Late Holocene climate variability and cultural transitions in the southeastern Iberian Peninsula recorded by speleothems

Speleothems serve as valuable archives for paleoclimate reconstructions; however, high-resolution stalagmite records from the southern Iberian Peninsula remain limited. We investigate two stalagmites from Larga Cave (Sierra de los Filabres range, Almería, 1980 m a.s.l.) using geochronology (U-Th dating), stable isotope analysis (δ¹⁸O and δ¹³C), trace element composition, micromorphology, and petrography. Additionally, environmental monitoring of the cave and modern calcite farming on glass substrates have been ongoing since November 2022, to obtain a better understanding of the cave's ventilation dynamics and how the climatic signal is recorded in the speleothems.

The ages of stalagmites CL-1 and CL-3 span from approximately 5,000 to 1,000 years BP, encompassing the late phase of the Los Millares culture and the rise and fall of the El Argar civilization in southeastern Iberia. Stalagmite CL-1 contains fragments of macroscopic endolithic charcoal, which have also been identified at various locations within the cave. Radiocarbon dating of this charcoal indicates an age of 3,900 calibrated years BP, suggesting that the cave was occupied either permanently or temporarily during the Early to Middle Bronze Age.

The decline of the El Argar civilization appears to coincide with a relatively drier period, as indicated by shifts in δ¹⁸O and δ¹³C values. This stage is further characterized by successive speleothem layers exhibiting retraction patterns, typically associated with reduced drip rates. Further geochemical analyses of these and other speleothems from Larga Cave will provide deeper insights into the extent to which ancient civilizations in southeastern Iberia were influenced by climatic conditions.