澳大利亚维多利亚州的地洼构造及金矿成矿作用

对澳大利亚维多利亚州地区的研究表明。按沉积建造、变质建造、岩浆建造及构造型相、地球物理场、地球化学的特征标志分析,其演化史可区分出:前地槽、地槽、地台、地洼发展阶段,现阶段大地构造属性应为地洼区。侧重分析了该区的地洼构造以及金的成矿作用,地洼阶段的构造-岩浆活动,对先存于地槽构造层中的金改造、富集作用的结果,形成金的矿床,它们在空间上分布受地槽构造层限制,时间上受地洼阶段的制约。

CHARACTERISTICS OF GEOTECTONICS AND GOLD MINERALIZATION OF VICTOIRA, AUSTRALIA

With studying its sedimentary and magmatic formations, structural style, geophysical and geochemical characteristics, it has been shown that Victoria geotectonically is a diwa region. Its evolution history can be divided into four stages, pregeosynclinal, geosynclinal, platform and diwa.The Precambrian is a pregeosynclinal stage.Its representative structural layer is a nowhere exposed basement of sialic composition.The geosynclinal stage began in the early Cambrian and extended to the Middle Silurian. Its sedimentary formation consists predominantly of flysch turbidite and shale. Magmatic activity was intense and extensive. Tight folds and faults dipping steeply are the major structural style. Regional metamorphism was also intense.The platform stage was initiated in the Late Silurian and lasted to the Middle Devonian. Its Structural layer consists of marine sandstone, shale and limestone. Tectono-magmatic activity was weak and no regional metamorphism took place.This area stepped into the diwa stage in the Late Devonian. The diwa stage is lasting to the Quaternary. The sedimentary formation is composed of terrestrial clastics sorted poorly. Magmatic activity occurred intensely and extensively. Structures are eharacterized by block-faults. Contact metamorphism took place occasionally and no regional metamorphism occurred.Gold is the most interesting mineral type of Victoria. Gold deposits are formed by reforming and enriching the greenstone belts of geosynclinal structural layer by diwa teetonomagmatie activity. Therefore, gold deposits are spatially restricted to the geosynelinal structural layer and temporally controlled by the diwa stage.