Atypical hotspot chains: evidence for a secondary melting zone below the Marquesas (French Polynesia) - Archive ouverte HAL
Article Dans Une Revue Terra Nova Année : 2006

Atypical hotspot chains: evidence for a secondary melting zone below the Marquesas (French Polynesia)

Résumé

The atypical age/distance to the hotspot relationships observed for the Marquesas linear chain, which present a considerable scatter, are best explained considering (1) a Pacific plate motion of 10.5 cm yr1 in the N115°E direction and (2) rejuvenation of volcanism in Ua Huka island. New K–Ar ages show that the main hotspot activity in Ua Huka emplaced successively shield olivine tholeiites and post-shield alkali basalts between 3.11 ± 0.04 and 2.43 ± 0.04 Ma. Then, after a quiescence period of 1.28 ± 0.06 Myr, two small basanitic volcanoes were emplaced between 1.15 ± 0.02 and 0.763 ± 0.013 Ma. With respect to the main hotspot volcanics, their lavas originated from weaker partial melting rates of a deeper source. Field, petrologic and geochemical arguments are consistent with the existence of a secondary melting zone located c. 140 km downstream the Marquesas hotspot, which produced the rejuvenated volcanics.

Domaines

Volcanologie

Dates et versions

hal-00111666 , version 1 (06-11-2006)

Identifiants

Citer

Christelle Legendre, René Maury, Sylvain Blais, Hervé Guillou, Joseph Cotten. Atypical hotspot chains: evidence for a secondary melting zone below the Marquesas (French Polynesia). Terra Nova, 2006, 18 (3), pp.210-216. ⟨10.1111/j.1365-3121.2006.00681.x⟩. ⟨hal-00111666⟩

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