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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Geomorphic evolution of small river-lake-systems in northeast Germany during the Late Quaternary
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Geomorphic evolution of small river-lake-systems in northeast Germany during the Late Quaternary

机译：第四纪晚期德国东北小河湖系统的地貌演化

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This study investigates the post-glacial development of four small river-lake systems in the Weichselian belt of northern central Europe. The valleys investigated are part of an immature drainage system characterized by frequent and abrupt changes in flow direction and the presence of numerous stagnant-ice depressions in the valley course. The depressions contain thick sedimentary sequences which provide excellent archives for the reconstruction of the post-glacial valley development. Study results indicate that the valleys reuse segments of former subglacial meltwater channels. During the Late Pleniglacial these channels carried meltwater streams. Stagnant-ice melting occurred in stages from the Oldest Dryas to the early Holocene and was often followed by the formation of lakes in the valley course. Flow reversals occurred during the Late-glacial-Holocene transition and were in response to general base-level lowering caused by stagnant-ice melting, headwater erosion and lake overspills. Lacustrine deposition typically started during the early Late-glacial comprising mainly silicate gyttjas, whereas organic gyttjas and peats accumulated during the Allerod. The Younger Dryas is associated with a marked increase in fluvial and aeolian sedimentation, and lake-level high stands. This was followed by early Holocene lake-level low stands and a subsequent stabilization phase with decreasing silicate input and increasing organic lacustrine deposition. In general, dramatic changes in Late Pleniglacial to early Holocene sedimentation suggest that small-scale catastrophic events played a more important role in triggering geomorphic changes then previously recognized. Infilling continued until peat accumulation and terrestrialization of lake basins became widespread during the mid- to late Holocene. Beginning in the late Holocene anthropogenic influences become important mainly involving an increase in sediment supply due to forest clearing and land use, followed by mill stowage, river course correction and anthropogenic lake-level manipulations. Copyright (c) 2007 John Wiley & Sons, Ltd.
机译：这项研究调查了中欧北部魏克塞勒带的四个小河湖系统的冰川后发展。所调查的山谷是不成熟排水系统的一部分，其特征是流向频繁而突然变化，并且在山谷路线中存在大量停滞的冰沉。凹陷处有厚厚的沉积层序，为冰川后山谷发育的重建提供了极好的档案。研究结果表明，山谷重复利用了以前的冰川下融水通道。在晚清末期，这些河道运送了融化水流。停滞的冰融化发生在从最古老的树妖到新世早期的阶段，并且通常在山谷中形成湖泊。流动逆转发生在晚冰期-全新世过渡期间，并且是由于停滞的冰融化，源头水蚀和湖泊溢流引起的总体基准水位降低。 Lacustrine沉积通常始于晚冰期早期，主要包括硅酸盐的gyttjas，而有机gyttjas和泥炭则在Allerod期间积累。幼树树苗与河流和风沙沉积以及湖泊水位高的明显增加有关。随后是全新世早期的湖水低位和随后的稳定阶段，即硅酸盐输入减少和有机湖相沉积增加。总的来说，晚新世至新世早期沉积发生了戏剧性的变化，表明小规模的灾难性事件在触发先前认识到的地貌变化中起着更重要的作用。填充一直持续到全新世中期至晚期，泥炭堆积和湖盆的陆缘化变得普遍为止。从全新世晚期开始，人为的影响就变得很重要，主要包括由于森林砍伐和土地利用而增加的沉积物供应，其次是工厂积载，河道整治和人为的湖面操纵。版权所有（c）2007 John Wiley＆Sons，Ltd.

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