丹霞地貌的坡地形态演化——以浙江新昌丹霞地貌为例

THE MORPHOLOGHICAL DEVELOPMENT OF DANXIA HILLSLOPE ——A Case Study of Xinchang Danxia Landform

在对新昌丹霞地貌进行调查、研究并对国内外的坡地研究回顾的基础上,对丹霞地貌的坡地形态、组成和演化方式及成因进行分析。丹霞地貌坡地在形态和演化方式上的特点比较符合King的坡地理论,在形态组成上可以分为凸形面、自由面、搬运坡和凹形面4部分,在演化上以平行后退和坡地替代两种方式为主。丹霞坡地的类型根据发育阶段可分为幼年期陡壁形态、中年期King型完整King模式形态及老年期丘陵坡地形态。丹霞坡地地貌演化的过程是自由面逐渐后退、缩小的过程,丹霞坡地在坡地退行速度上远小于其他现代坡地。

The study of landscape evolution is firstly and finally a study of hillslope form and process. After reviews some primary theory of hillslope research before, some basic problems of Danxia hillslope, included its form, construction and its evolution process, are discussed on the basis of field oberservation in Xinchang, Zhejiang Province, where classical Danxia landform developing in humid zone can be found. The result is that the form and evolution process of Danxia hillslope is very similar to the hillslope model of L. C. King, a famous geomorphologist. King's model can be available to account for hillslope landform development in arid and semi-arid zone such as those in South Africa, but King argued that his model would be applied to other climatic zones. His arguement partly is verified, because the climate in Xinchang is humid subtropical, and the climate zones where Danxia landform develops are varios. The form of Danxia hillslope can be divided into four parts: waxing slope, free face, debris slope and waning slope. Slope palretreat and replacement are the main evolution ways of Danxia hillslope. But the rate of Danxia hillslope retreat is far slower than that of other modern hillslope which develop in steady tectonic zone, for example, south America, Africa and Australia.