Hydrogeology and geochemistry of the sulfur karst springs at Santa Cesarea Terme (Apulia, southern Italy)

• Published in: Hydrogeology journal Vol. 29; no. 1; pp. 481 - 498
• Main Authors: D’Angeli, Ilenia M., De Waele, Jo, Fiorucci, Adriano, Vigna, Bartolomeo, Bernasconi, Stefano M., Florea, Lee J., Liso, Isabella S., Parise, Mario
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2021; Springer Nature B.V
• Subjects: Aquatic Pollution; Calcium carbonate; Caves; Chemical analysis; Earth and Environmental Science; Earth Sciences; Geochemistry; Geology; Geophysics/Geodesy; Hydrogeology; Hydrology/Water Resources; Isotopes; Karst; Karst springs; Limestone; Minerals; Morphology; Seawater; Stable isotopes; Sulfur; Sulfuric acid; Sulphur; Sulphuric acid; Waste Water Technology; Water analysis; Water Management; Water Pollution Control; Water Quality/Water Pollution; Water springs; Italy; Italy; Karst; Marine influence; Hypogene; Sulfuric acid speleogenesis
• ISSN: 1431-2174; 1435-0157
• DOI: 10.1007/s10040-020-02275-y

This work describes the geochemical and hydrogeological characteristics of Santa Cesarea Terme, an active sulfuric acid speleogenetic system located along the Adriatic coastline (Apulia, southern Italy). It represents a very peculiar site, where rising thermal and acidic waters mix with seawater creating undersaturated solutions with respect to CaCO
3
, able to dissolve and corrode limestone and create caves. The Santa Cesarea Terme system is composed of four caves: Fetida, Sulfurea, Gattulla, and Solfatara. Hypogene morphologies and abundant deposits of native sulfur (especially in Gattulla Cave) and sulfate minerals are present in these caves. Fetida and Gattulla caves were investigated primarily because they are easily accessible throughout the whole year through artificial entrances, the other caves being reachable only from the sea. Geochemical analysis of water, monitoring of cave atmosphere, and measurement of the stable isotopes of S, O, and H helped to identify the main processes occurring in this complex cave system. In particular, changes in Ba
2+
and Sr
2+
concentration allowed for the identification of two main domains of influence, characterized by marine and rising acidic waters.