张家界岩性特征对峰林地貌形成的影响研究  

The Contribution of Lithological Component to Sandstone Forest Landform Genesis in Zhangjiajie,Hunan Province

作　　者：黄林燕[1] 朱诚[1] 孔庆友[2] 

机构地区：[1]南京大学地理与海洋学院,江苏南京210093 [2]南京大学地球科学系,江苏南京210093

出　　处：《安徽师范大学学报（自然科学版）》2006年第5期484-489,共6页Journal of Anhui Normal University(Natural Science)

基　　金：国家自然科学基金重大研究计划(90411015);高校博士点基金(20050284011);国家自然科学基金(40271103);南京大学测试基金

摘　　要：岩性标本偏光镜鉴定及X荧光光谱分析发现,张家界石英砂岩SiO2含量在79.40%-97.20%,生物碎屑灰岩SiO2含量在1.90%-4.90%之间.SiO2含量高的石英砂岩通常比SiO2含量低的灰岩抗风化侵蚀能力强.石英砂岩中的CaO含量在180ppm-0.12%之间,而生物灰岩CaO含量90.90%-94.70%.含CaO多的岩体要比含CaO少的岩体更易被流水溶蚀和侵蚀,这也是石英砂岩和生物碎屑灰岩差异风化的原因所在.铁质石英砂岩多呈砂状结构,组成物质多为由单晶石英颗粒构成,胶结物多占15%-70%.上述岩性特征使得位于峰林上部的铁质石英砂岩不易受风化影响而易于长期保存,由此形成峰柱上部的铁帽,例如武士驯马和仙女献花等处的峰林景观.而中下部砂岩因抗风化能力差,加之垂直节理发育而易于形成崩塌和被流水搬运的峰林沟谷景观,以上是张家界峰林地貌形成的主要原因.Based on field investigation, identification （polariscope） of lithological samples and X-fluorescence spectroscopy analysis, we found that the content of SiO2 in quartzite in Zhangjiajie is 79.40 % - 97.20 %, while the content of SiO2 in bio-oddment limestone changes from 1.90 % to 4.90 %. Generally, the quartzite with high content of SiO2 is harder to weathering than bio-oddment limestone with low content. The content of CaO in bio-oddment limestone is much more than that in quartzite. Meanwhile, the content of CaO in quartzite in Zhangjiajie is 180ppm- 0.12%, while the content of CaO in biooddment limestone changes from 90.90% to 94.70%. The quartzite with low content of CaO is harder to weathering caused by the streamlet than biooddment limestone with high content, which is also the reason for why they have different weathering velocity. Most of the quartzites partially comprised by ferrite have sandstone structure. They are mainly made up by single crystal quartz and 15% - 70% are cemented. All the lithological characters above is the main reason for the genesis of landform in Zhangjiajie and is also the reason for why the upper sandstones still stand firmly instead of being weathered. As a result, the “Iron Cap” is formed and protects the whole sandstone pillar and shapes the image-building landforms called “the soldier who is taming the horses” and “the fairy with a bouquet”, etc. As for the middle and down parts of the sandstone pillars, they are apt to form the landscapes of forest, channels and vales caused by their fragility, vertical joints and weathering.

关 键 词：张家界 岩性抗风化程度 峰林地貌成因 

分 类 号：P931[天文地球—自然地理学]