Regional metallogenic structure based on aeromagnetic data in northern Chile

基于航磁资料揭示智利北部区域成矿构造（英文）

Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic- magmatic activities that migrate eastward and the types of mineral resources. In this paper, we processed and interpreted aeromagnetic data from northern Chile using reduction to pole, upward field continuation, the second derivative calculation in the vertical direction, inclination angle calculation, and analytical signal amplitude analysis. We revealed the locations and planar distribution characteristics of the regional deep faults along the NNE and NS directions. Furthermore, we observed that the major reasons for the formation of the tectonic-magmatic rocks belts were the nearly parallel deep faults distributed from west to east and multiple magmatic activities along these faults. We ascertained the locations of volcanic mechanisms and the relationships between them using these regional deep faults. We deduced the spatial distributions of the basic-intermediate, basic, and acidic igneous rocks, intrusive rocks, and sedimentary sequences. We showed the linear positive magnetic anomalies and magnetic anomaly gradient zones by slowly varying the background, negative magnetic anomaly field, which indicated the presence of strong magmatic activities in these regional deep faults; it also revealed the favorable areas of copper and polymetallic mineralization. This study provides some basic information for further research on the geology, structural characteristics, and mineral resource prospecting in northern Chile.

智利是安第斯成矿带最重要的矿业国家之一,智利北部阿卡塔玛和东部多明戈断裂系统控制了智利自西向东迁移的构造—岩浆活动和成矿类型。本文对智利北部航磁数据进行网格化、化极、向上延拓、垂向二次导数、倾斜角以及解析信号振幅处理,并对处理结果进行解释,揭示了研究区沿北北东向和南北向区域性深大断裂构造的位置和平面分布特征,确定了自西向东近于平行的断裂构造和多次岩浆活动是导致构造—岩浆岩分带性的主要原因;查明了研究区火山机构的分布位置及其与深大断裂的关系;推断了基性—中基性和酸性火山岩层、侵入岩相以及沉积岩序列分布的空间范围;展示了在低缓的背景负磁异常场上发育了线性正磁异常和磁异常梯级带,反映了沿深大断裂产生了强烈的岩浆岩活动,揭示了铜、多金属成矿的有利区带,为智利北部地区的地质、构造特征研究以及找矿远景区的圈定提供了基础性信息。