西太平洋岩石圈有效弹性厚度的空间分布与控制因素  

Spatial variations and controlling factors of the effective elastic thickness of the Western Pacific lithospheres

作　　者：刘文潇 李春峰[1,2] 朱塽 陆哲哲 吴招才 LIU WenXiao;LI ChunFeng;ZHU Shuang;LU ZheZhe;WU ZhaoCai(Department of Marine Sciences,Zhejiang University,Zhejiang Zhoushan 316021,China;Evalution and Detection Technology Laboratory of Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Shandong Qingdao 266237,China;Key Laboratory of Submarine Geosciences of Ministry of Natural Resources,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China)

机构地区：[1]浙江大学海洋科学系,浙江舟山316021 [2]青岛海洋科学与技术国家实验室,海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [3]自然资源部第二海洋研究所,自然资源部海底科学重点实验室,杭州310012

出　　处：《地球物理学报》2021年第6期1975-1986,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金重大研究计划重点项目(91858213);国家自然科学基金面上项目(41776057)联合资助.

摘　　要：西太平洋地区板块间相互作用强烈,热演化和构造演化过程复杂.为了揭示构造相互作用对岩石圈强度的影响,本文使用自由空气重力异常模型WGM2012和地形模型ETOPO1,基于小波变换的导纳法计算得到了该地区的岩石圈有效弹性厚度(Te).西太平洋区域的Te主要分布在5~85 km之间,南海等张裂环境地区Te普遍小于20 km,俯冲带附近Te一般大于80 km,与俯冲板片年龄呈正相关.参照平板冷却模型,弹性岩石圈底界面主要分布在200~500℃等温面之间,随洋壳年龄增大逐渐趋于平稳,热点及年轻洋壳部分地区弹性岩石圈底界面处于200℃等温面之上.西太平洋海山与年轻海盆等区域Te与居里点深度一般呈正相关,与地表热流一般呈负相关,但由于强烈的构造运动、热液循环、岩浆活动、地幔流变性等因素的影响,整体Te与居里点深度和地表热流所反映的岩石圈热结构相关性不高.The Western Pacific has strong tectonic interactions of several plates and has experienced complex thermal and dynamic evolution.The analysis of the effective elastic thickness of lithosphere(Te)helps better understand complex tectonic settings.Here we estimate spatial variations of Te by fan wavelet admittance between free-air gravity anomaly model WGM2012 and topography model ETOPO1.Te in the Western Pacific is mainly distributed in the range of 5~85 km.Low Te(less than 20 km)are distributed in young rifting/spreading areas such as the South China Sea.High Te(over 80 km)are found mainly near the subduction zones,and are correlated to the age of subducting plate.Referring to the plate cooling model,the bases of elastic lithospheres are mainly located between 200℃and 500℃isotherms,and gradually stablizes in depth as the oceanic crust ages.In many places,such as seamounts and young basins,Te is correlated positively with Curie point depth and negatively with surface heat flow.However,due to the strong tectonic activity,hydrothermal circulation,magmatic activities and mantle reology in the Western Pacific,the overall correlation between Te and lithospheric thermal proxies(Curie point depth and surface heat flow)is low.

关 键 词：岩石圈有效弹性厚度 西太平洋 导纳法 洋壳年龄 热结构 居里面 

分 类 号：P313[天文地球—固体地球物理学] P738[天文地球—地球物理学]