地球上古老岩石的来源:基于太古宙岩石^(146)Sm-^(142)Nd同位素证据  

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

作　　者：皮桥辉[1] 陈岳龙[1] 李泳泉[1] 刘雪敏[1] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《中国地质》2010年第1期88-93,共6页Geology in China

基　　金：国家自然科学基金项目(40673046;40234052)资助

摘　　要：通过构筑146Sm-142Nd同位素体系,应用于冥古宙(4.6～4.0Ga)时期地幔演化的研究,可以了解这一时期地幔演化过程。对太古宙岩石中142Nd的研究发现早期地幔出现明显的不均一性,造成这种不均一性的原因应该来源于地幔的分异作用。加拿大Nuvvuagittuq绿岩带来源于富集地幔和亏损地幔混合,但以富集地幔为主,格陵兰杂岩和变质砂岩来源于亏损地幔,而西澳大利亚伊儿岗片麻岩来源于富集地幔和亏损地幔的混合带,但主要以亏损地幔为主。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 Nuvvuagittuq 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 originated from the mixture of enriched and depleted mantle,with the depleted mantle being dominant.

关 键 词：早期演化 太古宙 146Sm-142Nd同位素 

分 类 号：P597.3[天文地球—地球化学]