Coasts Flashcards
1
Q
Rocky cliffs vs costal plains
A
**ROCKY CLIFFS*
- transition from land to sea is abrupt
- small foreshore
- 1000km of Uk coastline
COASTAL PLAINS
- gradual transition from land to sea
- mudflats
2
Q
Submerget vs Emergent
A
SUBMERGENT
- seas level rise inundated formly opposed land
- Dalmatian Haff
EMERGENT
- new backshore and new foreshore is visible
- tectonic uplift
3
Q
High energy vs Low energy
A
HIGH ENERGY
- exposed coastline
- onshore winds
- long fetch
- destructive
- erosion
LOW ENERGY
- sheltered coast
- limited fetch
- constructive
- deposition
4
Q
Tidal range
A
- micro = 0-2
- meso = 2-4
- macro = 4+
Evidence ➡️
- height of wave cut notches
- colouration, darker where wave action takes place
- beach height
5
Q
Primary vs secondary
A
PRIMARY
- Dominated by land based processes
- deposition from rivers
- Thames estuary
SECONDARY
- dominated by marine processes
- erosion from waves
- Flambough Head, Arches coves
6
Q
Arrangement of Strata
- concordant
A
Lulworth cove, Dorset
- rock layers arranged parallel to coastline
- marine erosion exploits a weakness (joint/fracture)
- hydraulic action
- breach in limestone,
- rapid lateral erosion
- form cove
7
Q
Arrangement of strata
Discordant
A
Durlstan Head
- strata arranged perpendicular to the coast
- less resident band of strata recess faster
- leaves protruding headlands
- wave refraction occurs
- therefore hydraulic action and abrasion occurs
- dissipation of wave energy into bay, deposition creates beach - Swanage bay
8
Q
Dalmatian Coast
A
- concordant
- African and Eurasian convergent plate boundaries 50 million years
- leads to fold mountains
- synclines flood
9
Q
Haff Coastline
A
- Baltic Sea,
- devension, water locked in cryosphere melts
- global average temp increases leading glaciers to thaw, deposit sediment into atwash plain
- global release of this water cause eustatic sea level rise
- constructive waves transport sediment to land
- unconsolidated ridge forms parallel to coastline forms
- lagoon forms behind ridge
- Curonian spit _ 98km long
10
Q
Folding
A
Bends in rocks, produced by sedmentary rock layers being squeezed by tectonic forces
More easily eroded
11
Q
Horizontal dip
A
- vertical cliff profile
- weather causes
- notches
12
Q
High angle of seaward dip
A
- sloping low angles profile with one rock layer facing the sea,
- vulnerable to rock slides
- unstable
13
Q
Low angle of seaward dip
A
- overhanging cliff profile
- vulnerable to rock fall
14
Q
Landward duping strata
A
- force of gravity pulls loosened rocks back to land
- very stable with few rockfals
15
Q
Joints
A
- fractures in rocks created without displacements occur in most rocks
- hydraulic action can exploit this
IGNEOUS
- cooling joints form when magma contracts and looses heat
SEDIMENTARY
- rock is subject to compression or stretching by tectonic forces of overlying rock
16
Q
Sedimentary rocks
A
- compression and compaction
- clastic structure
- 0.5 - 10 cm per year recession
- more weakness as they have release joints
17
Q
Igneous rock
A
- formed from magma that cooled beneath earths surface
- crystalline structure
- recession rates of 0.1 cm a year
- few weaknesses due to strong internal cohesion
18
Q
Metamorphic rocks
A
- formed by recrystallisation of sedimentary and igneous rocks through heat and pressure
- crystalline structure
- recedes at 0.1-0.3 cm a year
- often heavily folded and faulted as consequence of folding
19
Q
Unconsolidated rock
A
Sediment that has not yet been cemented to form solid rock
20
Q
Sand dunes
A
FORMBY BEACH
- Pioneer species (sea twitch) colonise
- bind trap
- forms embryo dunes
- roots stabilise, leaves encourage deposition.
- when vegetation dies it increase thanks matter
- less tolerant species develop (foredunes)
- area builds up more, grows out of high tide
- out compete pioneer species (Marram grass) long roots of 3m+
- yellow dunes build
- succession continues through seral stages
- climax community
PINE WOODLAND
21
Q
Salt marsh
A
- forms at mouth of river, behind spits, can form cuspate foreland
- fine mud and silts create mudflats (pioneer species) algae and eel grass colonise, can stand 11-12 hours inundation
- Halophytic species can stand salt water
- reach velocity of tidal ebb allowing sediment to be deposited
- next seral stages
- spartina makes better root systems ⬆️ stability
- growing conditions improve
- rain water washes away sat
- CLIMAX COMMUNITY (OAK WOODLAND)
22
Q
Mangroves
A
- dissipate wave energy
- 500m width
- tropical areas 30•N-30•S
- reduce wave height by 50%
- less energy therefore less erosion
