The interplay of fluvial, lacustrine and aeolian deposition and erosion along the Neales Cliffs and its relevance to the evolution of Kati Thanda-Lake Eyre, central Australia, during the Quaternary

ABSTRACT

A high-resolution record of fluvial, aeolian and lacustrine deposits of Late Pleistocene age is exposed along the Neales Cliff in the lower reaches of the Nappamurra-Neales River, western Kati Thanda-Lake Eyre (KT-LE). Five major stratigraphic units reflect a variety of changes in sedimentary processes, depositional environments and hence palaeo-lake level fluctuations. This detailed record of a dryland terrestrial sedimentary succession in the northern part of KT-LE enables comparison to contemporaneous sequences in the southern part of KT-LE. The sedimentary record from the Neales Cliff area is placed into a continental stratigraphic framework, in which changes in sediment accumulation and depositional style are linked to climatically driven palaeo-lake level fluctuations independent of eustatic sea-level changes. Following the ~200 ka interglacial maximum, a drying-up systems tract is represented by a fluvial fining-upward trend, capped by palaeosols. A wettening-up systems tract followed, when lake level rose to +10 m AHD during the last interglacial, resulting in a lacustrine succession but punctuated by regular desiccation events. During the following drying-up systems tract, progressive lake-level fall resulted in deep incision around 100 ka, followed by enhanced fluvial deposition of fine-grained sediments. A brief rise in base level resulted in a wettening-up systems tract comprising a thin veneer of fluvial/alluvial sediments followed by extensive dune build-up and desert pavement development during the Last Glacial Maximum. Subsequent lake level fall to the present lake level of −15 m AHD, resulted in deep incision of up to 10 m by the modern day Nappamurra-Neales River.

KEYWORDS:

• drylands
• wet-dry cycles
• lake level changes
• Kati Thanda-Lake Eyre

Acknowledgments

We acknowledge the Traditional Owners of the land on which we conducted our research, the Arabana people, and pay our respects to Elders past, present and emerging. This research was funded by the former Lake Eyre Basin Analogue Research Group Consortium (LEBARG) at the Australian School of Petroleum (now ASPER), The University of Adelaide. We thank former students and colleagues Mark Reilly, Victor Waclawik, Saju Menacherry, John Fischer, Tobias Payenberg, Steve Hasiotis, John Holbrook, Ian Moffat, Claire Davis, Ferran Colombo and all the LEBARG Phase 2 and 3 consortium members for fieldwork contributions, discussion and funding support. Travis Gotch is thanked for undertaking the RTK-DGPS survey in the study area. Thanks to Anna Creek station for facilitating access to the station. We thank present and past owners of the Williams Creek hotel and Dingo’s for their support over many field seasons, especially Trevor Wright. We thank Tim Cohen and an anonymous reviewer for their very helpful and insightful comments and reviews. We also would like to thank Jan-Hendrik May and Trevor Worthy for their exceptional editorial assistance and help.

Disclosure statement

No potential conflict of interest was reported by the author(s).