A fan-shaped sediment deposit formed by a stream that flows from a steep mountain valley or gorge onto a plain or the junction of a tributary stream with the main stream Alluvial fans contain active stream channels and boulder bars, and recently abandoned channels Alluvial fans are predominantly formed by alluvial deposits and are modified by infrequent sheetflood, channel avulsions and other stream processes They may also be subject to debris flow and debris torrents
Used to describe the fanning aspect of a stream as it leaves a mountain to disperse in a valley; also used in desert areas to describe the effects of a mineral breaking off the steep sides of mountains and being spread by later effects of water or wind
A low, outspread mass of loose materials and/or rock material, commonly with gentle slopes, shaped like an open fan or a segment of a cone, deposited by a stream (best expressed in semiarid regions) at the place where it issues from a narrow mountain or upland valley; or where a tributary stream is near or at its junction with the main stream It is steepest near its apex which points upstream and slopes gently and convexly outward (downstream) with a gradual decrease in gradient GG
A fan-shaped deposit of unconsolidated material and debris, forming at the point where a stream emerges from a narrow valley onto a broader, less sloping valley floor
A low, outspread, relatively flat to gently sloping mass of loose rock material, shaped like an open fan or a segment of a cone, deposited by a stream (esp in a semiarid region) at the place where it issues from a valley upon a plain or broad valley, or where a tributary stream is near or at its junction with the main stream, or wherever a constriction in a valley abruptly ceases or the gradient of the stream suddenly decreases; it is steepest near the mouth of the valley where its apex points upstream, and it slopes gently and convexly outward with gradually decreasing gradient
A low, outspread, relatively flat to gently sloping mass of loose rock material deposited by a stream where it flows from a narrow mountain valley onto a plain or broad valley
A sloping fan-shaped accumulation of sediment found where a stream leaves a narrow valley and spreads out over a broad geographic area Most frequently found in arid areas
a fan-shaped deposit of gravel, sand and silt dropped by a stream where there is a decrease in slope e g from mountains onto a level plain or into a lake or stream
Usually seen at a junction where a small stream joins a larger one or at the point where water flows through a narrow gorge that opens onto a plain, this fan-shaped deposit of soil is left behind
A fan-shaped deposit of generally coarse material created where a stream flows out onto a gentle plain; a geomorphologic feature characterized by a cone or fan-shaped deposit of clay, silt, sand, gravel, and boulders that have been eroded from mountain slopes, transported by flood flows, and deposited on the valley floor ADVANCE \x 540