An Evaluation of the Long-Term Stagnancy of Porewater in the Neogene Sedimentary Rocks in Northern Japan
Table 1
Sampling points (depth) investigated in this study and He and Ne concentrations, 3He/4He, 36Cl, δD and δ18O, and Cl− concentrations at the sampling points.
Name of borehole
Sampling points at length of bore hole (m)
Sampling points at (m)
Formation
He concentration
He concentration (corrected)
3He/4He ×10−7
Ne concentration
36Cl/Cl (×10−15)
δD
δ18O
Cl− ion concentration (mg/L)
Remarks
×10−6
×10−6
×10−7
HDB-9
77.5
−77.5
W
1.23
1.23
2.74
1.78
NM
−72
−10.1
180
226.2
−226.2
W
2.59
6.25
2.04
0.74
4.3 ± 2.1
−33
0.2
5000
267.5
−267.5
W
2.24
5.77
1.93
0.69
10.2 ± 2.1
−23
1.8
6100
367.5
−367.5
W
1.35
5.12
1.83
0.47
8.1 ± 2.3
−21
2.4
5900
460.2
−460.2
W
0.11
0.14
4.86
1.45
7.4 ± 1.4
−21
2.3
6200
HDB-10
145.5
134.5
K
2.60
2.51
2.95
4.76
4.4 ± 2.0
−54
−4.6
2800
237.5
42.6
K
2.90
2.80
3.09
4.97
4.6 ± 2.0
−50
−3.9
3700
338.5
−58.5
W
1.81
1.69
3.20
5.90
NM
−69
−8.6
750
454.0
−174.0
W
11.22
-
3.48
30.92
7.2 ± 1.5
−41
−1.2
6900
Noble gas data was Eliminated (high Ne concentration)
502.0
−222.0
W
4.85
5.43
3.82
1.59
8.6 ± 1.4
−42
−2.5
5600
HDB-11
70.4
389.6
K
0.90
2.35
1.53
0.68
0.0 ± 2.2
−62
−6.4
2000
181.2
278.8
K
0.74
1.18
1.67
1.12
2.7 ± 2.1
−30
0.8
8100
288.5
171.5
K
1.23
1.80
1.57
1.22
1.1 ± 2.1
−26
2.2
9700
377.0
83.0
K
1.93
-
2.51
15.55
NM
−34
0.8
6700
Noble gas data was Eliminated (high Ne concentration)
560.0
−100.0
W
1.38
3.19
1.46
0.77
5.8 ± 1.4
−22
2.6
9400
686.1
−226.1
W
15.91
21.79
1.63
1.30
8.5 ± 1.6
−19
3.1
9800
761.0
−301.0
W
0.30
0.29
2.65
2.02
6.7 ± 1.8
−22
2.9
8800
Bubble was observed on surface
805.1
−345.1
W
0.57
0.95
2.01
1.07
8.9 ± 2.1
−23
2.3
8600
Bubble was observed on surface
856.3
−396.3
W
0.97
2.34
1.61
0.74
6.8 ± 1.7
−23
2.4
8900
Bubble was observed on surface
905.4
−445.4
W
1.58
2.19
1.67
1.29
9.9 ± 5.1
−24
2.0
8900
Bubble was observed on surface
956.3
−496.3
W
0.43
3.05
1.80
0.25
6.8 ± 1.6
−23
2.5
9700
Bubble was observed on surface
1007.5
−547.5
W
0.57
0.86
1.81
1.18
7.3 ± 2.4
−22
2.8
9400
Bubble was observed on surface
HCD-2
303.0
−73.0
W
4.81
9.57
7.26
0.89
11.4 ± 2.9
−45
−3.8
2500
343.0
−101.9
W
5.26
5.14
7.56
5.82
11.0 ± 3.3
−47
−4.6
1500
392.0
−136.4
W
7.42
13.82
7.75
0.96
15.9 ± 4.3
−28
−0.2
5100
439.0
−171.3
W
5.69
11.20
7.23
0.90
7.5 ± 4.4
−21
1.6
8000
509.0
−220.1
W
9.67
-
8.25
107.89
6.3 ± 2.9
−14
2.9
8400
Noble gas data was Eliminated (high Ne concentration)
596.7
−268.5
W
4.65
8.36
6.94
0.99
8.9 ± 2.9
−24
0.9
7300
655.0
−297.6
W
9.39
14.35
6.55
1.17
NM
−19
1.8
8100
667.0
−303.3
W
14.86
14.84
5.98
2.36
NM
NM
NM
NM
675.0
−306.9
W
13.94
13.80
5.68
6.60
NM
NM
NM
NM
690.0
−313.6
W
20.14
20.12
5.54
2.38
NM
−16
2.5
9500
697.1
−316.7
W
4.83
6.65
5.69
1.29
NM
NM
NM
NM
704.0
−318.0
W
12.48
26.20
5.49
0.85
15.8 ± 5.0
−17
2.5
8800
Depth is expressed in the same manner as Figure 4; Formations K and W: the Koetoi and Wakkanai Formations, respectively.
