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An in situ trace element study of peridotites from the Gakkel Ridge

M. E. D'Errico, J. M. Warren and M. Godard
An in situ trace element study of peridotites from the Gakkel Ridge (in Goldschmidt abstracts 2013, Anonymous)
Mineralogical Magazine (2013) 77 (5): 934

Abstract

Abyssal peridotites from the Gakkel Ridge provide constraints on the roles of ridge segmentation, on-axis cooling, and pre-existing heterogeneity on melt generation at ultraslow spreading rates. At a rate of 6-15 mm/yr, the Gakkel Ridge has a very thin crust and no major transform faults along its entire length. A thick lithospheric lid due to on-axis conductive cooling is predicted to limit the degree of melting. However, we present geochemical data that demonstrates significant compositional depletion in peridotites. Peridotites in this study span the boundary between the Western Volcanic Zone and the Sparsely Magmatic Zone. We report in situ laser ablation ICP-MS trace element data for Cpx, Opx and olivine from a total of 14 samples. Based on lithology and rare earth element (REE) patterns, the harzburgite and lherzolite samples have each been divided into two groups. Group I harzburgites and lherzolites display typical REE patterns, with depletions in light REE relative to heavy REE. A single harzburgite in group II has a spoon-shaped pattern with enriched light REE, yet another sample within the same dredge has a typical REE pattern. Group II lherzolites have the highest degrees of depletion of any samples in this study. The small length-scale of compositional variability combined with thin oceanic crust suggests that pre-existing heterogeneity accounts for some of the depletion observed in peridotite compositions. The Gakkel peridotites thus provide evidence for a mantle that is the consequence of both inherited depletion and recent melting.


ISSN: 0026-461X
EISSN: 1471-8022
Serial Title: Mineralogical Magazine
Serial Volume: 77
Serial Issue: 5
Title: An in situ trace element study of peridotites from the Gakkel Ridge
Title: Goldschmidt abstracts 2013
Author(s): D'Errico, M. E.Warren, J. M.Godard, M.
Author(s): Anonymous
Affiliation: Stanford University, Stanford, CA, United States
Pages: 934
Published: 2013
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
Meeting name: Goldschmidt 2013
Meeting location: Florence, ITA, Italy
Meeting date: 20130825Aug. 25-30, 2013
Summary: Y
Accession Number: 2013-100554
Categories: Igneous and metamorphic petrology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Secondary Affiliation: Universite Montpellier II, FRA, France
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland
Update Code: 201357
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