Poster Presentation Australian Marine Sciences Association 2026 Conference

Reconstructing Holocene Sea-level change along the southeastern Australian margin: new field evidence from Broulee Head (139577)

Niranjana Joy Manayil 1 , Thomas Oliver 1 , Alissa Flatley 1 , Mark Hoggard 2
  1. University of New South Wales, Campbell, ACT, Australia
  2. Earth Sciences, The Australian National University, Canberra, ACT, Australia

Coastal sedimentary archives preserved along the southeastern Australian margin provide an opportunity to reconstruct palaeo sea-level positions and other paleoclimatic signals across glacial-interglacial cycles. This research addresses a critical gap in global palaeo sea-level databases by reconstructing relative sea-level (RSL) change along this tectonically stable far-field margin, with a focus on refining the timing and elevation of the Holocene highstand.

This study presents preliminary field evidence from Broulee Head, New South Wales, where raised beach and dune deposits have been sampled to reconstruct relative sea-level history. Radiocarbon dating of shell materials and OSL dating of dune sediments will provide geochronological constraints to establish the age of coastal landforms and derive new sea-level index points (SLIPs) for the region. These will be assessed against existing Australian sea-level curves to further constrain the Holocene highstand along the southeastern coast.

This work contributes to a broader multi-proxy reconstruction of palaeo shoreline positions along this margin. Future fieldwork at additional sites will expand the spatial coverage of this record. The collated field-derived RSL dataset will be used alongside GIA modelling to explore ice sheet and Earth structure controls on sea-level change, and to critically evaluate model predictions against field reconstructions.

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