부산대학교 도서관

The coast of the Great Australian Bight contains perhaps the largest concentrations of clifftop dunes in the world. It consists of 1350 km of calcarenite and limestone cliffs of which 508 km are capped by clifftop dunes covering an area of 958 km2. To develop a preliminary chronology of dune emplacement and an assessment of triggering mechanisms, 89 OSL dates were obtained from clifftop dunes spread around the Bight. Starting in the east, dunes were sampled for dating on Kangaroo Island, southern Yorke Peninsula, western Eyre Peninsula, Bunda (Nullarbor) Cliffs, Hampton Bluffs, Twilight Cove, Baxter Cliffs and the Wylie Scarp. In addition, the large Roe Plain dune complex that merge with the Baxter-Hampton clifftop dunes were also dated. The dunes are carbonate-rich in the east and center, to grading to quartz-rich to the west. Examining the entire Bight dune systems in a chronological order, the oldest dunes (>164 ka) were located on Kangaroo Island in the far east and are quartz-rich, but overlain by subsequent carbonate deposits, which also date >136 ka. Next were dunes deposited during sea-level highstands along the Baxter Cliffs during Marine Isotope Stage (MIS) 5a (∼80 ka) and MIS3 with dates between 60 and 40 ka, followed by reactivation during the Last Glacial Maximum (LGM) by strong westerly winds between 26–16 ka, particularly across the Roe Plain and on some Eyre Peninsula headlands. Initial Holocene clifftop emplacement accompanied the sea level transgression and stillstand between 10–6 ka. Most beaches and sand ramps that supplied the dunes have since been eroded, though ongoing reactivation on top of the cliffs has occurred at scattered sites throughout the late Holocene, a fact exacerbated by the general aridity, with some sites showing evidence to two to three reactivations. More dating is required to determine if the reactivation is periodic or more random together with a more complete chronology of the dune systems, including their initial emplacement. • Clifftop dunes along the 2000 km long Great Australian Bight. • Dune OSL ages spans early Pleistocene to present. • Multiple episodes of dune emplacement and reactivation. • Last Glacial Maximum dunes extend over 100 km inland. [ABSTRACT FROM AUTHOR]