A newly discovered 2030–2010 Ma magmatic suite records the dawn of Proterozoic extension on the southern margin of the Yilgarn Craton

• Published in: Precambrian research 2023-10, Vol.397, p.107192, Article 107192
• Main Authors: Tucker, Naomi M., Payne, Justin L., Kemp, Anthony I., Kirkland, Christopher L., Smyth, Ashleigh, Tunmer, Warrick, Harvey, Stephanie, Stinear, Melissa, Machuca, Adrian, Rangel Suarez, Samuel, De Waele, Bert
• Format: Article
• Language: English
• Subjects: Albany–Fraser Orogen; Bushveld; Lu–Hf isotope; Nuna; Yilgarn; zircon U–Pb geochronology
• ISSN: 0301-9268
• DOI: 10.1016/j.precamres.2023.107192

•We contribute 38 new U–Pb ages to the data-poor north-eastern Albany–Fraser Orogen;•Low sample volumes are used to meaningfully investigate concealed basement geology and the location of major Archean–Paleoproterozoic terrane boundaries;•A new and previously unrecognised felsic igneous suite is defined—the Moonyoora Suite (ca. 2030–2010 Ma);•Zircon U–Pb magmatic ages and Lu-Hf analyses indicate that the inception of Biranup Zone extension and magmatism on the southern margin of the Yilgarn Craton began ca. 200 Myr earlier than previously documented;•Emplacement of the Moonyoora Suite occurred at the start of a widespread extensional regime across the West Australian Craton, and a period of increased mafic magmatism globally. Uranium–lead zircon geochronology, zircon lutetium–hafnium isotope analyses and whole-rock geochemistry are used to investigate concealed basement geology and the location of Archean–Paleoproterozoic terrane boundaries in the northeastern Albany–Fraser Orogen (AFO). We identify a new major component of the AFO, and the first compelling evidence for ca. 2030–2010 Ma A-type felsic magmatism in western Australia. Prior to this study, the oldest rocks in the AFO that formed by extension and reworking of the southern Yilgarn Craton margin had protolith emplacement ages of ca. 1810–1800 Ma; our results extend this record by ca. 200 Myr and provide new insights into the crustal and tectonic evolution of the AFO. This phase of magmatism marks the start of a long-lived and widespread Paleoproterozoic extensional regime that prevailed across the West Australian Craton (WAC) for ∼ 400 Myr. Extension in the WAC was coeval with localised magmatism, volcanism and volcano-sedimentary basin formation in the North and South Australian cratons. Globally, our findings also correlate with the onset of prolonged extension and the generation of a vast tract of oceanic crust around the periphery of Nuna. We posit a petrogenetic link between ca. 2030–2010 Ma felsic rocks in the AFO and age–isotope-equivalent ultramafic–mafic rocks in the eastern Yilgarn Craton that are located along-strike and are interpreted to reflect a possible far-field and late-stage magmatic expression of the ca. 2060–2055 Ma Bushveld superplume.