C.M.Murray-Wallace, A.P Belperio, J.H.Cann, D.J.Huntley and J.R.Prescott.

Late Quaternary uplift history, Mount Gambier Region, South Australia

Zeitschrift fur Geomorphologie, Suppl.-Bd. 106, 41-56, 1996

Summary

A series of Quaternary highstand shoreline deposits are preserved on the Coorong coastal plain of South Australia. One of these, the Woakwine Range, developed during the last interglacial maximum (oxygen isotope substage 5e), is preserved in pristine form for up to 250 km parallel to the modern shoreline. The barrier shoreline complexes consist of transgressive aeolian dunes of quartz-skeletal carbonate composition, that interfinger with estuarine-lagoon and lacustrine facies to the lee of the barrier structure. The estuarine-lagoon facies contain a peritidal fauna that permit confident estimation of past sea-level. A progressive change in the height of the back-barrier estuarine-lagoon facies along the coastal plain reveals significant differential uplift during the late Quaternary. The last interglacial shoreline increases in elevation from 3 m at Salt Creek to 8 m near Robe, 100 km to the south, to 18 m at Mt. Gambier, a further 100 km south. Older shoreline deposits near Robe corresponding to stage 7e (Reedy Creek Range) and stage 9 (West Avenue Range) are preserved at 18 m and 24 m APSL respectively. Near Mt. Gambier, equivalent shoreline features mapped as Burleigh Range and Caveton Range are preserved at 34 and 38 m APSL respectively. Together, these data indicate spatial variation in rates of uplift with maxima centred on the Quaternary volcanic centres. Uplift rates range from 70 mm/ka near Robe to 130 mm/ka near the Holocene volcanic centres of Mounts Gambier and Schank.