Geoarchaeological study of Katarraktes cave system (Macedonia, Greece): isotopic evidence for environmental alterations

Archaeological excavations began in 2004 in the Katarraktes cave system, near Sidirokastro, Macedonia, Greece, and brought to the surface a great number of historical and prehistoric findings. Archaeological excavations concentrated on a rockshelter, with findings aged from Early Bronze Age. The main activity of that location seemed to be food preparation and storage. In order to investigate the correlation between human use of the cave and the environmental conditions of the area during those parts of prehistoric and historical time, an isotopic study was conducted dealing with the calcitic and organic deposits of a stalagmite from the cave. The analysis of the δ13C and δ18O isotopes in carbonate sediments provided information about the conditions at the time of precipitation of the carbonate material inside the cave. A succession of drier and wetter phases was highlighted, describing the unstable environment of the cave. A general reconstruction of the period of human occupation in the Katarraktes cave system was established, on the basis of a combination of the archaeological, geomorphological and isotopic data. The speleothem isotopic signatures indicate abrupt changes of the atmospheric conditions inside the cave, which are correlated to reported changes in rainfall during 3500-4500 BP in Mediterranean region.