Mantle-Derived Helium Emission near the Pohang EGS Site, South Korea: Implications for Active Fault Distribution

Table 2

Analysis of stable isotopes and noble gases in the Pohang area.

ID	Area	^3He/^4He	Error	^3He/^4He	^4He/^20Ne	^20Ne/^4He	^4He	^20Ne	δ^15N	Error	N2/^3He	δ^13C	Error	CO2/^3He	δ^13C	Error	CH^4/^3He
		R/Ra		Rc/Ra			ccSTP/g	ccSTP/g	N2	(1σ)		CO2	(1σ)		CH4	(1σ)
P-11	Heunghae	0.18	0.02	0.05	1.8	0.6	4.06.E-07	2.22.E-07	2.15	0.48	3.52E+10			1.53E+09			8.98E+07
P-12		3.83	0.01	3.92	7.7	0.1	1.91.E-06	2.48.E-07	3.15	0.35	7.70E+08	-19.49	0.31	6.64E+07			5.59E+06
P-14		2.69	0.01	2.71	21.4	0.1	2.66.E-06	1.24.E-07	3.16	0.53	5.11E+08	-19.49	0.31	4.72E+08	-70.04	0.41	5.78E+08
DS-1		0.87	0.02	0.80	0.7	1.4	1.65.E-07	2.37.E-07	2.43	0.28	1.89E+09	-27.33	0.6	1.09E+09			—
PH19-01		1.30	0.01	1.38	1.2	0.9	2.04.E-07	1.75.E-07	3.12	0.3	4.55E+10	-16.01	0.35	1.37E+10			2.38E+09
PH19-03		1.35	0.01	2.57	0.3	3.1	8.59.E-08	2.67.E-07	2.62	0.3	2.03E+10	-23.08	0.31	1.71E+10			6.78E+07
PH19-04		1.99	0.01	2.12	2.2	0.5	2.99.E-07	1.38.E-07	2.42	0.26	6.21E+09	-25.29	0.32	1.79E+09			5.05E+07
PH19-05		2.49	0.01	2.54	7.1	0.1	1.32.E-06	1.87.E-07	0.96	0.25	1.77E+09	-25.77	0.31	1.02E+09			3.83E+07
PH19-06		3.38	0.01	3.45	8.9	0.1	1.75.E-06	1.98.E-07	1.80	0.25	3.02E+08	-23.14	0.37	1.39E+08			1.87E+06
PH19-10		0.79	0.01	0.29	0.4	2.8	7.22.E-08	2.03.E-07	1.78	0.27	4.99E+10	-20.78	0.32	2.82E+10			4.92E+08
PH19-11		0.36	0.02	0.06	0.8	1.3	1.58.E-07	2.01.E-07	1.25	0.22	3.60E+10	-20.66	0.38	9.74E+09			5.10E+07
PH19-12		2.25	0.01	2.26	61.9	0.02	6.84.E-06	1.11.E-07	1.57	0.26	2.17E+08	-25.71	0.3	1.51E+08	-76.05	0.47	8.51E+07
PH19-07	Yeonil	3.09	0.01	3.09	145.3	0.01	1.07.E-05	7.35.E-08	1.26	0.24	4.92E+07	-21.66	0.34	5.88E+06	-75.40	0.35	2.91E+07
PH19-08		2.32	0.01	2.33	61.9	0.02	6.96.E-06	1.12.E-07	0.19	0.23	2.50E+08	-23.70	0.46	4.32E+07	-75.13	0.33	2.23E+08
PH19-09		1.00	0.01	1.00	0.4	2.8	4.83.E-08	1.36.E-07	2.06	0.24	7.60E+10	-20.09	0.34	2.36E+10			6.06E+07
PH-3		1.26	0.03	1.31	1.5	1.3			0.33	0.01	4.07E+10			8.81E+07	-71.47	0.1	2.10E+10
P-2	Sinkwang	0.90	0.02	0.33	0.3	3.4	1.21.E-07	4.11.E-07	1.44	0.21	4.21E+10	-26.31	0.41	7.35E+09			3.00E+07
P-3		0.91	0.01	0.70	0.4	2.8	7.35.E-08	2.07.E-07	3.56	0.36	3.66E+10	-26.69	0.47	1.19E+10			2.45E+07
P-4		0.96	0.02	0.86	0.4	2.8	8.41.E-08	2.37.E-07	1.21	0.22	4.54E+10	-25.43	0.36	1.87E+10			3.28E+07
P-5		1.09	0.01	1.51	0.3	3.3	7.74.E-08	2.55.E-07	3.07	0.27	1.27E+10	-25.57	0.38	8.62E+09			—
P-7		1.22	0.01	2.30	0.3	3.3	1.35.E-07	4.47.E-07	1.91	0.29	2.57E+10	-23.86	0.32	1.58E+10			2.09E+07

Note: the standards for δ¹⁵N and δ¹³C are air and Pee Dee Belemnite (PDB), respectively. Concentrations of ⁴He and ²⁰Ne of PH-3 were not measured because the sampling method was different. The carbon isotope ratios of CO₂ in P-11 and PH-3 were not measured due to their low concentrations.