Origin of Tafoni in the Late Cretaceous Aeolian Sandstones,Danxiashan UNESCO Global Geopark,South China

Tafoni occur generally in granular rocks around the world, but their origin remains controversial. In this study,the roles of lithology, micro–climate, and organism in tafoni development are investigated in the Danxiashan UNESCO Global Geopark of South China. The Jinshiyan Temple and Luyitang sites along the Jinjiang River are chosen to conduct tafoni morphometry, bedrock petrography, and micro–climate analyses. The research methods used in this study include field observations and measurements, Voronoi diagrams, polarizing microscopic and scanning electron microscopic(SEM)image analysis, and meteorological detection. The tafoni are mostly 2–10 cm in length and elliptical in shape. The Late Cretaceous Jinshiyan sandstones are characterized by a grain–to–grain contact fabric and moderate sorting with a high proportion of soluble grains and cements. The Voronoi diagrams developed through the Arc GIS software are largely consistent with the tafoni openings. Moreover, owing to exposure to solar insolation, the external temperature values are higher than the internal ones, while the external relative humidity values are lower than the internal ones. Therefore, the permeable Jinshiyan sandstones are fundamental for tafoni development, while the abundant moisture from the Jinjiang River and frequent rains is favorable for salt weathering in tandem with biological activities. At last, a five–stage development model is proposed for the tafoni progression in the study area.

Lithological and environmental controls on large tafoni along conglomerate cliffs in subtropic humid Danxiashan UNESCO Global Geopark

Tafoni are a type of cavernous weathering features widespread in different climate zones around the world,but their origin has not been fully understood.Little attention was paid on tafoni in conglomerates.Danxiashan UNESCO Global Geopark,located within the subtropic humid region of South China,has a landscape of large tafoni that occur on cliffs of red conglomerates.Both the Dinosaur Rock and Pagoda Peak of the geopark were selected to investigate the formation mechanisms of tafoni in conglomerates.During the field investigation,the size,rock hardness,and the external and internal meteorology of tafoni were measured and tested.The texture and composition of rock samples were observed,and the ion chromatography experiments were performed as well.Results show that tafoni have well ellipsoidal openings.Clasts of the conglomerates are largely sub-rounded and poorly sorted,and the cement is dominantly composed of calcite and iron oxide.The hardness of the lips is almost equal to that of the columns,and both are slightly higher than the backwalls.Compared with the external intense environmental changes,the interior of the tafoni is characterized by smaller temperature and relative humidity ranges and windless condition.Therefore,the porous and permeable conglomerates provide favorable lithology for tafoni development,and the micro-environment within the caverns is conducive to improving water utilization efficiency and enhancing salt weathering.The salts mainly consist of sulfates and nitrates,which might be derived from frequent raining,water evaporation and red beds as well.Consequently,tafoni are the result of the synergistic effects by multiple factors,rather than a single mechanism.

Upper Cretaceous alluvial fan deposits in the Jianglangshan Geopark of Southeast China:implications for bedrock control on Danxia landform evolution

The Jianglangshan Geopark in the western Zhejiang Province of Southeast China is well-known for its spectacular red-colored sandstone landforms. Little is known about the depositional processes of the conglomerate-dominated Fangyan Formation, the lithologic base of the Danxia landforms in this geopark. Based on detailed field investigation of lithology, sedimentary structures, bed thickness and geometry, five facies are recognized: facies A(matrixsupported cobble conglomerate), facies B(pebble conglomerate), facies C(pebbly sandstone), facies D(fine-grained sandstone) and facies E(mudstone). The results show that streamflow-dominated fans were the main depositional processes responsible for the accumulation of the Fangyan Formation along the mountain fronts. These fan conglomerates form the base for the evolution of the Danxia landscapes owing to the uplift and erosion of the study area. In contrast, the fine-grained sedimentary successions produced by fluvial floodplains in the distal part of the fans were thinner and more easily weathered. Such sedimentary facies distribution patterns were thought to be similar during Late Cretaceous across Southeast China. The Danxia landforms are largely the geographical expressions of the conglomerate-dominated redbeds in the proximal-middle fans.

