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Glacial geology
Published in Barry G. Clarke, Engineering of Glacial Deposits, 2017
Meltwater emerging from a glacier carries debris to form outwash fans, kames and kame terraces. The debris spreads out in front of the ice margin and backs over the ice; therefore, the topology of the glaciofluvial landforms depends on their location with respect to the ice margin, the presence of buried ice and the amount of transported sediment. Braided river systems develop downstream of the ice margin creating an outwash fan as the glacial debris is deposited (Figure 2.29). While these river systems form at the ice margins, they can contain buried ice, which on melting leads to kettle holes, water-filled pits that are gradually filled with further glacial debris possibly leading to conical lenses of distinctly different materials from the surrounding outwash fan. If the outwash fan crosses an extensive area of ice as the ice melts, it creates a hummocky surface to the rear of the outwash fan known as kame and kettle (hollows) topography. Kames, consisting of well-sorted deposits of sand and gravel, are formed at the ice margin creating either isolated hummocks or broad flat-elevated areas (Figure 2.30). The velocity of meltwater reduces rapidly as it emerges from a glacier resulting in coarser materials being deposited near to the outlet and finer material being carried further afield (cf. pipe discharge into a lagoon). As the ice retreats, the meltwater may be diverted along the ice margin creating a kame terrace. Kames can vary from a few hundred metres to over a kilometre in length. Kame terraces form parallel to the direction of ice flow from streams running along the sides of a glacier.
Glaciations at high-latitude Southern Australia during the Early Cretaceous
Published in Australian Journal of Earth Sciences, 2020
N. F. Alley, S. B. Hore, L. A. Frakes
Together we regard the sandstones and Sheehan Tillite Member facies at Pelican Well, Village Well and Western Spur to be part of a large proglacial outwash fan with the terminus of the glacier lying nearby within the ranges to the east (see below).