海河低平原盐渍区土壤磁化率研究初报

Preliminary study on magnetic susceptibility of saline soil

  • 摘要: 利用英国巴廷敦(Bartington)MS2型双频率感应磁化率仪测定分析了海河低平原盐渍区4个剖面土壤磁学性质。结果表明,该区土壤具有明显的磁化率空间分布差异,盐渍涝洼地段磁化率低(<34×10-8m3/kg),已脱盐地段磁化率高(>50×10-8m3/kg);同一剖面表土层较底土层土壤磁化率高。位于剖面中下部的河湖沉积胶泥层磁化率高,且频率依赖性系数甚高,指示粘层存在粒径<0.01μm左右的超顺磁铁磁态矿物。土壤磁化率测量适用于冲积性平原土壤磁学性质空间分布趋势的检测,亦作为土壤与生态环境演变指示特征之一。

     

    Abstract: A magnetic property of soils in saline region,lower Haihe Plain,was determined by means of a Bartington Meter(Model MS2).The results show that there is an obvious difference of soil magnetic susceptibility(MS) in spatial distribution.The low MS(<34×10-8m3/kg) occurs in saline and waterlogging section,and relatively higher one(>50×10-8m3/kg) in the gradual desaline section.And the MS of bottom soil with coarse texture is lowest in same profiles.For clay-deposit later formed by alluvial and lain in the middle or bottom of profile(M4),both the MS and the coefficient of frequency dependency(CFD) are greater than those of layers among all soil profiles.The higher CFD indicates the existence of superparamagnetic,ferrimagnetic phase with grains of the order of <0.01μm in size.The measure of MS is suitable for the soils in alluvial plain besides the southern weathering earth zone.Susceptibility data is useful to examine trends in mass magnetic susceptibility,down a soil profile or between different soil.Thus it can be used for one of indicators of soil and ecoenvironment evolution.

     

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