应用穆斯堡尔谱鉴别福建中亚热带黄红壤氧化铁矿物

应用穆斯堡尔谱技术鉴别福建中亚热带黄壤,黄红壤及红壤的诊断层粘粒中氧化铁矿物。结果表明,黄壤与红壤粘粒中氧化铁矿物组成主要差别在于红壤既含针铁矿又含赤铁矿,而黄壤只含针铁矿。此外,黄壤粘粒中铝硅酸盐矿物结构中含有较多的Fe~(2+)。黄红壤粘粒中氧化铁以针铁矿占优势,含有少量赤铁矿和Fe~(2+)。土壤剖面颜色呈黑-黄-红变化的次生黄红壤的黄色土层(B_1)粘粒只含针铁矿,红土层(B_2)含有针铁矿和赤铁矿。根据研究结果认为,这种土壤的土体上部黄化是由于古红土中赤铁矿转化为针铁矿引起的。

APPLICAION OF M SSBAUER SPECTROSCOPY TO IDENTIFYING IRON OXIDE MINERALS IN YELLOW/RED SOIL CLAYS FROM THE MID-SUBTROPICAL AREAS OF FUJIAN,CHINA

The technique of M ssbauer spectroscopy was used to distinguish iron oxide minerals of clays among yellow,yellow-red and red soils from the mid-subtropical areas of Fujian,China.The results showed that the main crystalline iron oxide minerals in the clay of red earth was goethite and hematite,but only goethite was detected in the clay of yellow soil. Furthermore,the M ssbauer spectra of the yellow soil clay contained a Fe~(2+)doublet which can be assigned to be silicate-bound iron. Goethite was predomiant in the clay of yellow-red soil containing a small amount of hematite and Fe~(2+).Both goethite and hematite were pre- sent in the clay of red B_2 horizon in the secondary yellow-red soil with bla- ck-yellow-red color profile but only goethite in the clay of yellow B_1 h- orizon.On the basis of present study it was suggested that the color tran- sition of red to yellow in the upper B horizon of the profile be due to the transformation of hematite to goethite.