Geophysical investigation of hydrological and archaeological features at travertine site Alicún de las Torres, UNESCO Global Geopark Granada, Spain

In the framework of an Arqus Alliance student winter-school in February 2025, geophysical measurements and training was performed at the UNESCO Global Geopark of Granada, in southern Spain. A unique feature in the area are immense palaeontological and archaeological records. The latter has culminated in so far 151 identified megalitic dolmen of copper age (Chalcolithic), forming a network in the Gor river valley, a deeply incised fluvial canyon tributary to the Fardes river.

A peripherical archaeological site is located at the Balneario Alicún de las Torres, a site where travertine limestone platforms and walls have formed by the rise and cooling of deep hydrothermal waters. The calcium carbonate and magnesium sulfate precipitation leads to the formation of naturally formed several meters high aqueducts. However, the origin of these aqueducts are prehistoric ground-level ditches that were used to convey water to a supposed nearby settlement. The dolmens in this area are located nearby the aqueducts, and several geophysical methods, Georadar, Geomagnetics and Geoelectrics have been used to shed light on the hydrological conditions and possible further archaeological remains.

Here we present the first results of these surveys. Geoelectrics revealed the limits between groundwater saturated sediments and dry limestone patches parallel to an old, abandoned travertine aqueduct. Localized high conductivity of the ground may be related to vains of hydrothermal water “leaking” from the aqueduct. Georadar revealed the possible location of another dolmen of similar size and geometry. Furthermore, we show localized magnetic anomalies for discussion of future continuation of this project.