流域上游基岩与下游冲积平原土壤化学组成的对比

Comparison between the chemical composition of bedrocks in the upper reaches and that of alluvial plain soils in the lower reaches of a drainage area

对海河水系流域、鄱阳湖水系流域上游的基岩与下游的冲积平原土壤之间化学组成的对比研究显示,下游冲积物土壤的化学组成明显地受源岩成分、形成过程和形成环境的影响。流域上游基岩的一些特征元素在冲积物土壤中被明显地继承,如海河流域基岩和土壤中的CO2、CaO、MgO、FeO、Sr,鄱阳湖流域基岩和土壤中的W、Sn、Bi、U、Th、Pb、Rb、Tl、As、Sb、Se、Hg、Nb、Ta、Hf、B、Be、Ge、Pt、Pd、Y。受形成过程和形成环境的影响,处于暖温带半湿润季风气候下的海河流域冲积平原土壤以极富集CO2、CaO、Na2O、Cl,显著富集MgO、FeO、Sr,富集P、S为特征;而处于亚热带湿润季风气候下的鄱阳湖流域冲积平原土壤则以显著富集Hg、Se和富集Al2O3、Fe2O3、H2O+、W、Sn、Bi、Mo、U、Th、Pb、Rb、Cs、Tl、Li、Be、B、Ga、Ge、Nb、Ta、Zr、Hf、As、Sb、Co、Cr、Ti、V、Zn、Pt、Pd、REE、Y为特征。无论是海河流域还是鄱阳湖流域的冲积平原土壤,均富集As、Sb、Hg、B、Cl、W、Sn、Bi、Pb、Se、Ge、Li、Cs、Cu、Au、Fe2O3、V、Cr、Ni、Zr、Hf、Y。

Comparative study of chemical compositions between bedrocks of the upper reaches and alluvial plain soils of the lower reaches of the Haihe River and Poyang Lake drainage areas indicates that chemical composition of alluvial plain soils of the lower reaches are remarkably affected by the composition of bedrocks and the process and environment of soil formation. Some characteristic elements in bedrocks of the upper reaches are obviously inherited in the alluvial soils. The examples are CO2, CaO, MgO, FeO and Sr in bedrocks and soils of the Haihe River drainage area and W, Sn, Bi, U, Th, Pb, Rb, Tl, As, Sb, Se, Hg, Nb, Ta, Hf,, B, Be, Ge, Pt, Pd and Y in bedrocks and soils of the Poyang Lake drainage area. Affected by the formation process and environment, the alluvial plain soils of the Haihe River drainage area in a semi-wet monsoonal climate of the warm temperate zone are characterized by extreme enrichment in CO2, CaO, Na2O and Cl, marked enrichment in MgO, FeO and Sr and enrichment in P and S. By contrast, the alluvial plain soils of the Poyang lake drainage area in a wet monsoonal climate of the subtropical zone are characterized by marked enrichment in Hg and Se and enrichment in Al2O3, Fe2O3, H2O^＋, W, Sn, Bi, Mo, U, Th, Pb, Rb, Cs, T1, Li, Be, B, Ga, Ge, Nb, Ta, Zr, Hf, As, Sb, Co, Cr, Ti, V, Zn, Pt, Pd, REE and Y. The alluvial plain soils of both the Haihe River and Poyang Lake drainage areas are enriched in As, Sb, Hg, B, Cl, W, Sn, Bi, Pb, Se, Ge, Li, Cs, Cu, Au, Fe2O3, V, Cr, Ni, Zr, Hfand Y.