Oceanic corrugated surfaces and the strength of the axial lithosphere at slow spreading ridges

Details

Serval ID
serval:BIB_DB55ECE30E9C
Type
Article: article from journal or magazin.
Collection
Publications
Title
Oceanic corrugated surfaces and the strength of the axial lithosphere at slow spreading ridges
Journal
Earth and Planetary Science Letters
Author(s)
Cannat M., Sauter D., Escartin J., Lavier L., Picazo S.
ISSN-L
0012-821X
Publication state
Published
Issued date
2009
Peer-reviewed
Oui
Volume
288
Pages
174-183
Language
english
Abstract
We analyse the topography and gravity signature of 39 corrugated
surfaces formed over the past 26 myrs in the footwall of axial
detachment faults at the eastern Southwest Indian Ridge. These
corrugated surfaces appear to have formed at a melt supply about half
the global melt supply average for mid-ocean ridges, and we find that
their presently elevated topography, relative to adjacent non-corrugated
seafloor, was mostly acquired at the end of their fort-nation, at the
``termination stage''. This configuration, which also characterizes
many off-axis corrugated surfaces in other oceans, suggests that the
plate flexural rigidity was very low during the formation of the
corrugated surface, and increased significantly at the termination
stage. Following Buck (1988), we hypothesize that stresses related to
bending of the plate cause internal deformation and damage in the
footwall of the fault, which is associated with weakening. As a possible
mechanism for enhanced footwall weakening while corrugated surfaces
form, we propose the formation of weak shear zones coated with hydrous
minerals such as talc, amphibole, chlorite and serpentine, in
mantle-derived ultramafics next to gabbro intrusions. If this hypothesis
is correct, the amount of footwall weakening and roll-over along axial
detachment faults at slow spreading ridges may be controlled both by
access to hydrothermal fluids in the footwall of the detachment, and by
the abundance and distribution of gabbros intrusions in exhumed
ultrannafics. (C) 2009 Elsevier B.V. All rights reserved.
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09/08/2013 12:42
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20/08/2019 16:00
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