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dc.contributor.authorBjerga, Anders
dc.contributor.authorStubseid, Håvard Hallås
dc.contributor.authorPedersen, Leif-Erik Rydland
dc.contributor.authorBeinlich, Andreas Michael
dc.contributor.authorPedersen, Rolf B.
dc.description.abstractThe Mohns Ridge is a very slow-spreading ridge that, together with the Knipovich Ridge, marks the boundary between the North American and Eurasian plates in the Norwegian-Greenland Sea. In this study, we report the major and trace element composition of spatially associated basalts and peridotites from a gabbro-peridotite complex ∼20 km west of the Mohns Ridge rift flank. Formation of the ∼4–5 Myr crustal section involved accretion of normal mid-ocean ridge basalts with Na-content suggesting derivation from a depleted mantle source. This is consistent with the degree of partial melting estimated for clinopyroxene poor harzburgites using the Cr-number of spinel (14%–18%) and rare earth element modeling of orthopyroxene (16%–24%) and reconstructed whole-rock composition (14%–20%). If all the melting took place beneath the paleo-Mohns Ridge, a crustal thickness of ∼7–8 km is expected, which is nearly double the observed thickness. Orthopyroxene trace elements are not consistent with typical fractional melting expected for mid-ocean ridges but rather resemble that seen in supra-subduction zone peridotites. The geochemistry of both the basalts and the peridotites suggests that a water-rich slab flux in the past has influenced the mantle source. In turn, this caused hydrous melting which increased the depletion of the pyroxene components, leading to a highly depleted mantle that is now underlying much of the Arctic Mid-Ocean Ridges and represents the source for the spreading related magmatism.en_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleA Highly Depleted and Subduction-Modified Mantle Beneath the Slow-Spreading Mohns Ridgeen_US
dc.typeJournal articleen_US
dc.typePeer revieweden_US
dc.rights.holderCopyright 2022 The Author(s)en_US
dc.source.journalGeochemistry Geophysics Geosystemsen_US
dc.identifier.citationGeochemistry Geophysics Geosystems. 2022, 23 (11), e2022GC010585.en_US

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal