This report presents geochemical constraints on the evolution of the Minbrie Gneiss and Carpa Granite, two magmatic units occurring in the southern Gawler Craton. These two units were previously assigned to the Palaeoproterozoic Lincoln Complex, however, recent geochronology has shown that they were emplaced over the interval c. 2520–2420 Ma and are therefore now recognised to be part of the Sleaford Complex (2570–2420 Ma). The Minbrie Gneiss is a heterogeneous unit comprising a range of lithological types including granitic gneiss, quartz-feldspar-biotite migmatitic gneiss, and minor paragneiss and sills of amphibolite, and shows a range of magmatic crystallisation ages, from 2520–2420 Ma. The Minbrie Gneiss is magnesian, calc-alkalic to alkalic and peraluminous in composition and has a juvenile and very narrow range of ?Nd(2520 Ma) values between -1.5 and 0 with a depleted mantle model age from 2.8–2.9 Ga. These isotopic compositions likely correspond to remelting of a source region similar in composition to the c. 2820 Ma Coolanie Gneiss, which crops out as a linear belt adjacent to the Minbrie Gneiss, and based on this observation is inferred to underlie it. The Carpa Granite is a massive, unfoliated to weakly foliated, medium-grained, quartz-K-feldspar-plagioclase-biotite-muscovite±garnet granite to monzogranite. Magmatic crystallisation ages range from c. 2520 to c. 2515 Ma. The Carpa Granite is high silica, magnesian, alkali-calcic and peraluminous. ?Nd(2520 Ma) values range from -6.4 to 2.8 and define distinct juvenile and evolved populations. Juvenile Carpa Granite has positive ?Nd(2500 Ma) values (1.7 to 2.7), indicating a significant mantle component. Evolved Carpa Granite has negative ?Nd(2500 Ma) values (-6.4 to -4.9), suggesting a significant crustal component, possibly reworking Mesoarchean (c. 2820 Ma Coolanie Gneiss or c. 3150 Ma Cooyerdoo Granite) basement.