Hot off the press! Paleoshorelines and lowstand sedimentation on subtropical shelves: a case study from the Fraser Shelf, Australia.

Fig 3. (a) Regional bathymetry (100 m grid) map of the study area encompassing the submerged geomorphic linear feature A and B, superimposed by high-resolution (6 m grid) multibeam swath mapping bathymetry shown in in colours. (b) Regional bathymetry with sub-bottom profiles across linear features A and B.

Please join me in congratulating former GRG Honours student Tiago Passos on the publication of his exciting new paper in the Australian Journal of Earth Sciences (AJES).

T. U. Passos, J. M. Webster, J. C. Braga, D. Voelker, W. Renema, R. J. Beaman, L. D. Nothdurft, G. Hinestrosa, S. Clarke, Y. Yokoyama, R. L. Barcellos, M. A. Kinsela, L. N. Nothdurft & T. Hubble (2019): Paleoshorelines and lowstand sedimentation on subtropical shelves: a case study from the Fraser Shelf, Australia, Australian Journal of Earth Sciences, DOI: 10.1080/08120099.2018.1558417

You can freely download the paper from the link below:

https://www.tandfonline.com/eprint/YgBVGXx5qj6Ceek4keTU/full?target=10.1080/08120099.2018.1558417

Please find a link below to a story recently published by ABC about the study:

https://www.abc.net.au/news/science/2018-12-19/ancient-sand-dunes-preserved-as-stone-under-the-sea/10615124

The key points of the paper are:

  • Dunes similar in shape and extent to those on Fraser Island were submerged about 12,000 years ago and are surprisingly well preserved.
  • The composition of the paleo-dunes are carbonate-dominated, contrasting with the composition of the sediments comprising the present day dunes on the Fraser Island, which are mainly composed of quartz grains (siliciclastic-dominated)
  • The preservation of these dunes on the sea floor is intriguing and the paper explains the processes by which the sediments were lithified.

This is a really interesting paper that looks at how the geomorphology of the now submerged aeolian dune and beach barrier system has changed in time and space as sea level flooded across the Fraser Shelf following the end of the Last Ice Age ~ 20,000 years ago. Our study confirms the marked contrast between lowstand and highstand depositional processes operating on mixed siliciclastic-carbonate subtropical shelves.

Cheers

Jody

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