鲁南岱崮地貌的特征与成因分析——以南岱崮为例

Analysis on the Geomorphic Characteristics and Genesis of Daigu in Southern Shandong —Taking Nan Daigu as an Example

摘要: 岱崮地貌具有顶平、身陡、麓缓的地貌特征，是一种特殊的方山地貌类型。“崮”由上下岩性不同的至少两部分组成，其顶部是坚硬、不易被侵蚀的张夏组巨厚层深灰色鲕粒灰岩，下部是相对软弱且易受侵蚀的页岩、泥灰岩等。本文以南岱崮为例，分析研究了鲁南岱崮地貌的特征与成因，得出了以下结论：1) 岱崮地貌主要集中分布在鲁南沂蒙地区，受该地区发育的NW-SE向断裂的影响，大致可分为三组走向，整体呈NW-SE向分布。2) 岱崮地貌是以古生代发育的水平岩层和崮体的不同岩性为基础，经受内外力作用形成的独特的地貌形态。在南岱崮的中寒武统九龙群张夏组底部发现两层软弱层，由于软弱层抗风化能力较弱，地层呈现出凹入的地貌特征，使上方厚层状鲕粒灰岩悬空、沿节理塌陷，这是南岱崮形成的直接原因。经研究，也是部分岱崮地貌形成的直接原因。

Abstract: Daigu landform has the characteristics of flat top, steep body and slow foot. It is a special type of Fangshan landform. “Gu” is composed of at least two parts with different lithology from the top to the bottom. The top is hard and nonerodible Zhangxia formation super thick dark gray Oolitic Limestone, and the lower part is relatively weak and erodible shale, marl, etc. Taking Nan Daigu as an example, this paper analyzes and studies the characteristics and causes of Daigu landform in southern Shandong, and draws the following conclusions: 1) Daigu landform is mainly distributed in Yimeng area, southern Shandong. Affected by the NW-SE faults developed in this area, it can be roughly divided into three groups, with an overall NW-SE distribution. 2) Daigu landform is a unique geomorphic form formed by internal and external forces based on the different lithology of the Paleozoic horizontal rock strata and Gu body. Two weak layers are found at the bottom of Zhangxia formation of Jiulong group of Middle Cambrian in Nan Daigu. Due to the weak weathering resistance of the weak layer, the stratum presents concave geomorphic characteristics, which makes the thick layered Oolitic Limestone hang in the air and collapse along the joint, which is the direct reason for the formation of Nan Daigu. After research, it is also the direct reason for the formation of some Daigu landforms.