摘要
基于盐风化作用和化学风化作用在砂岩风化洞穴形成中的意义,本文利用硫酸盐与氯化物等盐类物质对丹霞山岩壁上的红色砂岩进行盐浸泡实验,并对比浸泡前后岩石结构、化学成分及矿物组成的变化,旨在为盐类物质在丹霞山岩壁上洞穴形成中的意义积累科学数据。结果表明,盐浸泡可以使红色砂岩中的矿物组成产生变化;含SO_(4)^(2-)比含Cl^(-)的盐溶液对红色砂岩洞穴破坏更为显著,且浓度越高对砂岩表面的剥蚀作用越强烈;盐溶液会使红色砂岩胶结物严重流失,且盐类物质在砂岩孔隙中结晶后,因其粒径的逐渐增大,致使大颗粒石英附近的裂隙扩大,进而加快洞穴的形成。总体上,广东丹霞山红色砂岩崖壁上风化洞穴的成因可解释为长石溶蚀、胶结物流失与盐风化共同作用的结果。
Based on the significance of salt weathering and chemical weathering in the formation process of tafoni in the weathered sandstone, in this paper, we have conducted the salt immersion experiments of red sandstone collected from the cliff of the Danxiashan Mountain using sulfate and chloride, and compared the changes of rock structures, chemical compositions and mineral compositions of the red sandstones before and after the immersion experiment, aiming to accumulate scientific data for exploring the significance of salt weathering in the formation process of the tafoni in the red sandstone cliff of the Danxiashan Mountain. The results show that the salt immersion can result in the change of mineral composition of red sandstone. The salt solution containing SO_(4)^(2-)can cause more obvious damage to the soaked red sandstone than the Cl^(-)containing solution, and the higher the concentration of the SO_(4)^(2-)-containing salt solution, the stronger the surficial denudation of red sandstone. Salt solution can cause serious loss of cements of the red sandstone. After the crystallization of salts in pores of the sandstone, the gradual increase of the salt grain sizes had led to the enlargement of fissures near the large sized grains of quartz, and then had accelerated the formation of tafoni in the red sandstone cliff. Overall, the genesis of tafoni in the red sandstone cliffs of the Danxiashan Mountain can be explained as a result of the combined effect of the feldspar dissolution, cement loss, and salt weathering.
作者
胡金涛
杨志军
何旺
都衡恒
张珂
李宏卫
HU Jin-tao;YANG Zhi-jun;HE Wang;DU Heng-heng;ZHANG Ke;LI Hong-wei(School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai,Guangdong 519082,China;Guangdong Geological Survey Institute,Guangzhou 410440,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2023年第1期198-205,共8页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
广东省自然科学基金资助项目(2021A515011472)
韶关市丹霞山管理委员会委托项目(HT-9982020-040)
广东省国家公园建设专项资金资助项目(2021GJGY026)。
关键词
丹霞山
风化洞穴
矿物组成
盐浸泡实验
The Danxiashan mountain
tafone
mineral composition
salt immersion experiment
