Sedimentary processes and the pandora wreck, great barrier reef, Australia

The hydrodynamic and sedimentary processes at the seabed are particularly relevant to wreck formation processes. In conjunction with archaeological work in 1997, seismic and sediment surveys were undertaken around the wreck site of the H.M.S. Pandora (1791), on the eastern edge of the Great Barrier Reef northern Australia. Further, wave and current meters were deployed at the wreck site for a one-month period in order to characterize the local hydrodynamic regime. At the Pandora wreck site, tides occur twice daily, and have a stronger ebb tide than flood. The wreck is buried in sediments dominated by the remains of calcareous algae and foraminifera, and laboratory experiments on these sediments indicate that appreciable transport of sediment occurs at the site under the influence of large spring tides. Sedimentation is controlled by tidal and other unidirectional currents, except during major storm events when waves become important. Wreck disintegration can be considered using a model which relates the rate of wreck disintegration to sediment accumulation or removal. It is likely that the Pandora has undergone several episodes of burial and exposure, although further evidence is required to establish long-term cycles.