南美洲圭亚那地盾北部绿岩带地质特征、典型金矿床及金成矿作用

圭亚那地盾位于南美洲亚马孙克拉通的北部,其北部广泛发育太古宙典型的花岗岩-绿岩带,主要岩石组成为花岗岩、片麻岩和英云闪长岩,古元古代变质超基性-基性火山岩-侵入岩、其他变质火山岩等。由于独特的地质构造位置和复杂的构造演化历史,形成了良好的绿岩型金成矿地质背景,产生了大量的金矿床。通过总结圭亚那地盾北部绿岩带的岩石特征、成岩时代和构造演化历史,对委内瑞拉埃尔卡劳金矿、圭亚那欧迈金矿和苏里南罗瑟贝尔金矿进行典型矿床剖析,系统研究了该区绿岩带型金矿的成矿地质背景、成矿流体及成矿年代学特征,建立了区域绿岩带型金矿成矿模型,并在分析找矿要素的基础上,提出圭亚那地盾北部的金矿找矿方向。

Geological features of greenstone belt, typical gold deposits and gold mineralization in northern Guiana shield, South America

Guiana shield is located in the north of Amazon Craton, South America. Typical Archean granite-greenstone belt is developed extensively in the north part of Guiana shield. The rocks mainly include granite, gneiss, tonalite, Paleoproterozoic metamorphic ultrabasic-basic volcanic rock-intrusive rock and some other metavolcanic rocks. Guiana shield has a good geological background of greenstone-gold mineralization due to its unique tectonic position and complex tectonic evolution history. This paper provides a guideline for gold mine exploration in northern Guiana shield through a typical ore deposit analysis of Venezuela El Callao, Guiana Omai and Surinam Rosebel by Summarizing petrological features of Guiana greenstone belt in northern shield, petrogenic epoch as well as its tectonic evolutionary history. In addition, the authors made a systematic study of the metallogenic geological background of greenstone-gold deposit, ore-forming fluid, metallogenic chronology, and established a mineralization model for greenstone-gold mine. Exploration guides for gold deposits of Guiana shield are put forward based on the analysis of the ore-prospecting elements.