The Tieyon 1:100 000 mapsheet area is located on the South Australia – Northern Territory border in the central Far North of South Australia. It covers rock units of the Mesoproterozoic Musgrave Province, the Mesozoic Eromanga Basin and the Neogene Hamilton Basin. The oldest rocks on Tieyon belong to the Mesoproterozoic Birksgate Complex, and consist of felsic and mafic orthogneisses and felsic volcanic units, volcaniclastic units and paragneisses. These rocks formed in an inferred volcanic arc setting between c. 1630–1560 Ma. Isotopic data suggest a significant component of new crustal growth at this time, although some of the rock units display evolved isotopic signatures and contain Archaean inherited zircons, suggesting that a possible Archaean basement component is present in the eastern Musgrave region. After burial, these Birksgate Complex volcanic arc rocks were subsequently deformed and metamorphosed to amphibolite facies conditions during the Musgravian Orogeny at c. 1155 Ma, which led to significant crustal anatexis and the production of localised granitic bodies. Near-synchronous with this deformation and metamorphism was the intrusion of the voluminous, felsic, A-type granitoid rocks of the Pitjantjatjara Supersuite at c. 1150 Ma. Granitoid rocks of the Pitjantjatjara Supersuite form several large plutonic bodies distributed over Tieyon, and they dominate the basement outcrops exposed within the mapsheet area. The eastern Musgrave region was intruded by a number of mafic rock units that post-date the Musgravian Orogeny. Geochemical evidence suggests that at least some of the mafic bodies and dolerite dykes may belong to the Alcurra Dolerite, which has been associated with the c. 1080 Ma Giles Event. However, geochronological data obtained from one such ferrodolerite on Tieyon indicate that it is c. 760 Ma in age, and thus is possibly related to the c. 820 Ma Amata/Gairdner Dolerite. A second, discrete suite of narrow olivine dolerites is interpreted to have formed at c. 1000 Ma, and is attributed to the Kullal Dolerite. During the Mesozoic, the Tieyon area formed the western margin of the intracratonic Eromanga Basin. In the south and east of the mapsheet area, the Late Jurassic fluvial Algebuckina Sandstone unconformably overlies gneisses and granitoid rocks of the Proterozoic basement. Limited outcrops of the overlying Cretaceous paralic Cadna-owie Formation and marine Bulldog Shale are also preserved. The Cenozoic saw a change to a more arid climate, leading to intense chemical weathering and the development of siliceous and ferruginous duricrusts. During the Late Paleogene the landscape underwent widespread erosion, resulting in the creation of flat, silcrete- and ferricrete-capped mesas and associated colluvial slope and sand plain deposits that are predominantly covered in siliceous, ferruginous or lithic lags. During the Neogene, rivers incised up to 70 m into the older cover sediments and basement, discharging their load into the Lake Eyre Basin. The channels were subsequently infilled with clastic sediments during a warm and wet subtropical to tropical climate, forming the strata of the Hamilton Basin. During the Quaternary, the onset of aridity, with episodes of alluvial and aeolian activity, resulted in the formation of today’s landscape features that comprise alluvial plains, sand plains, and aeolian dunes and dunefields. Continued erosion led to the widespread deposition of colluvium and sheetwash sediments around outcrops and adjacent uplands. Sand plains with thick mulga cover and a distinctive banded-mosaic (tiger-bush) vegetative pattern occupy wide swathes of the landscape, mirroring the extent of the Hamilton Basin.