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dc.contributor.author
EIMF (Edinburgh Ion Microprobe Facility)
dc.contributor.author
McCarthy, Anders John
dc.contributor.author
Chelle-Michou, Cyril
dc.contributor.author
Blundy, Jonathan D.
dc.contributor.author
Dorais, Michael J.
dc.contributor.author
van der Zwan, Froukje M.
dc.contributor.author
Peate, David W.
dc.date.accessioned
2023-04-05T12:54:57Z
dc.date.available
2023-04-02T06:53:44Z
dc.date.available
2023-04-04T12:40:24Z
dc.date.available
2023-04-05T12:54:57Z
dc.date.issued
2023-05-20
dc.identifier.issn
0009-2541
dc.identifier.issn
1872-6836
dc.identifier.other
10.1016/j.chemgeo.2023.121415
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/606145
dc.identifier.doi
10.3929/ethz-b-000606145
dc.description.abstract
We present textural and chemical analyses of minerals from a 150 m thick sequence of submarine mid-ocean ridge basalts from the South China Sea in order to showcase the effect of variations in magma cooling rates on mineral texture and mineral composition. Groundmass plagioclase and clinopyroxene show gradual changes in texture and composition as flows grade from slowly cooled, meter-thick massive flows to more rapidly cooled dm-thick pillow lobes with quenched glassy margins. The corresponding change in cooling-rate is estimated to vary from <1 to ≥100 °C/h. With increasing cooling rate, plagioclase forms elongated, sector-zoned swallow-tail crystals. Sector zoning is associated with increasing FeO (up to 1.5 wt%) and MgO (up to 0.6 wt%) abundances at near-constant anorthite (An), related to a two orders of magnitude increase in growth rate. Sr, Ba, Li and Ti abundances remain constant and appear unaffected by kinetic factors at such growth rates. With increasing cooling rate clinopyroxene becomes dendritic, and its composition is sensitive to changes in crystallization conditions. Increasing cooling rate (<1 to ≥100 °C/h) leads to increasing Al2O3 (average of 3.2 to 4.3 wt%), TiO2 (1.3 to 2.8 wt%) and Na2O (0.37 to 0.44 wt%) and a decrease in SiO2 (50.1 to 46.4 wt%) and Mg#Fetot, i.e., molar MgO/(MgO + FeOtot), from 71.3 to 53.1. Trace element abundances (Y, Zr, Ce, V, Sr) in clinopyroxene increase by up to an order of magnitude at cooling rates ≥100 °C/h and become more heterogeneous spatially. These results support experimental evidence that rapid crystal growth leads to significant departure of mineral compositions from equilibrium, in particular for clinopyroxene. Although plagioclase composition remains relatively insensitive to changes in growth conditions at the studied cooling rates, the sensitivity of clinopyroxene composition to growth rates imply that it should be used with caution as a tool to infer magmatic crystallization conditions.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Elsevier
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
Cooling-rate
en_US
dc.subject
MORB
en_US
dc.subject
Rapid-crystal growth, clinopyroxene
en_US
dc.subject
Plagioclase
en_US
dc.subject
Disequilibrium crystallization
en_US
dc.title
The effect of variations in cooling rates on mineral compositions in mid-ocean ridge basalts
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
dc.date.published
2023-03-13
ethz.journal.title
Chemical Geology
ethz.journal.volume
625
en_US
ethz.journal.abbreviated
Chem. geol.
ethz.pages.start
121415
en_US
ethz.size
15 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.grant
Kinetic fractionation of isotopes: constraining rapid crystal growth of plagioclase and short timescales of subvolcanic magmatic systems
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Amsterdam
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::09656 - Chelle-Michou, Cyril / Chelle-Michou, Cyril
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::09656 - Chelle-Michou, Cyril / Chelle-Michou, Cyril
ethz.grant.agreementno
193471
ethz.grant.fundername
SNF
ethz.grant.funderDoi
10.13039/501100001711
ethz.grant.program
Ambizione
ethz.date.deposited
2023-04-02T06:53:45Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2023-04-05T12:54:58Z
ethz.rosetta.lastUpdated
2024-02-02T21:31:54Z
ethz.rosetta.versionExported
true
ethz.COinS
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