我国的第一批含金刚石金云火山岩──为贵州已知的含金刚石岩石正名  

The First Batch of Diamond-Bearing Lamproite in China: Renaming for the Known Diamond-Bearing Rocks in Guizhou

作　　者：罗会文 杨光树 盛学庸 

机构地区：[1]贵州地矿局101地质队,贵州地矿局科研所

出　　处：《贵州地质》1994年第1期8-26,共19页Guizhou Geology

摘　　要：重新研究贵州已知的含金刚石岩石表明，无论是其岩石学、矿物学和地球化学特征还是其产出的大地构造背景都与典型的金伯利岩不符，但却具有某些金云火山岩的典型特征，如：所含的大量镁铝榴石都不是金伯利岩特有的Ｇ１０，而是Ｇ９；岩石中含有属于金云火山岩所特有的白榴石、碱镁闪石及金伯利岩所不应有的长石类矿物；岩石不具金伯利岩所特有的圆斑结构等；贵州的大地构造背景与金伯利岩产出的典型背景不符，不是Ａ型克拉通，而是古老的环克拉通活动带（Ｔ型克拉通），与西澳含金刚石金云火山岩产出的背景相似。为此，笔者指出：贵州已知的含金刚石岩石应正名为金云火山岩；贵州具备金云火山岩型金刚石原生矿的成矿条件。进一步分析表明，贵州的某些地段在金刚石成矿后，还在一定程度上具备保存条件，这就给我省今后的金刚石找矿工作提供了前提。本文还进一步指出：有利的找矿部位是东西向的超壳断裂带，尤其是其中加里东期古地面上的后加里东盖层已遭剥蚀但该古地面所受剥蚀程度又不深的地段。The restudy for the known diamond-bearing rocks in Guizhou suggests that these rocks should be lamproites rather than kimberites, according to both the lithological minerological and geochemical characteristics and the tectonic setting of the occurence of these rocks.There are many features belonging to lamproite such as that all of the pyropes contained in the rocks are G9 but G10, there is no round-porhpyritic texture peculiar to kimberite, there are leucite, richterite which are typomophic minerals of lamproite and feldspar which shouldn't appears in kimberite, and so on.Tectonically, the setting of occurence of the rocks is a old mobile belt or T-type craton in which lamproite occurs, but not a A-type craton in which diamond-bearing kimberite occurs.Based on the above and the features of occurence of the known diamond-bearing rocks, the authors consider that these rocks should be renamed as lamproite rather than kimberite and point out that there is prospect for lamproite-type primary diamond deposits in Guizhou, especially on the E-W lithospheric fault zones.

关 键 词：金刚石 金云火山岩 火山岩 

分 类 号：P588.14[天文地球—岩石学]