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Signature of deep mantle melting in South Iceland olivine

Signature of deep mantle melting in South Iceland olivine

Title: Signature of deep mantle melting in South Iceland olivine
Author: Nikkola, Paavo   orcid.org/0000-0002-0512-9116
Guðfinnsson, Guðmundur   orcid.org/0000-0003-3275-9866
Bali, Eniko   orcid.org/0000-0001-7289-6393
Rämö, O. Tapani
Fusswinkel, Tobias
Thordarson, Thorvaldur   orcid.org/0000-0003-4011-7185
Date: 2019-05
Language: English
Scope: 43
University/Institute: Háskóli Íslands
University of Iceland
School: Verkfræði- og náttúruvísindasvið (HÍ)
School of Engineering and Natural Sciences (UI)
Department: Jarðvísindastofnun (HÍ)
Institute of Earth Sciences (UI)
Faculty of Earth Sciences (UI)
Jarðvísindadeild (HÍ)
Series: Contributions to Mineralogy and Petrology;174(5)
ISSN: 0010-7999
1432-0967 (eISSN)
DOI: 10.1007/s00410-019-1580-8
Subject: Iceland; Mantle heterogeneity; Mantle melting; Olivine; Trace elements; Jarðmöttull; Storkuberg
URI: https://hdl.handle.net/20.500.11815/1755

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Nikkola, P., Guðfinnsson, G.H., Bali, E. et al. Signature of deep mantle melting in South Iceland olivine. Contributions to Mineralogy and Petrology 174, 43 (2019). https://doi.org/10.1007/s00410-019-1580-8


We present new high-precision major and trace element data on olivine macrocrysts from various volcano-tectonic settings in Iceland and use these data as a proxy for mantle mode and melting conditions. Within individual sampling sites examined (seven lavas and one tephra) olivine-dominated fractional crystallization, magma mixing and diffusive re-equilibration control observed variability in olivine composition. High-pressure fractional crystallization of clinopyroxene may have lowered Ca and increased Fe/Mn in one olivine population and subsolidus diffusion of Ni and Fe–Mg affected the mantle-derived Ni/Fo ratio in some compositionally zoned olivine macrocrysts. Interestingly, magmas erupted at the southern tip of the Eastern Volcanic Zone (SEVZ), South Iceland, have olivines with elevated Ni and low Mn and Ca contents compared to olivines from elsewhere in Iceland, and some of the SEVZ olivines have relatively low Sc and V and high Cr, Ti, Zn, Cu and Li in comparison to depleted Iceland rift tholeiite. In these olivines, the high Ni and low Mn indicate relatively deep melting (Pfinal > 1.4 GPa, ~ 45 km), Sc, Ti and V are compatible with low-degree melts of lherzolite mantle, and elevated Zn may suggest modal (low-olivine) or geochemical (high Zn) enrichment in the source. The SEVZ olivine macrocrysts probably crystallized from magmas derived from olivine-bearing but relatively deep, enriched and fertile parts of the sub-Icelandic mantle, and indicate swift ascent of magma through the SEVZ lithosphere.


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Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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