导体与区域成矿动力作用的关系,向上运移的富矿岩浆也可能通过局部的隐伏构造运移到Pb-Zn和Fe-Cu矿床的位置,再演化形成矿体.

To understand the electrical structure in Narusongduo ore concentration district in the Tibetan Plateau and its constraints on mineralization, the magnetotellurics data in the district were carefully processed and analyzed, obtaining a reliable 2-D electrical model. The study shows that there are some conductors at depths of about 40-50 km, 20-30 km and 10 km, which may be resulted from the partial melting and aqueous fluids. As the deposits in the district belong to the magmatic-hydrothermal type, and the upwelling deep-seated magma played an important role in the mineralization, the crustal conductors may offer constraints to the ore-related magma reservoirs, and connecting these conductors also may represent the ancient ascending channels. The electrical structure indicates the relationship between the crustal conductors and the regional metallogenic dynamics in our study. The ascending ore-bearing magma also may migrate to the Pb-Zn and Fe-Cu locations by the local hidden structures, and subsequently evolved into the ore body.