The Peake and Denison Inliers (comprising the Davenport Range, Denison Range and small basement inliers to the east) form the dominant geological structure on WARRINA. The Inliers include outcrops of Palaeoproterozoic metamorphic basement which is intruded by granitic and mafic rocks of Palaeoproterozoic and Mesoproterozoic ages. However, the bulk of the Peake and Denison Inliers is made up of a very thick sequence of Neoproterozoic sediments and basal basic volcanics which were deformed and intruded by intermediate and basic igneous rocks and diapiric structures during the early Palaeozoic Delamerian Orogeny. The rocks of the Inliers are prospective for copper, gold, lead, zinc, uranium and thorium. Concealed metamorphic basement, with a similar magnetic character to that of the Palaeoproterozoic basement in the Peake and Denison Inliers, occurs in western WARRINA (north-eastern Gawler Craton). Other basement zones in this area are thought to be equivalent to Palaeoproterozoic metamorphic basement of the Mabel Creek Ridge and Mount Woods Inlier. Granitic and mafic intrusions of Palaeoproterozoic and Mesoproterozoic age are inferred. The Boorthanna Trough lies between the Peake and Denison Inliers and the Gawler Craton. Seismic evidence indicates an older fill of Neoproterozoic sediments with associated diapiric structures and basal basic volcanics, presumably similar to the sequence exposed in the adjacent Inliers. It is overlain by Cambrian and ?Devonian sediments. Concealed Warburton Basin sediments of ?Ordovician age are inferred to occur outside of the Trough in north-eastern WARRINA, east of the Peake and Denison Inliers and north of the Lake Eyre Fault. Younger Phanerozoic basins on WARRINA include the late Palaeozoic Arckaringa Basin and Mesozoic Eromanga Basin. The former contains large coal resources, including the Weedina deposit, and also the most prospective hydrocarbon source rocks, within the deeper parts of the Boorthanna Trough area. The Eromanga Basin sequence comprises fluvial to marine sediments of Late Jurassic to Early Cretaceous age. The basal fluvial sediments form the major artesian groundwater aquifer in the region, and are prospective for placer gold and diamonds. Tertiary deposits are limited to silcreted fluvial sediments at the terminus of the Mirackina Palaeochannel and around the margins of the ranges, and local occurrences of lacustrine limestone. The most extensive Quaternary units on WARRINA are colluvial regolith deposits characterised by a surface gravel armour and hummocky relief ('gilgai'). Alluvial channel, fan and floodplain sediments, and aeolian dune deposits were formed during humid and arid climatic periods, respectively. Gypsite duricrusts, and claypan, playa lake and mound spring deposits, are also present.