The Fractal Characteristics of Drainage Networks and Erosion Evolution Stages of Ten Kongduis in the Upper Reaches of the Yellow River,China     

YANG Hui  SHI Changxing 《资源与生态学报(英文版)》2017,8(2):165-173

The fractal characteristics of drainage in the ten kongduis of the upper Yellow River were obtained using the box counting dimension, and the evolution stages of the watershed topography were defined by different ranges of the fractal dimensions of river networks (Dg). The results show that the fractal scaleless range of the Maobula River is 20–370 m based on a combination of artificial judgment, correlation coefficient test and fitting error. Other kongduis show good fractal characteristics in this fractal scaleless range as well. The box counting dimension can be used as a quantitative index of watershed topography fractal characteristics. The fractal dimension of stream networks is independent of the threshold contributing area used for extracting the drainage networks from the DEM. The values of Dg in the upper ten kongduis are in the range of 1.08?1.14. Both the runoff yield and the sediment yield are positively and linearly related with Dg. The positive relation between the sediment yield and Dg reflects the effect of landform features on sediment yield in the young and/or mature stages of landform evolution of the study area. By revising the critical value of Dg, the value of Dg of the basin in the young evolution stage is less than 1.06, while it is more than 1.06 for the basin in mature or old evolution stage. The upper ten kongduis are in the mature stage of landform evolution.  相似文献   

Controls on the location,morphology and evolution of complex esker systems at decadal timescales,Breiðamerkurjökull,southeast Iceland          下载免费PDF全文

Robert D. Storrar  David J. A. Evans  Chris R. Stokes  Marek Ewertowski 《地球表面变化过程与地形》2015,40(11):1421-1438

This paper uses detailed mapping of eskers to address three questions which are important for reconstructing meltwater behaviour beneath contemporary and ancient ice masses: ‘What controls the morphology of simple and complex esker systems?’, ‘How do esker systems evolve through time?’ and ‘Are esker patterns compatible with groundwater controlled hydraulic spacing of esker tunnels?’. Esker crestlines and widths are mapped on the Breiðamerkurjökull foreland for eight time slices between 1945 and 2007, from high resolution (~50 cm) aerial photography, permitting their long‐term morphological evolution to be analysed in a high level of detail. We find that complex eskers develop where meltwater and sediment is abundant, such that sediment clogs channels, forming distributary eskers. Isolated eskers are simpler and smaller and reflect less abundant meltwater and sediment, which is unable to clog channels. Eskers may take several decades to emerge from outwash deposits containing buried ice and can increase or decrease in size when ice surrounding and underlying them melts out. It has been suggested that groundwater–channel coupling dictates the spacing between eskers at Breiðamerkurjökull. Our results do not dispute this, but suggest that the routing of sediment and meltwater through medial moraines is an additional important control on esker location and spacing. These results may be used to better understand the processes surrounding esker formation in a variety of geographical settings, enabling a more detailed understanding of the operation of meltwater drainage systems in sub‐marginal zones beneath glaciers and ice sheets. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Schmidt‐hammer exposure‐age dating (SHD) of snow‐avalanche impact ramparts in southern Norway: approaches,results and implications for landform age,dynamics and development          下载免费PDF全文

John A. Matthews  Lindsey J. McEwen  Geraint Owen 《地球表面变化过程与地形》2015,40(13):1705-1718

Schmidt‐hammer exposure‐age dating (SHD) was applied to the problem of dating the diachronous surfaces of five distal river‐bank boulder ramparts deposited by snow avalanches plunging into the Jostedøla and Sprongdøla rivers in the Jostedalsbreen region of southern Norway. Approaches to local high‐precision linear age calibration, which controlled in different ways for boulder roundness, were developed. The mean age (SHD_mean) and the maximum age (SHD_max) of surface boulders were estimated for whole ramparts, crests and distal fringes. Interpretation was further assisted by reference to R‐value distributions. SHD_mean ages (with 95% confidence intervals) ranged from 520 ± 270 years to 5375 ± 965 years, whereas SHD_max ages (expected to be exceeded by <5% of surface boulders) ranged from 675 to 9065 years. SHD ages from the Jostedøla ramparts tended to be older than those associated with the Sprongdøla, rampart crests were younger than the respective distal fringes, and use of relatively rounded boulders yielded more consistent SHD ages than angular boulders. The SHD_mean ages indicate differences in recent levels of snow‐avalanche activity between ramparts and provide insights into rampart dynamics as boulders are deposited on rampart crests and, in smaller numbers, on the distal fringes. SHD_max ages provide minimum age estimates of rampart age (i.e. the time elapsed since the ramparts began to form) and suggest that at least some of the ramparts have been developing since the early Holocene. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

内蒙古石人沟南山晶洞正长花岗岩地貌特征     

唐振  李伟  司秋亮  陶传忠  马永非  杨柳 《地质与资源》2014,23(4):364

通过详尽的野外调查工作对其地貌形态进行描述和成因分析,表明石人沟南山晶洞正长花岗岩发育有石蛋、晶洞等较为奇特的地貌.其造景岩石为早白垩世A型晶洞正长花岗岩.岩体中发育的北北东-北东向、北西向断裂、裂隙及节理是控制山峰形态和规模的主要构造.风化剥蚀、流水侵蚀和重力崩塌是地貌形成的主要外动力作用,其成景岩石独特,所成多种地貌是不可多得的地质遗迹与旅游开发资源.  相似文献   

