The Goshogake mud volcano field, Tohoku, northern Japan: An acidic, high-temperature system related to magmatic volcanism

摘要: Abstract The high-temperature (33–98 °C), highly acidic (pH 2.44–2.94) Goshogake mud volcano field in Akita Prefecture, northern Japan, is a system associated with the Quaternary andesitic composite Yakeyama. features observed include salsa ponds, gryphons, and pots. This rare example of systems linked magmatic volcanism full range landforms primarily low-temperature sedimentary settings. probably not simple hydrothermal related to volcano. Instead, it appears be hybrid system: deep sources strongly influenced by its surrounding volcanism. identified mineral species sampled quartz group, hydrous silica, muscovite, kaolinite, pyrite, sulfur. presence silica polymorphs (tridymite cristobalite) and/or microcrystalline opals (opal-C, opal-CT), an amorphous form (opal-A) mineralogy indicates that likely involves conditions processes such as high temperature, circulation, dehydration reaction at certain depths underneath field. Although source clearly determined, possible options 1) alteration products host rocks sediments, 2) fine-grained layer(s) depth, or 3) combination 2). In-situ measurement emitted gases from vents detected methane, which possibly organic-rich aside being product thermodynamic equilibrium CO2 under subsurface pressure-temperature conditions. increases δD δ18O water volcanoes respect values current meteoric was derived only water, deviation may explained evaporation mixing other waters deeper sources. Regarding driving mechanisms volcanoes, buoyancy muddy sediment, fluid pressure overpressured under-compacted due rapid sedimentation, together gas phase could key factors. currently maintains low-level activity resulting minor morphological changes landforms, enhanced activities have been documented last half century. historical records are inconclusive about relationship between earthquakes