Subsurface waters have been classified into meteoric water, ocean water, evolved connate water, magmatic water and juvenile water. Geothermal water is mostly meteoric and oceanic water although andesitic waters near subduction areas often contain significant proportions of evolved connate and magmatic waters. Geothermal waters have been classified with respect to their anion and cation contents...

U.S. Department of the Interior U.S. Geological Survey Wheeler Geologic Monument (Half Moon Pass quadrangle) provides exceptional exposures of three outflow tuff sheets erupted from the San Luis caldera complex. Lowest sheet is Rat Creek Tuff, which is nonwelded throughout but grades upward from light-tan rhyolite (~74% SiO 2 ) into pale brown dacite (~66% SiO 2 ) that contains sparse dark-brow...

Abstract Two recently discovered volcanoes (Las Margaritas 1 and 2) located near the city of Manizales in central Colombia (northern Andes) show that monogenetic can be both effusive fed by evolved compositions, unlike most other fields. This study presents results cartographic, petrographic, geochemical, geochronological analyses. Mapping indicates are purely effusive, where first erupted a do...

Abstract The behavior of nitrogen during magmatic degassing and the potential kinetic fractionation between N other volatile species (H, C, O, noble gases) are poorly known due to paucity diffusion data in silicate melts. To better constrain mobility processes, we investigated melts under reducing conditions. We developed uniaxial experiments at 1 atm, 1425 °C, nominally anhydrous conditions (f...

Abstract A detailed petrological study is presented to constrain the origin of a suite alkali olivine basalt and hawaiite (>5 wt% MgO) lavas that were erupted in rift zone within western Mexican arc (Trans-Mexican Volcanic Belt), adjacent Sangangüey andesitic stratovolcano, together with more evolved (mugearites benmoreites; <5 MgO). As previously documented literature, mafic are ...

Potential flank eruptions at the presently active Villarrica, Southern Andes Volcanic Zone (33.3–46 °S) require drawing of a comprehensive scenario eruptive style dynamics, which partially depends on degassing process. The case we consider in this study is from Los Nevados Subgroup 2 (LNG2) and constitutes post-glacial minor centers (MECs) basaltic–andesitic basaltic composition, associated wit...

Abstract Mafic magma intrusions into silica-rich magmatic reservoirs are commonly proposed to drive the eruptions of andesitic hybrid magmas that characterise many arc volcanoes. However, interactions between contrasting involve large gradients physical and chemical properties change over time, details such processes have proven difficult constrain. In this paper we investigate dynamics minglin...