A last interglacial embayment fill at Normanville, South Australia, and its neotectonic implications
Date
1999
Authors
Bourman, R.P.
Belperio, A.
Murray Wallace, C.
Cann, J.
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Advisors
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Journal article
Citation
Transactions of the Royal Society of South Australia, 1999; 123(1-2):1-15
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Abstract
Stratigraphic, sedimentological, amino acid racemisation, thermoluminescence (TL) and foraminiferal analyses of an embayment fill at Normanville, south of Adelaide, have established the presence of the last interracial (Oxygen Isotope Substage 5e) subtidal sediments of the Glanville Formation at elevations of up to 12 metres AHD. Overlying aeolian deposits, dated at about 60 to 50 ka, are possible equivalents of the Fulham Sand of the Adelaide area. TL dating of the Fulham Sand from its type borehole location yielded an age of 74.9 ± 6.9 ka, considerably older than previous estimates but compatible with a recent re-evaluation of the age of the Pooraka Formation. The altitude of the last interglacial shoreline at Normanville at + 12 m AHD is considerably higher than at Dry Creek (- 1.26 m AHD), Sellicks Beach (+ 4 to 5 m AHD), Victor Harbor (+ 6 m AHD) and Hindmarsh Island (+ 1 m AHD) and implies 10 m of uplift at this site relative to South Australian bench mark sites. The variation in altitude of the last interglacial Glanville Formation from Gulf St Vincent, across Fleurieu Peninsula to the Murray Basin reflects continuation of the tectonic activity revealed by dislocation of older Miocene and Earliest Pleistocene limestones.