Geometric characteristics of valley and basin of Suoshui River in Zhangjiajieof Hunan Province and their implications in landform evolution
Shi Changxing, Qi Deli
Key Laboratory of Water Cycle and Related Surface Processes, Institute of Geographic Sciences andNatural Resources Research,Chinese Academy of Sciences,Beijing 100101
Abstract：Using data of DEM,landform and geologic maps and surveys in fields,this study investigated the characteristics of valley geometry,hypsometry and the stage of landform evolution of the Suoshui River basin,in which most of the sandstone forests or pillars,the typical Zhangjiajie landform,are located.Results show that the mainstream of the Suoshui River has a concave longitudinal profile with a slope declining downstream and a concavity value of 0.70,and the principal tributaries of the river have a gradient much higher than that of the mainstream and a concavity in the range of 0.12-0.98.Along the mainstream downstream,the width and the width/depth ratio of the river valley increase and the depth decreases gradually.The cross-sectional concavity of the mainstream of the Suoshui valley is lower in the upper and lower reaches and higher in the middle reaches,and that of all the sampled sections is over 0.5 with an average of 0.63.The valleys of main tributaries in the upper and middle reaches are narrower than those in the lower reaches.They have a wide range of cross-sectional concavity but with an average larger than 0.5.The high cross-sectional concavity of the mainstream and tributaries is a reflection of the formation of U-shaped valleys with strips of floodplains along the valleys by lateral erosion during a long period of weak tectonic uplifting between two tectonic active periods,which are the characteristics of landforms in the middle and late mature stage.The lateral erosion and a higher value of cross-sectional concavity of valleys should be a favorable condition for the formation of the isolated sandstone pillars in Zhangjiajie.In the Suoshui basin,the hypsometric integral is higher in the lower part of the upper reaches and in the middle reaches with the highest values occurring around the Tianzishan peak.No relation of the hypsometric integral with relief and rock property is detected in the basin.The sandstone forests and pillars in Zhangjiajie concentrate in the areas with Devonian sandstone as the bedrock in the lower part of the upper reaches and upper part of the middle reaches,where the fluvial-erosional landforms are in their mature stage indicated by a mean hypsometric integral of 0.46.
Shi Changxing,Qi Deli. Geometric characteristics of valley and basin of Suoshui River in Zhangjiajieof Hunan Province and their implications in landform evolution[J]. JOPC, 2013, 15(6): 865-874.
陈国达.1993.武陵源峰林地貌形成的大地构造条件[J].大地构造与成矿学,17(2):103-112. 陈彦杰,郑光佑,宋国城.2005.面积尺度与空间分布对流域面积高度积分及其地质意义的影响[J].地理学报,39: 53-69. 黄林燕,朱诚,孔庆友.2006.张家界岩性特征对峰林地貌形成的影响研究[J].安徽师范大学学报(自然科学版),29(5):484-489. 平亚敏,杨桂芳,张绪教,等.2011.张家界砂岩地貌形成时代:来自阶地与溶洞对比的证据[J].地质论评,57(1):118-114. 唐云松,陈文光,朱诚.2005.张家界砂岩峰林景观成因机制[J].山地学报,23(3):308-312. 吴忱,张聪.2002.张家界风景区地貌的形成与演化[J].地理学与国土研究,18(2):52-55. 杨振.2011.基于RS和GIS的张家界砂岩地貌形成过程研究[D].中国地质大学(北京)硕士论文,57. Chen Y C,Sung Q C,Cheng K Y.2003.Along-strike variations of morphotectonic features in the Western Foothills of Taiwan: Tectonic implications based on stream-gradient and hypsometric analysis[J].Geomorphology,56: 109-137. Davis W M.1899.The geographical cycle[J].The Geographical Journal,14(5):481-504. Hurtrez J E,Sol C,Lucazeau F.1999.Effect of drainage area on hypsometry from an analysis of small-scale drainage basins in the Siwalik Hills(central Nepal)[J].Earth Surface Processes and Landform,24:799-808. Langbein W B.1964.Profiles of rivers of uniform discharge[J].United States Geological Survey Professional Paper,501 B: 119-122. Li J,Xie S,Kuang M.2001.Geomorphic evolution of the Yangtze Gorges and the time of their formation[J].Geomorphology,41: 125-135. Lifton N A,Chase C G.1992.Tectonic,climatic and lithologic influences on landscape fractal dimension and hypsometry: Implications for landscape evolution in the San Gabriel Mountains,California[J].Geomorphology,5(1-2): 77-114. Pike R J,Wilson S E.1971.Elevation-relief ratio,hypsometric integral,and geomorphic area-altitude analysis[J].Geological Society of America Bulletin,82:1079-1084. Strahler A N.1952.Hypsometric(area-altitude)analysis of erosional topography[J].Geological Society of America Bulletin, 63:1117-1142. Turowski J M,Hovius N,Meng-Long H. et al.2008.Distribution of erosion across bedrock channels[J].Earth Surface Processes and Landforms,33: 353-363. Whipple K X,Tucker G E.1999.Dynamics of the stream-power river incision model: Implications for height limits of mountain ranges,landscape response timescales,and research needs[J].Journal of Geophysical Research,104: 17661-17674. Whipple K X,Tucker G E.2002.Implications of sediment-flux-dependent river incision models for landscape evolution[J].Journal of Geophysical Research 107(B2): 2039.DOI: 10.1029/2000JB000044. Wood W F,Snell J B.1960.A Quantitative System for Classifying Landforms[M].Quartermaster Research and Engineering Command,U.S.Army,Technical Report EP-124. Yang G F,Zhang X J,Tian M Z, et al.2011.Alluvial terrace systems in Zhangjiajie of northwest Hunan,China: Implications for climatic change,tectonic uplift and geomorphic evolution[J].Quaternary International,233:27-39.
