【摘要】 前人基于大洋玄武岩的放射成因同位素组成定义了DMM、HIMU、EM1和EM2等地幔端元组分。然而,自"EM1"这一概念被提出以来,有关其成因的激烈争论持续不断,EM1因此被认为是最"神秘莫测"的地幔组分。对比研究大洋和大陆板内的EM1型玄武岩可为探讨EM1组分的属性和成因提供新的制约。本文总结了笔者最近针对典型EM1型玄武岩的研究进展,比较了南太平洋EM1型洋岛玄武岩(Pitcairn)和中国东北EM1型钾质玄武岩的元素和Mg-Sr-Nd-Pb-Hf同位素地球化学特征,阐述了这两类EM1型玄武岩在成因上的联系和区别。更多还原

【Abstract】 Geochemists defined several mantle end-members including DMM, HIMU, EM1 and EM2, based on radiogenic isotopic compositions of oceanic basalts. However, since the concept of EM1 was proposed, the origin of EM1 has been intensively debated, and the EM1 is therefore considered to be the most enigmatic mantle component. The comparative study of typical EM1-type oceanic-and continental-intraplate basalts can provide new constraints on the nature and origin of EM1. In this paper, we summarize our recent research progress on typical EM1-type intraplate basalts, compared elemental and Mg-Sr-Nd-Pb-Hf isotopic geochemical characteristics between the EM1-type oceanic basalt from Pitcairn Island in South Pacific and the EM1-type potassic basalt from Northeast China, and then discuss the genetic relationship and difference between these two types of EM1 basalts.更多还原