The Source of old terrestrial rocks：evidence from 146Sm-142Nd isotopes of Archean rocks

Abstract：Through the construction of the 146Sm-142Nd system and the application of Hadean(4.6～4.0Gy)mantle evolution,we can get to know the evolutionary process of this early epoch. Based on the 142Nd study of Archean rocks,the authors hold that early mantle was an inhomogeneous system because of the mantle differentiation. Canadian Nuvvuagittug greenstone originated from the mixture of enriched and depleted mantle, with the enriched mantle playing the dominant role. Greenland mixtite and Isua metamorphosed sediments originated from depleted mantle whereas North Australian Yilgam gneiss origineted from the mixture of enriched and mantle, with the depleted mantle being dominant.