应用矿物磁测技术和X射线衍射研究氧化土中的磁性矿物

MAGNETIC MINERALOGY OF OXISOLS IN TERMS OF MINERAL MAGNETIC MEASUREMENTS AND X-RAY DIFFRACTION ANALYSIS

应用矿物磁测、X射线衍射和化学分析对氧化土的磁性矿物进行了研究。结果表明矿物磁测及磁分离技术与X射线衍射结合是鉴别土壤中磁性矿物的类型及其晶粒特征的有效方法．证明氧化土中的主要氧化铁矿物是赤铁矿和磁赤铁矿，针铁矿次之，磁铁矿偶见，其磁赤铁矿的含量可达1．62％～1．92％。土壤中磁性矿物的晶粒特征多以超顺磁性和稳定单畴态存在，认为破性矿物的成因是通过缓慢的成土化学作用产生的。

The magnetic mineralogy of four oxisols derived from basalt in Hainan and Guangdong provinces was studied by mineral magnetic measurements,X-ray diffraction and selected chemical dissolution techniques. Results showed that magnetic measurements and X-ray diffraction combined with magnetic separation were effective enough to discriminate magnetic minerals in soils it was indicated that the predominant iron oxides in oxisols are hematite and maghemite. It was also indicated that goethite was present with magnetite occasionally seen,probably partially oxidized toward maghemite was probably present, maghemite accounts for about 1. 62% - 1. 97% in the soils. The rest of free iron occurs in hematite and goethite The ferrimagnetic minerals in oxisols are characterized by supermagnetic grains and stable single-domain grains. The occurrence of ferrimagnetic minerals in oxisols is mainly related with soil-forming processes.