津巴布韦太古宙花岗-绿岩型金矿类型与资源潜力

Gold mineralization types and resources potential of the Archaean granitiod-greenstone belts in Zimbabwe

津巴布韦太古宙花岗-绿岩型金矿床受构造的控制,金矿可分为褶皱控矿型、剪切带控矿型、层控型、深成花岗岩控矿型和构造-蚀变岩型等5类。津巴布韦花岗-绿岩型金矿多产于花岗质片麻岩与绿岩带的接触带上,金以自然金或金的硫化物形式产出。金矿成矿时代大致分为(2 660±50)Ma和(2 410±70)Ma(米德兰德绿岩带北部白钨矿Sm-Nd测年)2个时段,分别与新太古代TTG事件和大岩墙侵入相关。津巴布韦花岗-绿岩型金矿较多,但发现的中-大型绿岩型金矿较少,具有较好的金矿找矿前景。

Gold mineralization in the Archaean granitiod-greenstone belts of the Zimbabwe Craton is controlled by structure and can be divided into fold-control,shearing zone-control,stratabound,plutonic granite-control and cataclastic altered rock types.Gold deposits in the Archaean granitiod-greenstone belts occur generally at contact of the granitic gneiss and the greenstone belt.Gold occurs in native gold or sulfides.Sm-Nd age dating of scheelites in the north Midlands green stone belt is distinctly at two intervals of 2.66±0.05 Ga and 2.41±0.07 Ga related to the late Archean TTG events and the Great Dyke intrusion respectively.The Archaean granitiod-greenstone belts are scattered with many gold deposits and potential for further prospecting.