构造地貌及其分析方法述评   总被引：6，自引：0，他引：6  

王岸  王国灿 《地质科技情报》2005,24(4):7-12,20

构造地貌是指受构造内动力作用控制,通过内外地质动力的相互作用所奠定的能够反映一定构造特征的地貌形式.构造地貌学的研究内容为:地貌与构造的关系、构造地貌发生和发展过程以及构造地貌过程所揭示的地球内部构造动力过程;其分析方法可归纳为构造地貌格局分析法、构造地貌形态分析法、构造地貌相关沉积分析法和构造地貌年代分析法.构造地貌学从地形地貌的角度来分析构造过程,涉及不同圈层间的相互作用,响应了当前地球系统科学的研究思路,可以预见,构造地貌学将在圈层作用研究中发挥重要作用,同时朝着信息化、定量化的方向发展.  相似文献   

山西断陷系交城断裂全新世古地震活动初步研究   总被引：9，自引：0，他引：9  

江娃利  谢新生  王瑞  王焕贞  冯西英 《地震研究》2004,27(2):184-190

断错地貌调查及探槽开挖表明,晋中盆地西界分布的黄土台地的前、后缘均存在断层,断层的最新活动位于地表陡坎的前缘,地表见到的断层最新活动断面的上升盘是早全新世地层。同时,新民探槽开挖表明,该断裂在早全新世以后曾发生三次古地震事件,最新一次活动接近距今2748a,另两期古地震事件的时间分别距今4037～5910a及8360～5910a。如果取后两次古地震事件时间跨度的中值,这三次古地震事件的间隔分别是2225a和2162a,平均2193a。  相似文献   

脆弱地质景观评价体系研究-以江西鹰潭龙虎山丹霞地貌景观为例     

姜伏伟  郭福生  姜勇彪  胡中华  吴智勇 《火山地质与矿产》2012,(1):62-66

我国地质资源开发过程中对外部环境的抗干扰能力低、自身稳定性差、易破碎或消亡的脆弱地质景观缺乏足够认识。本文运用层次分析法建立脆弱地质景观评价体系,包含脆弱性和景观性两方面九个评价因子,并对评价因子赋值及划分脆弱地质景观等级。运用脆弱地质景观评价体系评价龙虎山丹霞地貌30处代表性景观,所得结果与实际调查吻合,且可为地质遗迹保护提供参考。  相似文献   

Spatial structure characteristics detecting of landform based on improved 3D Lacunarity model   总被引：1，自引：0，他引：1  

Josef STROBL 《中国地理科学(英文版)》2012,22(1):88-96

The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surface based on improved 3D Lacunarity model.Lacunarity curve and its numerical integration are used in this model to improve traditional classification result that different morphological types may share the close value of indexes based on global statistical analysis.Experiments at four test areas with different landform types show that improved 3D Lacunarity model can effectively distinguish different morphological types per texture analysis.Higher sensitivity in distinguishing the tiny differences of texture characteristics of terrain surface shows that the quantification method by 3D Lacu-narity model and its numerical integration presented in this paper could contribute to improving the accuracy of land-form classifications and relative studies.  相似文献   

中国雅丹地貌申报世界自然遗产的可行性研究   总被引：1，自引：1，他引：0  

郭峰  吴晋峰  王鑫  李蕾 《中国沙漠》2012,32(3):655-660

中国干旱区分布的大面积典型雅丹地貌具备申报世界自然遗产的条件,但是中国雅丹地貌的“申遗”工作长期以来被忽视。依据《世界遗产公约操作指南》中的相关标准,分析了中国雅丹地貌的世界自然遗产价值,论证了中国雅丹地貌申报世界自然遗产的条件,讨论了中国雅丹地貌申报世界自然遗产的重要意义,并建议有关部门尽快开展中国雅丹地貌“申遗”工作,使中国雅丹地貌尽早被世界遗产委员会列入《世界遗产名录》。  相似文献   

中国村庄宅基地空心化评价及其影响因素   总被引：14，自引：2，他引：12  

宋伟  陈百明  张英 《地理研究》2013,32(1):20-28

依托全国范围内村庄宅基地空心化的典型调查数据,分析了不同区域、区位和地形条件下村庄宅基地的空心化程度及其影响因素。研究显示:①调查村庄宅基地的平均空心化率为10.15%,其中东、中、西部区域村庄宅基地的空心化率分别为14.82%、9.11%和7.15%,呈现出由东向西依次递减的格局;②空间上,高空心化率省份主要集中分布在华北和东北地区;③城镇远郊村庄宅基地的空心化率(11.33%)高于城镇近郊村庄(7.81%),山地区村庄宅基地的空心化率(12.24%)高于平原区(9.91%)和丘岗区(5.86%);④村庄宅基地空心化率对于农村非农就业比重和耕地相对稀缺程度较为敏感。在当前背景下,如果能充分利用已有闲置和废弃宅基地,可满足我国未来10～20年新增农村人口的用地需求。  相似文献