Physical evolution of Grande Ronde Basalt magmas, Columbia River Basalt Group, north-western USA

Caprarelli, G; Reidel, SP

Physical evolution of Grande Ronde Basalt magmas, Columbia River Basalt Group, north-western USA

Caprarelli, G

Reidel, SP

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Publication Type:: Journal Article
Citation:: Mineralogy and Petrology, 2004, 80 (1-2), pp. 1 - 25
Issue Date:: 2004-01-01

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Field	Value	Language
dc.contributor.author	Caprarelli, G https://orcid.org/0000-0001-9578-3228	en_US
dc.contributor.author	Reidel, SP	en_US
dc.date.issued	2004-01-01	en_US
dc.identifier.citation	Mineralogy and Petrology, 2004, 80 (1-2), pp. 1 - 25	en_US
dc.identifier.issn	0930-0708	en_US
dc.identifier.uri	http://hdl.handle.net/10453/696
dc.description.abstract	In this paper we present what is, to the best of our knowledge, the first comprehensive study of clinopyroxenes and plagioclases contained in the flows of the Grande Ronde Basalt member of the Columbia River Basalt Group (northwestern USA). The rocks have MgO (wt%) <6, and trace amounts of Cr and Ni. About 56% of extracted solid containing normative clinopyroxene and plagioclase explains the liquid line of descent from the more mafic sample (MgO=5.89wt%) to the most evolved. The most ubiquitous phases in the basalts; are plagioclase and augite. Ilmenite and magnetite are accessories in all rocks. Olivine is present in small amount only in one sample (RT 89-7). Based on principles of Ca-Na plagioclase-liquid exchange, estimates of preeruptive magmatic water are <2.4wt%. From clinopyroxene-liquid equilibria, calculated pressures and temperatures of ascending magmas are between I atm and 0.617 GPa, and 1068°C and 1166°C, respectively. Compositions of magnetite-ilmenite pairs and olivine-clinopyroxene-oxide assemblages yield post-eruptive oxygen fugacities of △NNO =-1.923, and one pre-eruptive value of △NNO =-2.455. A simple model of asthenospheric melting and magma pending in the lower crust fits the physical parameters. © Springer-Verlag 2004.	en_US
dc.relation.ispartof	Mineralogy and Petrology	en_US
dc.relation.isbasedon	10.1007/s00710-003-0017-1	en_US
dc.subject.classification	Energy	en_US
dc.title	Physical evolution of Grande Ronde Basalt magmas, Columbia River Basalt Group, north-western USA	en_US
dc.type	Journal Article
utslib.citation.volume	1-2	en_US
utslib.citation.volume	80	en_US
utslib.for	0403 Geology	en_US
utslib.for	0402 Geochemistry	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	1-2	en_US
pubs.publication-status	Published	en_US
pubs.volume	80	en_US

Abstract:

In this paper we present what is, to the best of our knowledge, the first comprehensive study of clinopyroxenes and plagioclases contained in the flows of the Grande Ronde Basalt member of the Columbia River Basalt Group (northwestern USA). The rocks have MgO (wt%) <6, and trace amounts of Cr and Ni. About 56% of extracted solid containing normative clinopyroxene and plagioclase explains the liquid line of descent from the more mafic sample (MgO=5.89wt%) to the most evolved. The most ubiquitous phases in the basalts; are plagioclase and augite. Ilmenite and magnetite are accessories in all rocks. Olivine is present in small amount only in one sample (RT 89-7). Based on principles of Ca-Na plagioclase-liquid exchange, estimates of preeruptive magmatic water are <2.4wt%. From clinopyroxene-liquid equilibria, calculated pressures and temperatures of ascending magmas are between I atm and 0.617 GPa, and 1068°C and 1166°C, respectively. Compositions of magnetite-ilmenite pairs and olivine-clinopyroxene-oxide assemblages yield post-eruptive oxygen fugacities of △NNO =-1.923, and one pre-eruptive value of △NNO =-2.455. A simple model of asthenospheric melting and magma pending in the lower crust fits the physical parameters. © Springer-Verlag 2004.

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http://hdl.handle.net/10453/696