What environment do you typically find braided streams?
What environment do you typically find braided streams?
Braided streams tend to occur in rivers with high sediment loads and/or coarse grain sizes, and in rivers with steeper slopes than typical rivers with straight or meandering channel patterns.
Where do erosion and deposition occur in a braided stream?
The sediment in braided rivers is commonly coarse in the middle, and finer sediment is deposited in the shallow areas. Bars, which block the flow, will erode on the upstream side, and create areas of low flow on the downstream side, allowing for deposition to occur.
Why are braided streams common deposits found in ancient sedimentary rocks?
Braided rivers develop when the proportion of bed load sediment is high, which produces abundant bedforms and promotes the development of bars, and thus, the braided character of the river. The sediment is commonly coarse, which requires fast flow and steep gradients for the sediment to be transported.
How are braided streams formed?
A stream consisting of multiple small, shallow channels that divide and recombine numerous times forming a pattern resembling the strands of a braid. Braided streams form where the sediment load is so heavy that some of the sediments are deposited as shifting islands or bars between the channels.
What does braided stream mean in geography?
A stream or river bed is said to have a braided pattern when the deeper channels form a lacy or reticulate network of divergent and convergent members. “Rivers are described as braided when the channel is extremely wide and shallow and the flow passes through a number of small interlaced channels separated by bars.
How are braided rivers and meandering rivers different?
Braided rivers are typically wider and shallower than meanders of similar discharge; they transport more bedload and scour and fill their beds more dramatically; and above all they erode their banks more rapidly, extensively, and unpredictably.
Why are braided streams so common in association with glaciers?
First, due to high levels of suspended sediment, glacial rivers develop a braided or anabraching (split channel form) in order to maximize hydraulic efficiency to optimize the conveyance of water and sediment.
Why do braided channels occur and how are they formed?
Braided streams typically get their start when a central sediment bar begins to form in a channel due to reduced streamflow or an increase in sediment load. The central bar causes water to flow into the two smaller cross sections on either side. The process is then repeated and more channels are created.
Why are braided rivers so common in actively glaciated areas?
In mountainous terrain, such as that in western Alberta and B.C., steep youthful streams typically flow into wide and relatively low-gradient U-shaped glaciated valleys. Braided streams can develop anywhere there is more sediment than a stream is able to transport.
Why are braided rivers common in glaciated areas?
What are features of the braided stream?
Braided streams and rivers have multi-threaded channels that branch and merge to create the characteristic braided pattern. Braided channels are highly dynamic with mid-channel bars which are formed, consumed, and re-formed continuously. The development of braided channels is favored by several factors.
How does a braided stream differ from a meandering stream?
How does a braided stream differ from a meandering stream? A braided stream have numerous, subparallel braided channel strands. A meandering stream consists of a single highly sinuous channel. Thus, during normal flow, the sediment settles out and the channel becomes choked with sediment.
Is there a generalized sedimentation model for braided-stream deposits?
A review of the braided-river depositional environment. Earth-Sci. Rev., 13: 1–62. Generalized sedimentation models have been developed from a review of more than sixty recent papers on modern and ancient braided-stream deposits.
How many facies are in a braided stream deposit?
Braided-stream deposits consist of up to three gravel facies, five sand facies and two fine-grained facies. Vertical sequences recorded in modern and ancient deposits are of several types: flood-, channel fill-, valley fill-, channel re-occupation- and point bar-cycles.
What are the characteristics of a braided stream?
Braided streams typically have wide channels. The braiding generally results from a flood‐deposited midchannel bar that splits the flow. The water is diverted to the sides and erodes stream banks, widening the channel. Streams will usually be braided if they have high bed loads and easily erodible banks.
Where are sediments deposited in a stream?
Sediments are deposited throughout the length of the stream as bars or floodplain deposits. At the mouth of the stream, the sediments are usually deposited in alluvial fans or deltas, which represent a lower‐energy, more “permanent” depositional environment that is less susceptible to changes in the stream flow. Bars.
