南美洲铁矿重要成矿区带与成矿规律研究

A study of key metallogenetic zones and principal metallogeic regularities of iron ore resources in South American countries

南美洲铁矿资源丰富、分布广泛、矿床规模大、矿石品位高、类型较齐全。从南美洲大地构造格架分析,分布在克拉通地盾区或其边缘的沉积-变质型铁矿和分布在安第斯海岸造山带的火山成因型铁矿最为重要,沉积-变质型铁矿主要形成于太古宙—元古宙,火山成因型铁矿主要形成于中新生代。综合研究分析,圈出10个铁矿重要成矿区带,主要分布在委内瑞拉的玻利瓦尔州,巴西的阿马帕州、帕拉州、米纳斯吉拉斯州、北里奥格兰德州、巴拉伊巴州、巴伊亚州、南马托格罗索州,玻利维亚的圣克鲁斯州,秘鲁的伊卡—阿雷基帕海岸带和智利的卡拉马—圣地亚哥海岸带等。通过对重要成矿区带内典型矿床的剖析,并采用统计分析方法总结南美洲铁矿成矿时空分布规律,为未来在该区寻找更多的铁矿资源提供参考。

South America is rich in iron ore resources,which are characterized by widely distributed world-class iron deposits,high grade of orebodies,and a variety of deposit types.An analysis of tectonic framework of South America shows that the most important types of iron deposits include sedimentary metamorphic type which is distributed in cratonic shield area and its edge,and volcanic origin type which is distributed in Andean coastal orogenic belt.The former mainly formed in the Archean Proterozoic,whereas the latter mainly formed in Mesozoic and Cenozoic.The results of comprehensive studies show that10important iron metallogenic zones can be delineated:Bolivar iron zone of Venezuela,Amapa iron zone of Brazil,Para iron zone of Brazil,Minas gerais iron zone of Brazil,Rio Grande do Norte iron zone of Brazil,balaiba iron zone of Brazil,Bahia iron zone of Brazil,Mato Grosso do Sul iron zone of Brazil,Santa Cruz iron zone of Bolivia,Ika-Arequipa iron zone of Peru,and Calama-Santiago coastal iron zone of Chile.Based on an analysis of typical deposits in important metallogenic zones and statistical analysis methods,the authors have summarized the temporal and spatial distribution regularities of iron mineralization in South America with the purpose of providing references so as to find more iron ore resources in this area in the future.