Using monazite geochronology to test the plume model for carbonatites: The example of Gifford Creek Carbonatite Complex, Australia
MetadataShow full item record
Carbonatites are carbonate-dominated igneous rocks derived by low-degree partial melting of metasomatized mantle, although the geodynamic processes responsible for their emplacement into the crust are disputed. Current models favor either reactivation of lithospheric structures in response to plate movements, or the impingement of mantle plumes. Geochronology provides a means of testing these models, but constraining the age of carbonatites and related metasomatic events is rarely straightforward. We use in situ U-Th-Pb analysis of monazite by SHRIMP to constrain the emplacement age and hydrothermal history of the rare earth element-bearing Gifford Creek Carbonatite Complex in Western Australia, which has been linked to plume magmatism at ca. 1075 Ma. Monazite in carbonatites and related metasomatic rocks (fenites) from the carbonatite complex dates the initial emplacement of the carbonatite at 1361 ± 10 Ma (n = 22, MSWD = 0.91). The complex was subjected to multiple stages of magmatic/hydrothermal overprinting from ca. 1300 Ma to 900 Ma during later regional tectonothermal events. Carbonatite emplacement at ca. 1360 Ma appears to be an isolated igneous event in the region, and occurred about 300 million years before intrusion of the ca. 1075 Ma Warakurna large igneous province, thus precluding a genetic connection. The Gifford Creek Carbonatite Complex occurs within a major crustal suture, and probably formed in response to reactivation of this suture during plate reorganization. Our study demonstrates the veracity of monazite geochronology in determining the magmatic and hydrothermal histories of a carbonatite complex, critical for evaluating competing geodynamic models for carbonatites. The approach involving in situ SHRIMP U-Th-Pb dating of monazite from a wide spectrum of rocks in a carbonatite complex is best suited to establishing the intrusive age and hydrothermal history of carbonatites.
Showing items related by title, author, creator and subject.
Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range Carbonatite Complex, Halls Creek Orogen, Kimberley region, Western AustraliaDownes, P.; Dunkley, D.; Fletcher, I.; McNaughton, Neal; Rasmussen, B.; Jaques, A.; Verrall, M.; Sweetapple, M. (2016)In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb ...
Stable H–C–O isotope and trace element geochemistry of the Cummins Range Carbonatite Complex, Kimberley region, Western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regionsDownes, P.; Demeny, A.; Czuppon, G.; Jacques, A.; Verrall, M.; Sweetapple, M.; Adams, D.; McNaughton, Neal; Gwalani, L.; Griffin, B.J. (2014)The Neoproterozoic Cummins Range Carbonatite Complex (CRCC) is situated in the southern Halls Creek Orogen adjacent to the Kimberley Craton in northern Western Australia. The CRCC is a composite, subvertical to vertical ...
Origin of carbonatites in the South Qinling orogen: Implications for crustal recycling and timing of collision between the South and North China BlocksXu, C.; Chakhmouradian, A.; Taylor, R.; Kynicky, J.; Li, W.; Song, W.; Fletcher, Ian (2014)Most studies of compositional heterogeneities in the mantle, related to recycling of crustal sediments or delaminated subcontinental lithosphere, come from oceanic setting basalts. In this work, we present direct ...