Holocene sea-level change and coastal landscape evolution in the southern Gulf of Carpentaria, Australia

A Holocene sea-level history for the southern Gulf of Carpentaria has been constructed based on a review of previously published data, combined with data collected for this study from a variety of sea-level proxies. These sea-level proxies include beach ridges, claypans, mangrove swamps, fossilized in situcoral reefs, beachrock and aeolinite deposits. Results confirm that rising sea-levels during the last Post-Glacial Marine transgression beached the Arafura Sill ca. 11,700 years ago (-53 m), resulting in a change from lacustrine to a marine environment. Sea levels continued to rise to ca. -30 m by 10,000 years ago. By 7,700 cal. yr BP sea-level reached PMSL and continued to rise an elevation of between 1.5 and 2 m above present mean sea-level by 7,000 years ago. Elevated sea levels resulted in the development of raised coral reefs, beach-rock and aeolinite deposits, and the initiation of chenier plains and beach ridges. Sea-level remained ca. +1.5 m above PMSL during the Holocene highstand, accompanied by distinct phases of beach-ridge and chenier plain development. The highstand was followed by arapid regression to within ±0.5 m of PMSL by ca. 3,500 cal. yr BP. When placed into a wider regional context results from this study show thatcoastal landscape evolution in the tropical north of Australia was not only dependenton sea-level change but also show a direct correlation with Holocene climatevariability. Specifically, the formation and preservation of beach-rock deposits,intertidal successions, beach and chenier ridge systems hold valuable sea-level and Holoceneclimate proxies that can contribute to the growing research into lowerlatitude Holocene sea-level and climate histories. ©2019 The Authors.

Keywords

Quaternary period, Sea level, Rocks, Coastal regions, Climatic change, Australia

Citation

Sloss, C., Nothdurft, L., Hua, Q., Oconnor, S., Moss, P., Rosendahl, D., Petherick, L., Nanson, R., Mackenzie, L., Sternes, A., Jacobsen, G., & Ulm, S. (2019). Holocene sea-level change and coastal landscape evolution in the southern Gulf of Carpentaria, Australia. Poster presented to the 20th INQUA Congress 25th - 31st July 2019, Dublin, Ireland. Retrieved from: https://virtual.oxfordabstracts.com/#/event/public/574/submission/2892