Linking top and subsoil types, alteration and degassing processes at Rotokawa geothermal field, New Zealand

Surface geothermal expressions such as mud pools, fumaroles, mineral deposits, collapse pits, and hydrothermal eruption craters vary in scale type over space time. The evolution time of these surficial thermal features strongly relates to alteration processes caused by fluids. changes the physical mechanical properties top subsoils that can control fluid flow, degassing patterns, occurrence hazards remain understudied. area located south Rotokawa field (New Zealand) includes a variety major natural surface widespread sulphur deposits precipitated acid–sulphate fluids steam-heated zones. Decades mining induced formation new features. Such setting represents an exemplary case study for investigating old recently formed features, soil characteristics, types patterns superposed alteration, processes. We combined laboratory methods define groups types, associated alteration. Their spatial distribution indicates circulation, intensity, are influenced local regional geological structural settings, well activity. found at water table level within excavated areas, acidic led deposition sinters, stromatolites around warm springs pools. In vadose, portions, generally leach degrade Taupo Pumice, resulting broad unstable grounds structures, while extensive sulphur-encrusted sulphur-rich soils sites. this framework, circulation affected dominant layer type, turn its granulometry, texture, state. Our yields precious insights into expression variability, fluid–rock interaction processes, Processes may influence migration manifestations, gas outputs, ground subsidence environments. From broader perspective, our results will help assess activity related similar areas worldwide.