Mantle Flow Deflected by Arc–Continent Collision and Continental Subduction in Eastern Indonesia

Author:

Harris Cooper W.1ORCID,Miller Meghan S.2ORCID

Affiliation:

1. Department of Earth Science, University of Southern California, Los Angeles, California, U.S.A.

2. Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia

Abstract

Abstract We investigate seismic anisotropy across southeastern Indonesia where the Indo-Australian plate subducts beneath and collides with the Sunda-Banda arc. Geochemical, geodetic, and tomographic studies reveal an along-strike transition from oceanic subduction to continental subduction and collision near central Flores that is due to a change of lithospheric composition in the subducting plate. To investigate the anisotropic fabric and dynamics of the upper mantle surrounding this young (∼5 Ma) arc–continent collision, we perform shear wave splitting analysis on local and teleseismic S waves recorded by an array of broadband seismometers that crosses the subduction–collision boundary. Seismic anisotropy inferred from our local S dataset shows that anisotropic sources above the slab extend to depths exceeding 100 km. Analysis of teleseismic SKS and SKKS waves reveal a shift in subslab fast axes from trench-parallel to trench-perpendicular near the ocean–continent boundary in the lower plate, which we relate to regional subslab mantle flow being deflected around the subducted continental lithosphere. Along-strike variations in anisotropic fast axes from teleseismic phases overlap with distinct structural and tectonic boundaries that divide distinct regions of the collision, implying the effects of the collision transcend any one dataset and highlighting the complexity of collisional boundaries. These results shed light on the interaction between tectonic structure and mantle dynamics in an emergent collision, and help constrain the nature of upper mantle deformation in the early stages of collision.

Publisher

Seismological Society of America (SSA)

Subject

Geophysics

Reference146 articles.

1. Geochronology of some Banda Arc volcanics;Abbot,1981

2. Geological evidence for the geographical pattern of mantle return flow and the driving mechanism of plate tectonics;Alvarez;J. Geophys. Res.,1982

3. Amaru M. L. 2007. Global travel time tomography with 3-D reference models, Ph.D. Thesis, Utrecht University, Utrecht, Netherlands.

4. Subduction and eduction of continental crust: Major mechanisms during continent-continent collision and orogenic extensional collapse, a model based on the south Norwegian Caledonides;Andersen;Terra Nova,1991

5. The geology of Portuguese Timor;Audley-Charles;Geol. Soc. Lond. Mem.,1968

Cited by 3 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3