| 广西凌云天坑群特征及成因分析 |
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| 引用本文：潘天望,史文强,李成展,陈伟海,唐亮亮,陈志强.2026.广西凌云天坑群特征及成因分析[J].地球学报,47(3):688-702. |
| DOI：10.3975/cagsb.2025.120821 |
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| 基金项目:本文由中国地质调查局地质调查项目“渝东南地区岩溶地貌地质遗迹立典调查评价”(编号: DD20242325)和中国地质科学院岩溶地质研究所基本科研业务费项目“重庆金佛洞望天宫冰洞成景机制研究”(编号: 2023005)联合资助。 |
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| 中文摘要:广西凌云天坑群是位于澄碧河流域小型地下河系统中的高密度塌陷型天坑集群, 由19个天坑组成, 并伴生有岩溶峡谷、湖泊、天窗、漏斗、峰丛、洼地、谷地、洞穴及地下河等多种岩溶地貌景观, 其独特的发育演化模式揭示了孤立碳酸盐岩台地区域岩溶地貌发育演化的独特性, 为西南地区岩溶地貌发育演化研究提供关键案例。通过野外调查与室内分析, 文章系统研究了该天坑群的形成条件与发育演化机制。结果表明: (1)研究区巨厚、质纯且连续沉积的泥盆系—二叠系碳酸盐岩为天坑发育提供了优越的物质基础, NE与NW向断裂及其次生陡倾节理带控制了天坑发育的空间格局, 水热配套的亚热带季风气候及来自周边碎屑岩区的“越境式外源水”强烈补给, 是形成天坑群的关键外动力机制。(2)本区岩溶洞穴早期地下河剖面光释光(OSL)、碳十四(14C)和铀系(U-Th)测年分析显示, 中更新世晚期构造抬升导致本区地下河下切增强, 促进洞厅崩塌与天坑形成。(3)凌云天坑群具有独特的“越境式外源水岩溶天坑演化模式”, 形成“地下河→洞穴大厅→天坑→复合天坑→峰丛谷地”完整的发育演化序列, 为理解小型地下河流域高密度天坑集群的成因提供了重要案例与理论依据。 |
| 中文关键词:天坑群 成因分析 演化模式 凌云县 广西 |
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| Features and Genesis of the Lingyun Tiankeng Cluster, Guangxi |
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| Abstract:The Lingyun tiankeng cluster in Guangxi is a high-density assemblage of collapse-type tiankengs situated within a small-scale underground river system of the Chengbi River Basin. It consists of 19 tiankengs, accompanied by a variety of karst landforms including canyons, lakes, skylights (tianchuang), dolines, peak clusters, depressions, valleys, caves, and underground rivers. Its distinctive evolutionary pattern exemplifies unique karst processes on isolated carbonate platforms and offers key insights into the landscape evolution of karst regions in Southwest China. Based on field investigations and laboratory analyses, this study systematically examines the formation conditions and evolutionary mechanisms of the tiankeng cluster. The key findings are as follows: (1) The exceptionally thick, pure, and continuously deposited Devonian to Permian carbonate rocks provide an optimal material foundation for tiankeng development. NE- and NW-trending faults and steeply dipping joint zones control the spatial pattern of karstification. The hot and humid subtropical monsoon climate, coupled with substantial recharge from allogenic water sourced from surrounding clastic rock areas, serves as the critical external dynamic mechanism for the formation of the tiankeng cluster. (2) Chronological analyses, including optically stimulated luminescence (OSL), radiocarbon (14C), and uranium-thorium dating of paleo-underground river passages indicate that tectonic uplift during the late Middle Pleistocene enhanced river incision in the region, which promoted chamber collapse and tiankeng formation. (3) The Lingyun tiankeng cluster exhibits a unique “evolutionary model of karst tiankengs fed by allogenic water”, demonstrating a complete developmental sequence from underground river → cave chamber → tiankeng → composite tiankeng → peak-cluster valley. This study provides a significant case and theoretical basis for understanding the genesis of high-density tiankeng clusters in small-scale underground river basins. |
| keywords:tiankeng cluster genesis analysis evolution model Lingyun County Guangxi |
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