Methods and techniques of topographic survey applied to archaeology in submerged karst cavities with zero visibility. The Falconera Project

Abstract

The purpose of this work is to show the use of a specific underwater archaeological survey methodology, used in the first phase of study of a submerged karst cavity with little or no visibility, due to the contamination of its waters, called Cueva de la Falconera. which is located on the Garraf coast near the town of Sitges, in the province of Barcelona. For this, the research has used different topographic and prospective techniques applied to the preliminary archaeological study of the interior of this underwater cavity, using an innovative methodology that has allowed the development of a 3D map of part of the cavity, as a necessary previous step for the geopositioning of an area of concrete intervention in which an archaeological survey can be carried out. The present study defends a historical hypothesis that aims to demonstrate the use of the cavity as a temporary habitat and as a drinking water supply point for the ancient inhabitants of Garraf. For this reason, the geopositioning of the possible fertile archaeological zones, together with a future micro-geoarchaeological study of the different layers of the paleosol buried under the sandy sediment, may demonstrate the high probability of an anthropic use of the cavity. The ultimate purpose of this research is to validate the definition of “underwater topographic archaeological prospecting”, as a necessary preliminary phase before any underwater archaeological study in confined cavities. For this reason, the innovation in the classical topographic techniques in the measurement of traverse, together with the use of technological tools such as the AUV (Autonomous Underwater Vehicle) SPARUS II, the MNEMO wire mapping device and the Geographic Information Systems (GIS), have been shown to reduce immersion time, rule out obsolete or lax work procedures, correct important topographic errors, guarantee the safety of scientific immersion equipment, and improve underwater archaeological methodology in submerged karst cavities.