Existing measurements from South Australia define a broad (>250 km wide) zone of anomalously high surface heat flow (92±10 mW m−2). This zone is centred on the western margin of the Adelaide Fold Belt (Neoproterozoic to early Phanerozoic cover floored by Palaeoproterozoic to Mesoproterozoic basement), where it borders the eastern Gawler Craton and Stuart Shelf (Palaeoproterozoic–Mesoproterozoic). To the west, in the western Gawler Craton (Archaean to Palaeoproterozoic), heat flow averages ∼54 mW m−2 while to the east in the Willyama Inliers (Palaeoproterozoic) heat flow averages ∼75 mW m−2. We use a regional geochemical dataset comprising >2500 analyses to show that the anomalous heat flow zone correlates with exceptional surface heat production values, mainly hosted in Palaeoproterozoic to Mesoproterozoic granites. The median heat production of Precambrian ‘basement’ rocks increases from