Deltas and River Mouths

What are deltas?

• Areas of deposited alluvial material at the river mouth

• Areas of deep water in the ocean

• Areas of high tides near the coast

• Areas of volcanic activity

Where do deltas form?

• In the middle of the river

• At the source of the river

• At the mouth of the river where it enters the sea or lakes

• Along the entire length of the river

What causes deposition in deltas?

• High velocity of the river

• Flocculation of clay particles

• Erosion of sediment

• Lack of vegetation

What is flocculation?

• The process of erosion in deltas

• The reaction between fresh and sea water

• The movement of sediment along the river

• The colonization of vegetation in deltas

What are foreset beds in deltas?

• Horizontal layers of sediment

• Deposits of heavy clay particles

• Medium calibre sediment forming a steep angled wedge

• Channels that break up the river

What are topset beds in deltas?

• Horizontal layers of sediment

• Deposits of heavy clay particles

• Medium calibre sediment forming a steep angled wedge

• Channels that break up the river

What are distributaries in deltas?

• Areas of deep water in the ocean

• Channels that break up the river

• Deposits of heavy clay particles

• Horizontal layers of sediment

What is bioconstruction in deltas?

• The process of erosion in deltas

• The reaction between fresh and sea water

• The colonization of vegetation in deltas

• The movement of sediment along the river

What are the two types of deltas mentioned?

• Birds foot and arcuate

• Straight and meandering

• Braiding and bioconstruction

• Foreset and topset

What does vegetation do in deltas?

• Increases erosion of sediment

• Prevents deposition

• Increases stabilisation of the sediment and prevents erosion

• Causes flocculation of clay particles