Water-rock interaction processes and hydrogeological pathways in seismically active areas as revealed by a multi-isotopic (C, S, O, H, B, Sr) approach
Year: 2025
Type: article
Abstract: Waters circulating in the seismically active (up to 6.4 M w ) Pesaro-Urbino province (central Italy) were investigated to understand water–rock interaction processes and groundwater circulation patterns through a multi-isotopic approach. The investigated waters showed different geochemical facies: Ca-HCO 3 , Ca-SO 4 , Ca-HCO 3 -SO 4 , and Na-HCO 3 . Water geochemistry and isotopic composition suggest that Ca-HCO 3 waters are related to the dissolution of carbonate-rich rocks and, subordinately, Al-silicate minerals and are generally characterized by shallow or fast hydrogeological circuits. In contrast, Ca-SO 4 , Ca-HCO 3 -SO 4 , and Na-HCO 3 waters relate to longer water–rock interaction and/or deeper circulation patterns within the aquifers. All the waters show biogenically derived δ 13 C-TIDC values and δ 2 H- and δ 18 O-H 2 O signatures indicative of meteoric origin. The combination of δ 34 S-SO 4 and 87 Sr/ 86 Sr values suggest that the Ca-HCO 3 -SO 4 and Ca-SO 4 waters interact with the evaporitic anhydrite-rich rocks of the Triassic Burano formation that constitute the regional basal aquiclude, making these waters interesting to be monitored for seismic tracers, being likely able to carry possible deep seismic signals (e.g., deep-sourced gases inflow, enhanced metals mobility), similarly to what found in comparable geological contexts. Contrarily, Na-HCO 3 waters show 87 Sr/ 86 Sr ratios and δ 11 B values approaching those of the siliciclastic Marnoso Arenacea Fm, consistent with long-lasting interactions with Na-bearing silicates. Our results suggest that the hydrogeochemical and multi-isotopic approach provided paramount information to detect sites more prone to record possible geochemical variations during the build-up phase of seismic events, making it suitable for application to other seismically active areas.
Source: Journal of Hydrology
Institutions: University of Urbino, University of Florence, Istituto Nazionale di Geofisica e Vulcanologia, Institute of Geosciences and Earth Resources, National Research Council, INGV Sezione di Roma 1, INGV Sezione di Palermo, Consejo Superior de Investigaciones Científicas, Universidad de Granada, Instituto Andaluz de Ciencias de la Tierra, Marche Polytechnic University
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,030
OpenAlex ID: W4410459164