Deltas

Question 1

What are deltas

Answer 1

Deltas are areas of alluvial material which extend from the mouth of the river into the lake or sea

Question 2

When do deltas form

Answer 2

Deltas form where a flowing river meets a sea or lake and the river flow slows, depositing material faster than the sea can erode it

Question 3

4 factors for a delta formation

Answer 3

Sediment load
Coastal energy
Flocculations
Sea floor gradient

Question 4

Explain why deltas form due to sea floor gradient

Answer 4

A gentle and shallow sea floor gradient allows sediment to build upwards to reach the surface

Question 5

Coastal energy

Answer 5

A low energy environment with a small tidal range and weak currents so rate of deposition exceeds rate of erosion

Question 6

Flocculation

Answer 6

Chemical process where fresh water mixes with sea water and a chemical reaction with the salt causes fine clay particles to coagulate and this increases their weight which increases deposition

Question 7

Sediment load

Answer 7

Deltas are found at the mouth and at the mouth there is a high sediment load so deposition exceeds rate of erosion

Question 8

How do arcuate deltas form

Answer 8

Arcuate deltas grow out from coastline with a convex outer edge.
DELTA OF THE NILE.
Deposition at the mouth of a river usually triangular in shape» this is due to the BLOCKING OF THE RIVER MOUTH which forces the river to break into distributaries due to BRAIDING at angles to the original coarse
The distributaries WEAVE BACK AND FOURTH , depositing sediment which overtime forms a FAN SHAPE

Question 9

Birds foot delta

Answer 9

Forms where delta for,action is more river dominant, less tides
Deposition pattern haphazard
MULTILOBED SHAPE
Resembling a birds foot
MISSISSIPPI RIVER