黄土中可溶盐含量及意义

The concentrations of K~+,Na~+,Ca~(2+),Mg~(2+),F~-,Cl~-,NO_3~-,SO_4~(2-) and HCO_3~- in Lantian, Binxian, Ningxian, Qingyang, Mubo and Jiyuan loess sections by last interglacial on China Loess Plateau and its conductance are determinated. The results are: According to the average ions concentration in different sections, the soluble salts in south sections are mainly transported from land dusts which fall with rain, but the most salts in north sections are released from minerals by soil formation. The spatial changes of dominating soluble salts ,gypsum in south sections and Glauber'salt and fluorite in north sections, indicates the different arid degrees on Loess Plateau. The north sections are more arid than south, so that the diffluent ions become the main component in soluble salts. The salts enriched in Stage2 and 4, the arid and cold paleoclimate period, in south loess sections because that the soluble ions were swept by water, although they sedimented in warm period. On north Loess Plateau, as evaporation became the determinative factor on salts sediment, the soluble matter enriched in Stage 1,3 and 5, the warm and humid paleoclimate period. According to the conductance of different oxygen isotope period in loess sections, on Stage 1 and 5, the salts enrichment were charged by temperature and participate at the same time, so its concentrations are high on central Loess Plateau; on Stage2,3 and 4, the salts concentrations in south sections are higher than north because their weak movement. The diffluent ions are not sensitive to climate changes on China Loess Plateau, but Ca~(2+), Mg~(2+), NO_3~-SO_4~(2-) are sensitive.