Erosion and sedimentation as processes controlling the BSR-derived heat flow on the Eastern Nankai margin

被引:45
作者
Martin, V
Henry, P
Nouzé, H
Noble, M
Ashi, J
Pascal, G
机构
[1] Ecole Normale Super, Geol Lab, UMR 8538, F-75231 Paris 05, France
[2] IFREMER, Dept Geosci Marines, F-29280 Plouzane, France
[3] Ecole Mines, Ctr Rech Geophys, F-77305 Fontainebleau, France
[4] Univ Tokyo, Ocean Res Inst, Nakano Ku, Tokyo 1648639, Japan
关键词
bottom-simulating reflector; heat flow; surface processes; Eastern Nankai margin;
D O I
10.1016/j.epsl.2004.02.020
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
In 2000, a 3D MCS survey was carried out on the Eastern Nankai Trough. A strong and widespread bottom-simulating reflector (BSR) was observed and mapped after a preserved amplitude 3D prestack migration of the seismic data. We use this BSR to calculate a heat flow map over the 3D survey area. This map presents some high and low heat flow areas, that cannot be correlated to known active wedge faults and previously observed fluid venting sites. Since the heat flow anomalies are not correlated to known major faults or fluid venting sites, large fluid circulation is not likely to explain the varying BSR-derived heat flow distribution. In order to explain this heat flow distribution quantitatively, we calculate the rates of erosion and sedimentation that are necessary to create these anomalies. These rates are in good agreement with observations on seismic profiles, and are locally consistent with a sedimentation rate calculated from slope basin depth, and reflect the distribution of erosion, landsliding and deposition on the margin slope. We therefore propose that the observed BSR-derived heat flow anomalies are mainly due to active erosion and sedimentation, and that heat flow distribution on the margin section of the 3D survey is controlled by surface processes. Fluid migration could occur where a BSR is absent, but is probably episodic or limited where a BSR is present, and does not affect the BSR-derived heat flow in this part of the margin. These surface processes are the consequence of the tectonic and seismic activity of the wedge and are influenced by the subduction of a wide oceanic ridge below the Eastern Nankai margin. (C) 2004 Elsevier B.V. All rights reserved.
引用
收藏
页码:131 / 144
页数:14
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