“亚喀斯特”概念与景观特征的初步探讨——以贵州为例

Preliminary discussion on concept and landscape features of "Semi-Karst" : A case study of Guizhou province

"亚喀斯特"作为贵州等地喀斯特生态环境的特殊组成部分,属典型的生态脆弱区,理清其概念内涵及景观特征是认识这一特殊环境的重要途径,本文拟对其概念内涵、景观特征进行初步探讨。分析认为,亚喀斯特是介于一般典型喀斯特与非喀斯特间的另一种地貌景观,三者在岩层特性、地貌发育、景观特征及生态环境效应若干方面均存在显著差异。构成亚喀斯特的岩性主要是不纯碳酸盐岩(如泥质白云岩、泥质灰岩)及碳酸盐岩与非碳酸盐岩组合的夹层,岩石含泥质成分高,洞穴分布极少,地下水资源模数较大;地貌以丘陵谷地、浅中丘、浅切割低中山为主,地形起伏较缓;成土母质丰富,土层较厚,宜农耕地较多,农用价值相对较大,但同等条件下土壤侵蚀量较高;植被生长茂盛、覆盖度高,生态环境相对较好。

The ＂Semi-Karst＂, as a special part of karst ecological environment of Guizhou, is a typical ecological fragile zone. Clearly defining and fully understanding its concept and connotation, combined with analysis of characteristics of its landscape, is an important way to cognize this special landscape. In this paper, the concept of ＂Semi- Karst＂, as well as its landscape characteristics and ecological environmental effect, have been involved in a preliminary discussion. Analysis holds that ＂Semi-Karst＂ is a transitional landscape developing in impure carbonate rocks and the interlayer of carbonate rocks and non-carbonate rocks. It is another kind of karst landscape different from typical karst and non- karst in development of stratum and lithology, landscape characteristics and ecological environment effect. ＂SemiKarst＂ is mainly constituted by impure carbonate rocks and interlayer of carbonate rocks and non- carbonate rocks. Carbonate rocks mainly include the argillaceous dolomite and argillaceous limestone, with middle Triassic Guanling Formation（T2g） as most typical. And non- carbonate rocks mainly include interbedded reservoir of Daye Formation（T1d）, Ziyun Formation（T1z）, and Luolou Formation（T1l）. In ＂Semi- Karst＂ regions, rocks mostly contain high argillaceous composition; karst development is not as good as in typical karst regions;landforms mainly include hill and valley, low and middle hill, shallow cutting low and middle mountain; terrain fluctuation and surface cutting level are relatively small; slope is nearly between 8 and 35 degrees; peak cluster and peak forest are rare, which are common in typical karst regions. At the same time, few underground karst caves can be found, and karst caves are relatively small on height and length; modulus of groundwater resources is big, and drought and surface water shortage are not as serious as in typical karst areas. Due to rock in ＂SemiKarst＂ of high content of argillaceous rock composition and insoluble residues and low rate of dissolution, these regions are featured by rich soil parent material, fast soil formation rate, thick soil layer, and medium p H of soil. ＂Semi- Karst＂ regions have a large amount of cultivated lands and high agricultural value, which can relieve the conflict between people and land to a certain extent. In addition, in ＂Semi- Karst＂ areas soil covers are continuously distributed,natural vegetation grows densely, Pinus massoniana and cypress are widely distributed, the ecological environment effect is good, and the ecosystem is relatively stable. However, due to factors such as human activities, the quantity of soil erosion in ＂Semi-Karst＂ area is larger than that in typical karst area under the same conditions. Therefore, more significance should be attached to ＂Semi-Karst＂ area and a lot of related researches are needed in the future.