12:00 PM - 12:15 PM
[SMP09-08] Comparison of Sr-Nd isotope data from N. Mozambique and Dronning Maud Land and Sor Rondane, Antarctica.
Keywords:N. and S. Gondwana, Sr and Nd isotopes, mega-nappe model, Kuunga Orogeny
Differences in published geochronological data from the metamorphic belts of the various areas are fundamental to defining the various components of the mega-nappe model. Comparison of published and unpublished Sr and Nd radiogenic isotope data, calculated at 500Ma from the metamorphic belt basement gneisses of the mega-nappe component areas, show broad differences between the different areas from N and S Gondwana.
Neoproterozoic to Cambrian-age granitoids which intrude the various areas mostly mirror their host country rocks suggesting localised anatexis without significant juvenile input. Sr and Nd isotope data from some of these intrusions suggest that they were sourced in the footwall but intrude the hanging wall components of the mega-nappe. The Sr-Nd data from the N Gondwana correlated areas dominantly show marginally negative, less evolved εNd characteristics but similar, positive, wide ranged εSr characteristics compared to the S. Gondwana correlated areas.
Comparison of the Sr-Nd isotopic provinces show broad similarities with various geophysical domains defined by recently published aeromagnetic and gravity data sets from Antarctica.
The data are evaluated in terms of their implications for the meg-nappe model for the Kuunga Orogeny.