How does a delta form? Please help!!!?

Answer 1

Delta (geologic formation), deposit of soil or silt formed wherever a swift stream or river empties into a lake, ocean, or slower river, so called because its triangular shape resembles the Greek letter (delta). The term was first used by the Greek historian Herodotus in the 5th century bc to describe the Nile delta. The triangular shape and the great width at the base are due to blocking of the river mouth by silt, with resulting continual formation of distributaries at angles to the original course. Deltas are usually characterized by highly fertile soil. The combined delta of the Ganges and Brahmaputra rivers in India, and the deltas of the Nile River in Egypt and the Mississippi River in the United States are the world's largest.
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The deposit at the mouth of a river is usually roughly triangular in shape. The triangular shape and the increased width at the base are due to blocking of the river mouth by silt, with resulting continual formation of distributaries at angles to the original course. Herodotus the great historian used this term for the Nile river delta because the sediment deposit at its mouth had the shape of upper-case Greek letter Delta: Δ.

Where delta formation is river-dominated and less subject to tidal or wave action, a delta may take on a multi-lobed shape which resembles a bird's foot. The Mississippi Delta is an example of this type.

The most famous delta is that of the Nile River, and it is this delta from which the term is derived, because the Nile delta has a very characteristic triangular shape, like the (upper-case) Greek letter delta (Delta). Other rivers with notable deltas include the Ganges/Brahmaputra combination (this delta spans most of Bangladesh and West Bengal), the Sacramento-San Joaquin, the Rhine, the Rhône, the Danube, the Ebro, the Volga, the Lena, the Tigris-Euphrates, the Indus, the Krishna-Godavari, the Kaveri, the Ayeyarwady, and the Mekong.

Other rivers, in particular at coasts with significant tidal range, do not form a delta but enter into the sea in form of an estuary. Notable examples are the Saint Lawrence River and the Amazon.

In rare cases the river delta is located inside a large valley and is called an inverted river delta. Sometimes a river will divide into multiple branches in an inland area, only to rejoin and continue to the sea; such an area is known as an inland delta, and often occur on former lake beds. The Niger Inland Delta is the most notable example.

Answer 2

Where Does A Delta Form

Answer 3

tony is right but his wording is a bit off.

as the river goes along it picks up lots of sand, gravel, and other detritus. all of this material is swept along with the river as long as the speed of the river is adequate. when the river slows down it can no longer hold these particles and so they settle out of the river, forming the familiar delta pattern at the end of a river.

tony was right but the materials in a delta weren't in a solution and they didn't precipitate out. just words really.

Answer 4

As a river flows out to sea it carries silt, sediment, rocks ... etc
that settled at the river mouth and formed banks around which the river has to find its' way. Over hundreds, maybe thousands of years, these banks built up until there are many branches of the river flowing to the sea.

(Incidentally, as a matter of interest, it was these silt and sediment deposits together with dead sea life and vegetation that was buried under many strata of rock, sand and shale built up over thousands of millenia that formed hydrocarbons in the rocks deep in the earth's crust).

Answer 5

Sediments are carried down river and stay in solution because of the speed of the current. However, as soon as the river widens or dumps into an ocean, the speed of the current falls. This causes the sediments to precipitate out of solution.

Answer 6

a delta is formed by all the silt and sediment washed down stream

Answer 7

I have been surfing the web more than three hours today searching for answers to the same question, yet I haven't found a more interesting discussion like this. it's pretty worth enough for me.

Answer 8

That's a good point