Heat source for an amagmatic hydrothermal system, Noto Peninsula, Central Japan

Umeda, Koji; Ninomiya, Atsushi; Negi, Tateyuki

Although there is no geological evidence of volcanism during the Pliocene and Quaternary in the Noto Peninsula, Central Japan, the peninsula has long been known to be unusual and atypical of non-volcanic regions, as indicated by the presence of high-temperature hot springs and the high geothermal gradient values of more than 50 K/km. In this work, we present new helium isotope data from the Noto Peninsula and examine a possible source of excess heat in this non-volcanic region, including geophysical evidence such as seismic velocity, resistivity structures, and heat flow data.