In late Pleistocene time Lake Dieri (ancestral ‘Greater Lake Eyre') was permanently filled during a wet climatic phase. Towards the close of Pleistocene time the watertable fell, Lake Dieri dried up, and its sediments deflated. Later the watertable rose, establishing ephemeral Lake Eyre in the deflated area, and Holocene sedimentation commenced. At about this time Lake Eyre tilted to the south and three sedimentary environments developed: (1)a saline playa environmentwithout saltcrusts in the northern end of the lake, where water drains away before wholly evaporating; (2)a terminal salina environmentin the south end, where evaporation of brines leaves saltcrusts overlying gypseous sediments; and (3) asaline flocculation environmentbetween the playa and salina environments, where sediments are deposited by flocculation when muddy floodwater from the north meets highly saline water of the southern salina.