| Fraction | Geochemical phases | Extraction Reagent/Condition |
| F1 | Exchangeable | 8 ml, IM MgCl2, adjust pH with Acetic acid to pH 7, shake for 1 hr, room temp. (Mechanical shaker Julabo sw-20c was used)* (see note) |
| F2 | Bound to carbonate | 8 ml, 1 M sodium acetate, added drops of Acetic acid for PH adjustment to PH 5, shaken for 5 hrs at room temp (Mechanical shaker Julabo sw-20c was used) |
| F3 | Bound to iron and manganese oxide | 20 ml, 1 M Hydroxylamine hydrochloride + 25% V/V acetic acid, PH2, 96˚C, Shaken for 3hrs (Mechanical shaker Julabo sw-20c was used) |
| F4 | Bound to organic matter and sulphides | 5 ml, 30% hydrogen peroxide Add added drop wise allowing initial reaction to subsidies then add 3 ml, 0.02M nitric acid, pH 2, heat for 5 hrs at 80˚C, occasionally shaking |
| F5 | Residual | Digested with 20 ml 1:3 HCL acid:Nitric acid (aqua regia) for 3hrs in Teflon beakers |