发育于石英岩之上的表土磁学性质及其环境磁学意义

通过对石英岩及发育于石英岩之上表土的磁化率(X)、频率磁化率(Xfd)、等温剩磁(IRM)、非磁滞剩磁(ARM)、κ-T曲线等磁学参数测定和石英岩显微镜下观察,结果表明,石英岩中磁性矿物含量极少;表土中含磁铁矿、磁赤铁矿、铁的氢氧化物等磁性矿物,磁性矿物主要以稳定单畴(SSD)和超顺磁性颗粒(SP)形式存在,磁赤铁矿是石英岩在成土过程中形成的次生矿物.表土磁性增强,说明石英岩的磁性对表土磁性影响甚小,而成土作用对表土磁性增强起到了重要作用.表土的磁化率值和磁赤铁矿含量都反映了成土作用的强弱.

Magnetic Property and Environmental Magnetism Significance of Surface Soil Derived from Quartzite

Mineral magnetic parameters, including magnetic susceptibility, frequency dependent susceptibility, isothermal remanent magnetization, anhysteretic remanent magnetization, temperature-dependence of susceptibility, were measured on quartzite and surface soil derived from quartzite. The results in combination with the microscope observation indicated little magnetic mineral in quartzite but a few magnetite, maghemite, iron oxyhydroxides in surface soil. The magnetic grains were mainly superparamagnetic (SP) and stable single domain (SSD). Maghemite is secondary mineral formed in the process of pedogenesis. The magnetic enhancement of surface soil showed that quartzite magnetism influenced little the magnetism of surface soil, but pedogenesis influenced it obviously. The magnetic susceptibility and maghemite content of surface soil can reflect process of pedogenesis.