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灰色片麻岩一这种英闪质—奥长花岗质成分的长英质岩石;广泛分布在由早前寒武纪岩石组成的地区。这类岩石占地球最古老岩石地段面积的50—80％;其中某些岩石经测定,年龄为36—38亿年。已知并经过研究的最老花岗岩类和英闪质—奥长花岗质片麻岩的地区,有科拉半岛、卡累利阿、加拿大地盾和拉布拉多半岛;在西格陵兰灰色片麻岩首次获得最老年龄;在明尼苏达、南非、圭亚那地盾和西澳大利亚花岗一绿岩区也发现了类似的岩石。很显然,
The gray gneiss, a type of English-flaccid-olivine granitoids, is a long quartzitic rock widely distributed in areas formed by early Precambrian rocks. Such rocks account for 50-80% of the area of the Earth’s oldest rock mass; some of these rocks have been measured at 3.6-38 billion years of age. Known and studied in the oldest granite and the British flaccid-authigenic granitic gneiss areas, the Kola Peninsula, Karelia, the Canadian Shield and the Labrador; gray tablets in West Greenland Gneiss was the oldest of its kind for the first time; similar rocks were found in Minnesota, South Africa, the Guyana shield and the granite-greenstone area of Western Australia. obviously,