The Amsterdam-St. Paul Plateau: A complex hot spot/DUPAL-flavored MORB interaction - Archive ouverte HAL Access content directly
Journal Articles Geochemistry, Geophysics, Geosystems Year : 2012

The Amsterdam-St. Paul Plateau: A complex hot spot/DUPAL-flavored MORB interaction

(1, 2) , (1) , (1) , (1) , (3) , (4)
1
2
3
4

Abstract

The Amsterdam-St Paul (ASP) oceanic plateau results from the interaction between the ASP hot spot and the Southeast Indian ridge. A volcanic chain, named the Chain of the Dead Poets (CDP), lies to its northward tip and is related to the hot spot intraplate activity. The ASP plateau and CDP study reveals that ASP plume composition is inherited from oceanic crust and pelagic sediments recycled in the mantle through a 1.5 Ga subduction process. The ASP plateau lavas have a composition (major and trace elements and Sr-Nd-Pb-Hf isotopes) reflecting the interaction between ASP plume and the Indian MORB mantle, including some clear DUPAL input. The Indian upper mantle below ASP plateau is heterogeneous and made of a depleted mantle with lower continental crust (LCC) fragments probably delaminated during the Gondwana break-up. The lower continental crust is one of the possible reservoirs for the DUPAL anomaly origin that our data support. The range of magnitude of each end-member required in ASP plateau samples is (1) 45% to 75% of ASP plume and (2) 25% to 55% of Indian DM within 0% to a maximum of 6% of LCC layers included within. The three end-members involved (plume, upper mantle and lower continental crust) and their mixing in different proportions enhances the geochemical variability in the plateau lavas. Consequently, the apparent composition homogeneity of Amsterdam Island, an aerial summit of the plateau, may result from the presence of intermediate magmatic chambers into the plateau structure.
Fichier principal
Vignette du fichier
G3-Janin.pdf (2.11 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

insu-00737400 , version 1 (01-04-2013)

Identifiers

Cite

Myriam Janin, Christophe C Hémond, Marcia Maia, Philippe Nonnotte, Emmanuel Ponzevera, et al.. The Amsterdam-St. Paul Plateau: A complex hot spot/DUPAL-flavored MORB interaction. Geochemistry, Geophysics, Geosystems, 2012, 13, pp.Q09016. ⟨10.1029/2012GC004165⟩. ⟨insu-00737400⟩
636 View
668 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More