High And Low Energy Environments Flashcards

1
Q

What is an example of a HIGH ENERGY coastline?

A

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

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2
Q

Geology of Saltburn to Flamborough

A
  • 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
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3
Q

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

A

*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)

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4
Q

Example of a bay along s to f coastline

A

Filey bay

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5
Q

What are sediment sources for s to f coastline

A
  • 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.
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6
Q

what are the cliffs like at Flamborough Head?

A

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.

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7
Q

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

A

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

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8
Q

when are steeper slopes formed?

A

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

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9
Q

what LANDFORMS can be found at Robin Hoods bay?

A

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).

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10
Q

what does the prominent headland at Flamborough consist of?

A

CHALK
deep bays made of CLAY

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11
Q

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

A

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)

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12
Q

What is an example of a LOW ENERGY COASTAL ENVIRONMENT?

A

the Nile Delta

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13
Q

What is a delta?

A

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

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14
Q

How do deltas form?

A

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)

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15
Q

What is an ARCUATE delta?

A

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

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16
Q

How long is the RIVER NILE?

17
Q

What is the Niles CATCHMENT AREA?

A

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

19
Q

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

A

30% clay
40% silt
30% fine sand

20
Q

Where does the coastal plain of the nile delta occupy?

A

Northern part of nile delta

21
Q

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

A

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

22
Q

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

23
Q

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

A
  • 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.
25
Q

What is the mean rainfall in the delta?

A

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