南美洲大型-超大型金矿地质特征与成矿作用研究

摘要

金是南美洲仅次于铜的优势矿种,据美国地质调查局统计,2016年秘鲁金矿储量2800 t,巴西金矿储量2400 t,智利仅公布到2014年金矿储量3900 t.通过对南美安第斯成矿带和南美地台金矿地质背景分析,根据对31个大型-超大型金矿的综合研究,剖析斑岩型、浅成低温热液型、IOCG型、造山型等不同类型金矿床的时空分布、地质特征,梳理重要成矿区特征,摸清区域构造岩浆-成矿作用演化的关系,为以后在南美洲金矿的勘查开发提供科学依据.在安第斯成矿带,金成矿作用与太平洋板块向南美大陆板块的俯冲密切相关,大型-超大型金矿类型主要是以浅成低温热液型,以及与铜共生的斑岩型、IOCG型矿床为主,大规模金成矿作用集中在新生代,形成了众多世界著名的金矿床.南美地台成矿带位于亚马孙陆块边缘,受古元古代(2.5~1.8 Ga)Trans-Amazonian旋回影响,经历了反复俯冲造山运动,大型-超大型金矿以造山带型金矿为主,主要成矿期在太古宙—新元古代.南美的金资源相当丰富,未来具有巨大的勘查开发潜力.%Gold is a dominant mineral species in South America, whose importance is only second to that of copper. According to gold reserves statistics from the USGS, the gold reserves were 2800 tons in Peru and 2400 tons in Brazil in 2016, and 3900 tons in Chile in 2014. The main 31 large and superlarge gold deposits were comprehensively studied in this paper on the basis of the geological background analysis of gold deposits in South American Andean metallogenic belt and South American platform. The spatial and temporal distribution and geological characteristics of gold deposits, such as porphyry copper-gold deposits, epithermal gold deposits, IOCG gold deposits, and orogenic gold deposits, were analyzed in detail. The authors rearranged the characteristics of the metallogenic region and found out the relationship between regional tectonic magmatic and mineralization evolution, with the purpose of providing scientific basis for future exploration and exploitation of gold mines in South America. In the Andean metallogenic belt, the gold mineralization was closely related to the subduction of the Pacific plate to the South American Plate. The large and superlarge gold deposits are mainly porphyry copper-gold deposits, epithermal gold deposits, IOCG gold deposits and so on. The main gold mineralization is concentrated in the new generation, forming a number of famous gold deposits in the world. In the South America platform,the gold metallogenic belt is located at the edge of the Amazonian block and was influenced by the Trans-Amazonian cycle in Paleoproterozoic (2.5-1.8 Ga) , which had undergone repeated subduction and orogeny. The large and superlarge gold deposits are main orogenic gold deposits. The metallogenic period is mainly the Archean-Late Proterozoic period. The gold resources are quite rich in South America, and it has great potential for exploration and exploitation in the future.