Figure 5
From: Arima hot spring waters as a deep-seated brine from subducting slab
Helium and carbon systematics of the sampled waters and gases. (a) 4He/20He versus 3He/4Ne diagram of the sampled waters and gases. Light blue diamonds represent samples from Arima; dark blue diamonds (TW-1 and TW-2) represent samples from Takarazuka. Red circles represent gas samples. Two mixing curves are drawn, one between air-saturated water (ASW) and the upper mantle component and the other between ASW and a component having 3He/4He ratio of 8 × 10-6, considering possible but slight crustal contamination. (b) δ13C versus CO2/3He diagram of the sampled waters. Yellow, pink, and purple boxes represent the three end-members of sediment-, limestone-, and mid-ocean ridge basalt (MORB)-derived carbon, respectively (Sano and Marty 1995). Solid curves represent mixing between MORB and limestone and MORB and sediment. Open gray box represents the compositional range for arc volcanic gases (Sano and Marty 1995).