古红土中球粒状磁颗粒的发现及氧化铁矿物

Discovery of spherulitic magnetic grains and its iron oxide mineralogy in paleosols:

在第四纪古红土中发现了球粒状磁颗粒，经扫描电镜（ｓｃａｎｎｉｎｇ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ，ＳＥＭ） 观察认为是超顺磁性颗粒的集合体。透射电镜（ｔｒａｎｓｍｉｓｓｉｏｎ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ，ＴＥＭ） ，Ｘ衍射和矿物磁测证明球粒状磁颗粒由石英、赤铁矿、磁赤铁矿和针铁矿组成。ＴＥＭ 观察到球粒状磁颗粒中赤铁矿呈圆片状，磁赤铁矿呈鱼鳞片状，针铁矿呈针状。

The morphology and mineralogy of spherulitic magnetic grains separated by high gradient magnetic separation in paleosols have been investigated by scanning and transmission electron microscope,magnetic measurements and X ray diffraction.The spherulitic magnetic grains had a size of 250-1 000 μm in diameter,indicating that they were complex of suparaparamagnetic and stable single domain ferrimagnetic minerals.TEM,magnetic measurement and X ray diffraction indicated that mineralogy of spherulitic magnetic grains were comprised of quartz,hematite,maghemite and goethite.