Classification of Australian Clastic Coastal Depositional Environments Based Upon a Quantitative Analysis of Wave, Tidal, and River Power

Abstract

A statistical assessment of wave, tide, and river power was carried out using a database of 721 Australian clastic coastal depositional environments to test whether their geomorphology could be predicted from numerical values. The geomorphic classification of each environment (wave- and tide-dominated deltas, wave- and tide-dominated estuaries, lagoons, strand plains, and tidal flats) was established independently from remotely sensed imagery. To our knowledge, such a systematic numerical analysis has not been previously attempted for any region on earth. The results of our analysis indicate that a relationship exists between the ratio of annual mean wave power to mean tidal power and the geomorphic development of clastic coastal depositional environments. Deltas and estuaries are associated with statistically significant differences in mean wave and tidal power. Statistically significant distinctions between populations of deltas, estuaries, strand plains, and tidal flats are also associated with river discharge and river flow rate (defined as discharge divided by open water area). Our results support the hypotheses of previous workers that wave, tide, and river power exert the principal control over the gross geomorphology and facies distribution patterns in clastic coastal depositional environments. Mean values and confidence limits of wave power, tide power, and river flow for the coastal depositional environments targeted in this study may provide a basis for the comparison of modern environments as well as constraints for paleo-reconstructions.