基于俯冲倾角的马里亚纳海沟挠曲模拟  

Deflection simulation of the Mariana Trench based on subduction dip angle

作　　者：彭祎辉 赵俐红[1,2] 凌子龙 李沐洁 ENNShinn Hway PENG Yihui;ZHAO Lihong;LING Zilong;LI Mujie;ENN Shinn Hway(Shandong University of Science and Technology,Qingdao 266590,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)

机构地区：[1]山东科技大学,青岛266590 [2]青岛海洋科学与技术试点国家实验室,青岛266237

出　　处：《海洋地质前沿》2022年第5期23-32,共10页Marine Geology Frontiers

基　　金：国家自然科学基金面上项目“北冰洋美亚海盆岩石圈的挠曲形变特征”(41676039)。

摘　　要：马里亚纳海沟是西太平洋“沟-弧-盆”构造体系的重要区域,对马里亚纳海沟特征的研究有助于了解海沟各部分间的形成演化差异。基于研究区的沉积物与水深数据,计算了海沟的初始俯冲倾角(β_(0))与轴线的挠曲(w_(0)),模拟了马里亚纳海沟岩石圈的挠曲,得到了马里亚纳海沟各段的岩石圈有效弹性厚度(Te)。模拟结果显示,马里亚纳海沟的挠曲位置约在40~125 km,挠曲幅度w_(b)约为60~840 m,有效弹性厚度约为5~40 km,初始俯冲倾角β_(0)约为0.5°~5°,轴线的挠曲w_(0)约为1.3~4.7 km,整体变化幅度较大;海沟中段的有效弹性厚度最高,南段的有效弹性厚度相对北段略高;海沟中段被大量不同规模的海山侵入,其挠曲幅度、有效弹性厚度、初始俯冲倾角与轴线的挠曲变化幅度都非常大;海沟南段的轴线挠曲很大,明显高于北段与中段,可能与Caroline洋脊的俯冲作用与Caroline热点的影响有关;俯冲初始倾角与有效弹性厚度、挠曲位置、轴线挠曲没有明显的相关关系。The Mariana Trench is an important area in the evolution of the trench arc basin tectonic system in the Western Pacific Ocean.The study of the characteristics of the Mariana Trench is helpful to understand the differences in the formation and evolution of the trench parts.Based on the sediment and water depth data in the study area,the initial subduction dip angle(β_(0))and the axis flexion(w_(0))of the trench were calculated,the lithospheric flexion of the Mariana Trench was simulated,and the lithospheric effective elastic thickness(Te)of the Mariana Trench was obtained.The results show that the flexural position of the Mariana Trench is about 40~125 km,the flexural amplitude w_(b) is about 60~840 m,the effective elastic thickness is about 5~40 km,the initial subduction Angleβ_(0) is about 0.5°~5°,and the flexural w_(0) of the axis is about 1.3~4.7 km.The effective elastic thickness of the middle trench is the highest,and the effective elastic thickness of the northern trench is slightly higher than that of the southern trench.The middle part of the trench is invaded by a large number of seamounts of different sizes,and the range of deflection,effective elastic thickness,initial subduction dip angle and deflection of axis are very large.The axial flexure of the southern segment of the trench is much higher than that of the northern segment and the middle segment,which may be related to the effect of the subduction of Caroline ridge and Caroline hot spot.There is no obvious correlation between the initial subduction dip angle and effective elastic thickness,deflection position and axis deflection.

关 键 词：初始俯冲倾角 挠曲 有效弹性厚度 马里亚纳海沟 

分 类 号：P313[天文地球—固体地球物理学]