Enriched continental flood basalts from depleted mantle melts : modeling the lithospheric contamination of Karoo lavas from Antarctica

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dc.contributor.author Heinonen, Jussi S.
dc.contributor.author Luttinen, Arto V.
dc.contributor.author Bohrson, Wendy A.
dc.date.accessioned 2016-01-21T13:12:01Z
dc.date.available 2016-01-21T13:12:01Z
dc.date.issued 2016-01
dc.identifier.citation Heinonen , J S , Luttinen , A V & Bohrson , W A 2016 , ' Enriched continental flood basalts from depleted mantle melts : modeling the lithospheric contamination of Karoo lavas from Antarctica ' , Contributions to Mineralogy and Petrology , vol. 171 , no. 1 , 9 . https://doi.org/10.1007/s00410-015-1214-8
dc.identifier.other PURE: 56494107
dc.identifier.other PURE UUID: aeadde7f-7a60-4198-897d-617de26f3acd
dc.identifier.other WOS: 000368702600009
dc.identifier.other Scopus: 84951079216
dc.identifier.other ORCID: /0000-0002-3129-0392/work/30885302
dc.identifier.uri http://hdl.handle.net/10138/159633
dc.description.abstract Continental flood basalts (CFBs) represent large-scale melting events in the Earth’s upper mantle and show considerable geochemical heterogeneity that is typically linked to substantial contribution from underlying continental lithosphere. Large-scale partial melting of the cold subcontinental lithospheric mantle and the large amounts of crustal contamination suggested by traditional binary mixing or assimilation-fractional crystallization models are difficult to reconcile with the thermal and compositional characteristics of continental lithosphere,however. The well-exposed CFBs of Vestfjella, western Dronning Maud Land,Antarctica, belong to the Jurassic Karoo large igneous province and provide a prime locality to quantify mass contributions of lithospheric and sublithospheric sources for two reasons: 1) recently discovered CFB dikes show isotopic characteristics akin to mid-ocean ridge basalts, and thus help to constrain asthenospheric parental melt compositions, and 2) the well-exposed basaltic lavas have been divided into four different geochemical magma types that exhibit considerable trace element and radiogenic isotope heterogeneity (e.g., initial εNd from-16 to +2 at 180 Ma). We simulate the geochemical evolution of Vestfjella CFBs using 1) energy-constrained assimilation-fractional crystallization equations that account for heating and partial melting of crustal wallrock and 2)assimilation-fractional crystallization equations for lithospheric mantle contamination by using highly alkaline continental volcanic rocks (i.e. partial melts of mantle lithosphere) as contaminants. Calculations indicate that the different magma types can be produced by just minor (1–15 wt. %) contamination of asthenospheric parental magmas by melts from variable lithospheric reservoirs. Our models imply that the role of continental lithosphere as a CFB source component or contaminant may have been overestimated in many cases. Thus, CFBs may represent major juvenile crustal growth events rather than just recycling of old lithospheric materials. fi
dc.description.abstract Continental flood basalts (CFBs) represent large-scale melting events in the Earth’s upper mantle and show considerable geochemical heterogeneity that is typically linked to substantial contribution from underlying continental lithosphere. Large-scale partial melting of the cold subcontinental lithospheric mantle and the large amounts of crustal contamination suggested by traditional binary mixing or assimilation-fractional crystallization models are difficult to reconcile with the thermal and compositional characteristics of continental lithosphere,however. The well-exposed CFBs of Vestfjella, western Dronning Maud Land,Antarctica, belong to the Jurassic Karoo large igneous province and provide a prime locality to quantify mass contributions of lithospheric and sublithospheric sources for two reasons: 1) recently discovered CFB dikes show isotopic characteristics akin to mid-ocean ridge basalts, and thus help to constrain asthenospheric parental melt compositions, and 2) the well-exposed basaltic lavas have been divided into four different geochemical magma types that exhibit considerable trace element and radiogenic isotope heterogeneity (e.g., initial εNd from-16 to +2 at 180 Ma). We simulate the geochemical evolution of Vestfjella CFBs using 1) energy-constrained assimilation-fractional crystallization equations that account for heating and partial melting of crustal wallrock and 2)assimilation-fractional crystallization equations for lithospheric mantle contamination by using highly alkaline continental volcanic rocks (i.e. partial melts of mantle lithosphere) as contaminants. Calculations indicate that the different magma types can be produced by just minor (1–15 wt. %) contamination of asthenospheric parental magmas by melts from variable lithospheric reservoirs. Our models imply that the role of continental lithosphere as a CFB source component or contaminant may have been overestimated in many cases. Thus, CFBs may represent major juvenile crustal growth events rather than just recycling of old lithospheric materials. en
dc.format.extent 22
dc.language.iso eng
dc.relation.ispartof Contributions to Mineralogy and Petrology
dc.rights.uri info:eu-repo/semantics/openAccess
dc.subject 1171 Geosciences
dc.subject CONTINENTAL FLOOD BASALTS
dc.subject KAROO IGNEOUS PROVINCE
dc.subject mantle source
dc.subject CONTAMINATION
dc.title Enriched continental flood basalts from depleted mantle melts : modeling the lithospheric contamination of Karoo lavas from Antarctica en
dc.title.alternative Rikastuneita mantereisia laakiobasaltteja köyhtyneistä vaipan sulista: litosfäärikontaminaation mallinnus Antarktiksen Karoo-laavoille fi
dc.type Article
dc.contributor.organization Department of Geosciences and Geography
dc.contributor.organization Finnish Museum of Natural History
dc.contributor.organization Natural Sciences Unit
dc.description.reviewstatus Peer reviewed
dc.relation.doi https://doi.org/10.1007/s00410-015-1214-8
dc.relation.issn 0010-7999
dc.rights.accesslevel openAccess
dc.type.version acceptedVersion
dc.identifier.url http://link.springer.com/content/pdf/10.1007%2Fs00410-015-1214-8.pdf

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