Why does delta often form where a river and an ocean meet?

Answer 1

A delta is a landform where the mouth of a river flows into an ocean, sea, desert, estuary, lake or another river . It builds up sediment outwards into the flat area which the river 's flow encounters (as a deltaic deposit) transported by the water and set down as the currents slow. Deltaic deposits of larger, heavily-laden rivers are characterized by the main channel dividing amongst often substantial land masses into multiple streams known as distributaries. These divide and come together again to form a maze of active and inactive channels. This hydrogeologic formation is known as an alluvial fan. 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, with resulting continual formation of distributaries at angles to the original course. These distributaries start out flowing fairly fast, but slow as more sediment is deposited and ultimately, the water flows elsewhere. This change in flow affects the particle size in the suspended and bed loads, the size of the particles decrease as the flow slows and the larger particles are deposited. This deposition goes on continually in a cyclic fashion, creating alternating sediment beds of coarse and fine grain deposits. 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.

Answer 2

Rivers move slowly at the river mouth. The river carries a lot of sediment and mud. The river deposits (drops) its sediment and mud at its mouth. This sediment and mud spreads out into a fan- like shape, or delta, across the mouth of the river.

If the force of the sea tides and water is not very strong, the mud deposits cannot be washed away. Instead, the deposits break up the flow of the river water into many smaller channels. The delta gradually gets bigger and bigger. The new land is made up of billions of pieces of mud, sediment and small rocks.

This sediment has been carried by the river from its source to its mouth.

A delta is often triangular in shape. It gets its name from the Greek letter 'delta' which is shaped like a triangle. Not all deltas look the same, but they all split the river into many different channels. The channels in a delta are called distributaries.

Answer 3

The landforms are generally in the shape of the Greek letter delta (D), an inverted triangle pointing back into the land. The word "fan-shaped" is used to describe deltas that spread through multiple channels at the mouth.

Answer 4

a delta occurs when a river meets an expanse of water (lake, resevoir, ocean) and the river does not need to keep to its thin channel. this results in a larve v-shaped mouth, as the river is now a considerable ammount wider, the water velocity lesses or the river slows down. this means all carried materials in the river (pebbles, rocks, sand) are dropped, making the delta considerably shallower.

Answer 5

the water slows down, causing the sediment to sink

Answer 6

The river leaves sediments at the mouth of the large body of water. Over time they build up and you get a delta.