Doctor of Philosophy
School of Earth, Atmospheric and Life Sciences
The study of relative sea-level changes and ultimately glacio-eustatic sea-level for the Late Quaternary, is commonly addressed by analysing the ocean-land interface from continental shelves, which represent submerged former coastal plains established during periods of low sea-level. In Late Quaternary time, only during the last interglacial MIS 5e highstand (128 – 116 ka) and during the present, Holocene interglacial, has sea level been near or above present sea-level. The Lacepede Shelf is a large (30,000 km2), wide (180 km) and shallow (up to 120 m) embayment, which has been partly or entirely subaerially exposed during the Late Quaternary. The shelf is a far-field environment from Pleistocene ice sheets and is tectonically stable in a global context. The Lacepede Shelf is bordered to the north by the Murray Basin, a Paleogene–Quaternary epicratonic sedimentary basin. The high level of tectonic stability of the region implies that environmental changes experienced on the shelf were largely a function of sea-level changes. The Murray Basin and Coorong Coastal Plain, adjacent to the Lacepede Shelf, represent a sequence of Paleogene to Quaternary emergent interglacial barriers of international significance in the study of the Quaternary sea-level fluctuations. The Coorong Coastal Plain extends up to 100 km inland from the modern shoreline and its 20 barriers record their formation during interglacial and warm interstadial highstands. In contrast, the Lacepede Shelf preservers a record of Late Pleistocene lowstand deposition, and a rising-stage period of sea-level, associated with the post-Last Glacial Maximum transgression. Accordingly, the Lacepede Shelf is an ideal realm for the study of aspects of Late Quaternary sea-level changes.
While Late Quaternary glacio-eustatic sea-levels are well established, controversies remain regarding the magnitude of highstands and lowstands, the timing of the Last Glacial Maximum (LGM) and the number of highstands during MIS 3 (North Greenland Ice Core Project, NGRIP, core vs. sedimentary record). To address some of these controversies at a regional scale, this thesis focuses on reconstructing palaeoenvironmental changes associated with sea-level oscillations on the Lacepede Shelf. The study is based on five sediment cores located broadly in a north-south transect across the depocenter of the continental platform. The core sites correspond with the location of the former courses of the River Murray, at the time of glacial low sea-level.
Lahuerta Piñeiro, Núria, Late Quaternary environmental reconstruction of the Lacepede Shelf, southern Australia, Doctor of Philosophy thesis, School of Earth, Atmospheric and Life Sciences, University of Wollongong, 2021. https://ro.uow.edu.au/theses1/1418
FoR codes (2008)
040308 Palaeontology (incl. Palynology), 040310 Sedimentology, 040311 Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy), 040606 Quaternary Environments
Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.