Investigation of the Upalinna Diapir, located 20 km east of Wilpena Pound in the Adelaide Geosyncline, has identified a number of structural and sedimentary features normally associated with evaporite diapirs. The Upalinna Diapir is a small, polygonal-shaped structure that is centrally located within a domal anticline defined by bedding of the Umberatana Group. It is structurally asymmetrical, being fault-bounded on the western side. These diapir rim faults may be an upper level expression of basement-anchored master faults that acted as conduits for brecciated material, or may be related to the growth of withdrawal features that have offset strata of the Tapley Hill Formation. The brecciated core of the diapir is dominantly composed of siltstone, heavy mineral-laminated sandstone and well-bedded limestone that are assigned to the Niggly Gap Beds and Arkaba Hill Beds of the Callanna Group. Brecciation of the Niggly Gap Beds is interpreted as the result of large-scale dissolution of salt. It is suggested that salt in this unit was responsible for the viscosity contrast that led to diapiric emplacement of Callanna Group sediments. Outcrop of the diapir appears to display an erosional section through a mushroom-shaped bulb that contains a number of small diapirs within a larger diapiric body. The mushroom model has important implications for the concept of diapirism in the Flinders Ranges and exploration of domal structures in the Adelaide Geosyncline. The Umberatana Group, adjacent to the Upalinna Diapir, is a succession of late Precambrian shale, sandstone and dolomite. Sequence stratigraphy of the upper Umberatana Group has provided a framework for intra-regional chronostratigraphic correlation, and has identified 4 major sequence boundaries. Each is represented by an unconformity, found at the base respectively of the Wilyerpa Formation, Tapley Hill Formation, Tarcowie Siltstone and Elatina Formation. Sequence analysis has also been used to explain the apparent diachronous nature of the Etina Formation, and suggests that the base of the Marinoan in the Adelaide Geosyncline is a sequence boundary. A relatively thin succession of shallow marine sediments, belonging to the Wilyerpa Formation, is interpreted to have been deposited during diapiric emplacement of the breccia. A low-angle unconformity between the Wilyerpa Formation and Tapley Hill Formation also suggests that the diapir was possibly active at the time of sedimentation. A number of members of the Tapley Hill Formation have been differentiated. The Wockerawirra Dolomite Member of the Tapley Hill Formation is unconformably overlain by a thin oolitic limestone. The oolitic limestone is assigned to the Cox Sandstone Member of the Tarcowie Siltstone. The occurrence of these prominent unconformities in close proximity to the Upalinna Diapir suggests an intimate relationship between periods of active diapirism and the development of sequence boundaries in the Umberatana and Wilpena Groups of the central and northern Flinders Ranges.