Species Diversity of Rock Plant Community in Danxia Landform of Zhejiang Province

In order to provide scientific basis for vegetation and biodiversity conservation,species diversity of rock plant in Danxia landform of Zhejiang Province was analyzed in this study.According to the results,there were 195 species belonging to 143 genera and 82 families.The changing trend in Margalef index,Simpson index and Shannon-Wiener index of the same community in different layers was the same,namely herb layer>shrub layer>moss layer>liana layer;the order of Pielou index was moss layer>liana layer>herb layer>shrub layer.Comparing species diversity in different regions,we found that the index of all layers on Jianglang Mountain was higher except the moss layer.

Comparative studies of Danxia landforms in China

Danxia geomorphology originates fi＇om China. This paper studies the spatial distribution and differences in characteristics of Danxia landforms. Based on relevant research and investigations, three congregated areas of Danxia landform in China are discussed in this paper. They are the southeast area （including Jiangxi, Fujian, Zhejiang, Hunan and Guangxi provinces）, the southwest area （the transitional zone of Yunnan-Guizhou Plateau and Sichuan Basin） and the northwest area （including Longshan mountain and along the banks of the Huanghe River and its anabranches）. Not only the conditions of geology and geography of the three areas but also the differences of Danxia landforms of the three areas are analyzed. The Danxia landscape, characterized by upright-shaped peaks, Danxia mesa, stone wall, cave and vertical cave, ＂Danxia natural bridge＂, ＂a narrow strip of sky＂ and so on, often presents in the southeast area. The landscape of southwest area is characterized by Danxia escarpment faces and waterfalls. In the northwest area, the Danxia landscape has the traits of arid areas simultaneously, for example, mud-coating type, columniation type, board type, moreover, it is greatly different between these environmental factors such as the microclimate, water, wind, and the loess cover. Finally it explores the causes which lead differences in landform and also explains the landform formation process and its mechanism with reference to the rates of crustal uplift, the tectonic red-basin, and the external processes including working of running water, weathering, biogenic, gravity in each area of Danxia Landforms in China.

Danxia landform genesis of the Qiyun Mountain, Anhui Province

The Danxia landform of Qiyun Mountain is mainly developed on the red granule conglomerates named Xiaoyan Group （K2x^1） of middle Cretaceous series, which is controlled mainly by three faulted zones, namely, Jingdezhen-Qimen faulted zone, Jiangwan-Jiekou compressional faulted zone and Kaihua-Chun＇an folding faulted zone. During the Cretaceous period, this area firstly experienced massif subsidence to become a continental faulted basin, then having thick Cretaceous red sediments accumulated on it. In the supervened neotectonism, this area experienced an uplifting process, which made the thick Cretaceous sediments into a mountain with an altitude of 500-600 m. After undergoing the processes of vertical joint development, weathering, denudation and transportation, as well as evidently differential weathering and denudation influenced by lithology and structure between sandstone and conglomerate, the grand Danxia landscape consisting of peak forests, steep cliffs, caves, mesas, castellated peaks, natural bridges and so on formed. The three nick points located respectively at 585 m, 400 m and 150 m generally reflect the three dominated uplifting processes during the neotectonism.

Research on the Genesis and Development of Danxia Landform in the South Sichuan

The South Sichuan is one of the areas in China famous for Danxia Landform. Danxia Landform in the South Sichuan is characterized by wide distribution and square shaped hills. However, there is no systematic research on the genesis of those Danxia Landforms at present. Based on the study of spatial distribution and the genesis of the Danxia Landforms in the South Sichuan, we discovered that the lithostratigraphy, regional tectonic, crustal uplift and external forces contribute together to the formation of the Danxia Landform. On the basis of learning the development experiences from famous scenic spots and the updated national policies and regulations, proposals were made to boost the development of Danxia Landform resources in the South Sichuan by excavating its historic, cultural, natural and scientific connotation in the form of educational tourism.

The Poverty Alleviation Model for Poor Nationalities in the Mountainous Areas of Western China: A Case Study of “Promotion for the Entire Lisu Nationality” in Naimu Danxia Village Group

