Table 2.

δ18O v.δD composition of Taal MCL waters and chemical and He isotopic composition of dissolved gases in Taal MCL waters

SampleDepth (m)Dateδ18OδDCO2 (cm3 STP l−1)He (cm3 STP l−1)N2 (cm3 STP l−1)O2 (cm3 STP l−1)3He/4He (Ra)*4He/20Ne3He/4He corr (Ra)
March 2011 profile026 March 20111.1±0.1−19±2nanananananana
5026 March 20111.0±0.1−20±2nanananananana
6026 March 20111.0±0.1−17±2nanananananana
June 2011 profile1028 June 2011nana912.84.4×10−335.012.87.22±0.0896.807.48±0.100
2028 June 20112.6±0.1−5±2nananana7.19±0.0836.307.47±0.096
3028 June 20111.2±0.1−7±2913.94.7×10−335.711.83.15±0.0430.417.59±1.911
4028 June 20111.0±0.1−9±3885.43.9×10−331.210.36.59±0.0852.237.37±0.158
5028 June 20111.1±0.1−9±4749.53.2×10−328.89.57.27±0.0846.017.57±0.098
6028 June 20110.8±0.1−7±4838.14.1×10−331.99.86.86±0.0573.367.38±0.100
7028 June 20111.9±0.1−9±4960.84.6×10−330.110.47.06±0.1045.597.37±0.119
  • *Normalized to the atmospheric 3He/4He ratio=1.4×10−6 (Ozima & Podosek 2002).

  • Air-corrected 3He/4He ratio using (4He/20Ne)air=0.318.

  • na, not analysed.