中国丹霞景观空间分异及其影响因素

Spatial differentiation of Danxia landscapes in China and its influencing factors

丹霞景观指以丹霞地貌为主体的景观风貌,在中国分布广泛。丹霞地貌学科发展和保护利用离不开全国尺度上对其景观分异的深入认识。本文依据岩性、崖壁高度、岩层产状、岩石强度等数据,定量分析丹霞景观特征的空间格局;结合对中国超过200处丹霞地貌的实地调查所获认识,半定量地确定了中国丹霞景观的空间分异;综合地质、地貌等因素,将中国丹霞景观划分为东南部、川渝黔边区、鄂尔多斯高原、鄂尔多斯盆地西南部、“天山—祁连”沿线和青藏高原地区6个各具特色的丹霞景观片区。通过全国尺度丹霞景观的对比发现:①红层沉积范围和喜马拉雅运动的地壳升降格局共同控制了丹霞地貌的空间分布;②喜马拉雅运动在中国不同区域构造变形特征控制了丹霞成景地层倾斜程度;③不同类型盆地岩性的差异,影响崖壁平整程度等坡面形态;④岩石强度对崖壁高度影响较小,但垂向岩石强度的差异导致水平凹槽或洞穴的形成,并导致以崩塌为主的地貌过程;⑤地貌演化阶段影响单体和群体景观的丰富程度;⑥气候主要影响当前活跃的地貌过程,植被和水体等自然地理要素与地貌的组合塑造了不同的丹霞景观特色和美感。全国尺度上,丹霞景观特征在空间上的分异是构造演化历史、地表环境等因素的区域性表现。

Danxia landscapes are a landscape feature with the Danxia landform as the main body,and are widely distributed in China.An in-depth understanding of the landscape differentiation on a national scale is essential for the protection and utilization of Danxia landscapes as tourism resource.Based on data such as lithology,cliff height,stratum attitude,rock strength,and other data,this study quantitatively analyzes the spatial pattern of Danxia landscapes.Combining these data with the understanding from an on-site survey of more than 200 Danxia landforms across the country,the differentiation of Chinese Danxia landscapes is semi-quantitatively determined.Based on multiple geologic and geomorphologic factors,the Danxia landscape in China is divided into six distinctive regions:Southeast China,the Sichuan-Chongqing-Guizhou junction,the Ordos Plateau,the southwestern Ordos Basin,"Tianshan-Qilian",and the Qinghai-Tibet Plateau.Through the national-scale comparison of Danxia landscapes,six key characteristics are noted.The basin size of red-bed deposits and the crustal uplift and subsidence during the Himalayan movement jointly controlled the spatial distribution of the Danxia landforms,while the tectonic deformation characteristics in different regions controlled the inclination of strata.The spatial lithological differences among different types of the basins affect the slope morphology.Rock strength has little effect on cliff height,but the difference in vertical rock strength affects the slope shape,which in turn affects the geomorphological process.The landform evolution stages affect the richness of individual and group landscapes.Finally,climate influences the currently active geomorphic processes,and the combination of vegetation and landforms in different climate zones shapes different Danxia landscape features and aesthetics.Nationally,the spatial distribution of Danxia characteristics is a regional manifestation of tectonic evolution,Earth's surface environment,and other factors.