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The distribution of chemical elements in the Weinan loess section shows that: (1) carbonate is the critical constituent affecting loess chemistry. The leaching of carbonates may cause !apparent“ enrichment of some other constituents. (2) CaCO-3, SiO-2, FeO, MgO, K-2O and Na-2O are mobile while Al-2O-3, Fe-2O-3 and TiO-2 are inert components. The mobility sequence may follow the order of CaCO-3>FeO>MgO>Na-2O>K-2O>SiO-2>Al-2O-3>TiO-2>Fe-2O-3. (3) No obvious migration is noticed of iron, except changes in valence and forms, during the pedogenic process. Little iron has been supplied to paleosol from precipitation. (4) Carbonates and, to a lesser extent, iron are most sensitive to, and can be therefore used as good indicators of, environmental changes.
The distribution of chemical elements in the Weinan loess section shows that: (1) carbonate is the critical constituent affecting loess chemistry. The leaching of carbonates may cause ”apparent " enrichment of some other constituents. (2) CaCO - 3, SiO - 2, FeO, MgO, K - 2O and Na - 2O are mobile while Al - 2O - 3, Fe - 2O - 3 and TiO - 2 is inert components. The mobility sequence may follow the order of CaCO -> FeO> MgO> Na - 2O> K - 2O> SiO - 2> Al - 2O - 3 > TiO - 2> Fe - 2O - 3. (3) No obvious migration is noticed of iron, except changes in valence and forms, during the pedogenic process. Little iron has been supplied to paleosol from precipitation. (4) Carbonates and, to a lesser extent, iron are most sensitive to, and can be therefore used as good indicators of, environmental changes.