2:10 PM - 2:25 PM
[SGL29-02] New implications for the cause and mechanism of a high-temperature mud volcano, Goshogake, via mineralogy and geology
Keywords:mud volcano, opal, Vitrinite reflectance
We found that the erupted mud includes much silica (45-75 wt.%) such as opal-A, opal-CT and quartz and clay minerals (15-40 wt.%) based on XRD quantitative analysis and that the mud erupts from ~700 m depth by using Vitrinite reflectance. Based on the mineral composition, estimated source depth, and geological information, we found i) that the erupted mud comes from the shallow sedimentary layer deposited at a caldera lake, ii) that both rapid sedimentation and the dehydration of both opal and clay minerals make this MV active, and iii) that higher geothermal gradient due to the magmatic and hydrothermal activity in this hydrothermal region increases the temperature in the source layer. Especially, as the dehydration of opal in MVs has been not reported clearly, the new possible candidate of the driving force of MVs is proposed in this study. In conclusion, we clarified the cause and mechanism such as the source layer and driving force of the Goshogake high-T MV field.