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中文摘要：
本文对发育于花岗岩上的两个亚热带红土剖面进行了系统的岩石磁学研究，测试了磁化率、频率磁化率、等温剩磁、非磁滞剩磁、磁滞回线等常温磁学参数，选取代表性样品进行了高低温岩石磁学分析，拟探讨亚热带红土磁性矿物的特征及湿热环境下土壤中磁性矿物的转化规律。实验结果表明：亚热带红土的强磁性矿物为磁铁矿、磁赤铁矿；弱磁性矿物为赤铁矿和针铁矿，滞水土层中含有纤铁矿。花岗岩具有较强的磁性，在其上发育的红土也因此具有较强的磁性。花岗岩中的亚铁磁性矿物的磁畴以多畴占主导地位，随着风化强度的增强，逐渐形成较细粒的超顺磁与单畴磁性矿物。亚热带红土中的磁赤铁矿与位于半干旱区黄土高原成土作用形成的磁赤铁矿存在着磁学性质上的差异，表现为具有更高的居里点（约600℃和640℃），可能说明亚热带红土中的磁赤铁矿粒径更粗。两个剖面在磁学性质上存在着明显的差异，泉州剖面磁性矿物以磁铁矿为主，磁化率最高可达1823×10^-8m^3/kg，平均值为1033．1×10^-3m^3/kg，具有较低的剩磁矫顽力；福州剖面磁性矿物以磁铁矿和部分热稳定磁赤铁矿为主，磁化率最高为385．73×10^-8m^3/kg，平均值为91．5x10^-8m^3/kg。基于磁学参数分析，认为母质与后期成土作用共同造成了两个剖面的磁学性质差异，但后者起主导作用。磁化率在两个剖面中，均随着深度减小而减小，与温带地区表层土磁化率增强有很大区别。湿热环境条件下，强磁性矿物溶解或转化为弱磁性矿物的程度主导剖面磁化率变化。
英文摘要：
Magnetic susceptibility of loess-paleosol sequences in Chinese Loess Plateau has been widely used as a proxy of summer monsoon. Red soils, extensively distributing in Southern China of subtropical-tropical zone, are considered to be good archives of Quaternary paleoenvironment and paleoclimate. Although the red soils have been studied using methods of rock magnetism and environmental magnetism as their applications in loess, the relationship between magnetic properties of red soils and their environmental implications is still unclear. The fundamental and crucial work to address this question is the understanding of the rock magnetic properties of different types of red soil in different regions, which is the focus of this study. Here in the red soils developed on granite were collected from Fuzhou（26°13.938＇N, 119°21.622＇E; FZ section） and Quanzhou （25~22.801,N, 118o10.096,E; QZ section）, Fujian province and measured with rock magnetic parameters,including low-field magnetic susceptibility（Xif）, frequency dependent magnetic susceptibility （ Xfd）, anhysteretic remanent magnetization （ ARM ） , saturation isothermal remanent magnetization （ SIRM ） , and measurements of magnetic hysteresis loops and thermomagnetic curves（M-T ＆ k-T curves）. The results show that magnetite and maghemite are predominant in the red soils with presence of hematite and goethite as well; the signal of lepidocroeite was detected in the waterlogged layer. The high values of magnetic susceptibility of red soils are attributed to their parent strongly magnetic granite. The magnetic domain size of the granite is multi-domain （ MD）, and becomes finer in states of superparamagnetic（SP） and single-domain（SD） due to weathering. The maghemite in red soils has a higher Curie point（ca.600℃ and 640℃ ） than that in loess,suggesting its larger domain size. The differences with respect to magnetic minerals in types, magnetic domain and concentration between the two sections can be summarized
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