Occurrence of inherited supra-subduction zone mantle in the oceanic lithosphere as inferred from mantle xenoliths from Dragon Seamount (southern Tore-Madeira Rise)

Details

Serval ID
serval:BIB_6DD5EA4C8BF8
Type
Article: article from journal or magazin.
Collection
Publications
Title
Occurrence of inherited supra-subduction zone mantle in the oceanic lithosphere as inferred from mantle xenoliths from Dragon Seamount (southern Tore-Madeira Rise)
Journal
Journal of the Geological Society
Author(s)
Merle R., Kaczmarek M.-A., Tronche E., Girardeau J.
ISSN-L
0016-7649
Publication state
Published
Issued date
2012
Peer-reviewed
Oui
Volume
169
Pages
251-267
Language
english
Abstract
Spinel-bearing peridotite and pyroxenite xenoliths dredged from the
Dragon Seamount (southern Tore-Madeira Rise, West Iberia and Morocco
margin) give an insight into the composition of the underlying
lithosphere. These xenoliths are devoid of evidence of strong host
lava-peridotite interaction and re-equilibration or late impregnation in
the plagioclase facies. The spinels and pyroxenes from the Dragon
peridotites have compositions distinct from those of both Iherzolites
and harzburgites from the Iberia margin and the Mid-Atlantic Ridge. They
display a highly depleted composition, in particular, high Cr-number, up
to 0.63 in the spinels, consistent with a melting degree between 12 and
19%. Because of the strong chemical similarities between the
Tore-Madeira Rise, Newfoundland peridotites, and peridotites from
supra-subduction zones, we propose that the Dragon peridotites formed in
a similar context. The pyroxenites display a cumulate texture and are
probably a high-temperature-high-pressure cumulate formed by fractional
crystallization from a melt. The Tore-Madeira Rise peridotites may
represent a former mantle wedge in an oceanic arc, later included into
the continental lithosphere and finally tectonically disseminated within
the lithosphere during the rifting of the Newfoundland-Iberia
continental lithosphere. As a consequence, rifting processes may produce
heterogeneities in the oceanic lithosphere and influence isotopic
compositions of ocean island basalt-type lavas during plume-lithosphere
interactions, as inferred for the southern Tore-Madeira Rise.
Create date
01/04/2013 16:12
Last modification date
20/08/2019 15:27
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