龙虎山世界地质公园象鼻山栈道洞穴地貌成因  

Origin Analysis of the Cavities along the Xiangbishan Cliffs in the Longhushan Global Geopark,Southeast China

作　　者：李馨敏 郭福生[1,2] 陈留勤[1,2] 王凤之 李余亮 LI Xinmin;GUO Fusheng;CHEN Liuqin;WANG Fengzhi;LI Yuliang(State Key Laboratory Breeding Base of Nuclear Resources and Environment,Nanchang 330013,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学省部共建核资源与环境国家重点实验室培育基地,南昌330013 [2]东华理工大学地球科学学院,南昌330013

出　　处：《山地学报》2018年第4期509-518,共10页Mountain Research

基　　金：国家自然科学基金项目(41772197;41602113);省部共建核资源与环境国家重点实验室开放基金项目(NRE1605);江西省研究生创新基金项目(YC2015-S271)~~

摘　　要：龙虎山世界地质公园的丹霞地貌主要产于晚白垩世河口组红层中,分布在陡峻崖壁上的洞穴地貌,是丹霞地貌成景系统的重要组成部分。通过测量象鼻山栈道1个露头剖面和383个洞穴的大小、形态、岩性组成,认为大多数洞穴的形成主要受控于岩性不同而导致的差异风化作用。砾岩层中粗大砾石、筛状沉积的聚集状砾岩透水性强易于风化脱落形成洞穴雏形。夹于砾岩层之间的抗风化能力较弱的砂岩层易于风化凹进形成洞穴,横向上沿层理方向断续排列,持续风化可使其联结成为岩槽、扁平洞。暴雨天气顺陡崖壁倾泻而下的快速水流对洞穴形成具有重要影响,经冲刷等侵蚀作用,岩壁表面形成垂向分布的洞穴地貌。后期水流侵蚀、化学和物理风化、微观气候变化以及生物活动等使洞穴进一步扩大。在洞穴发展的晚期阶段,岩壁悬空而发生崩塌后退,形成新的赤壁丹崖。The Late Cretaceous Hekou Formation in the Longhushan Global Geopark constitutes the bedrock of the present-day Danxia landforms.A large number of different cavities found along the rock cliffs are an important element of Danxia scenery system.The origin of these cavities has stimulated great interests among geologists and geomorphologists for a long time.One outcrop section and the three-dimensional size,shape and lithology of 383 cavities were measured and recorded.The research results showed that the cavities were largely caused by differential weathering related with lithologic changes.The outsized pebbles and concentrated pebbles were easily weathered to form small cavities.The interbedded sandstone beds between the conglomerate beds were readily weathered to generate intermittent cavities,which were coalesced to form rock toughs and flat cavities because of continuous weathering.The rapid water flows caused by torrential rains had an important effect on the formation of the cavities.The vertical distribution pattern of the cavities were produced by erosion on the cliff faces.In addition,the water erosion,chemical and physical weathering,microscale climate changes,and biological activities also possibly enhanced the enlargement of the cavities.The rock walls would become unstable and suffer from sudden collapse at the late stage of the cavity development.

关 键 词：丹霞地貌 崖壁洞穴 岩性差异 流水侵蚀 龙虎山 

分 类 号：P931[天文地球—自然地理学]