Source data related to the submitted manuscript "Methane seepage dynamics and ground heating phenomena in the southern Po Valley: the case study of Santa Maria Nuova (Italy)" (https://doi.org/10.1016/j.apgeochem.2025.106565). The files contain: 1) Raw measurements of diffuse CO₂ and CH₄ fluxes and gas chemical and isotopic composition at the study site, and 2) drone thermal survey

Source data related to the submitted manuscript "Methane seepage dynamics and ground heating phenomena in the southern Po Valley: the case study of Santa Maria Nuova (Italy)" (https://doi.org/10.1016/j.apgeochem.2025.106565). The files contain: 1) Raw measurements of diffuse CO₂ and CH₄ fluxes and gas chemical and isotopic composition at the study site, and 2) drone thermal survey

Source data related to the submitted manuscript "Methane seepage dynamics and ground heating phenomena in the southern Po Valley: the case study of Santa Maria Nuova (Italy)" (https://doi.org/10.1016/j.apgeochem.2025.106565). The files contain: 1) Raw measurements of diffuse CO₂ and CH₄ fluxes and gas chemical and isotopic composition at the study site, and 2) drone thermal survey

chemical and isotopic data of gases

chemical and isotopic data of gases

Fumarole and steam condensate samples were collected from Mount Mageik and Trident volcano, Katmai Volcanic Cluster, Alaska in July 2013. Specifically, samples were collected from the northeast wall of the summit crater of Mount Mageik on 12 July 2013 (local time), and within the southeast flank fumarole field of Trident I on 16 July 2013. At each site, the following samples were collected: (1) total gas composition using a modified version of the Giggenbach method where samples were collected in 50 mL evacuated bottles containing 20 mL of a 0.15 M Cd(OH)2 and 4 M NaOH solution, (2) dry gas, and (3) steam condensate. The integrated analyses of these three samples from two locations at each of the two volcanoes are presented here.

Extensive geochemical investigation (of water, travertine, soil and diffuse gas), coupled with geo-structural analysis, provides new insights into local fault–fluid interaction and allows us to pinpoint basic elements in the geological origin (or geomythology) of the Delphic Oracle, still debated by geologists. Delphi hosted the most famous oracle of antiquity, supposed to prophesy under the effects of intoxicating gas exhaling from a chasm in the ground. CO₂–H₂S-rich, ethylene-rich or CH₄-rich gases have been invoked to explain the mantic vapours. Although previous interpretations dismissed the results achieved by classical scholars, this study fits together history, archaeology, mythology and geology in a single coherent frame. We highlight that no hydrocarbon gas discharges are released at present to the surface in the area. The lack of any geochemical ‘anomaly’ indicates that the Delphi active fault does not at present constitute a preferential route for the circulation of thermogenic deep fluids. The mythological gas-exhaling chasm can plausibly be related to episodic seismic ruptures in the ancient past, which affected for a limited time gas pockets fed by a relatively deep confined hydrothermal system. The Delphi fault has produced shocks up to Ms=6.7 (1 August 1870), and similar seismic faulting events in the past could have episodically triggered CO₂–H₂S-rich emissions.

Extensive geochemical investigation (of water, travertine, soil and diffuse gas), coupled with geo-structural analysis, provides new insights into local fault–fluid interaction and allows us to pinpoint basic elements in the geological origin (or geomythology) of the Delphic Oracle, still debated by geologists. Delphi hosted the most famous oracle of antiquity, supposed to prophesy under the effects of intoxicating gas exhaling from a chasm in the ground. CO₂–H₂S-rich, ethylene-rich or CH₄-rich gases have been invoked to explain the mantic vapours. Although previous interpretations dismissed the results achieved by classical scholars, this study fits together history, archaeology, mythology and geology in a single coherent frame. We highlight that no hydrocarbon gas discharges are released at present to the surface in the area. The lack of any geochemical ‘anomaly’ indicates that the Delphi active fault does not at present constitute a preferential route for the circulation of thermogenic deep fluids. The mythological gas-exhaling chasm can plausibly be related to episodic seismic ruptures in the ancient past, which affected for a limited time gas pockets fed by a relatively deep confined hydrothermal system. The Delphi fault has produced shocks up to Ms=6.7 (1 August 1870), and similar seismic faulting events in the past could have episodically triggered CO₂–H₂S-rich emissions.