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Incipient subduction at the contact with stretched continental crust: The Puysegur Trench

Gurnis, Michael and Van Avendonk, Harm and Gulick, Sean P. S. and Stock, Joann and Sutherland, Rupert and Hightower, Erin and Shuck, Brandon and Patel, Jiten and Williams, Ethan and Kardell, Dominik and Herzig, Erich and Idini, Benjamin and Graham, Kenny and Estep, Justin and Carrington, Luke (2019) Incipient subduction at the contact with stretched continental crust: The Puysegur Trench. Earth and Planetary Science Letters, 520 . pp. 212-219. ISSN 0012-821X. doi:10.1016/j.epsl.2019.05.044.

[img] PDF (Figures which show maps for earthquake seismic focal mechanisms along with selected cross sections. Additional figures show detailed MCS lines in the vicinity of the Puysegur Trench) - Supplemental Material
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A seismic Benioff zone and plate kinematics show Puysegur Trench south of New Zealand transitioning to subduction. Because the local structure and its influence on subduction initiation is poorly understood, we conducted a seismic survey with ocean bottom seismometers and multichannel seismic profiles. Our early results show that the overriding Pacific Plate beneath the Solander Basin is composed of block-faulted and thinned continental crust, and the inner trench wall of northern Puysegur Ridge is composed of folded and faulted sediment. The megathrust interface has been imaged and shows ∼500 m of downgoing, undisturbed sediments. Combining plate kinematic history with seismic velocity-inferred density, we show that the density difference across the plate boundary changed as oblique strike-slip plate motion juxtaposed dense oceanic crust with thinned continental crust. The density difference rapidly increased 18 to 15 Ma, coincident with subduction initiation, suggesting that compositional differences have a large influence on subduction initiation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Gurnis, Michael0000-0003-1704-597X
Van Avendonk, Harm0000-0002-8016-2653
Gulick, Sean P. S.0000-0003-4740-9068
Stock, Joann0000-0003-4816-7865
Hightower, Erin0000-0002-4734-5159
Shuck, Brandon0000-0003-2543-721X
Williams, Ethan0000-0002-7917-4104
Idini, Benjamin0000-0002-2697-3893
Estep, Justin0000-0002-2004-4786
Additional Information:© 2019 Elsevier B.V. Received 30 January 2019, Revised 16 April 2019, Accepted 28 May 2019, Available online 13 June 2019. Supported by the National Science Foundation through awards OCE-1654766 (to Caltech) and OCE-1654689 (to UT Austin). We thank the Captain and crew of the R/V Marcus G. Langseth and S. Saustrup, M. Davis and D. Duncan from UTIG for their exceptional effort during the expedition. We thank T. Gerya for a helpful review of an earlier version of our manuscript. All seismic data will be made available at the Academic Seismic Portal (ASP) at UTIG while all remaining data will be available at the Rolling Deck to Repository (R2R). This is UTIG Contribution #3455.
Group:Seismological Laboratory
Funding AgencyGrant Number
Subject Keywords:plate tectonics; subduction; subduction initiation; oceanic crust; oceanic lithosphere
Record Number:CaltechAUTHORS:20190613-105022288
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Official Citation:Michael Gurnis, Harm Van Avendonk, Sean P.S. Gulick, Joann Stock, Rupert Sutherland, Erin Hightower, Brandon Shuck, Jiten Patel, Ethan Williams, Dominik Kardell, Erich Herzig, Benjamin Idini, Kenny Graham, Justin Estep, Luke Carrington, Incipient subduction at the contact with stretched continental crust: The Puysegur Trench, Earth and Planetary Science Letters, Volume 520, 2019, Pages 212-219, ISSN 0012-821X, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96362
Deposited By: Tony Diaz
Deposited On:13 Jun 2019 18:05
Last Modified:16 Nov 2021 17:20

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