Time scales of melt extraction revealed by distribution of lava composition across a ridge axis | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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

Publication Type:

Journal Article

Source:

Geochemistry Geophysics Geosystems, Volume 11 (2010)

ISBN:

1525-2027

Accession Number:

WOS:000279823200004

URL:

http://www.agu.org/pubs/crossref/2010/2010GC003074.shtml

Keywords:

Géosciences marines ; spreading ridge ; basaltic lavas ; mantle processes, UMR 7154

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.

Notes:

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