Chemical and Noble Gas Isotope Compositions of Formation Gases from a 3 km Deep Scientific Borehole in the Koyna Seismogenic Zone, Western India
Table 2
Noble gas composition of gas samples collected during water flushing after core run 7/8 in the pilot hole KFD1 at Gothane, near Koyna, Western India.
Sample
Depth (m)
4He (ppmv)
±
20Ne (ppmv)
±
40Ar (ppmv)
±
4He/20Ne
±
3He/4He (Ra)
±
Crustal contribution (%)
Atmospheric contribution (%)
RIH14
1833
5.96
0.67
17.5
2.0
9900
1100
0.3449
0.0091
0.912
0.059
7.5
92.5
RIH15
1929
6.67
0.75
16.6
1.9
9400
1100
0.406
0.011
0.782
0.032
21.4
78.6
RIH16
2025
7.88
0.88
17.5
2.0
10000
1100
0.455
0.012
0.705
0.036
29.8
70.2
RIH17
2121
7.12
0.80
16.4
1.8
9300
1000
0.440
0.012
0.703
0.050
27.5
72.5
RIH18
2217
12.8
1.4
17.1
1.9
9300
1000
0.751
0.020
0.426
0.022
57.5
42.5
RIH19
2313
10.7
1.2
17.3
1.9
9700
1100
0.624
0.017
0.522
0.027
48.9
51.1
RIH20
2409
12.2
1.4
18.2
2.0
10200
1100
0.682
0.018
0.482
0.034
53.2
46.8
RIH21
2514
11.3
1.3
17.3
1.9
9900
1100
0.659
0.017
0.479
0.020
51.6
48.4
RIH22
2610
10.2
1.1
17.3
1.9
9900
1100
0.593
0.016
0.547
0.028
46.2
53.8
RIH24
2763
9.8
1.1
17.1
1.9
9800
1100
0.574
0.015
0.546
0.018
44.4
55.6
RIH25
2831
10.2
1.1
17.6
2.0
9900
1100
0.588
0.016
0.556
0.030
45.7
54.3
Depths are referenced to the kelly bushing, which was located at 3.5 m elevation with respect to ground level. Gas samples collected during running in and flushing out of water are designated by the prefix RIH. All errors are 2σ.
