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Petrogenetic variability along the North–South Propagating Spreading Center of the North Fiji Basin
Fleutelot, C and Eissen, JP and Dosso, L and Juteau, T and Launeau, P and Bollinger, C and Cotten, J and Danyushevsky, LV and Savoyant, L (2005) Petrogenetic variability along the North–South Propagating Spreading Center of the North Fiji Basin. Mineralogy and Petrology, 83 (1). pp. 55-86. ISSN 0930-0708
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Previous studies on propagating rifts suggested that segmentation of a spreading axis
could represent the superficial mark of mantle behavior (Sinton et al., 1983; Nicolas,
1989; Gente et al., 1995). The study of North–South Propagating Spreading Center (NSPSC)
from the North Fiji Basin (NFB) brings new insights to this debate. Basalts from the
central part of the propagator have more variable incompatible and isotopic ratios then
those from its northern tip. A model of dynamic partial melting of a thermally and
slightly geochemically and isotopically heterogeneous mantle is proposed. Beneath the
central segment, the partial fusion starts deeper (ca. 30 km) and reaches a higher rate (ca.
22%). Further open system differentiation occurs within shallow permanent magma
reservoirs along most of the central segment. Below the segment closest to the tip of
the propagator the partial fusion starts shallower (ca. 25 km) and stays at a lower rate (ca.
16%). The maximum of differentiation occurs close to the propagator, in small, periodically
disconnected, magma bodies resulting in the production of ferrobasalts close to the
tip. In order to explain these variations, the presence of an asthenospheric diapir focused
beneath the central part of the NS-PSC is proposed. The petrogenetic processes of
propagating spreading centers of mature oceanic basins or back-arc basins are identical.
|Keywords:||geochemistry, backarc basin basalts, isotopes, propagating spreading centre, Southwest Pacific, North Fiji Basin|
|Journal or Publication Title:||Mineralogy and Petrology|
|Page Range:||pp. 55-86|
|Identification Number - DOI:||10.1007/s00710-004-0061-5|
The original publication is available at www.springerlink.com
|Date Deposited:||12 Oct 2007 23:56|
|Last Modified:||18 Nov 2014 03:22|
|Item Statistics:||View statistics for this item|
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