FN Archimer Export Format
PT J
TI High-resolution bathymetry reveals contrasting landslide activity shaping the walls of the Mid-Atlantic Ridge axial valley
BT 
AF CANNAT, Mathilde
   MANGENEY, Anne
   ONDREAS, Helene
   FOUQUET, Yves
   NORMAND, Alain
AS 1:1;2:2;3:3;4:3;5:3;
FF 1:;2:;3:PDG-REM-GM-LGM;4:PDG-REM-GM-LGM;5:PDG-REM-GM-CTDI;
C1 Inst Phys Globe Paris, PRES Sorbonne, Equipe Geosci Marines, CNRS UMR7154, Paris, France.
   Univ Paris Diderot, PRES Sorbonne, Inst Phys Globe Paris, Equipe Sismol,CNRS UMR7154, Paris, France.
   Geosci Marines Geochim Met, Brest, France.
C2 IPGP, FRANCE
   UNIV PARIS 07, FRANCE
   IFREMER, FRANCE
SI BREST
SE PDG-REM-GM-LGM
   PDG-REM-GM-CTDI
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 3.054
TC 26
TU Centre national de la recherche scientifique
   Institut National de l'Information Géographique et Forestière
   Institut de physique du globe
   Université Paris Diderot
   Université Pierre et Marie Curie
   Université de La Réunion
UR https://archimer.ifremer.fr/doc/00284/39516/38004.pdf
LA English
DT Article
CR FARANAUT/15N
   RIDELENTE
   SERPENTINE
BO L'Atalante
   Jean Charcot
   Pourquoi pas ?
DE ;Landslides;detachment faults;basalts;mid-ocean ridges;serpentinized peridotites
AB Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to 50 m for shipboard multibeam bathymetry), revealing the role played by landslides. Slow-spreading ridge axial valleys also commonly expose mantle-derived serpentinized peridotites in the footwalls of large offset normal faults (detachments). In our map of the Ashadze area (lat. 13 degrees N), ultramafic outcrops have an average slope of 18 degrees and behave as sliding deformable rock masses, with little fragmentation. By contrast, the basaltic seafloor in the Krasnov area (lat. 16 degrees 38N) has an average slope of 32 degrees and the erosion of the steep basaltic rock faces leads to extensive fragmentation, forming debris with morphologies consistent with noncohesive granular flow. Comparison with laboratory experiments suggests that the repose angle for this basaltic debris is > 25 degrees. We discuss the interplay between the normal faults that bound the axial valley and the observed mass wasting processes. We propose that, along axial valley walls where serpentinized peridotites are exposed by detachment faults, mass wasting results in average slopes 20 degrees, even in places where the emergence angle of the detachment is larger.
PY 2013
PD APR
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU Amer Geophysical Union
VL 14
IS 4
UT 000319410100015
BP 996
EP 1011
DI 10.1002/ggge.20056
ID 39516
ER

EF