Precipitation of secondary minerals in acid sulphate-chloride waters traced by major, minor and rare earth elements in waters: The case of Puracé volcano (Colombia)

摘要: Abstract Major, minor and rare earth elements were analyzed in the acid sulphate - chloride thermal springs associated to Purace volcano – hydrothermal system. The waters of classified 2 different groups as a function physico-chemical parameters element distributions. Group 1 is characterized by highest pH (⁓ 3.5), an outlet temperature ⁓ 81 °C strong depletion Fe, Al, Si Ba with respect isochemical dissolution average volcanic local rock. have lower values 1.9 48 °C) compared 1. Moreover, not typical pathway representing congruent rock shows distribution major that more close near-congruent These geochemical features allow propose chemical composition strongly affected precipitation secondary minerals such alunite, jarosite, kaolinite, barite polymorphs SiO2. grouping also supported dissolved REE normalized patterns depleted light (LREE), water formed alunitic and/or kaolinitic rocks. On contrary, flat patterns, according acidic Nevado del Ruiz Azufral Colombian volcanoes recognized advanced argillic alteration (alunite, gypsum kaolinite). Precipitation proposed common process depleting LREE chlorine systems. Furthermore, fractionation was interpreted together corresponding distributions order trace interaction processes. Saturation indexes most identified alterations calculated using PHREEQC software range from 25 250 °C. This approach allows identify possible mineral or well at which reached equilibrium given set minerals. In 1, enriched (alunite kaolinite) traced higher than 101 °C.