热带地区玄武岩发育时间序列土壤中石英颗粒微形态特征

Study on Micromorphological Characteristics of Quartz Grains in Basalt-derived Chronosequence Soils in Tropical Area of China

利用扫描电镜研究了热带地区雷州半岛和琼北地区不同年代喷发的玄武岩土发育的时间序列土壤中石英颗粒的表面形态特征，结果表明：①同一剖面中表层土壤中石英的风化程度相对较大。②从新成土到铁铝土阶段（0．01～1．33Ma），石英颗粒表面风化程度逐渐加深，机械作用形成的特征完全消失。成土时间较长的铁铝土（6．12Ma）中石英颗粒出现裂解现象。③本研究一方面证实Darmody评估方法在研究我国热带地区土壤石英颗粒表面风化程度的可行性，同时也说明在相同母质和环境条件下发育的土壤中，石英颗粒表面的风化状况在一定程度上可以指示土壤的相对发育程度。

The quartz grains from basalt-derived chronoscqucncc soils in Leizhou Peninsula and Hainan Island were examined under scanning electronic microscope for their external morphological characteristics. The results showed that in the same profile, the weathering degree of quartz grains was stronger in the surface horizon. During soil development, the weathering degree increased gradually from Primosols to Ferralsols phase （0.01-1.33Ma）, and mechanically-formed features totally obliterated. In Fcrrallitic soil phase （6.12Ma）, decomposition phenomena occurred in quartz grains. This study confirmed the validity of the weathering score method of Darmody in the tropical area of China, and also showed that the surface weathering status of quartz grains from soil which developed from the same parent material and under the same environmental conditions can indicate the relative degree of soil development.