Geochronology of metasedimentary and igneous rocks in the Lamboo Province, Kimberley region: reassessing collisional geodynamic models
Résumé
U–Pb and Lu–Hf isotope data for detrital zircons from metasedimentary rocks of the Lamboo Province have been used to test collisional and intraplate geodynamic models for the Paleoproterozoic development of the Kimberley region. The 1870–1840 Ma turbiditic metasedimentary rocks deposited across the Western, Central and Eastern Zones of the Lamboo Province have remarkably consistent detrital zircon age signatures, with a dominant 1875–1860 Ma age component and a subsidiary c. 2500 Ma age component. These age components have similar Lu–Hf isotope values across all three zones, consistent with a common source for the sedimentary protoliths. The close similarities in provenance suggest that all three zones of the Lamboo Province developed in a continental intraplate setting prior to the 1837–1808 Ma Halls Creek Orogeny, which has previously been considered to represent a collision between an exotic Kimberley Craton and the proto- North Australian Craton. Comparable provenance signatures of coeval metasedimentary rocks across the broader North Australian Craton suggest that assembly of the main craton elements was complete prior to c. 1885 Ma.
Domaines
Géochimie
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