摘要：
颍河上游主要包括登封盆地和禹州平原两个地貌单元,基于SRTM数据用GIS方法计算了两地的山前曲折度、流域圆度、河流分支比、河流坡降、高程-面积曲线和Hack曲线等流域地貌参数.结果显示登封盆地为构造活动区,禹州平原为构造稳定区,颍河上游河流地貌处于壮年期发育阶段.根据两处龙山时期人类遗址的地层环境指标和河流阶地特征,用“构造-气候驱动模式”讨论了末次冰期以来颍河上游的河流地貌过程.研究表明,登封盆地属于构造活动主导下的复合型地貌区,新石器时期的河流作用以下切侵蚀为主;禹州平原属于气候过程主导型河流地貌区,新石器时期的河流堆积期长于侵蚀期.构造型地貌对气候变迁的响应弱于气候主导下的平原地貌,因而登封盆地内水系格局相对稳定而禹州平原区的水系网络相对多变,颍河上游的史前聚落因而集中于登封盆地.同时,史前聚落的地理分布与其生业需求相关,新石器早期聚落为规避气候灾害选址于有稳定水系的登封盆地,而新石器晚期聚落则为迎合农业发展倾向于气候地貌区,但其发展进程常困扰于灾害性气候过程和多变的水系格局.%The upper reach of the Ying River is one of the important birthplaces of the Neolithic cultures in Central China.And the area includes two geomorphological subareas:the Dengfeng Basin and the Yuzhou Plain.The focus of this paper is at the relationship between landform changes and and Neolithic settlement distribution on terraces of both banks of the Ying River and so,we gave more study on the fluvial landform processes and its impacts.30 stratigraphic samples of the Wangchenggagn profile which covered the Yangshao,Longshan and Erlitou cultural periods and 39 samples of the Wadian profile deposited in the late Longshan cultural period were implemented to measure their element contents,frequency magnetic susceptibilities and particle grain sizes respectively.Results showed that the study area in the Middle Holocene had experienced a warm-wet stage in the Yangshao cultural period,a warm-dry stage in the Longshan cultural period and cold-wet stage after 4 ka cooling event.As considering correlation of weathering environment,climate and landform,we investigated the differences of the two subareas in tectonic activities and river systems.Therefore,tectonic-climatic driven model was introduced to interpret fluvial landform processes of the Ying River.Using SRTM DEM imagery and ArcGIS 10.0 software,we calculated mountain front sinuosity,circularity ratio,bifurcation ratio,river gradient,elevation-area integral curve and Hack curve,so as to identify tectonic activity intensity of different landform areas.Results indicated that the Dengfeng Basin had been deeply influenced by tectonic uplift since the Late Pleistocene and could be considered as tectonic-dominated landform area.While the Yuzhou Plain was of comparatively tectonic stability over long term,but its river system responded rapidly to climate changes due to channel silting and could be regarded as climate-controlled area.Meanwhile,the Ying River network and its fluvial land-forms are in early mature stage (HI =0.463;Fractal Dimension =1.083).According to stratigraphic sequences of two typical sites and river terraces,the authors discussed fluvial processes of the Ying River since Last Glacial age based on tectonic-climate driven model and suggested that the river continued to erode downward in the Dengfeng Basin over the study period and but,lateral erosion and accumulation prevailed in the Yuzhou Plain.Which endowed the Dengfeng Basin with highland,fast-draining and relatively insensitive to climate change,however the later was characterized by lowland with stagnant water and fast feedback to climate change especially under persistent rainfall,which would make river networks changeable in the Yuzhou Plain,and correspondingly constrained human subsistence and settlement sizes.As to distribution of settlements,it was controlled by in what stage was the subsistence model.Additionally,in late Longshan period humans preferred to locate their settlements near river confluences or bends where the landform was good for farming and defensing,accordingly the settlement distribution consists with tributaries of the Ying River.
