High And Low Energy Environments

Question 1

What is an example of a HIGH ENERGY coastline?

Answer 1

Saltburn to Flamborough Head- Yorkshire
(Rocky, upland are, 60km coastline)

Question 2

Geology of Saltburn to Flamborough

Answer 2

• Flamborough Head- Southern stretch of coastline:
  Large chalk headland; spectacular cliffs topped with till (deposit left behind by glaciers during Devensian glacial period); Bays+ headlands and high cliffs (varied scenery) due to differences in rock resistance.
• North rock moors: 400m above sea level; mainly sandstones, shales, limestone (jurassic period) + some carboniferous rock

Question 3

what is the dominant wave direction and fetch length of s to f?
what about rates of erosion?
wave height?

Answer 3

*Dominant waves from north + northwest
*fetch over 1500km
*most exposed coast is northfacing e.g. nearest Saltburn (relieves highest inputs of wave energy)
*rates of erosion: due to differences in wave energy and geology; weak shale + clay areas rate is 0.8m p.a. and more resistant sandstones+ limestones is 0.1m p.a.
*wave height- often exceeded 4m even in summer (usually less stormy)
*high energy inputs responsible for longshore drift (North to south)- in some places sediment movement interrupted by headlands; sand and shingle accumulates forming beaches and bays (e.g Filey Bay)

Question 4

Example of a bay along s to f coastline

Answer 4

Filey bay

Question 5

What are sediment sources for s to f coastline

Answer 5

• cliff erosion
• only large river (the esk) enters north sea at Whitby - limited fluvial supply of sediment due to construction of weirs and reinforced banks along its course.

Question 6

what are the cliffs like at Flamborough Head?

Answer 6

made of chalk- physically very strong; vertical cliffs typically 20-30m high, with overlying till lowered by mass movement processes to angle about 40 degrees.

Question 7

what are the cliffs like between Robin Hoods Bay and Saltburn?

Answer 7

further north than Flamborough: higher cliffs, often with stepped profile (more varied geology)

Question 8

when are steeper slopes formed?

Answer 8

more resistant sandstones and limestones; gentler slopes corresponding to weaker clays.

Question 9

what LANDFORMS can be found at Robin Hoods bay?

Answer 9

high energy waves + active erosion means cliffs are retreating, leaving behind WAVE- CUT PLATFORMS.
HEADLANDS AND BAYS: discordant coastline, weaker rock retreated and more resistant rock forming headlands (limestone and chalk).

Question 10

what does the prominent headland at Flamborough consist of?

Answer 10

CHALK
deep bays made of CLAY

Question 11

what landforms have formed on these headlands from s to f?

Answer 11

WAVE REFRACTION- wave energy concentrated of headlands that project out to north sea; weaknesses e.g. CRACKS AND JOINTS are exploited + enlarged to form caves + arches. (e.g. SELWICK’S BAY at Flamborough Head).
GREEN STACKS PINNACLE: a stack at end of headland.
over 50 GEOS along coastline (aligned to NE/ NEE dom. wind direction)

Question 12

What is an example of a LOW ENERGY COASTAL ENVIRONMENT?

Answer 12

the Nile Delta

Question 13

What is a delta?

Answer 13

Large areas of sediment found at mouths of rivers- deposited by rivers+ tidal currents

Question 14

How do deltas form?

Answer 14

Sediment is deposited at a faster rate than wave/ tides can remove it.
Typically form where:
* rivers entering sea carry large loads
* low tidal range
* low energy environments on coastline (e.g. bay)

Question 15

What is an ARCUATE delta?

Answer 15

Sufficient sediment supply available for delta to grow seawards, but wave action is strong enough to smooth leading edge - has lagoons.

Question 16

How long is the RIVER NILE?

Answer 16

6650km

Question 17

What is the Niles CATCHMENT AREA?

Answer 17

Over 3 million km³
Large proportion of Nile flow originates in Ethiopia + comes from summer monsoon rains- some from central Africa

Question 19

The nile carries a huge sediment loaf despite relatively low discharge, what sediment can be found in the suspended load?

Answer 19

30% clay
40% silt
30% fine sand

Question 20

Where does the coastal plain of the nile delta occupy?

Answer 20

Northern part of nile delta

Question 21

What landforms/ features are found on the foreshore plain of the delta?

Answer 21

Lagoons, salt marshes and alluvial deposits in the depressions between them

Question 22

What features/ landforms can be found at the sandy zone at the delta?

Answer 22

Dunes

Question 23

Where does the delta split into two distributaries?
What has formed here?

Answer 23

• Cairo
• wave action in Mediterranean redistributes segment at front of delta - reworked sediment forms series of CURVED BARR8ER BARS; closes of segments of Mediterranean sea to form LAGOONS.

Question 24

What is the mean rainfall in the delta?

Answer 24

Nile’s mean annual rainfall: 600mm
However, input of PRECIPITION varies SPACIALLY and TEMPORALLY
avg in DELTA: 100-200mm (most in winter)