关于冀西北孔达岩系时代的新认识  

A new knowledge of the Khondalites in northwestern Hebei

作　　者：杨书桐 胡受奚 

出　　处：《地层学杂志》1993年第3期228-231,共4页Journal of Stratigraphy

摘　　要：八十年代下半期前,在我国对早前寒武系地层(>1850Ma),如“太华群”、“登封群”、“胶东群”、“阜平群”和“桑干群”等常笼统地划归太古宙,从而造成早元古宙(2550—1850Ma)地层的“空缺”和混乱。如果我们将富有特征和能反映大气圈、水圈。In northwestern Hebei occurred a suit of amphibolite and granulite-facies khondalites consisting of pelitic paragneisses with intercalated marbles and graphlites. Previously they were ascribed to the middle-early Archean, however, on the basis of geological, geochemical (i.e. LILE, HFSE, FME and REE) and geochronological (l.e.zircon U-Pb isochron)data, the khondalites were formed at ca. 2.1 Ga, marking asharp change in atmospheric, biospheric and hydrospheric conditions.

关 键 词：孔达岩 片麻岩 时代 冀西北 

分 类 号：P588.345[天文地球—岩石学]