摘要
岛弧岩浆是俯冲活动的重要产物,其增生速率是表征岛弧岩浆活动强度的重要指标.岛弧地壳增生过程受到俯冲倾角、汇聚速率、板块年龄等多个因素的协同影响,但是各个因素对岛弧地壳增生速率的影响规律尚不清晰.通过数值模拟,可以使得影响岛弧岩浆活动的各参数逐一变化,从而得到各个参数对岛弧地壳增生速率的影响规律.本文利用ASPECT软件,以运动学-动力学耦合的方式,建立变主控因素情形下的俯冲带演化模型,并综合考虑矿物脱水、水迁移、地幔熔融及熔体抽取等过程,模拟了岛弧地壳增生速率的演变.在本文数值模拟结果和前人对多个俯冲带研究成果相互印证的基础上,得到如下规律:(1)岛弧地壳增生速率随汇聚速率增加而变大.(2)俯冲倾角由30°递增到45°的变化区间中,岛弧地壳增生速率逐步增加;从45°继续增大到60°的变化区间中,岛弧地壳增生速率逐渐减少;(3)上覆板块年龄越大,岛弧地壳增生速率越小;(4)俯冲板块年龄从15 Myr增大到60 Myr的变化区间,岛弧地壳增生速率增大;从60 Myr进一步增大到105 Myr的变化区间,岛弧地壳增生速率减小.
Island arc magma is a primary product of the subduction process,and its growth rate serves as a key indicator of island arc magmatic intensity.The growth of island arc crust is influenced by various factors such as subduction dip angle,convergence rate,and plate age.However,the specific impact pattern of each factor on the island arc crustal growth rate remains unclear.Numerical simulations allow for systematic variation of each parameter affecting island arc magmatic activity to illustrate its individual influence on crustal growth rate.In this study,the subduction process was simulated using ASPECT,considering processes such as mineral dehydration,water migration,mantle melting,and melt extraction.Based on our simulations and previous research on multiple subduction zones,several trends were identified:(1)Increasing convergence rate is associated with higher island arc crustal growth rates.(2)The change in island arc crustal growth rates shows a gradual increase as the subduction angle increases from 30°to 45°.Beyond 45°up to 60°,there is a gradual decrease in the island arc crustal growth rates.(3)Older overriding plate age corresponds to lower island arc crustal growth rates.(4)Increasing the age of the subducting plate from 15 Myr to 60 Myr tends to increase the island arc crustal growth rate,while an age increase from 60 Myr to 105 Myr typically decreases the island arc crustal growth rate.
作者
张文昭
白永良
田佳浩
董冬冬
吴时国
刘远鹏
ZHANG WenZhao;BAI YongLiang;TIAN JiaHao;DONG DongDong;WU ShiGuo;LIU YuanPeng(College of Oceanography and Space Informatics,China University of Petroleum,Qingdao 266580,China;Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Laboratory of Marine Geophysics and Georesource,Institute of Deep-sea Science and Engineering,Chinese Academy of Sciences,Sanya Hainan 57200,China)
出处
《地球物理学报》
北大核心
2025年第8期3162-3173,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(92058213,42176068,42476063)资助.
关键词
岛弧岩浆
汇聚速率
俯冲倾角
上覆板块年龄
俯冲板块年龄
岛弧地壳增生速率
Island-arc magma
Convergence rate
Subduction dip angle
Overriding plate age
Subducting plate age
Island-arc crustal growth rate
