福建明溪橄榄玄武岩土壤中的球状埃洛石

Spheroidal Halloysite in Soils from Olivine Basalt in Mingxi County, Fujian Province, China

在福建明溪橄榄玄武岩红壤B层和由橄榄玄武岩坡积物发育的潜育型水稻土潜育层粘粒中发现了一种形态特异的矿物.经X射线衍射、差热分析、透射电镜、扫描电镜及电子探针综合鉴定后,确认这种矿物为球状埃洛石.其形态多为扁平的圆形或次圆形颗粒,少数为球形;多数颗粒中央较薄,有的甚至中空,少数颗粒整体厚度较大;粒径多在0.25μm以下.初步观察结果表明这种矿物可能是由层状晶层构成的,层状晶层的脱失可能与细管状埃洛石有关,扁平颗粒可能是球形颗粒演变而来的.上述演变关系尚需进一步研究才能得到证实.

One kind of mineral with strange morphology was found in the clays of the B horizon of a red soil derived from olivine basalt and the gley horizon of a gleyed paddy soil developed from olivine—basaltic slope deposit in Mingxi county, Fujian province. The mineral was established as spheroidal halloysite by the identification with X-ray diffraction, differential thermal analysis, transmission electron microscope, scanning electron microscope and electron probe. Most of the halloysite particles were oblate, rounded or subrounded, empty or thinner in the middle, with diameters less than 0.25μm, only a few of them assumed typical spheroical shape. The following conclusions were drawn from the preliminary observation: the spheroidal halloysite probably consisted of banded layers; when the spheroidal particle decomposed while the indensity of weathering increased, its exterior layer seperated; the lost exterior layer become tiny tubular halloysite while the middle part transformed into oblate particle. These conclusions must be confirmed by further studies.