“Rootless” serpentinite seamount on the southern Izu-Bonin forearc: Implications for basal erosion at convergent plate margins
- 1Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan
- 2Japan National Oil Corporation, 2-2-2 Uchisaiwai-cho, Chiyoda, Tokyo 100-8511, Japan
- 3Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan
Abstract
We use multichannel seismic reflection (MCS) and gravity data from the southern Izu-Bonin convergent plate margin to test for tectonic erosion. The Hahajima Seamount is a serpentinite seamount on the Izu-Bonin forearc. This serpentinite body likely originated from the mantle wedge beneath the Izu-Bonin arc, but it subsequently detached. MCS data and gravity modeling demonstrate that the Ogasawara Plateau on the incoming Pacific plate has been partly subducted beneath the Hahajima Seamount. Our analysis indicates that the Hahajima Seamount is a “rootless” serpentinite seamount, and the “root” of the serpentinite body was eroded during subduction of the western edge of the Ogasawara Plateau. Structural features of the Hahajima Seamount, the Ogasawara Plateau, and the Philippine Sea plate suggest that tectonic erosion, particularly basal erosion, has been occurring throughout this area.
- subduction
- serpentinite seamount
- seismic reflection data
- gravity modeling
- Izu-Bonin Trench
- basal erosion
Footnotes
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↵Loose insert: Figure 2 (see pdf). Common midpoint, stacked, migrated, and depth-converted multichannel seismic reflection data for profile D00-2.
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- Accepted February 21, 2004.
- Received November 8, 2003.
- Revision received February 20, 2004.
- Geological Society of America
