The University of Southampton
University of Southampton Institutional Repository

Deformation and in situ stress in the Nankai Accretionary Prism from resistivity-at-bit images, ODP Leg 196

Deformation and in situ stress in the Nankai Accretionary Prism from resistivity-at-bit images, ODP Leg 196
Deformation and in situ stress in the Nankai Accretionary Prism from resistivity-at-bit images, ODP Leg 196
Borehole resistivity images from ODP Leg 196 allow rapid and complete qualitative assessment of deformation within the toe of the Nankai prism, Japan. Borehole breakouts were common within the prism but prominent in the trench-wedge unit around the frontal thrust, suggesting reduced sediment strength. Breakouts indicate consistent ?2 orientations (?050°), compatible with northwesterly convergence. Deformation is dominated by discrete zones, including the frontal thrust and décollement zone. Prism fractures trend ?NE–SW, consistent with convergence. The décollement shows minimal deformation and the dominant structural trend is ?N–S. Prism deformation zones are characterized by high resistivity (compaction), whereas the décollement is apparently dilated, both with conductive fractures. Distribution of fracture orientations varies between log units confirming lithologic and rheologic influence. Pore pressure is elevated within the décollement and the misalignment of conductive fractures may reduce permeability.
0094-8276
L02602
McNeill, L.C.
1fe6a1e0-ca1a-4b6f-8469-309d0f9de0cf
Ienaga, M.
77202d6e-8ba3-4aa4-915c-2bf7e5624c81
Tobin, H.
5d03d688-2ef4-4d95-adf9-1cbc91ad788b
Saito, S.
5a819d3c-9621-43ed-83a3-d326c2575e57
Goldberg, D.
c02ac60f-1414-492c-8d4c-4f5a7670c8fe
Moore, J.C.
9be1ffee-43da-4991-a287-241f7b6367ca
Mikada, H.
9bdd1768-af85-4c77-a40a-080f372b2296
McNeill, L.C.
1fe6a1e0-ca1a-4b6f-8469-309d0f9de0cf
Ienaga, M.
77202d6e-8ba3-4aa4-915c-2bf7e5624c81
Tobin, H.
5d03d688-2ef4-4d95-adf9-1cbc91ad788b
Saito, S.
5a819d3c-9621-43ed-83a3-d326c2575e57
Goldberg, D.
c02ac60f-1414-492c-8d4c-4f5a7670c8fe
Moore, J.C.
9be1ffee-43da-4991-a287-241f7b6367ca
Mikada, H.
9bdd1768-af85-4c77-a40a-080f372b2296

McNeill, L.C., Ienaga, M., Tobin, H., Saito, S., Goldberg, D., Moore, J.C. and Mikada, H. (2004) Deformation and in situ stress in the Nankai Accretionary Prism from resistivity-at-bit images, ODP Leg 196. Geophysical Research Letters, 31 (2), L02602. (doi:10.1029/2003GL018799).

Record type: Article

Abstract

Borehole resistivity images from ODP Leg 196 allow rapid and complete qualitative assessment of deformation within the toe of the Nankai prism, Japan. Borehole breakouts were common within the prism but prominent in the trench-wedge unit around the frontal thrust, suggesting reduced sediment strength. Breakouts indicate consistent ?2 orientations (?050°), compatible with northwesterly convergence. Deformation is dominated by discrete zones, including the frontal thrust and décollement zone. Prism fractures trend ?NE–SW, consistent with convergence. The décollement shows minimal deformation and the dominant structural trend is ?N–S. Prism deformation zones are characterized by high resistivity (compaction), whereas the décollement is apparently dilated, both with conductive fractures. Distribution of fracture orientations varies between log units confirming lithologic and rheologic influence. Pore pressure is elevated within the décollement and the misalignment of conductive fractures may reduce permeability.

This record has no associated files available for download.

More information

Published date: 2004
Organisations: Ocean and Earth Science

Identifiers

Local EPrints ID: 9856
URI: http://eprints.soton.ac.uk/id/eprint/9856
ISSN: 0094-8276
PURE UUID: a3194910-431e-40d4-8b82-5d52c7117543
ORCID for L.C. McNeill: ORCID iD orcid.org/0000-0002-8689-5882

Catalogue record

Date deposited: 13 Oct 2004
Last modified: 16 Mar 2024 03:20

Export record

Altmetrics

Contributors

Author: L.C. McNeill ORCID iD
Author: M. Ienaga
Author: H. Tobin
Author: S. Saito
Author: D. Goldberg
Author: J.C. Moore
Author: H. Mikada

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×