FN Archimer Export Format
PT J
TI Variations in axial morphology, segmentation, and seafloor roughness along the Pacific-Antarctic Ridge between 56 degrees S and 66 degrees S
BT 
AF ONDREAS, Helene
   ASLANIAN, Daniel
   GELI, Louis
   OLIVET, Jean-Louis
   BRIAIS, Anne
AS 1:1;2:1;3:1;4:1;5:2;
FF 1:PDG-DRO-GM-GEOPHYSIQUE;2:PDG-DRO-GM-GEOPHYSIQUE;3:PDG-DRO-GM-GEOPHYSIQUE;4:PDG-DRO-GM-GEOPHYSIQUE;5:;
C1 IFREMER, Dept Geosci Marines, F-29280 Plouzane, France.
   Observ Midi Pyrenees, Lab Etud Geophys & Oceanog Spatiale, CNRS, F-31401 Toulouse 4, France.
C2 IFREMER, FRANCE
   OBSERV MIDI PYRENEES, FRANCE
SI BREST
SE PDG-DRO-GM-GEOPHYSIQUE
IN WOS Ifremer jusqu'en 2018
IF 2.609
TC 16
UR https://archimer.ifremer.fr/doc/2001/publication-438.pdf
LA English
DT Article
CR PACANTARCTIC
BO L'Atalante
DE ;Spreading;Segmentation;Geomorphology;Seafloor;Ridge
AB The spreading rate at the Pacific-Antarctic Ridge (PAR) increases rapidly from 54 mm/yr near Pitman Fracture Zone (FZ) up to 76 mm/yr near Udintsev FZ, resulting in three domains of axial morphology: an axial valley south of Pitman FZ, an axial high north of Saint Exupery FZ, and in between, the transitional domain extends over 650 km. It comprises sections of ridge with an axial valley or an axial high and generally displays a very low cross-sectional relief. It is also characterized by two propagating rifts. Two domains of different seafloor roughness appear south of Udintsev FZ: east of 157 degreesW these two domains are separated by a 1000-km V-shaped boundary. West of 157 degreesW, the boundary approximately coincides with Chron 3a or Chron 4. The southward migration of the transitional area during the last 35 Myr explains the V-shaped boundary: (1) increases in spreading rate above a threshold value produced changes in axial morphology; and (2) in the transition zone, rotations of the spreading direction were accommodated by the plate boundary, either by rift propagation or by transitions from fracture zones to non transform discontinuities, leaving trails on the seafloor that presently delineate the V. Seafloor roughness variations are not controlled by exactly the same spreading rate dependence as changes in axial morphology. The transition from rough to smooth seems to have occurred everywhere for spreading rates greater than 50 mm/yr, except in a domain presently centered on Saint-Exupery FZ, where it occurred for spreading rates > 60 to 65 mm/yr. Independent results from melting model calculations of major elements [Vlastelic et al., 2000] indicate that the upper mantle temperature is likely to be cooler between Antipodes and La Rose FZs. The combination of these two results reveals the existence of a 700-km-long segmentation of the upper mantle, with a "cool" area centered on Saint-Exupery FZ.
PY 2001
PD MAY
SO Journal of Geophysical Research - section B - Solid earth
SN 0148-0227
PU American Geophysical Union
VL 106
IS B5
UT 000168593200002
BP 8521
EP 8546
DI 10.1029/2000JB900394
ID 438
ER

EF