Composite xenoliths from Spitsbergen: evidence of the circulation of MORB-related melts within the upper mantle

Michel Grégoire; June Chevet; Sven Maaloe

doi:10.1144/SP337.4

Composite xenoliths from Spitsbergen: evidence of the circulation of MORB-related melts within the upper mantle

Michel Grégoire^*, June Chevet, Sven Maaloe

^*Corresponding author for this work

ARC Centre of Excellence for Core to Crust Fluid Systems (incorporation ARC National Key Centre for Geochemical evolution and Metallogeny of Continents (GEMOC))

Research output: Contribution to journal › Conference paper › peer-review

9 Citations (Scopus)

Abstract

The Sverrefjell Quaternary volcano in Spitsbergen contains composite xenoliths showing lherzolite rocks cross-cut by websterite veins. These two rock types are characterized by similar major element compositions of olivines, orthopyroxenes, clinopyroxenes and spinels, as well as similar trace element composition for clinopyroxene. The clinopyroxenes of both rock types mostly display upwards convex or spoon-shaped REE (rare earth elements) patterns with a systematic enrichment in La over Ce (Ce_N/Yb_N 0.72-1.32; Sm_N/Yb_N 0.86-1.93 and La_N/Ce_N 1.27-1.93), except for one sample (SV-69) in which clinopyroxenes show a pattern characterized by low LREE compare to HREE (Ce_N/Yb_N 0.33-0.35). Metasomatic processes appear to be the most reasonable origin to form the lherzolite-websterite associations. We therefore propose that the Spitsbergen mantle has undergone at least two events: (1) a sub-alkaline (tholeiitic) metasomatism followed by (2) an alkaline metasomatic event.

Original language	English
Pages (from-to)	71-86
Number of pages	16
Journal	Geological Society Special Publication
Volume	337
Issue number	1
DOIs	https://doi.org/10.1144/SP337.4
Publication status	Published - 2010
Event	European MAntle Workshop (EMAW): Petrological evolution of the European Lithospheric Mantle: from Archean to Present Day - Ferrara, Italy Duration: 29 Aug 2007 → 31 Aug 2007

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title = "Composite xenoliths from Spitsbergen: evidence of the circulation of MORB-related melts within the upper mantle",

abstract = "The Sverrefjell Quaternary volcano in Spitsbergen contains composite xenoliths showing lherzolite rocks cross-cut by websterite veins. These two rock types are characterized by similar major element compositions of olivines, orthopyroxenes, clinopyroxenes and spinels, as well as similar trace element composition for clinopyroxene. The clinopyroxenes of both rock types mostly display upwards convex or spoon-shaped REE (rare earth elements) patterns with a systematic enrichment in La over Ce (CeN/YbN 0.72-1.32; SmN/YbN 0.86-1.93 and LaN/CeN 1.27-1.93), except for one sample (SV-69) in which clinopyroxenes show a pattern characterized by low LREE compare to HREE (CeN/YbN 0.33-0.35). Metasomatic processes appear to be the most reasonable origin to form the lherzolite-websterite associations. We therefore propose that the Spitsbergen mantle has undergone at least two events: (1) a sub-alkaline (tholeiitic) metasomatism followed by (2) an alkaline metasomatic event.",

author = "Michel Gr{\'e}goire and June Chevet and Sven Maaloe",

year = "2010",

doi = "10.1144/SP337.4",

language = "English",

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pages = "71--86",

journal = "Geological Society Special Publication",

issn = "0305-8719",

publisher = "Geological Society Publishing House",

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T1 - Composite xenoliths from Spitsbergen

T2 - European MAntle Workshop (EMAW): Petrological evolution of the European Lithospheric Mantle: from Archean to Present Day

AU - Grégoire, Michel

AU - Chevet, June

AU - Maaloe, Sven

PY - 2010

Y1 - 2010

N2 - The Sverrefjell Quaternary volcano in Spitsbergen contains composite xenoliths showing lherzolite rocks cross-cut by websterite veins. These two rock types are characterized by similar major element compositions of olivines, orthopyroxenes, clinopyroxenes and spinels, as well as similar trace element composition for clinopyroxene. The clinopyroxenes of both rock types mostly display upwards convex or spoon-shaped REE (rare earth elements) patterns with a systematic enrichment in La over Ce (CeN/YbN 0.72-1.32; SmN/YbN 0.86-1.93 and LaN/CeN 1.27-1.93), except for one sample (SV-69) in which clinopyroxenes show a pattern characterized by low LREE compare to HREE (CeN/YbN 0.33-0.35). Metasomatic processes appear to be the most reasonable origin to form the lherzolite-websterite associations. We therefore propose that the Spitsbergen mantle has undergone at least two events: (1) a sub-alkaline (tholeiitic) metasomatism followed by (2) an alkaline metasomatic event.

AB - The Sverrefjell Quaternary volcano in Spitsbergen contains composite xenoliths showing lherzolite rocks cross-cut by websterite veins. These two rock types are characterized by similar major element compositions of olivines, orthopyroxenes, clinopyroxenes and spinels, as well as similar trace element composition for clinopyroxene. The clinopyroxenes of both rock types mostly display upwards convex or spoon-shaped REE (rare earth elements) patterns with a systematic enrichment in La over Ce (CeN/YbN 0.72-1.32; SmN/YbN 0.86-1.93 and LaN/CeN 1.27-1.93), except for one sample (SV-69) in which clinopyroxenes show a pattern characterized by low LREE compare to HREE (CeN/YbN 0.33-0.35). Metasomatic processes appear to be the most reasonable origin to form the lherzolite-websterite associations. We therefore propose that the Spitsbergen mantle has undergone at least two events: (1) a sub-alkaline (tholeiitic) metasomatism followed by (2) an alkaline metasomatic event.

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DO - 10.1144/SP337.4

M3 - Conference paper

AN - SCOPUS:77955998757

SN - 0305-8719

VL - 337

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JO - Geological Society Special Publication

JF - Geological Society Special Publication

IS - 1

Y2 - 29 August 2007 through 31 August 2007

ER -

Composite xenoliths from Spitsbergen: evidence of the circulation of MORB-related melts within the upper mantle

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