| Werstern Senegal | Islands Cape Verde | ||||
| Tertiary | Quaternary | Quaternary | Tertiary | ||
| K2O | Number of samples (Cape Verde Peninsula) | Number of samples (Thiès Plateau) | Number of samples (Cape Verde Peninsula) | Number of samples Fogo (active volcano) | Number of samples |
| 0 - 0.2 | 0 | 0 | 0 | 0 | 0 |
| 0.2 - 0.8 | 14 | 1 | 4 | 0 | 6 |
| 0.8 - 3 | 11 | 8 | 4 | 6 | 16 |