Figure 1

(a) Location of Lake Zóñar. The main paleoclimate records used for comparison in this study are indicated: (1) geochemical proxies of the Lake Zóñar sedimentary sequence^2,14,18,19, (2) the Laguna de la Mula⁷ and (3) Borreguil de la Caldera lacustrine sequences⁸, (4) the Sima Blanca Cave gypsum stalactite²⁴, (5) sediment cores from the Alboran Sea¹⁴, (6) pollen-based rainfall amount reconstructions from the southern Iberian Peninsula¹¹ and (7) a carbonate speleothem record from Buraca Gloriosa Cave²⁵. The coring site in Lake Zóñar is indicated in Fig. 1a, as well as the location of the main springs feeding the system. We also indicate the areas where remnants of Roman infrastructures have been found, including the vestiges of a rustic Roman villae (1st BCE century to fourth century CE) on the northwest shore of the lake [figure created by InkScape 0.92.4 (https://inkscape.org)]. Evidence of an ancient burial site, presumably of Roman age and usually under the water level, is also marked on the map, as well as remains of water conductions that channelized the Zóñar spring (Fig. 1b and 1c) (photographs taken by Dr. Dolores Ruíz-Lara).