| 丹霞地貌定义、分类及丹霞作用研究 |
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| 引用本文： | 郭福生,陈留勤,严兆彬,刘富军,潘志新,张炜强,胡海平.丹霞地貌定义、分类及丹霞作用研究[J].地质学报,2020,94(2):361-374. |
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| 作者姓名： | 郭福生 陈留勤 严兆彬 刘富军 潘志新 张炜强 胡海平 |
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| 作者单位： | 1) 东华理工大学核资源与环境国家重点实验室，南昌，330013,2) 东华理工大学地球科学学院，南昌，330013,1) 东华理工大学核资源与环境国家重点实验室，南昌，330013,2) 东华理工大学地球科学学院，南昌，330013,3) 海南大学，海口，570228,2) 东华理工大学地球科学学院，南昌，330013,2) 东华理工大学地球科学学院，南昌，330013 |
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| 基金项目： | 本文为国家自然科学基金项目（编号41772197、41962009、41761002）和韶关市丹霞山管委会科研基金项目资助成果。 |
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| 摘 要： | 丹霞地貌以广东丹霞山最为典型而得名,是一种发育赤壁丹崖群的特殊地貌类型,近年来随着旅游开发不断升温而成为景观地貌学关注的重要对象,但其中一些基本问题长期争论不休。本文从命名地的地质、地貌特征和我国区域地质发展史角度出发,重新厘定了丹霞地貌的定义与分类,强调丹霞地貌的三大基本要素:赤壁丹崖地貌特征、燕山旋回以来陆相红层基础和以流水侵蚀为主的地质营力。西北地区也广泛发育丹霞地貌,一类是黄土覆盖下的古丹霞,另一类是干旱区片流侵蚀和泥乳贴膜的丹霞。丹霞作用是对中新生代陆相碎屑岩经流水侵蚀、重力崩塌和风化剥落等多种地质作用的统称,其产物就是丹霞地貌。岩性控制和崖壁片流垂蚀是丹霞作用的两种特殊机理。红层盆地的沉积相及其岩性差异控制着丹霞地貌的发育及其景观类型,据此在地貌发育的构造、外力和时间三个因素基础上增加了岩性因素。南方典型的红层盆地中,边缘冲积扇相粗碎屑岩地区可经历青年、中年和老年等发展阶段,盆地中央湖泊相泥岩、粉砂岩却没有经历过绝壁陡崖发展阶段。暴雨水流在丹霞崖壁上发生近垂直向下的侵蚀作用叫片流垂蚀作用。其中冲蚀作用形成竖状沟槽、竖状洞穴,涡蚀作用(借助风力吹动发展成垂直崖壁的涡旋)形成圆锥状洞穴、串珠状洞穴,后者使得洞穴沿软弱岩层分布,进一步扩大成扁平状洞穴。这些洞穴形成年代具有垂向一致性,不具有上老下新变化趋势,而在水平方向上,不同部位洞穴的形成年代可能不同。
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| 关 键 词： | 丹霞地貌 丹霞作用 红层 地貌演化模式 片流垂蚀作用 |
| 收稿时间： | 2019/9/2 0:00:00 |
| 修稿时间： | 2019/11/24 0:00:00 |
Definition, classification, and danxianization of Danxia landscapes |
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| GUO Fusheng,CHEN Liuqin,YAN Zhaobin,LIU Fujun,PAN Zhixin,ZHANG Weiqiang and HU Haiping.Definition, classification, and danxianization of Danxia landscapes[J].Acta Geologica Sinica,2020,94(2):361-374. |
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| Authors: | GUO Fusheng CHEN Liuqin YAN Zhaobin LIU Fujun PAN Zhixin ZHANG Weiqiang and HU Haiping |
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| Institution: | 1) State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, 330013,2) School of Earth Sciences, East China University of Technology, Nanchang, 330013,1) State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, 330013,2) School of Earth Sciences, East China University of Technology, Nanchang, 330013,3) School of Tourism, Hainan University, Haikou, 570228,2) School of Earth Sciences, East China University of Technology, Nanchang, 330013 and 2) School of Earth Sciences, East China University of Technology, Nanchang, 330013 |
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| Abstract: | The representative Danxia landscape, named after Mt. Danxia of Guangdong Province, is a special type of landscape characterized by red cliffs. With the rise of tourism in recent years, it has become a focus of geomorphological research. However, there are still controversies in some basic issues of Danxia landscape. Based on the geological, geomorphological characteristics and regional geologic evolution of the named place, this paper proposes a new definition and classification of Danxia landscape with emphasis on three fundmental elements: prominent red cliffs, continental red beds deposited since Yanshanian cycle as material basis, and water erosion as a dominant external force. Moreover, the Danxia landscapes are also widely distributed in NW China and they can be classified into two types: one is the old Danxia landscape covered by Quaternary loess, another is characterized by water erosion and covered by mud. This paper proposes the concept of danxianization which involves various geologic processes such as water erosion, gravity collapse, and weathering and deterioration of the Mesozoic- Cenozoic continental clastic rocks, resulting in the formation of Danxia landscapes. The danxianization includes two special mechanisms of lithofacies control and vertical overflow erosion. The differences in red bed lithofacies control the development and type of Danxia landscape. Therefore, Danxia landscape evolution model is hereby revised as the function of lithofacies, geologic structure, external forces, and time. In typical red bed basins of South China, the coarse- grained alluvial fan deposits at basin margin have the early, middle, and late development stages. In contrast, mudstones and siltstones deposited in the middle of the basin are thought to have not experienced the development stage of prominent cliffs. Water erosion during the torrential rain on the cliff sides along the vertical trench is called vertical overflow erosion which results in the formation of vertical grooves and cavities. The vortex action is caused by rotating and drilling by wind to generate cone- shaped cavities, beaded tafoni, which are then coalesced laterally to form flat caves. Thus, it is proposed that the ages of the beaded cavities are vertically consistent, they may form at different ages in horizontal direction. |
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| Keywords: | Danxia landscape danxianization red beds geomorphic evolution model vertical erosion of overflow |
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