大方清虚洞穴景观资源特征及形成机制的初步研究

探测清虚洞发育特征及景观资源组成,研究清虚洞形成机理,为科学开发、保护提供参考。本文在探测清虚洞的基础上,根据清虚系统的洞道结构和空间展布特征,分析其资源构成及特征;分析区内地形地貌、地质构造和水文等自然条件,对清虚洞形成的影响;以区域新构造演进为主线,讨论清虚洞形成与演化过程。结果表明:(1)清虚洞洞穴系统属于大型洞穴系统,其洞道结构为"一桥、两坑、一窗、一支洞";(2)天生桥、天坑、天窗、洞内景观及边缘坡立谷等,是清虚洞景观资源的重要组成部分,其中边缘坡立谷、清虚洞天生桥及云坛天坑构成了核心资源;(3)区内地形特征及下伏非碳酸岩夜郎组(T_1y)地层,为外源水流入碳酸岩地层溶蚀成洞提供了隔水条件;(4)区内地下水不仅沿着构造节理和裂隙运移溶蚀,而且单斜构造条件也有利于地下水沿着层间裂隙溶蚀、侵蚀,是控制清虚洞成因之一;(5)清虚洞穴系统在形成演化过程中,主要经历溶蚀期、崩塌期和下切3个时期。区内岩层空间展布和区域构造是清虚洞形成的前提条件,外源水是清虚洞形成的基本动力,在区内地文演进过程塑造了世界罕有的天生桥景观。

Preliminary Study on the Characteristics and Formation Mechanism of Qingxudong Cave in Dafang County

The development characteristics and landscape resource composition of Qingxudong cave were explored,and the formation mechanism of Qingxudong cave was studied to provide reference for scientific development and protection.Based on the detection of Qingxudong cave and according to the tunnel structure and spatial distribution characteristics of the Qingxu system,the composition and characteristics of the resources were analyzed and the influence of the topographical features,geological structures and hydrological conditions on the formation of the Qingxudong cave was analyzed.Taking the evolution of regional neotectonics as the main line,the formation and evolution of Qingxudong cave was discussed.The results show that:(1) the cave system of Qingxudong cave belongs to a large cave system with a tunnel structure of "one bridge,two pits,one window and one hole".(2) Tiansheng bridge,Tiankeng,skylight,landscape in cave and edge slope valley are the important landscape resources of Qingxudong cave,among which edge slope valley,Qingxudong cave,Tiansheng bridge and Yuntan tiankeng constitute the core resources.(3) The topographical features in the area and the underlying non-carbonated rock (aquiclude) Yelang group (T₁y) provide conditions for the inflow of exogenous water into the carbonated rock formation to dissolve and form holes.(4) Groundwater in the area not only migrates and erodes along the structural joints and fissures,but also the monoclinic structural conditions are conducive to groundwater erosion and erosion along the interstratified fissures and become one of the controlling factors for the formation of Qingxudong cave.(5) In the process of formation and evolution,the Qingxudong cave system mainly experiences three periods:dissolution period,collapse period and undercutting period.The spatial distribution of rock strata and regional structure in the area are prerequisites for the formation of the Qingxudong cave,and exogenous water is the basic driving force for the formation of the Qingxudong cave.In the process of geography evolution in the region,the world''s rare natural bridge landscape is created.