Paleoflood Slack-Water Deposits
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摘要: 古洪水研究依赖古洪水沉积获得古水文信息。古洪水平流沉积是古洪水泛滥于死水断面范围内形成的薄层细颗粒沉积。以长江三峡下段与黄河三门峡以下河段为例,古洪水平流沉积被掩埋保存在部分缓倾斜岸坡平台上,主要的识别标志,在沉积构造方面为发育微薄层理,末端翘起并尖灭,此外还具有特定的粒度结构以及多种重矿物的百分含量方面的特征。Abstract: Paleoflood study depends on the flood information drown from paleoflood deposits. Among those,the most valuable one is the paleoflood slack-water deposit. The paleoflood slack-water deposits at thedown reach from the Three Gorges of Yangtze River and from the Sanmen Gorge of the Yellow Riverwere burried and preserved on some terraces in gentle slope. They have slight stratification, which risesup at depositional termination, special grain size as well as the relative amount of every heavy mineral.The features above are also the important mark of looking for and ascertaining the paleoflood slack-wa-ter deposit for paleoflood study on different reaches in different drainage areas.
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Key words:
- paleoflood /
- slack-water deposit
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[1] O ' C onnor, J E, and webb, R H. Hydraulic modeling for pale-oflood analysis, in Baker, V R, Kochel, R C, and Patton, P C,eds, Flood Geomorphology: New York, John Wiley, 1988, 393~ 402. [2] Knox, J C. Larg e increases in flood magnitude in response tomodest chang e in climate, Nature, 1993, 361: 430 ~ 432. [3] O' Connor, J E, Ely, L L, Wohl, E E, Stevens, L E, Melis, T S,Kale, V S, and Baker, V R, 1994, A: 4500-year record of largefloods on the Colorado River in the Grand Canyon, Arizona,Jour Geology, 1994, 102: 1 ~ 9. [4] Baker, V R and Kochel, R C, Flood sedimentation in bedrockfluvial systens, in V R Baker, R C Kochel and P C Patton eds,Flood Geomorphology: New York, John wiley & sons, 1988,123 ~ 137. [5] Schmidt, J C, Recirculating flow and sedimentation in the Col-o rado River in Grand Canyon, Arizona, Jour, Geolog y, 1990,98: 709 ~ 724. -

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