Table 4. Average, median, minimum, and maximum values for gas composition and isotopic compositions of sediment gas from within 0.3 to 11 m of recovered gas hydrate and gas from dissociated gas hydrate listed in Table 3.
| Sample type | Function | C1 (%) |
C2 (ppmv) |
C3 (ppmv) |
i-C4 (ppmv) |
n-C4 (ppmv) | CO2 (%) |
C1/C2+C3 |  13C
C1(  SMOW) |
D
C1 ( PDB) |
13C
CO2 ( PDB) |
D
H2O ( SMOW) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Free gas |
Average |
92.5 |
445 |
14.7 |
9.7 |
2.7 |
7.5 |
3390 |
-66.1 |
-7.6 |
||
Free gas |
Median |
98.1 |
629 |
19.5 |
6.2 |
1.9 |
1.9 |
1510 |
-65.0 |
-195.8 |
-6.5 |
|
Free gas |
Min. value |
73.9 |
125 |
0.0 |
1.7 |
0.4 |
0.2 |
1240 |
-68.2 |
-195.8 |
-11.7 |
|
Free gas |
Max. value |
99.8 |
776 |
22.3 |
23.4 |
6.4 |
26.1 |
7330 |
-65.0 |
-195.8 |
-4.4 |
|
Hydrate gas |
Average |
99.4 |
694 |
8.8 |
1.8 |
0.5 |
0.5 |
2380 |
-67.5 |
-191.0 |
-20.2 |
11.7 |
Hydrate gas |
Median |
99.5 |
750 |
8.1 |
1.7 |
0.6 |
0.4 |
1310 |
-67.0 |
-194.6 |
-21.9 |
10.4 |
Hydrate gas |
Min. value |
98.4 |
86 |
0.5 |
0.0 |
0.0 |
0.0 |
970 |
-70.7 |
-199.7 |
-26.9 |
8.1 |
Hydrate gas |
Max. value |
99.9 |
1010 |
18.3 |
4.3 |
0.9 |
1.6 |
11200 |
-65.8 |
-175.0 |
-5.7 |
17.1 |