Magmatism and metamorphism at ca. 1.45 Ga in the northern Gawler Craton: the Australian record of rifting within Nuna (Columbia)

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dc.contributor.authorMorrissey, L.J.
dc.contributor.authorBarovich, K.M.
dc.contributor.authorHand, M.
dc.contributor.authorHoward, K.E.
dc.contributor.authorPayne, J.L.
dc.date.issued2019
dc.description.abstractU–Pb monazite and zircon geochronology and calculated metamorphic phase diagrams from drill holes in the northern Gawler Craton, southern Australia, reveal the presence of ca. 1.45 Ga magmatism and metamorphism. Magmatism and granulite facies metamorphism of this age has not previously been recognised in the Gawler Craton. The magmatic rocks have steep LREE-enriched patterns and high Ga/Al values, suggesting they are A-type granites. Calculated metamorphic forward models suggest that this event was associated with high apparent thermal gradients and reached pressures of 3.2–5.4 kbar and temperatures of 775–815 °C. The high apparent thermal gradients may reflect pluton-enhanced metamorphism, consistent with the presence of A-type granites. The recognition of ca. 1.45 Ga tectonism in the northern Gawler Craton is added to a compilation of ca. 1.50–1.40 Ga magmatism, shear zone reactivation, rift basin development and isotope resetting throughout the South and North Australian Cratons that shows that this event was widespread in eastern Proterozoic Australia. This event is stylistically similar to ca. 1.45 Ga A-type magmatism and high thermal gradient metamorphism in Laurentia in this interval and provides further support for a connection between Australia and Laurentia during the Mesoproterozoic. The tectonic setting of the 1.50–1.40 Ga event is unclear but may record rifting within the Nuna (or Columbia) supercontinent, or a period of intracontinental extension within a long-lived convergent setting.
dc.description.statementofresponsibilityLaura J. Morrissey, Karin M. Barovich, Martin Hand, Katherine E. Howard, Justin L. Payne
dc.identifier.citationGeoscience Frontiers, 2019; 10(1):175-194
dc.identifier.doi10.1016/j.gsf.2018.07.006
dc.identifier.issn1674-9871
dc.identifier.orcidMorrissey, L.J. [0000-0001-7506-6117]
dc.identifier.orcidHand, M. [0000-0003-3743-9706]
dc.identifier.urihttp://hdl.handle.net/2440/117634
dc.language.isoen
dc.publisherChina University of Geosciences (Beijing) and Peking University; Elsevier
dc.relation.granthttp://purl.org/au-research/grants/arc/LP160100578
dc.relation.granthttp://purl.org/au-research/grants/arc/DP160104637
dc.rights© 2018, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NCND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
dc.source.urihttps://doi.org/10.1016/j.gsf.2018.07.006
dc.subjectGawler Craton; Laurentia; metamorphism; U-Pb geochronology; paleogeographic reconstruction
dc.titleMagmatism and metamorphism at ca. 1.45 Ga in the northern Gawler Craton: the Australian record of rifting within Nuna (Columbia)
dc.typeJournal article
pubs.publication-statusPublished

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