花岗岩片麻岩微生物风化作用效果研究

THE STUDY OF WEATHERING EFFECTS OF GRANITE AND GNEISS UNDER MICROORGANISM

本文通过利用培养基中不同浓度两种混合真菌(Xerocomus chrysenteron、Cortinariussu blanatus)对花岗岩、片麻岩的直接的风化作用。此外,对风化作用前的花岗岩、片麻岩用XRD和XRF作了岩石组成成分分析和全岩分析。结果表明:花岗岩、片麻岩在混合真菌作用下,岩石组成成分中的蒙脱石、云母比正长石更易被风化;大部分金属离子的溶出量与作用时间和菌浓度均呈现"U"型曲线图;Ca2+、K+、Mg2+、Al3+、P5+最易溶出并且K+、P5+、Na+的溶出量仅与作用时间关系紧密,但是与菌的浓度关系不紧密,尽管含菌的样品与对照差异显著。Mg2+、Al3+溶出量则与作用时间和真菌浓度都有关系,Ca2+的溶出过程复杂。研究结果表明真菌对岩石风化作用显著,所以在植苗造林中,采用接种过菌根菌的苗木,既有利于提高苗木抗性,又有助于岩石风化。

This paper examined weathering effect of granite and gneiss by mixing Xerocomus chrysenteron and Cortinarius sublanatus in the culture medium as an example.Whole rock analysis was conducted for the original rocks by XRF and the original mineral composition was determined by XRD.The results showed that under the mixed fungi effect,montmorillonite and mica were more susceptible to weathering than feldspar in the mixed granite and gneiss composition.The dissolved quantities of most metal cations showed ＂U＂ type curves versus incubation time and fungus concentration respectively.During the weathering process,Ca^2＋,K^＋,Mg^2＋,Al^3＋and P^5＋ were more readily dissolved than other cations.The dissolution of K^＋,P^5＋ and Na＋ was closely related with the incubation time,but not with the fungi concentrations though the samples with fungi showed remarkable effects compared with the control.However,the dissolution of Mg^2＋and Al^3＋ was affected by both the incubation time and fungi concentrations.The dissolution process of Ca^2＋ was complicated.Based on our experimental results,it is concluded that the fungi is significant to weathering of granite and gneiss.So,seedlings with mycorrhizal fungi should be used during reforestation.It would improve seedling drought resistance and cold resistance and help rock weathering.