The Development of the Princess Charlotte Bay Chenier Plain

Abstract

Chenier plains record changes in the mode of coastal progradation between periods of mudflat progradation and coarse sediment deposition. There are several environmental forces responsible for these changes. Chenier research worldwide has led to an understanding of these forces in some settings. In Australia, however, the causes of these changes are still not well understood. Several conflicting theories have been proposed to explain the development of a chenier plain in Princess Charlotte Bay on the eastern coast of Cape York, northern Queensland, Australia. These include an internal dynamic, climate fluctuations, and storm activity. Since these were put forward, both our methods and our understanding of Holocene environmental processes have improved. Improvements include new dating methods with luminescence techniques. Improvements to our understanding include a body of research regarding Holocene climate and sea level changes. These have allowed a re-examination of the development of the Princess Charlotte Bay chenier plain. Data was obtained from a different section of the bay than was examined previously. Optically-stimulated luminescence and radiocarbon ages from eight of the 11 chenier ridges yielded estimates of Holocene chenier ridge building phases. These were: (1) An early phase from around 4000 yr BP 2000 yr BP (seven ridges built); (2) a phase centred on approximately 1350 yr BP (two ridges built); and (3) a phase since 820 yr BP (one ridge built). Six models for chenier plain formation were tested. It was proposed that the development of the chenier plain has been driven by several environmental forces acting in a morphodynamic hierarchy. From first order to fourth order, these forces are: (1) Holocene climate and sea level changes, (2) tropical cyclone activity, (3) mangrove distribution, and longshore currents, and (4) river channel changes. A statistical reassessment of Australian chenier ridge ages was also undertaken and revealed periods of non-localised chenier ridge building across multiple northern Australia sites at around 620, 1120, 1850, and 2230 cal yr BP, and around the entire continent between 2400 and 1300 cal yr BP. These results provide further support that sea level oscillations have played a role in chenier plain development in Australia.