*蛇形丘*冰水的存款从泥沙携带冰川下的隧道。水床上走出一条隧道的冰盖和冰川会慢下来。由于泥沙运动速度取决于水沉积物沉积。结果是一个高度本地化的沉积。当冰川撤退点出现的水当然会变化与冰川的边缘。因此,沉积会逐步沉淀积累进一步上游离开一条狭窄的小径。更能说但有时结果是山脊数百公里长,延长过去冰川边缘,几乎垂直于水流的方式从内到冰川的边缘。*冰砾阜*是丘地形形成的材料,已经被冰川融化水运输。小丘的原因是,当沉积物沉积,大块的冰被埋的沉积物和当冰融化了丘地形形成。这里关键是沉积物的沉积泥沙运输将无法形成不规则的圆丘般的地形作为主要功能,必须有其他的过程。 Kames are therefore usually an extensive land form that does not necessarily have a preferred extension. As with eskers the origin of the water and sediment is the same, the base of the glacier. Finally, *drumlins*. These forms are elongated land forms, in the direction of ice flow, often some kilometres in length, width of a few hundred metres and a height of tens of metres. This varies a lot though. These forms are not formed by running water and sediment transport but formed beneath the ice. In the literature they have been described as both depositional and erosional land forms, although a depositional formation seems to be most common. They seem to consist of whatever material is present beneath the ice but because the most common sediment beneath glaciers is till this is also what most drumlins consist of. So eskers and eskers have som relationship in the origin of the sediment that make them up. Drumlins are of completely different processes. Much more could be said and all details are not completely understood when it comes to many glacial landforms and their formation. ADDED: The formation of drumlins, and hence also their characteristics is too complex to be explained in a short answer here. Three scientific papers that will help gaining a deeper understanding of drumlin formation are (I suggest googling on the titles to find copies): Patterson, C.J., Hooke, R.L., 1995. Physical environment of drumlin formation. Journal of Glaciology 41 (137), 30–38. Stokes, C.R., Spagnolo, M., Clark, C.D., 2011. The composition and internal structure of drumlins: complexity, commonality, and implications for a unifying theory of their formation. Earth-Science Reviews 107, 398–422. Roger LeB. Hooke, Aaron Medford, 2013. Are drumlins a product of a thermo-mechanical instability? Quaternary Research. [http://dx.doi.org/10.1016/j.yqres.2012.12.002][1] [1]: http://dx.doi.org/10.1016/j.yqres.2012.12.002
Baidu
map