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本文第一部分简述了巴西中东部主要太古宙地体的特征及其分布概况。现有资料表明,一些具有重要经济意义的太古宙金矿化皆局限于绿岩型岩层中,如巴西中东部的Sao Francisco克拉通及Jequie活动带和Goias活动带的金矿化。这种与绿岩带共生的矿化有两种不同的成因类型:①与含矿主岩紧密共生的层状同生矿床;②与热水溶液有关的受构造控制的表生矿床。对层状同生矿床的研究,包括对Iron Ouadrangle主要金矿山的详尽描述;在该区金矿化与各种类型的条带状含铁建造紧密共生。这种研究提供了与这些金矿化同生的喷气火山-沉积成因的明显的地质和地球化学证据。Rio Itapicuru绿岩带镁铁质变火山岩单元中的Faixa Weber矿体,及其他如产在Cri-xas绿碧带的小型金矿点。是表生金矿化的最好实例。
The first part of this paper briefly describes the characteristics and distribution of the major Archean terroids in central and eastern Brazil. Available data indicate that a number of economically significant Archean gold mineralizations are confined to greenstone formations such as the Sao Francisco craton and Jequie belts and the gold mineralization of the Goias belt in the central and eastern Brazil. There are two different genetic types of this mineralization associated with the greenstone belt: stratigraphic metaplasia closely interbedded with host ore; and structurally controlled epoch-related deposits related to hot water solution. The study of stratigraphic metaplasia, including a detailed description of the major Iron Ouadrangle gold mines, is where gold mineralization is closely interbedded with various types of banded iron-containing constructions. This study provides clear geological and geochemical evidence of the genesis of jet-volcano-sediment that coincides with these gold mineralizations. Faixa Weber ore bodies in the mafic volcanic units of the Rio Itapicuru greenstone belt and other small gold mines, such as the green belt of Cri-xas. Is the best example of epigenetic gold mineralization.