The age of the Koputaroa dunes, southwest North Island, New Zealand

Four recent dune phases have previously been identified in the Manawatu and Horowhenua regions of southwest North Island, New Zealand. The oldest of these dune phases, the Koputaroa dunes, occur over a restricted area near the town of Levin. Previous estimates of the age of these dunes have largely been based upon the occurrence of Aokautere ash, an airfall member of the Kawakawa tephra (ca. 22 C-14 ka B.P.), interbedded within the dune sands. Nine samples of Koputaroa dune sand were collected from five sites and dated using infrared stimulated luminescence (IRSL). The results suggest that the dunes were originally deposited at or before 40-50 ka, and that they were then re-mobilised in the period from 24 to 10 ka. These periods of dune activity are compared with records of loess deposition in Wanganui basin, aeolian influx of quartz in Taranaki, and dust flux in the Vostok ice core.