Table 5 Relative intensities of the CP/MAS 13 C NMR spectra in different particle-size fractions isolated from the O/A horizon (0–10 cm) in 3 topographic positions
Topographic | Particle-size | C functional groups (%) | A/ O-A ratioa | Aromaticityb | ||||
|---|---|---|---|---|---|---|---|---|
position | (μm) | alkyl | O- alkyl | di- O-alkyl | aromatic | carboxyl | ||
Summit | Coarse (>250) | 28.4 | 42.9 | 9.9 | 13.7 | 5.1 | 0.54 | 0.14 |
Medium (250 ~ 53) | 31.2 | 42.4 | 9.3 | 11.8 | 5.3 | 0.60 | 0.12 | |
Fine (53 ~ 2) | 36.9 | 41.8 | 8.2 | 8.3 | 4.7 | 0.74 | 0.09 | |
Very fine (<2) | 41.2 | 41.7 | 7.1 | 5.3 | 4.6 | 0.84 | 0.06 | |
Footslope | Coarse (>250) | 29.5 | 41.5 | 9.5 | 13.5 | 6.0 | 0.58 | 0.14 |
Medium (250 ~ 53) | 31.8 | 42.2 | 8.9 | 11.5 | 5.5 | 0.62 | 0.12 | |
Fine (53 ~ 2) | 34.9 | 39.4 | 8.5 | 11.4 | 5.8 | 0.73 | 0.12 | |
Very fine (<2) | 41.5 | 35.7 | 6.8 | 9.3 | 6.7 | 0.98 | 0.10 | |
Lakeshore | Coarse (>250) | 28.8 | 45.3 | 10.2 | 11.1 | 4.6 | 0.52 | 0.12 |
Medium (250 ~ 53) | 28.4 | 44.4 | 10.6 | 11.8 | 4.9 | 0.52 | 0.12 | |
Fine (53 ~ 2) | 34.7 | 41.8 | 8.7 | 9.2 | 5.6 | 0.69 | 0.10 | |
Very fine (<2) | 38.3 | 42.1 | 7.8 | 6.9 | 4.9 | 0.77 | 0.07 | |