| | Natural Gases | Catalytic Gases |
|---|
| | mean | sd × 104 | V× 106 | Mean | sd × 104 | v× 107 |
|---|
13
C
1
/
12
C
1
| 0.00991 | 0.55 | 5.8 | 0.00991 | 0.40 | 0.30 |
13
C
2
/
12
C
2
| 0.02031 | 1.07 | 5.2 | 0.02030 | 0.63 | 1.78 |
13
C
3
/
12
C
3
| 0.03090 | 1.50 | 4.4 | 0.03090 | 0.97 | 1.9 |
Q
1,2
| 2.0486 | 70.6 | 2.2 | 2.0481 | 35.7 | 5.7 |
Q
1,3
| 3.1175 | 130 | 3.3 | 3.1172 | 30.6 | 1.8 |
- Natural gas data was taken from USGS Energy Resource Organic Geochemistry Data Base, http://energy.cr.usgs.gov/prov/og/. Catalytic gases are from octadecene decomposition over reduced nickel oxide (180 – 210°C) [18]. C1–C3 compositions were normalized to % wt carbon. δ13C values were converted to mass ratios which were used to calculate wt 13C at each carbon number: x1 at C1, x2 at C2, and x3 at C3. Wt 13C1 = x1; Wt 13C2 is wt C2 with composition 13C12C = x2+((12/13.00335)x2); wt 13C3 is wt C3 with composition 13C12C2 = x3+((24/13.00335)x3). Wt 12C at C2 was calculated as the total wt 12C at C2 minus the wt 12C in 13C2. Wt 12C at C3 was also the total wt 12C at C3 minus the wt 12C in 13C3. Weights (per 100 g) were converted to moles/(100 g C1–C3) which were used throughout our analysis. The quotient Q1,2 = (13C2)*(12C1)/(13C1)*(12C2) and Q1,3 = (13C3)*(12C1)/(13C1)*(12C3), where concentrations are moles/100 g. Variance (v) is (sd)2 for log (ratio).
