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Revised Pacific-Antarctic plate motions and geophysics of the Menard Fracture Zone

Croon, Marcel B. and Cande, Steven C. and Stock, Joann M. (2008) Revised Pacific-Antarctic plate motions and geophysics of the Menard Fracture Zone. Geochemistry, Geophysics, Geosystems, 9 (7). 2008GC002019. ISSN 1525-2027. doi:10.1029/2008GC002019.

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A reconnaissance survey of multibeam bathymetry and magnetic anomaly data of the Menard Fracture Zone allows for significant refinement of plate motion history of the South Pacific over the last 44 million years. The right-stepping Menard Fracture Zone developed at the northern end of the Pacific-Antarctic Ridge within a propagating rift system that generated the Hudson microplate and formed the conjugate Henry and Hudson Troughs as a response to a major plate reorganization ∼45 million years ago. Two splays, originally about 30 to 35 km apart, narrowed gradually to a corridor of 5 to 10 km width, while lineation azimuths experienced an 8° counterclockwise reorientation owing to changes in spreading direction between chrons C13o and C6C (33 to 24 million years ago). We use the improved Pacific-Antarctic plate motions to analyze the development of the southwest end of the Pacific-Antarctic Ridge. Owing to a 45° counterclockwise reorientation between chrons C27 and C20 (61 to 44 million years ago) this section of the ridge became a long transform fault connected to the Macquarie Triple Junction. Following a clockwise change starting around chron C13o (33 million years ago), the transform fault opened. A counterclockwise change starting around chron C10y (28 millions years ago) again led to a long transform fault between chrons C6C and C5y (24 to 10 million years ago). A second period of clockwise reorientation starting around chron C5y (10 million years ago) put the transform fault into extension, forming an array of 15 en echelon transform faults and short linking spreading centers.

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Stock, Joann M.0000-0003-4816-7865
Additional Information:Copyright 2008 by the American Geophysical Union. Received 5 March 2008; accepted 15 May 2008; published 1 July 2008. This study was made possible through a series of grants from the NSF-Office of Polar Programs supporting the acquisition of geophysical data along transits of the R/VIB Nathaniel B. Palmer: grants OPP-0338317, OPP-0338346, OPP-0126334, and OPP-0126340. We thank the officers, crew, and scientific staff of the R/VIB Nathaniel B. Palmer and the many students who sailed on these cruises. Caltech contribution 9005.
Group:Seismological Laboratory
Funding AgencyGrant Number
National Science Foundation, Office of Polar ProgramsOPP-0338317
National Science Foundation, Office of Polar ProgramsOPP-0338346
National Science Foundation, Office of Polar ProgramsOPP-0126334
National Science Foundation, Office of Polar ProgramsOPP-0126340
Subject Keywords:Pacific-Antarctic Ridge; Menard Fracture Zone; relative motions; uncertainties; tectonics; magnetic anomalies
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Other Numbering System NameOther Numbering System ID
Geological and Planetary Sciences9005
Issue or Number:7
Record Number:CaltechAUTHORS:CROggg08
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Official Citation:Croon, M. B., S. C. Cande, and J. M. Stock (2008), Revised Pacific-Antarctic plate motions and geophysics of the Menard Fracture Zone, Geochem. Geophys. Geosyst., 9, Q07001, doi:10.1029/2008GC002019.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11235
Deposited By: Archive Administrator
Deposited On:26 Jul 2008 03:46
Last Modified:08 Nov 2021 21:56

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