Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results ...Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results show that the variations of element abundance and 10Be with depth are similar to those of δ18O in DSDP, and may be considered as an indicator of climatic and environmental changes.展开更多
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 so...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.展开更多
文摘Eighty-one samples were selected from the Late Pleistocene Xifeng loess profile and analyzed for their element abundances using instrumental neutron activation analysis, and for 10Be using the AMS method. The results show that the variations of element abundance and 10Be with depth are similar to those of δ18O in DSDP, and may be considered as an indicator of climatic and environmental changes.
文摘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.
