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dc.contributor.author
Leuthold, Julien
dc.contributor.author
Lissenberg, C. Johan
dc.contributor.author
O’Driscoll, Brian
dc.contributor.author
Karakas, Ozge
dc.contributor.author
Falloon, Trevor
dc.contributor.author
Klimentyeva, Dina N.
dc.contributor.author
Ulmer, Peter
dc.date.accessioned
2021-07-30T14:23:21Z
dc.date.available
2018-03-15T15:32:19Z
dc.date.available
2018-03-16T06:49:59Z
dc.date.available
2019-01-16T10:22:53Z
dc.date.available
2021-07-30T14:23:21Z
dc.date.issued
2018-03-08
dc.identifier.issn
2296-6463
dc.identifier.other
10.3389/feart.2018.00015
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/250402
dc.identifier.doi
10.3929/ethz-b-000250402
dc.description.abstract
Successive magma batches underplate, ascend, stall and erupt along spreading ridges, building the oceanic crust. It is therefore important to understand the processes and conditions under which magma differentiates at mid ocean ridges. Although fractional crystallization is considered to be the dominant mechanism for magma differentiation, open-system igneous complexes also experience Melting-Assimilation-Storage-Hybridization (MASH, Hildreth and Moorbath, 1988) processes. Here, we examine crystal-scale records of partial melting in lower crustal gabbroic cumulates from the slow-spreading Atlantic oceanic ridge (Kane Megamullion; collected with Jason ROV) and the fast-spreading East Pacific Rise (Hess Deep; IODP expedition 345). Clinopyroxene oikocrysts in these gabbros preserve marked intra-crystal geochemical variations that point to crystallization-dissolution episodes in the gabbro eutectic assemblage. Kane Megamullion and Hess Deep clinopyroxene core1 primocrysts and their plagioclase inclusions indicate crystallization from high temperature basalt (>1,160 and >1,200◦C, respectively), close to clinopyroxene saturation temperature (<50% and <25% crystallization). Step-like compatible Cr (and co-varying Al) and incompatible Ti, Zr, Y and rare earth elements (REE) decrease from anhedral core1 to overgrown core2, while Mg# and Sr/Sr∗ ratios increase. We show that partial resorption textures and geochemical zoning result from partial melting of REE-poor lower oceanic crust gabbroic cumulate (protolith) following intrusion by hot primitive mantle-derived melt, and subsequent overgrowth crystallization (refertilization) from a hybrid melt. In addition, toward the outer rims of crystals, Ti, Zr, Y and the REE strongly increase and Al, Cr, Mg#, Eu/Eu∗, and Sr/Sr∗ decrease, suggesting crystallization either from late-stage percolating relatively differentiated melt or from in situ trapped melt. Intrusion of primitive hot reactive melt and percolation of interstitial differentiated melt are two distinct MASH processes in the lower oceanic crust. They are potentially fundamental mechanisms for generating the wide compositional variation observed in mid-ocean ridge basalts. We furthermore propose that such processes operate at both slow- and fast-spreading ocean ridges.Thermal numerical modeling shows that the degree of lower crustal partial melting at slow-spreading ridges can locally increase up to 50%, but the overall crustal melt volume is low (less than ca. 5% of total mantle-derived and crustal melts; ca. 20% in fast-spreading ridges).
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Frontiers
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
spreading ridge
en_US
dc.subject
lower oceanic crust
en_US
dc.subject
partial melting
en_US
dc.subject
poikilitic gabbro
en_US
dc.subject
clinopyroxene
en_US
dc.subject
primocryst
en_US
dc.subject
zoning
en_US
dc.subject
MORB petrogenesis
en_US
dc.title
Partial Melting of Lower Oceanic Crust Gabbro: Constraints From Poikilitic Clinopyroxene Primocrysts
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
ethz.journal.title
Frontiers in Earth Science
ethz.journal.volume
6
en_US
ethz.journal.issue
6
en_US
ethz.journal.abbreviated
Front. Earth Sci.
ethz.pages.start
15
en_US
ethz.size
21 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Lausanne
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier::08786 - Ulmer, Peter (Tit.-Prof.)
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03417 - Heinrich, Christoph A. (emeritus) / Heinrich, Christoph A. (emeritus)
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier::08786 - Ulmer, Peter (Tit.-Prof.)
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03417 - Heinrich, Christoph A. (emeritus) / Heinrich, Christoph A. (emeritus)
ethz.date.deposited
2018-03-15T15:32:21Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2018-03-16T06:50:07Z
ethz.rosetta.lastUpdated
2022-03-29T10:50:51Z
ethz.rosetta.versionExported
true
ethz.COinS
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