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dc.contributor.authorLindsay, JJ
dc.contributor.authorAndersen, JCØ
dc.contributor.authorHughes, HSR
dc.contributor.authorMcDonald, I
dc.contributor.authorHastie, AR
dc.contributor.authorBesser, ML
dc.contributor.authorLicht, OAB
dc.contributor.authorArioli, EE
dc.date.accessioned2021-08-09T08:11:18Z
dc.date.issued2021-08-02
dc.description.abstractThe 135 Ma Paraná-Etendeka Large Igneous Province (PELIP) is one of the largest areas of continental flood basalt (CFB) volcanism in the world and is widely agreed to be a product of intracontinental melts related to thermal anomalies from the Tristan mantle plume. The province rifted during the break-up of Gondwana, as the plume transitioned into an oceanic geodynamic environment. This study reports analyses of plume-derived basalts from the Brazilian side of the PELIP (the Serra Geral Group) to investigate major, trace and platinum-group element (PGE) abundances in an evolving plume-rift metallogenic setting, with the aim of contextualising metallogenic controls alongside existing magmatic interpretations of the region. The chalcophile geochemistry of these basalts defines three distinct metallogenic groupings that fit with three modern multi-element magma classifications for Serra Geral lavas. In this scheme, Type 4 lavas have a distinctive PGE-poor signature, Type 1 (Central-Northern) lavas are enriched in Pd, Au and Cu, and Type 1 (Southern) lavas are enriched in Ru and Rh. Our trace element melt modelling indicates that the compositional variations result from changes in the melting regime between the garnet and spinel stability fields, in response to the thinning and ‘unlidding’ of the rifting continent above. This process imposes progressively shallower melting depths and higher degrees of partial melting. Accordingly, Type 4 magmas formed from small degree melts, reducing the likelihood of sulfide exhaustion/chalcophile acquisition at source. Type 1 (Central-Northern) magmas incorporated components of the sub-continental lithospheric mantle (SCLM)-derived in higher-degree partial melts; the SCLM was heterogeneously enriched via metasomatism prior to plume melting, and this produced enrichment in volatile metals (Pd, Cu, and Au) in these magmas. In contrast, the Ru-Rh enrichment in Type 1 (Southern) lavas is attributed to increased spinel-group mineral and sulphide incorporation from the mantle into higher degree partial melts close to the continental rift zone. Our models confirm the importance of contributions from SCLM melts in precious metal mineral systems within CFB provinces, and reinforce the role of heterogeneous metasomatic enrichment underneath cratons in boosting intracontinental prospectivity with respect to ore deposits.en_GB
dc.description.sponsorshipUniversity of Exeteren_GB
dc.identifier.citationPublished online 2 August 2021en_GB
dc.identifier.doi10.1016/j.gca.2021.07.035
dc.identifier.urihttp://hdl.handle.net/10871/126713
dc.language.isoenen_GB
dc.publisherElsevier / Meteoritical Society / Geochemical Societyen_GB
dc.rights© 2021. Open access. This version is made available under the CC-BY-NC-ND 4.0 license: https://creativecommons.org/licenses/by-nc-nd/4.0/  en_GB
dc.subjectPGEen_GB
dc.subjectgeochemistryen_GB
dc.subjectparanáen_GB
dc.subjectplumeen_GB
dc.subjectflood basalten_GB
dc.subjectIgneousen_GB
dc.subjectMantleen_GB
dc.titlePlatinum-group element geochemistry of the Paraná flood basalts – modelling metallogenesis in rifting continental plume environmentsen_GB
dc.typeArticleen_GB
dc.date.available2021-08-09T08:11:18Z
dc.identifier.issn0016-7037
dc.descriptionThis is the author accepted manuscript. The final version is available on open access from Elsevier via the DOI in this recorden_GB
dc.identifier.journalGeochimica et Cosmochimica Actaen_GB
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/  en_GB
dcterms.dateAccepted2021-07-27
rioxxterms.versionAMen_GB
rioxxterms.licenseref.startdate2021-08-02
rioxxterms.typeJournal Article/Reviewen_GB
refterms.dateFCD2021-08-09T08:08:05Z
refterms.versionFCDAM
refterms.dateFOA2021-08-09T08:11:29Z
refterms.panelBen_GB


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© 2021. Open access. This version is made available under the CC-BY-NC-ND 4.0 license: https://creativecommons.org/licenses/by-nc-nd/4.0/  
Except where otherwise noted, this item's licence is described as © 2021. Open access. This version is made available under the CC-BY-NC-ND 4.0 license: https://creativecommons.org/licenses/by-nc-nd/4.0/