FN Archimer Export Format
PT J
TI Intraplate versus ridge volcanism on the Pacific-Antarctic Ridge near 37°S -111°W
BT 
AF HEKINIAN, Roger
   STOFFERS, Peter
   DEVEY, Colin
   ACKERMAN, Dietrich
   HEMOND, Christophe
   O'CONNOR, John
   BINARD, Nicolas
   MAIA, Marcia
AS 1:1;2:2;3:2;4:2;5:3;6:2;7:2;8:3;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 IFREMER, CTR BREST, BP 70, F-29280 PLOUZANE, FRANCE.
   CHRISTIAN ALBRECHTS UNIV KIEL, INST GEOL PALAONTOL, D-2300 KIEL, GERMANY.
   UNIV BRETAGNE OCCIDENTALE, DEPT SCI TERRE, BREST, FRANCE.
C2 IFREMER, FRANCE
   UNIV KIEL, GERMANY
   UBO, FRANCE
IN WOS Ifremer jusqu'en 2018
TC 24
UR https://archimer.ifremer.fr/doc/00336/44707/44913.pdf
LA English
DT Article
AB Exploration of the Foundation Volcanic Chain (33 degrees S-131 degrees W; 37 degrees S-111 degrees W) revealed the existence of different magmatic provinces with relation to their geological settings. (1) The Pacific-Antarctic Ridge (PAR) is made up of several en echelon segments where both glassy midocean ridge basalts (MORBs) with low incompatible elements (K2O<200 ppm, Zr<120 ppm and Ce <20 ppm) as well as andesites and dacites have erupted, (2) Oblique Ridges located up to 300 lan from the PAR axis are topped with seamounts made up essentially of transitional (T) and enriched (E) MORBs with intermediate incompatible elements (K2O=0.11-0.40 %, Zr=70-140 ppm and Ce=15-30 ppm), (3) the Foundation Seamounts (FS) consisting essentially of isolated volcanoes which have erupted alkalic lavas (alkali basalt, trachybasalt and trachyandesite) with high incompatible elements (K2O (0.50-1.1 %, Zr (>150 ppm) and Ce (>48 ppm)) at about 306-1300 km from the PAR axis, (4) The Old Pacific Seamounts built on a crust older than 23 m. y. located west of longitude 124 degrees W (> 1300 km from the PAR axis) consist of T and EMORB. On the PAR axis, extensive crystal fractionation (>65%) produced the silicic lavas. On the basis of Pacific plate reconstruction using a half spreading rate of about 50 mm/yr and integrating the observed compositional changes with respect to the structural settings, it is inferred that the last volcanic events giving rise to the FS took place at about 110 km from the PAR axis about 5 m. y. ago. The Oblique Ridges built between 5 m. y. and <1 m. y. are believed to represent ancient leaky transforms and/or large discontinuities between accreting ridge segments filled by volcanic cones during the interaction (mixing) of the enriched plume components of the FS with PAR depleted (MORB type) magmatism. The Old Pacific Seamounts built on ancient crust (>23 m. y.) with MORB volcanics comparable to those of the the Oblique Ridge-PAR provinces, could also have been formed by an interaction between the Foundation Seamount (dredge site 28) hotspot magmatism and that of an ancient accreting ridge magmatism precursor of the PAR.
PY 1997
PD JUL
SO Journal Of Geophysical Research-solid Earth
SN 0148-0027
PU Amer Geophysical Union
VL 102
IS B6
UT A1997XD57800039
BP 12265
EP 12286
DI 10.1029/96JB03856
ID 44707
ER

EF