In poor minority areas, poor living conditions, single industrial structure and weak public basic services often lead to a deep degree of poverty. This is the most difficult problem to solve in the fight against poverty. Yunlong Township, Luquan Yi and Miao Autonomous County, which is located in the alpine canyon area of Jinsha River in China, is a semi-closed agricultural township integrating "nationality, mountain area, poverty and backwardness". Located in the Xinshan Village Committee of this township, Naimu Danxia village group is a typical Lisu settlement. It is a key village group with a deep degree of poverty, and the incidence of poverty is 17.00%. In recent years, Naimu Danxia village group has adhered to the direction of unified promotion, internal and external blood creation and resource integration in the poverty alleviation work of the Lisu nationality in Luquan County. It has successfully taken a road of national unity, self-reliance and common poverty alleviation, and formed a unique poverty alleviation model of "promotion for the entire nationality". At the end of 2018, the incidence of poverty dropped to 0, successfully building a "demonstration village of national unity" at the municipal level in Kunming. Based on the field research and interviews, this paper analyzes and summarizes the specific methods, main achievements, practical experience and popularization and application measures regarding the poverty alleviation model of "promotion for the entire Lisu nationality" in the village group. It tries to provide necessary reference for accurate poverty alleviation and poverty eradication in similar minority areas in Yunnan Province and other provinces.

Danxia Landforms: Rosy Clouds on Earth

A Danxia landform is a red-bed landform characterized by steep cliffs. It was initially discovered and named by Chinese scholars. Although there are red-bed landforms in many parts of the world, China, with a special fondness for the color red, boasts the most widely distributed Danxia possessing unique characteristics. This is a mesmerizing natural formation and a special gift that nature has bestowed upon this country.

生态足迹在“丹霞”区域旅游中的应用研究——以湖南省溆浦县思蒙“丹霞”为例(英文)

Based on the theory and methods of tourism ecological footprint, from the perspective of the general geomorphology of "Danxia", seven sub-models of tourism ecological footprint had been established which were tourism ecological carrying capacity, transport, water, waste, visiting, entertainment and food. By taking "Danxia" in Hunan Province for example, tourism ecological footprint had been calculated and analyzed. Through researches on ecological profit and loss and nontransferable ecological footprint, the fact that eco-tourism development scale was reasonable or not had been judged. The results showed that ecological deficit was 669.05 hm2 and nontransferable ecological footprint was 1,357.88 hm2. Finally, the paper had proposed countermeasures for eco-tourism sustainable development in "Danxia", hoping to provide reference for the sustainable development of regional tourist ecological economy.

浙江江郎山丹霞地貌发育的年代与成因(英文)

Jianglang Mountain is situated at the transitional zone of South China fold-system, Jiangshan-Shaoxing deep fracture zone and Baoan-Xiakou-Zhangcun fracture zone. The forming of the Xiakou basin was attributed to the pull-apart fault depression by the above fractures in earlier Cretaceous, afterward, series deposits such as Guantou formation （K1g）, Chaochuan formation （K1c） and Fangyan formation （K1f） which belong to Yongkang group, the lower Cretaceous layer accumulated in the Xiakou basin. In late Cretaceous, the above fractures occurred to extrude and the basin began to uplift, meanwhile, amounts of tension fissures and joints were produced since Cenozoic, which accelerated water-dicing into bed-rock. Consequently, landform-building processing： weathering, eroding and collapsing etc. were prevalent as finally to develop the so-called Danxia landform. The Jianglang Mountain landscape zone of the Danxia landform to apply for world natural relics are relying on unique and unparalleled peak, sky-split valley with vivid stones and reviving of platform. What is more, there is significance of study at lithology, stratigraphy and paleo-biology. According to dating for specimen of ophitic vein through-crossing the Yongkang group of Yafeng Peak by K-Ar method, this article revealed the uplift age of red-bed basin to be 77.89±2.6 MaBP （K2） i.e. late Cretaceous, and it is the first chronological datum of Danxia landform research in China.

Land degradation and management of red beds in China:Two case studies

Red beds cover approximately 9.5%of China,and are home to approximately 144 million people.In total,83%of these lands are distributed in humid regions making it an important part of research on red bed soil erosion in China in these areas.This paper presents the main types of land degradation in red bed landscapes and the status of current soil erosion in a typical red bed basin,the Nanxiong Basin located in the north of Guangdong Province,China,and establishes the connection between management strategies and regional economic development in humid red bed regions of China.The soil erosive modulus was calculated in the Nanxiong Basin by using RUSLE(The Revised Universal Soil Loss Equation).The results of overlapping analyses demonstrated that appropriate measures,such as the Return Farmland to Forests initiative,should be taken at the junction of central red bed areas and mountainous areas in order to mitigate current soil erosion.Two examples are presented to demonstrate this:the tourism development in Mt.Danxiashan,a noted scenic mountainous area near Nanxiong Basin,and the land degradation mitigation in the Nanxiong Basin.Both examples promote local economic growth while simultaneously protecting the environment.A‘stakeholder'strategy is pursued at Mt.Danxiashan,which can help residents to understand their positive effects on the environment as well as increase their income.The second example,in Nanxiong City,showcases how local farmers became stakeholders by implementing contract responsibility and self-support systems for economic forests and terraced land in the 1980s.

