There are numerous geological and geomorphic features in King Sound and the tide-dominated delta of the Fitzroy River that are of International to National geoheritage significance. Set in a tropical semiarid climate, the delta of the Fitzroy River has the largest tidal range of any tide-dominated delta in the World. Within King Sound, the Quaternary stratigraphy, comprised of early Holocene gulf-filling mud formed under mangrove cover and followed by middle to late Holocene deltaic sedimentation, and the relationship between Pleistocene linear desert dunes and Holocene tidal flat sediment are globally unique and provide important stratigraphic and climate history models. The principles of erosion, where sheet, cliff and tidal creek erosion combine to develop tidal landscapes and influence (mangrove) ecological responses also provide a unique global classroom for such processes. The high tidal parts of the deltaic system are muddy salt flats with groundwater salinity ranging up to hypersaline. Responding to this, carbonate nodules of various mineralogy are precipitated. Locally, linear sand dunes discharge freshwater into the hypersaline salt flats. With erosion, there is widespread exposure along creek banks and low tidal flats of Holocene and Pleistocene stratigraphy, and development of spits and cheniers in specific portions of the coast
