outwash

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Sorted deposits which have been dropped by meltwater streams issuing from an ice front. Such streams tend to be heavily laden with debris, so that deposition occurs with only small decreases in stream velocity. The material deposited is coarse near the ice front, becoming progressively finer with distance from it. Outwash fabric tends to be well bedded, and current bedding is common. The finest elements of the outwash may be deposited in proglacial lakes to form varves. While one stream may form a gently sloping outwash fan in a lowland area, a series of streams flowing over a plain may produce several fans which coalesce to form an outwash plain. This latter term is synonymous with valley train.