Time scales of melt extraction revealed by distribution of lava composition across a ridge axis - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Geochemistry, Geophysics, Geosystems Year : 2010

Time scales of melt extraction revealed by distribution of lava composition across a ridge axis

Mathieu Benoit
Christophe C Hémond
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J. Dyment
Bernard Le Gall
Anne Briais

Abstract

Temporal fluctuations of magmatic processes during the last 800 kyr have been investigated for the slow spreading Central Indian Ridge. The fluctuations are recorded by variations in lava chemistry along a 40 km long profile across the ridge. The temporal relations of the basalts were accurately restored using magnetic microanomalies. We report on the occurrence of ancient lavas enriched in incompatible elements whereas on-axis samples are typical normal mid-ocean ridge basalts. The enriched lavas are symmetrically distributed on either side of the ridge, implying that enriched melts reached the seafloor at intervals of about 150–200 kyr. This periodicity is viewed as a characteristic time scale in the aggregation processes of the melts produced from a heterogeneous mantle source. Geochemical variations of zero-age mid-ocean ridge basalts may primarily reflect such periodic processes rather than the spatial distribution of mantle heterogeneities.
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Dates and versions

insu-00563239 , version 1 (15-02-2011)

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Carole Cordier, Mathieu Benoit, Christophe C Hémond, J. Dyment, Bernard Le Gall, et al.. Time scales of melt extraction revealed by distribution of lava composition across a ridge axis. Geochemistry, Geophysics, Geosystems, 2010, 11, pp.Q0AC06. ⟨10.1029/2010GC003074⟩. ⟨insu-00563239⟩
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