软流圈地幔成分不均一性的研究进展与意义  

Compositional heterogeneity of the asthenosphere:Advancement and implications

作　　者：刘传周[1,2] 杨阳 刘博达[1] 刘通 LIU ChuanZhou;YANG AlexandraYang;LIU BoDa;LIU Tong(State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Ocean and Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510301,China)

机构地区：[1]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049 [3]中国科学院广州地球化学研究所边缘海与大洋地质重点实验室,广州510301

出　　处：《岩石学报》2022年第12期3712-3734,共23页Acta Petrologica Sinica

基　　金：国家杰出青年基金项目(42025201)资助.

摘　　要：软流圈通常是指位于岩石圈之下、地幔过渡带之上的地幔圈层,可以发生长期缓慢变形,从而可以在全球范围内对流。软流圈是地球上岩浆岩的重要源区,并作为重要的参考体系广泛应用于讨论地球形成演化、壳幔相互作用、地壳生长等一系列重大地质问题。根据大洋玄武岩的研究结果,软流圈地幔被普遍认为具有相对均一的地球化学组成。然而,深海橄榄岩的元素与同位素组成却显示软流圈的成分存在强烈的不均一性。大量的研究显示软流圈中广泛残存有古老的再循环地幔,其来源既包括再循环的俯冲大洋岩石圈地幔,也包括通过不同方式进入软流圈的古老克拉通地幔。蛇绿岩的研究结果表明这种不均一性也同样存在于不同地质时期的软流圈地幔。本文通过总结洋中脊玄武岩、深海橄榄岩和蛇绿岩的相关研究,揭示软流圈地幔中不均一性的组成与来源,并讨论了它们对于软流圈在洋中脊下方熔融过程的影响。Asthenosphere is the mechanically weak and ductile region of Earth s upper mantle,which lies beneath the lithosphere and extends as deep as the mantle transition zone.Its global convection is responsible for driving tectonic movement of the plates.The asthenosphere is an important source of magmatic rocks on the Earth and has been regarded as essential reference reservoir applied to discussion on significant geological issues,such as Earth s formation and evolution,crust-mantle interaction,and crustal growth.Previous studies on oceanic basalts have proposed that the asthenosphere is relatively homogeneous in composition.Nevertheless,compositions of abyssal peridotites have shown that the asthenosphere is strongly heterogeneous.Numerous studies have shown that ancient mantle domains are ubiquitous within the asthenosphere,which could be originated from the recycled oceanic mantle and cratonic mantle dislodged through different mechanisms.Such compositional heterogeneities of the asthenosphere have been widely documented in global ophiolites of different ages.This paper summarized the relevant studies on mid-ocean ridge basalts,abyssal peridotites and ophiolites to disclose various origins of the mantle heterogeneities of the asthenosphere.Effects of these heterogeneities on partial melting of asthenosphere beneath mid-ocean ridges have also been discussed.

关 键 词：软流圈地幔 洋中脊玄武岩 深海橄榄岩 蛇绿岩 

分 类 号：P542.5[天文地球—构造地质学] P595[天文地球—地质学]