Journal article

Age constraints on Oligocene sedimentation in the Torquay Basin, southeastern Australia

S McLaren, MW Wallace, SJ Gallagher, JA Dickinson, A McAllister



The Otway, Gippsland and central coast basins (including the Torquay Basin, Sorrento Graben and Port Phillip Basin) preserve one of the most complete records of Mesozoic and Cenozoic sedimentation in southern Australia. However, robust age constraints on sedimentation are scarce. Strontium isotope analysis of calcitic bioclasts from the Jan Juc Marl of the Torquay Group, Torquay Basin, gives a range of possible ages between 24.2 and 27.9 Ma for the Jan Juc Marl, and an age of 24.24 Ma (+1.3 Ma, -1.2 Ma) for the base of the Point Addis Limestone. These data demonstrate that the Jan Juc Marl and the lower Point Addis Limestone are age-equivalent facies representing deep- and shallow-water sedi..

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Awarded by Australian Research Council

Funding Acknowledgements

Ian McDougall and Qianyu Li are thanked for their helpful and detailed reviews of the manuscript. Strontium-isotope analysis was undertaken at the School of Earth and Environmental Sciences at the University of Adelaide and we thank David Bruce for his careful analytical work. Argon isotopic analyses were undertaken in the School of Earth Sciences at the University of Melbourne and we thank David Phillips and Stan Szczepanski for their assistance. SM, MWW and SJG acknowledge the support of Australian Research Council Discovery Grants DP0558705 and DP0558150, and SM acknowledges support of a University of Melbourne Faculty of Science Centenary Research Fellowship.