Evidence for pleistocene and holocene raised marine deposits, Sandon Point, New South Wales
Titel:
Evidence for pleistocene and holocene raised marine deposits, Sandon Point, New South Wales
Auteur:
Bryant, E.A. Young, R.W. Price, D.M. Short, S.A.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 39 (1992) nr. 4 pagina's 481-493
Jaar:
1992-09
Inhoud:
In New South Wales there has been an elusive search for coastal deposits that might substantiate an elevated Holocene sea-level. Chronostratigraphic evidence is presented for estuarine and beach deposits raised more than 1 and 2 m respectively above Australian Height Datum around Sandon Point, New South Wales, between 6900 and 1520 bp. The chronology is based upon 14C dating of shell and in situ mangrove stumps, and upon thermoluminescence dating of quartz sand. These elevations concur with other results determined along the east coast of Australia and in the south Pacific. Moreover the Holocene beach sediments lie above Pleistocene aeolian sand dating between 25 300 and 32 700 bp and estuarine mud which must be at least Last Interglacial in age. The latter units also lie more than 2 m above Australian Height Datum. Fossil coral found along the adjacent coast plus the elevation and orientation of the raised marine deposits imply that ocean temperature was warmer around 2800 bp by up to 2°C, that sea-levels from 6000 to 1500 bp were over 1 m higher than present, and that a benign northeast swell may have dominated in the mid-Holocene. The marine deposits show little indication that they were deposited by storms but the role of tsunami in their formation cannot be ignored.