地球早期大陆地壳的形成与演化  

The origin and evolution of Earth's oldest continental crust

作　　者：樊海龙 杨高学[3] 郭建明 马雪云 刘翔 FAN Hailong;YANG Gaoxue;GUO Jianming;MA Xueyun;LIU Xiang(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an,710069;Key Laboratory of Road Construction Technology and Equipment,Ministry of Education,School of Construction Machinery,Chang’an University,Xi’an,710064;Ministry of Education,Key Laboratory of Western China’s Mineral Resources and Geological Engineering,School of Earth Science and Resources,Chang’an University Xi’an,710054;Key Laboratory of Petroleum Resources,Gansu Province,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou,730000;The Second Monitoring and Application Center,China Earthquake Administration,Xi’an,710054)

机构地区：[1]大陆动力学国家重点实验室,西北大学地质学系,西安710069 [2]道路施工技术与装备教育部重点实验室,长安大学工程机械学院,西安710064 [3]西部矿产资源与地质工程教育部重点实验室,长安大学地球科学与资源学院,西安710054 [4]甘肃省油气资源研究重点实验室,中国科学院西北生态环境资源研究院,兰州730000 [5]中国地震局第二监测中心,西安710054

出　　处：《地质论评》2023年第2期669-690,共22页Geological Review

基　　金：国家自然科学基金资助项目(编号:41872226、41303027);陕西省自然科学基础研究计划(编号:2022JM-249)的成果。

摘　　要：现代地球岩石圈主要由镁铁质上地幔和长英质地壳两个储集层组成,研究大陆地壳的形成和演化对揭示地球早期地质过程和物质循环、厘定板块构造启动时限具有重要意义。冥古宙—始太古代具有更高的地幔潜能温度和地温梯度,岩浆海冷却形成薄的原始地壳;大洋岩石圈表现为韧性,主要构造机制应为停滞盖层模式,有地幔柱参与。太古宙片麻岩中奥长花岗岩—英云闪长岩—花岗闪长岩(TTG)的出现标志着镁铁质原始地壳向长英质陆壳转变的开始。本文总结了地球早期停滞盖层模式到现代板块构造模式下含水玄武岩部分熔融、结晶分异形成大陆地壳的过程,主要包含幔源岩浆停滞盖层(“自下而上”的热管火山岩和“自上而下”的深成侵入岩构造模式)、增厚镁铁质地壳部分熔融、俯冲洋壳、岛弧及洋底高原部分熔融模式;陆壳的破坏和消减主要受陨石撞击、分层沉降、重力不稳导致拆沉控制;板块构造的出现进一步促进了地球内部的热量扩散,俯冲作用加快了洋壳和陆壳之间的物质循环。最后,结合太古宙变质岩、古老克拉通岩石学特征和锆石Hf、O及全岩Nd、Sr、Ar、Ti同位素组成,讨论了陆壳的形成时间和演化过程:3.0 Ga之前形成了现有陆壳体积的60%~70%,厚度约为20~40 km;3.0~2.5 Ga,地壳改造速率明显增加,陆壳生长和破坏速率达到动态平衡,表明全球性现代板块构造体制逐渐成为控制大陆形成、裂解和陆壳演化的主要因素。The Earth is currently comprised of two major silicate reservoirs,the upper mantle lithosphere is ultramafic in composition,whereas the crust has undergone varying degrees of differentiation and is mafic to felsic in composition.The continental crust provides an important material basis for revealing the geological process and understanding earth history,as well as determining the starting time of plate tectonics.The Archean gray gneiss is mainly characterized by trondhjemite—tonalite—granodiorite( TTGs),and the formation of TTG suite marks the beginning of the transformation from mafic proto-crust to felsic continental crust.This paper reviews the process of partial melting and crystallization differentiation of hydrated basalts to form rigid continental crust.The continental crust growth model mainly includes mantle derived magma stagnant-lid,partial melting of thickened mafic crust,subducted oceanic crust,island arc and ocean floor plateau,whereas the destruction and cycle of continental crust are mainly predominated by meteorite impact,delamination and layered subsidence caused by gravity instability.Plate tectonism further promotes the heat diffusion in the earth,and subduction accelerates the material circulation between oceanic crust and continental crust.Even though less than 10% of the Archean rocks have been preserved today,it is widely accepted that at least 60% ~ 70% of the continental crust formed by the end of the Archean.The evidence of Hf,O isotopes in zircon,Nd,Sr,Ar,Ti isotopes in whole rocks,and Archean craton geological characteristics indicate that the reduction in crustal growth at ca.3 Ga is attributed to an increase in the rates at which differentiated continental crust was destroyed,and that coupled with the other changes at the end of the Archean are taken to reflect the onset of plate tectonics as the dominant global regime.

关 键 词：大陆起源 陆壳演化 部分熔融 板块构造 地幔潜能温度 TTG岩系 

分 类 号：P542[天文地球—构造地质学]