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Detailed Reference Information |
Hekinian, R., Stoffers, P., Devey, C., Ackerman, D., Hémond, C., O’Connor, J., Binard, N. and Maia, M. (1997). Intraplate versus ridge volcanism on the Pacific-Antarctic Ridge near 37¿°S–111¿°W. Journal of Geophysical Research 102: doi: 10.1029/96JB03856. issn: 0148-0227. |
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Exploration of the Foundation Volcanic Chain (33 ¿S--131 ¿W;37 ¿S--111 ¿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 mid-ocean ridge basalts (MORBs) with low incompatible elements (K2O150 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 ¿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 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.¿ 1997 American Geophysical Union |
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Abstract |
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Keywords
Mineralogy and Petrology, Igneous petrology, Geochemistry, Composition of the crust, Marine Geology and Geophysics, Midocean ridge processes, Planetology, Solid Surface Planets, Volcanism |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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