Beyond the thermal plume paradigm | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Beyond the thermal plume paradigm

Type de publication:

Journal Article

Source:

Geophysical Research Letters, Volume 32, Ticket 7, p.doi:1029/2005GL022360 (2005)

ISBN:

0094-8276

URL:

http://www.agu.org/grl/cont9697.html

Mots-clés:

LAVAS; PB

Résumé:

<p>Geodynamic models of thermo-chemical plumes rising in a mantle wind suggest that we should abandon some paradigms based on the dynamics of purely thermal axisymmetric plumes. The head-tail structure is possible but not unique and the lack of a plume head does not preclude a deep origin. Our results suggest that the surface expression of some thermo-chemical plumes may be a headless, age-progressive volcanic chain. Plume tails are laterally heterogeneous, rather than concentrically zoned, because deep heterogeneities are sheared into distinct and long-lasting filaments that will be successively sampled by different volcanoes, as the oceanic plate moves over the plume tail. Finally, calculated S-wave velocity anomalies are consistent with recent plume tomographic images, showing that compositional heterogeneities in the lowermost mantle favour the coexistence of a great variety of plume shapes and sizes.</p>

Notes:

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