CATASTROPHIC WAVE (TSUNAMI-QUESTIONABLE) TRANSPORT OF BOULDERS IN SOUTHERN NEW-SOUTH-WALES, AUSTRALIA

Deposits of large boulders above modern limits of storm waves along th e coast of southern New South Wales record catastrophic wave action. T he largest boulders that were moved weigh 80-90 tonnes, and the maximu m height of wave action was 32m. Hydraulic reconstruction indicates fl ow depths of 3.4 and perhaps > 4 m and velocities of 5.5 m/s to 10.3 m /s. Cavitation features on some rock surfaces support the estimates of maximum velocities. A remarkably limited range in the orientation of imbricated boulders along 150 km indicates that the deposits record a single event that approached from the SE. to SSE. The fabric and size of the deposits point to a tsunami wave train rather than to exception al storm waves. The most probable source of the wave train is the Macq uarie Ridge in the south Tasman Sea. An earliest Holocene age for the event is indicated by a thermoluminescence determination of 9.5ka from sand associated with one boulder deposit, and by che transport of som e boulders from below present sea level.