川西高原甘孜黄土A剖面常量元素地球化学特征初步研究

Geochemical Characteristics of Major Elements of Ganzi loess in the Western Sichuan Province

本文以位于青藏高原东南缘的川西高原甘孜A剖面S0-S2黄土—古土壤序列为材料,利用X-荧光光谱仪对常量元素进行了测试分析。结果表明,SiO2,Al2O3,Fe2O3,MgO,K2O,MnO和TiO2随着黄土层和古土壤层的交替叠覆含量由低到高呈现明显的旋回变化特征,而CaO则相反;在化学风化过程中,元素Si,Al,Fe,Mg,K,Mn,Ti之间具相似性而与元素Ca具差异性;粒度对各常量元素分布具一定控制效应,Fe,Mn,K等元素分布与2~8μm黏土粒级含量具显著正相关,与30~64μm粉沙粒级含量具显著反相关。

The West Sichuan Plateau is located in the southeast margin of the Tibet Plateau,where the climate is mainly influenced by the Indian southwest summer monsoon and the Tibet Plateau monsoon.Major elements of loess-paleosol from the sequence of S0-S2 stratigraphy of the Garzê A section are measured by X-Ray Fluorescence Spectrometry.The results show that the content of SiO2,Al2O3,Fe2O3,MgO,K2O,MnO and TiO2 vary from low to high values with significant change cycles,which varies with the alternately superimposition of loess layer and paleosol layers,however,the pattern of Ca is opposite.The chemical properties of Si,Al,Fe,Mg,K,Mn,Ti but Ca show a similarity during the process of chemical weathering.There are good correlations between elements of Fe,Mn,K,Al,Ti and the clay(2～8 μm) and the silt(30～64 μm) in loess,suggesting that the distribution of major elements is mainly controlled by the grain size of loess in the region.