downcutting


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downcutting

[′dau̇n‚kəd·iŋ]
(geology)
Stream erosion in which the cutting is directed in a downward direction.
References in periodicals archive ?
Overflows of the Cache River in this broad, lowland area were probably more frequent before drainage accelerated channel erosion, evidenced by downcutting, and lowering of the level of the river.
The exposed glaciomarine sediments show relict deformation structures likely related to fluvial downcutting of exposed sediments shortly after a drop in sea-level that exposed the sediments.
Downcutting by upper Mud Brook is limited by a sandstone knickpoint near the intersection of State Route 8 and Graham Road in the southwestern part of the study area (Fig.
Steep downcutting and erosion of the rift flanks - first by rivers and then, about 34 million years ago, by the first glaciers of the East Antarctic Ice Sheet - further unloaded the crust, which buoyed the range higher, the authors suggested.
Urbanization lowers base flow, and creates downcutting due to lack of space to meander (Bernhardt and Palme, 2007).
Although timing of this event is poorly constrained, the initial spillover most likely occurred between 2 and 4 Ma with subsequent slow downcutting of the divide (Wood and Clemens, 2002).
Fresh downcutting on creek walls was also observed.
Downcutting of fine-grained lake bed substrates may accelerate formation of deeper water offshore and result in increased wave energy to the near shore.
In this case the process included: 1) deep incision of a valley meander into bedrock, 2) partial alluvial backfilling of that valley, mostly by outwash of one of the pre-Wisconsinan glaciers, 3) opportunistic relocation of the channel across the bedrock neck of the meander at a low spot, and 4) downcutting of the new channel as base level was lowered (Bajza 1944).
The northward advance of the Pennsylvanian sea across the area caused the streams that had been actively downcutting to begin aggrading and filling their valleys with the Caseyville alluvial sediments.
Its geomorphological history over the last 20,000 years has been reconstructed from studies of repeated sequences (or cyclothems) of deposits in the delta, in lower and mid valley, and swamps of the Sudan which suggest a series of downcutting, aggradation and channel avulsion events.
He concluded that the suburban development caused expansion of the stream floodplains and subsequent downcutting of the stream channels.