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[AHW18-01] Fluid formation mechanism of deep chloride hot spring waters from the central Kanto Plain, Central Japan
Keywords:Central Kanto Plain, chloride hot spring water, diagenetic evolution
These chemical and δ18O compositions can be reasonably explained by the following diagenetic processes; Sulphate reduction process, calcite cementation, reaction of volcanic material to form smectite, ion exchange of smectite, and smectite-illite transformation. The oxygen isotope negative shift of the fossil sea water reserved in Kazusa Group reflects pervasive reaction of volcanic material to form smectite. Meanwhile, the oxygen isotope has positive shift of the fossil sea water reserved in the Annaka and Awa Groups, resulting from smectite-illite transformation.