安徽齐云山丹霞地貌成因

齐云山丹霞地貌主要发育于中白垩统小岩组K₂x¹红色砂砾岩层中, 该区地貌发育主要受景德镇-祁门断裂带、江湾-街口挤压破裂带和开化-淳安褶断带三大断裂带控制。在白垩世该区经历了地块沉降, 成为陆上的断陷湖盆, 由此接受了巨厚的白垩系红层堆积。在新构造运动中, 该区经历了隆升过程, 巨厚的白垩系沉积物变成了海拔500~600 m的山体。白垩系红色砂砾岩在经历了垂直节理发育、风化破坏阶段及剥蚀搬运阶段后, 同时受岩性本身砂岩与砾岩在组分和结构上的影响, 差异性风化剥蚀显著, 因此形成了壮观的峰林、崖、洞、方山、城堡及天生桥景观。该区585 m、400 m和150 m处的三级裂点, 大致反映了该区新构造运动中三次主要的抬升过程。

Danxia Landform Genesis on Qiyun Mountain, Anhui Province

The Danxia landform of Qiyun Mountain is mainly developed on red sands tone and conglomerate of middle Cretaceous series (K2x1). The landform developme nt in this area is mainly controlled by three faulted zones, that is, Jingdezhen -Qimen faulted zone, Jiangwan-Jiekou faulted zone and Kaihua-Chun'an faulted zon e. During the Cretaceous period, this area firstly experienced massif subsidence to a continental fault basin, and received thick Cretaceous red beds to accumul ation. Then, during neotectonism, this area experienced an uplift process, the t hick Cretaceous sediments became a mountain body with an altitude of 500-600 m. After having undergone the processes of vertical joints development, weathering, denudation and transportation, as well as influenced by the lithological compon ent and structure between the sandstone and the conglomerate, grand Danxia lands cape has formed in this area such as peak forest, steep cliff, cave, mesa, caste llated peak and natural bridge. The three-grade knick points of Qiyun Mountain i llustrates that the area has experienced three major uplift processes during the neotectonism.