Climatic Fluctuations in the Early and Middle Copper Age – First Isotope Investigations at the Water Supply of Los Millares in SE Spain

The Copper Age fortification of Los Millares is located 15 km north of Almería in Andalusia. At least between 3,541 BC (+/- 92 years) and 2,591 BC (+/- 22 years) there existed a water conduit, the so-called "aqueduct of Los Millares", with which water was conveyed to the settlement from a spring located about 1.25 km outside. U and Sr isotope analyses of groundwater samples in the catchment area as well as of the calcareous sinter deposits of the conduit provided evidence that a mixture of thermal water and near-surface groundwater had flowed in. An interpretation of the climate on the basis of the 13C/12C and 18O/16O ratios of the sinters is therefore not straightforward. However, climatic information can be obtained. The calcareous sinter from the area of the spring, which was formed at the end of the Copper Age or at the beginning of the Bronze Age, during the so-called 4.2 ka cal BP event, showed a percentage increase of the thermal water content of the spring water, which can be explained by a less groundwater recharge of the near-surface water during the long-lasting drought. By means of Sr isotope investigations of all aqueduct sinters, precisely dated paleoclimate data of the early and middle Copper Age can be obtained. So far, these have only been carried out on four sinter samples. For further investigations of climatic fluctuations based on Sr isotope ratios, 56 sinter samples from the aqueduct and the spring are available. A corresponding study is in preparation. (Poster)