望春玉兰—‘丹霞似火’新品种选育初报

2014-2018年,在望春玉兰种质资源调查的基础上,对特异单株通过嫁接或种子繁殖,培育一代、二代苗木,对其花、药蕾、叶、枝等形状的稳定性、一致性和特异性进行观测记录,选育出‘丹霞似火’望春玉兰植物新品种。

Experimental studies on the Danxia landscape morphogenesis in Mt. Danxiashan, South China

The formation of Danxia landscapes is too slow to be observed in our life time and the paleoclimates in which Danxia landscapes developed are significantly different from the present. Thus, this study adopted experimental approaches to examine the lithological and paleoclimatic control on the formation of various landscape morphologies in the Mt. Danxiashan, South China. A total of 122 rock samples were collected from a range of Danxia landscape morphologies such as white spots, small and large through caves, honeycomb caves, horizontal grooves, natural bridges, stone pillars, and squama stones. Analyses of the collected samples were conducted in different kinds of experiments, including uniaxial mechanical strength testing; rock resistance against sulfuric acid erosion, freezing, and thawing; X-ray fluorescence spectrometry（XRF） analysis; inductively coupled plasma mass spectrometry（ICP-MS） analysis; and identification analysis under a polarizing microscope. The results indicated that the formation of the various Danxia landscape morphologies could result from one or more of the following processes： differential erosion due to lithological difference, chemical dissolution and recrystallization, freezing and thawing actions, acid corrosion, weathering, lateral erosion of river flows, and tectonic uplifts. Water erosion in humid monsoon climate and the alternations of intensive freezing and thawing actions in the Quaternary glacial stages and the interglacial stages could have had great influences on the formation of Danxia landscape topographies.

Danxia geomorphology of China: A review

Danxia Landform belongs to red terrestrial clastic rock landform, which is characterized by its red cliffed scarp. The development of Danxia Landform research in China experienced three historic stages, i.e. initial establishment, taking shape and expanding since the concept 'Danxia Landform' raised by Prof. Chen Guoda in 1939. As a new branch of geomorphology, Danxia geomorphology research is now stepping its ripe stage. In the 1990s, the search enters into an unprecedented grand occasion at the prompting of tourism exploit.

Geological Evolution of Longhushan World Geopark in Relation to Global Tectonics

The South China fold belt has experienced a complex series of tectonic events that span 1.0 billion years of earth history. Longhushan （龙虎山） World Geopark is located on the Proterozoic suture between the Yangtze craton and Cathyasia block and highlights the long history of this belt. Collision of the Cathyasia and Yangtze cratons 1.0 billion years ago was associated with the formation of the Rodinian supercontinent where most of the planet＇s landmasses were amalgamated into one block. Jurassic through Early Cretaceous magmatism was associated with the inland migration of the continental margin arc associated with the penetration of a flat slab after subduction of the Kula-Farallon ridge. Slab roll-back in the Early to Middle Cretaceous opened many extensional basins across the South China fold belt, including the Xinjiang （信江） basin in which Longhushan is located, and these were filled largely with continental red beds deposited by fluvial systems in the hot torrid climate. The beds are richly fossiliferous, including remains of many dinosaurs and dinosaur eggs. Subduction of the Kula-Pacific plate in the Middle Cretaceous caused a short magmatic pulse, and then, the basins subsided slowly through the remainder of the Cretaceous. Cenozoic uplift of the red bed basins was initiated by the India- Asia collision. The uplift was associated with the formation of many faults, joints, and brittle structures that dissected the red bed deposits. Fluvial erosion of the red beds was enhanced along the brittle structures, and different locations have developed very distinctive and structuraliy controlled geomorphological features including mesas, kopjies, and isolated stone peaks that are known in China as Danxia （丹霞） land-forms. Together, these features form Danxia landscapes, and Longhushan World Geopark exhibits a complete range of the Danxia landscapes from juvenile, to mature and to old stages of development. The United Nations Educational, Scientific, and Cultural Organization （UNESCO） World Geopark program ensures that these features and geologic history will be preserved in their pristine state and be available for study and appreciation for generations to come.