alluvial fan and cone
Answers
HELLO MATE ✌✌
⤵⤵ANSWER⤵⤵
Alluvial fans and deltas are sedimentary landforms deposited by flowing water. From above you can easily see their fan, or pie wedge shape.
Alluvial (stream) deposits contain intermixed gravel, sand and cobble sized rocks. The size of sediment moved by a stream depends on the speed of the flowing water. The faster water flows, the larger sediment size the stream can carry. Sediment settles out of flow when stream flow slows down, meaning the energy decreases in flow. This happens as flow reaches a broad, flat surface or a standing body of water (like a lake or ocean).
Alluvial fans are often found at the base of arid / semiarid mountain ranges where intermittent streams flow. For a stream to be intermittent it flows only went it rains or snow melts. Sediment drops out of stream flow as energy decreases due to widening of the channel. Over time sediment builds up in the channels at the base of mountains and forces the stream to carve another channel. When channels fill in the process starts again. Streams filling in and moving to the side form fan shaped deposits. Alluvial fan examples can be found in Death Valley National Park and along the sides of the Colorado River at Grand Canyon National Park.
If intermittent activity continues over a long time the fan can grow very large, sometimes interconnecting with nearby fans forming a bajada. Death Valley National Park has well exposed examples of bajadas. In the west many people like to build on alluvial fan these deposits because they offer beautiful views of valleys and farmers like to farm them because of their fertile soil.
Deltas are similar to alluvial fans in shape, but are deposited in a different environment. Sediments that form deltas are transported in continuous flowing water. Delta deposits are found at the mouths of streams or rivers as they empty into lakes and oceans. As water flows into standing bodies of water, it looses energy and can no longer carry the sediment it once did. The sediment settles to the bottom and forms an under water fan. Delta's get their name from of their similarity to the triangular shape of the Greek letter "Delta". Examples of deltaic deposits are found at the end of the Mississippi River in the Gulf of Mexico and various smaller deltas located on the southern end of Florida.
River channels cross delta and alluvial fan deposits. As deposits thicken the channels shift side to side and continue forming new deltaic and alluvial fan structures. As old deposits erode away, the river channel eventually migrates back to the original site and redeposits another fan or delta. The process continues until the river entirely changes course.
Hope it helps u✌✌
thanks❤