Exhumation of serpentinized peridotite in the northern Manila subduction zone inferred from forward gravity modeling
Journal
Geophysical Research Letters
Journal Volume
42
Journal Issue
19
Pages
7977-7982
Date Issued
2015
Author(s)
DOI
GPRLA
Abstract
The Taiwan Integrated Geodynamic Research program (TAIGER) collected two wide-angle and reflection seismic transects across the northern Manila subduction zone that provide constraints on the seismic velocity structure of the crust. Two-dimensional gravity modeling along these two transects shows a significant, relatively high density (3.12 and 3.02 g/cm3) in the fore-arc region, at the interface between the subducting Eurasian Plate and the accretionary prism in front of the Luzon arc on the overriding Philippine Sea Plate. The anomalous density in this zone is higher than that in the fore-arc crust and the accretionary prism but lower than that in mantle. Numerous geophysical and geological data, together with numerical models, have indicated that serpentinization of the fore-arc mantle is both expected and observed. Serpentinization of mantle rocks can dramatically reduce their seismic velocity and therefore their seismic velocity in a density to velocity conversion. Therefore, the source of the high-density material could be serpentinized fore-arc mantle, with serpentinization caused by the dehydration of the subducting Eurasian Plate. We interpret that positive buoyancy combined with weak plate coupling forces in the northern Manila subduction zone is resulting in this serpentinized fore-arc mantle peridotite being exhumed. Key Points Two-dimensional gravity modeling shows a significant high-density structure in the fore-arc region Positive buoyancy and weak plate coupling result in serpentinized peridotite exhumed Exhumed serpentinized materials in the northern Manila subduction zone are found © 2015. American Geophysical Union. All Rights Reserved.
Subjects
Buoyancy; Geodynamics; Plates (structural components); Prisms; Seismic waves; Seismology; Velocity; exhumation; Gravity model; High-density structures; Seismic velocity structure; Serpentinization; Serpentinized peridotites; Subduction zones; Two-dimensional gravity; Tectonics; accretionary prism; Eurasian plate; exhumation; forearc basin; gravity field; oceanic crust; peridotite; seismic reflection; serpentinization; subduction zone; two-dimensional modeling; velocity structure; Luzon; Manila; National Capital Region; Pacific Ocean; Philippine Sea; Philippines; Taiwan
SDGs
Publisher
Blackwell Publishing Ltd
Type
journal article