Isotope Geochemistry of Sulphur Springs, an Acid-Sulphate System in Valles Caldera, New Mexico

Abstract

Sulphur Springs is a area of acid hot springs, mud pots, gaseous cold springs and fumaroles that issue from the western flank of the resurgent dome inside Valles Caldera, a 1.1 Myr old silicic cauldron. From assessment of D and values in fumarole steam at Sulphur Springs and deep reservoir fluid in the Redondo Creek area we suggest that steam reaches the surface either by a two-stage boiling process through an intermediate level reservoir at roughly or (2) by vaporizing relatively shallow groundwater at Comparison of and between from well cuttings and C02 from fumarole steam indicates a fractionation temperature between 200 and by decarbonation of hydrothermally altered Paleozoic limestone and vein calcite in the reservoir.