A pluvial episode identified in arid Australia during the Medieval Climatic Anomaly

Optically stimulated luminescence (OSL) ages from a relict shoreline on Lake Callabonna record a major pluvial episode in southern central Australia between 1050 ± 70 and 1100 ± 60 Common Era (CE), within the Medieval Climatic Anomaly (MCA). During this pluvial interval Lake Callabonna filled to 10-12 times the volume of the largest historical filling (1974) and reached maximum depths of 4-5 m, compared to the 0.5-1.0 m achieved today. Until now there has been no direct evidence for the MCA in the arid interior of Australia. A multi-proxy, analogue-based atmospheric circulation reconstruction indicates that the pluvial episode was associated with an anomalous meridional atmospheric circulation pattern over the Southern extratropics, with high sea-level pressure ridges in the central Indian Ocean and Tasman Sea, and a trough extending from the Southern Ocean into central Australia. A major decline in the mobility of the Australian aboriginal hunter-gatherer coincides with this MCA period, in southern central Australia.