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Revisiting the structure, age, and evolution of the Wharton Basin to better understand subduction under Indonesia.

DRS at CSIR-National Institute of Oceanography

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Title Revisiting the structure, age, and evolution of the Wharton Basin to better understand subduction under Indonesia.
 
Creator Jacob, J.
Dyment, J.
Yatheesh, V.
 
Subject Plate tectonics
Subduction zone
 
Description Understanding the subduction processes along the Sunda Trench requires detailed constraints on the subducting lithosphere. We build a detailed tectonic map of the Wharton Basin based on reinterpretation of satellite-derived gravity anomalies and marine magnetic anomalies. TheWharton Basin is characterized by a fossil ridge, dated ~36.5Ma, offset by N-S fracture zones.Magnetic anomalies 18 to 34 (38–84 Ma) are identified on both flanks, although a large part of the basin has been subducted. We analyze the past plate kinematic evolution of the Wharton Basin by two-plate (India-Australia) and three-plate (India-Australia-Antarctica) reconstructions. Despite the diffuse plate boundaries within the Indo-Australian plate for the last 20 Ma, we obtain finite rotation parameters that we apply to reconstruct the subducted Wharton Basin and constrain the thickness, buoyancy, and rheology of the subducting plate. The lower subductability of younger lithosphere off Sumatra has important consequences on the morphology, with a shallower trench, forearc islands, and a significant inward deviation of the subduction system. This deviation decreases in the youngest area, where theWharton fossil spreading center enters subduction: The discontinuous magmatic crust and serpentinized upper mantle, consequences of the slow spreading rates at which this area was formed, weaken the mechanical resistance to subduction and facilitate the restoration of the accretionary prism. Deeper effects include the possible creation of asthenospheric windows beneath the Andaman Sea, in relation to the long-offset fracture zones, and east of 105°E, as a result of subduction of the spreading center.
 
Date 2014-04-07T08:58:02Z
2014-04-07T08:58:02Z
2014
 
Type Journal Article
 
Identifier Journal Of Geophysical Research: Solid Earth, vol.119; 2014; 169–190
http://drs.nio.org/drs/handle/2264/4502
 
Language en
 
Rights An edited version of this paper was published by AGU. Copyright [2014] AGU. To view the published open abstract, go to http://dx.doi.org/10.1002/2013JB010285
 
Publisher American Geophysical Union