Table 2 Noble gas nuclide abundances (⁴He, ²⁰Ne, ⁴⁰Ar, ⁸⁴Kr and ¹³²Xe), isotope ratios (³He/⁴He, ²⁰Ne/²²Ne, ²¹Ne/²²Ne, ⁴⁰Ar/³⁶Ar, and ³⁸Ar/³⁶Ar), nuclide ratios (⁴He/²⁰Ne and ³He/²⁰Ne), air-corrected ³He/⁴He ratios and the relative proportions of atmospheric, crustal and mantle helium from 12 drilling mud gas samples covering the depth range 950–3050 mbsf from site C0002

950

338 C0002F

0.00515 ± 0.00026

0.01367 ± 0.00068

7.75 ± 0.39

0.000544 ± 0.000027

0.0000229 ± 0.0000014

1.348 ± 0.041

9.798 ± 0.010

0.02896 ± 0.00024

296.9 ± 1.6

0.18707 ± 0.00094

0.3770 ± 0.0029

7.05E−07 ± 2.2E−08

3.26 ± 0.28

85

9

6

1400

338 C0002F

0.00531 ± 0.00027

0.01446 ± 0.00072

7.47 ± 0.37

0.000495 ± 0.000025

0.0000185 ± 0.0000013

1.044 ± 0.045

9.8331 ± 0.0088

0.02900 ± 0.00025

294.7 ± 1.4

0.1882 ± 0.0012

0.3675 ± 0.0029

5.33E−07 ± 2.3E−08

1.33 ± 0.34

87

11

2

1700

338 C0002F

0.00539 ± 0.00027

0.01559 ± 0.00078

8.43 ± 0.42

0.000557 ± 0.000028

0.0000210 ± 0.0000015

1.114 ± 0.037

9.832 ± 0.010

0.02900 ± 0.00025

294.8 ± 1.3

0.1878 ± 0.0011

0.3460 ± 0.0027

5.35E−07 ± 1.8E−08

2.46 ± 0.49

92

5

2

1800

338 C0002F

0.00553 ± 0.00028

0.01482 ± 0.00074

8.07 ± 0.40

0.000552 ± 0.000029

0.0000215 ± 0.0000015

0.919 ± 0.034

9.8109 ± 0.0090

0.02896 ± 0.00043

n.a.

n.a.

0.3731 ± 0.0029

4.76E−07 ± 1.8E−08

0.44 ± 0.24

85

14

1

1850

338 C0002F

0.00538 ± 0.00027

0.01617 ± 0.00081

9.03 ± 0.45

0.000643 ± 0.000033

0.0000233 ± 0.0000015

1.067 ± 0.031

9.7926 ± 0.0082

0.02894 ± 0.00024

296.6 ± 1.4

0.1884 ± 0.0011

0.3330 ± 0.0026

4.93E−07 ± 1.5E−08

2.59 ± 0.79

96

3

1

2050

348 C0002N

0.00614 ± 0.00031

0.01870 ± 0.00093

10.78 ± 0.54

0.000761 ± 0.000038

0.0000309 ± 0.0000019

1.034 ± 0.046

9.7930 ± 0.0089

0.02895 ± 0.00027

295.9 ± 1.3

0.1884 ± 0.0011

0.3304 ± 0.0026

4.74E−07 ± 2.1E−08

1.99 ± 1.35

97

3

1

2200

348 C0002N

0.00632 ± 0.00032

0.01900 ± 0.00095

10.33 ± 0.52

0.000718 ± 0.000036

0.0000305 ± 0.0000064

1.054 ± 0.045

9.7977 ± 0.0089

0.02897 ± 0.00027

297.5 ± 1.4

0.1884 ± 0.0013

0.3345 ± 0.0027

4.89E−07 ± 2.1E−08

2.17 ± 0.99

95

3

1

2349.5 A

348 C0002P

0.00608 ± 0.00030

0.01769 ± 0.00088

9.93 ± 0.50

0.000717 ± 0.000036

0.0000264 ± 0.0000018

1.100 ± 0.036

9.7904 ± 0.0087

0.02897 ± 0.00028

295.2 ± 1.4

0.1882 ± 0.0011

0.3457 ± 0.0027

5.28E−07 ± 1.8E−08

2.29 ± 0.48

92

6

2

2349.5 B

348 C0002P

0.00627 ± 0.00031

0.01889 ± 0.00094

10.79 ± 0.54

0.000750 ± 0.000038

0.0000275 ± 0.0000057

1.033 ± 0.035

9.8013 ± 0.0089

0.02900 ± 0.00027

296.6 ± 1.5

0.1883 ± 0.0012

0.3338 ± 0.0027

4.79E−07 ± 1.7E−08

1.74 ± 0.80

96

4

1

2850

348 C0002P

0.00672 ± 0.00034

0.01977 ± 0.00099

11.24 ± 0.56

0.000794 ± 0.000040

0.0000288 ± 0.0000060

1.090 ± 0.034

9.7987 ± 0.0090

0.02897 ± 0.00027

295.9 ± 1.3

0.1883 ± 0.0011

0.3421 ± 0.0027

5.18E−07 ± 1.7E−08

2.33 ± 0.52

93

5

2

2968.5

348 C0002P

0.00800 ± 0.00040

0.01610 ± 0.00081

9.48 ± 0.47

0.000674 ± 0.000034

0.0000243 ± 0.0000050

1.522 ± 0.039

9.798 ± 0.017

0.02899 ± 0.00028

296.4 ± 1.6

0.1884 ± 0.0013

0.5000 ± 0.0040

1.056E−06 ± 2.8E−08

2.44 ± 0.11

64

25

11

3050

348 C0002P

0.00655 ± 0.00033

0.01952 ± 0.00098

10.98 ± 0.55

0.000763 ± 0.000039

0.0000307 ± 0.0000063

1.048 ± 0.030

9.7966 ± 0.0092

0.02897 ± 0.00027

296.3 ± 1.6

0.1886 ± 0.0010

0.3375 ± 0.0027

4.91E−07 ± 1.5E−08

1.88 ± 0.56

95

4

1

Air

0.00531

0.0167

9.42

0.000658

0.0000237

1

9.80

0.0290

295.5

0.1880

0.319

4.43E−07

–

(100)

–

–