Louis Géli,
*
Henri Bougault,
Daniel Aslanian,
Anne Briais,
Laure Dosso,
Joël Etoubleau,
Jean-Pierre Le Formal,
Marcia Maia,
Hélène Ondréas,
Jean-Louis Olivet,
Chris Richardson,
Keizo Sayanagi,
Nobukazu Seama,
Anjana Shah,
Ivan Vlastelic,
Michiko Yamamoto
Because of the proximity of the Euler poles of rotation of the
Pacific and Antarctic plates, small variations in plate kinematics are
fully recorded in the axial morphology and in the geometry of the
Pacific-Antarctic Ridge south of the Udintsev fracture zone. Swath
bathymetry and magnetic data show that clockwise rotations of the
relative motion between the Pacific and Antarctic plates over the last
6 million years resulted in rift propagation or in the linkage of ridge
segments, with transitions from transform faults to giant overlapping
spreading centers. This bimodal axial rearrangement has propagated
southward for the last 30 to 35 million years, leaving trails on the
sea floor along a 1000-kilometer-long V-shaped structure south of the
Udintsev fracture zone.
L. Géli, H. Bougault, J. Etoubleau, J.-P. Le Formal, H. Ondréas, J.-L. Olivet, I. Vlastelic, Institut Francais de
Recherche pour l'Exploitation de la Mer (IFREMER), Boite Postale 70, 29280 Plouzané, France.
D. Aslanian and C. Richardson, Bullard Laboratories, University of
Cambridge, Cambridge, CB3OEZ, UK.
A. Briais, Observatoire Midi-Pyrénnées, 18 Avenue Edouard
Belin, 31055 Toulouse-Cédex, France.
L. Dosso, CNRS-IFREMER, Boite Postale 70, 29280 Plouzané, France.
M. Maia, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu,
29285 Brest, France.
K. Sayanagi, Geological Survey of Japan, 1-1-3, Higashi, Tsukuba,
Ibaraki, 305, Japan.
N. Seama and M. Yamamoto, Chiba University, 1-33, 263 Inage-Bu-Chiba,
Chiba, Japan.
A. Shah, School of Oceanography, University of Seattle, Seattle, WA
98195, USA.
*
To whom correspondence should be addressed.
