Multi‐Stage Evolution of the South Australian Craton: Petrological Constraints on the Architecture, Lithology, and Geochemistry of the Lithospheric Mantle

To improve the understanding of formation and evolution sub-continental lithospheric mantle (SCLM) underlying South Australian Craton we have conducted a detailed petrological study on >3,000 xenocrysts from 13 kimberlites emplaced across craton. Pressure (P) temperature (T) estimates Cr diopside garnet been coupled with their chemical concentrations to constrain thickness chemo-lithostratigraphy. We show that is greatest beneath Gawler Craton, whereas thinner lithosphere occurs Adelaide Fold Belt. Mineral compositions highlight two litho-chemical domains within shallow deep SCLM are separated by mid-lithosphere discontinuity (MLD). The (60–130 km) comprises low Cr2O3 lherzolite wehrlite. Shallow record depleted refertilized enriched in light rare earth elements related metasomatism kimberlite or melts. (130–160 which may relate layer pargasite lherzolite. (>160 high elevated TiO2 FeO. interpret stratification reflect multi-stage top-down growth. reflects an amalgamation Precambrian cratonic nuclei characterized heterogeneity geochemical enrichment depletion. Interaction plumes accreted melts along paleo-lithosphere-asthenosphere boundary, now as MLD. represents residue formed during plume impingement thickened orogenesis. This domain has metasomatized high-T asthenosphere.