NEW EVIDENCE FOR THE HOLOCENE SEA-LEVEL HIGH FROM THE INNER SHELF, CENTRAL GREAT-BARRIER-REEF, AUSTRALIA

Radiocarbon dates from fossil oyster beds of intertidal origin on Magn etic Island, north Queensland indicate that the local Holocene maximum of relative sea level was attained no later than 5660 +/- 50 B.P. (co nventional uncorrected age) and remained at 1.6-1.7 m above modern lev els until 4040 +/- 50 B.P. Given the tectonic stability of the area, t his implies that eustatic sea level remained at its Holocene peak for at least ca. 1600 yr. The new high-precision sea-level data indicate s ea levels 1-5 m higher than those of the same age inferred from buried mangrove deposits on the inner shelf in north Queensland. Uncertainti es in deriving relative sea level from such mangrove deposits may be a significant source of error in worldwide attempts to distinguish the eustatic and crustal warping components of relative sea-level change, especially in the tropics.