Underwater Cave Excavation in Gibraltar
In this project we will undertake excavation of underwater caves offshore of Gibraltar and at a depth of 20-25 m, using a diving team trained in mixed gas diving, which allows safe and prolonged working time underwater. We will combine this with mapping of the wider area around the caves using remote sensing equipment to identify the character of the original terrestrial landscape and to place the caves into their wide landscape setting. Ongoing investigations of the famous Gibraltar cave sites on the present-day shoreline, with long sequences extending over the past 125,000 years and numerous remains of Neanderthals will provide additional context and points of reference to place the results of underwater exploration into a wider archaeological context. The results of this work will show whether archaeological deposits are preserved underwater in such conditions, and in what ways any archaeological data recovered from them provide new information about patterns of human occupation of coastlines and use of marine resources during periods of lowered sea level. The work will also provide experience in the development of techniques of underwater archaeological investigation and results that can be built on by other similar projects in other parts of the world.
We will use swath bathymetry and sub-bottom profiling to identify and map traces of the submerged landscape in the wider area of the submerged shelf, including major topographic features, palaeoshorelines and stream channels, and to identify the thickness and character of the marine-sediment overburden. This will enable the cave sites to be placed in their wider landscape setting, and may also identify additional features of archaeological significance. For excavation, we will work with relays of divers trained in the use of nitrox, which allows safe and prolonged diving (for up to 2 hours at a time) at depths of 20–25 m where the normal air mixture used in scuba diving limits dive time, blunts mental acuity and increases the risk of oxygen poisoning and decompression sickness.