The Hoyran Lake Basin is an example of a Neogene rift basin in southwest Turkey. Initially red coloured, poorly-sorted, angular cobble to pebble conglomerates were deposited close to the boundary faults. These conglomerates then passed into the finer-grained, calcite-cemented pebble to granule conglomerates towards the basin interior. The distributions of other lacustrine lithofacies (siltstone/claystone, marlstone, limestone and magnesite) appear to have been dependent on the proximity of the lake margins. These occurrences show that the basin was subject to some climatic and tectonic controls. Humid seasons and/or tectonic activities resulted in increased clastic input from the lake margins, drier conditions enhanced evaporation and significantly modified the water chemistry. Ultramafic and dolomitic older rocks around the basin are considered to have been an important source for the ion concentrations implicated in the precipitation of dolomite and magnesite in the Hoyran Lake deposits.