中南部非洲金刚石矿床的成矿地质背景、成矿类型及矿床特征  

Metallogenic Geological Setting,Types and Characters of the Diamond Deposits in Central and Southern Africa

作　　者：许康康[1] 王杰[1] 任军平[1] 左立波[1] 刘晓阳[1] 何胜飞[1] 龚鹏辉[1] 孙凯[1] 刘宇[1] 贺福清[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所,天津300170

出　　处：《地质论评》2016年第2期362-374,共13页Geological Review

基　　金：中国地质调查局项目"非洲中南部重要矿床地质背景;成矿作用和找矿潜力研究"(编号:1212011220910)的成果~~

摘　　要：中南部非洲是世界上金刚石资源最为丰富的地区之一,其金刚石矿床主要产于津巴布韦克拉通和卡普瓦尔克拉通内,主要分为两种类型:①原生金刚石矿床;②次生金刚石矿床,且以原生金刚石矿床的研究程度较高,代表了中南部非洲的研究现状。本文通过总结前人研究资料发现,该地区的金伯利岩分为Ⅰ型和Ⅱ型,其内包体可以分为两种:橄榄岩型和榴辉岩型;金刚石可以分为三类:橄榄岩型、榴辉岩型及两者的过渡类型——二辉岩型。其中,橄榄岩型和部分榴辉岩型金刚石来自于地幔结晶堆晶体,而另一部分榴辉岩型则与板块俯冲的构造—热事件有关。金伯利岩的年龄主要分布于白垩纪、二叠纪、寒武纪及元古宙,而金刚石的年龄主要为元古宙和太古宙,金伯利岩和金刚石为不同时期的产物,金刚石为金伯利岩侵位期间捕获的上地幔物理破碎产物。其中900～1000Ma左右的金刚石为板块构造—热事件的产物,并对早期金刚石进行了改造破坏。次生金刚石矿床为原生矿床风化后的产物,可分为四种类型,构造特征、基岩地质及地貌演化等对该类矿床的分布具有重要的影响作用。Central and southern Africa is one of the regions with the richest diamond ore resources in the world. The diamond deposits predominantly occur in the Zimbabwe craton and Kaapvaal craton, there are two types： （1） the primary diamond deposits; （2） the secondary diamond deposits, the first type is highly studied and represents the status of central and southern Africa. Through summarizing the previous studies, this paper finds that the kimberlites of this area can be divided into two types： Ⅰ type and Ⅱ type, its enclaves include the peridotitic type and the eclogitic type. the diamonds have three types： the peridotitic type, the eclogitic type and the websteritic type wich is the transitional type of the former two. Among them, the peridotitic type and part of the eclogitic type diamonds derive from mantle cumulates, the rest of the eclogitic type diamonds have relations with a tectono thermal event which is plate subduction. The ages of the kimberlites are mainly Cretaceous, Permian, Cambrian and Proterozoic, but the ages of the diamonds are mainly Proterozoic and Archaean, therefore they generated at different times, the diamonds are the fragments of the upper mantle and taken by the kimberlites when they instrude and emplacement. The diamonds whose ages are 900~1000 Ma are the productions of a tectono thermal event, this event changed and destroyed the former diamonds. The secondary diamond deposites which have four types are the weathering products of the primary diamond deposits, structural characteristics, bedrock geology and geomorphic evolution and so on have an important influence for the distribution of them.

关 键 词：成矿地质背景 金伯利岩特征 金刚石特征 次生金刚石矿床 中南部非洲 

分 类 号：P619.241[天文地球—矿床学]