coastal processes that affect differences between landscapes Flashcards
define the littoral zone.
the wider coastal zone including adjacent land areas and shallow parts of the sea just offshore
what are the 4 subzones that a littoral zone can be divided into?
backshore
foreshore
nearshore
offshore
how do you classify coastal environments using formation processes??
Primary coasts - dominated by land based processes such as deposition at the coast from rivers or new coastal land formed from lava flows
Secondary coasts - dominated by marine erosion or deposition processes
how do you classify coastal environments using relative sea level change?
emergent coasts - where coasts are rising relative to sea level
submergent coasts - being flooded by the sea eitehr due to rising sea levels or subsiding land
how do you classify coastal environments using tidal range?
microtidal coasts- tidal range 0m -2m
mesotidal coasts- tidal range 2m-4m
macrotidal coasts- tidal range - greater than 4 m
how do you classify coastal environments using wave energy ?
low energy- sheltered coasts with limited fetch and low wind speeds resulting in small waves
high energy- exposed coasts facing prevailing winds with long wave fetches resulting in powerful waves
define cliff profile
the height and angle of a cliff face as well as it’s features such as wave cut notches or changes in slope angle
Rank 5 different rocks in terms of coastal recession rate from slowest to fastest.
Granite (igneous) limestone (S) chalk (S) sandstone (S) boulder clay (unconsolidated)
what are coastal plains ?
low-lying, low-relief areas close to the coast,
Define coastal accretion
The deposition of sediments at the coast and the seaward growth of the coast line creating new land .
it often involves sediment deposition being stabilized by vegetation
Dynamic equilibrium
The balance state of a system when inputs and outputs balance overtime .
E.g; by a process of feedback the system adjusts to a change through the other components of the system changing in response and the equilibrium is regained.
Give an example of a resistant rock coastline in the UK
Northern and western Britain ;
- igneous Grannite or bustled in so can withstand frequent storms with little erosion
-
high energy coastline;
rate of erosion exceeds deposition
- stretches of Atlantic facing coasts were waves of powerful for most of the year
- landforms include headlands ,Cliffs and Shoreline platforms
Give an example of a low energy coastline in the UK
Eastern and southern England where coastal plain /low lying landscapes are dominant.
Holderness;
- Younger weaker sedimentary rocks; clay sandstone, chalks
- low energy coastline;
• deposition exceeds the rate of erosion
• Stretches of coast where waves are less powerful or sheltered from strong waves
- One example is the Holderness coast it has a mix of a high energy and low energy environment
Geological structure and landscape ; outline the differences in the 3 dimensions of rock arrangements , strata, deformation and faulting.
- Strata is different layers of rock within an area and how they relate to one another
- Deformation is the degree to which rock units have been deformed ( tilted or folded ) by tectonic activity
- faulting is the presence of major fractures that move rocks from their original positions
Concordant coasts
Generated when rock strata run parallel to the coast line
Discordant. Coasts
Form when different rock strata intersects the coast at an angle
faults
major fractures in rocks produced by tectonic forces and involving the displacement of rocks on either side of the fault line.
anticlines
convex up (A-shaped) folds
synclines
concave down (U shaped) folds
give the 3 rock types and order them from slow-fast erosion rate
igneous - very slow
metamorphic - slow
sedimentary - moderate to fast
give examples of igneous rock and why their erosion rate is VERY slow
granite/basalt
- interlocking crystlas in their crystalline structures makes for erosion-resistant rock
- have few joints so limited weaknesses that erosion can exploit
give examples of metamorphic rock and why their erosion rate is slow?
e. g ; slate, marble
- crystalline structures however foliation feature (crystals oriented in one direction) = weakness
- can be folded and heavily fractured which is a weakness that erosion can exploit
give examples of sedimentary rock and why their erosion rate is MODERATE- FAST ?
e. g ; sandstone, limestone
- most are clastic (rocks composed of older broken rock pieces)
- rocks with many bedding places and fractures, such as shale , are often most vulnerable to erosion
difference between permeable and impermeable
permeable; allow water to flow through
impermeable; does not allow groundwater to flow through
give examples of permeable and impermeable rocks?
permeable; sandstones and limestones
impermeable; clays, mudstones , most ig. and met. rocks
halophyte characteristics
can tolerate salt water , either around their roots of being submerged in saltwater , being submerged in saltwater or salt spray from the sea
xerophyte characterstics
can tolerate very dry conditions such as coastal sand dune conditions where sandy soil retains very little water due to drainage
weakest coastal material?
unconsolidated sediment
define plant succession
the changing structure of a plant community over time as an area of initially bare sediment is colonised by plants
psammosere
sand dune eco sys.
halosere
salt marsh eco .sys.
give the adaptations of marram grass that makes sand dune succession reliant on it?
- copes with being ‘sand blasted ‘ in gale force winds
due to long flexible waxy leaves - leaves are also designed to limit water loss through transpiration
- has roots of up to 3m long and can tap water far below dune surface
- tolerates temp of up to 60 degrees
- grows up to 1m per yr so can keep up with deposition of wind-blown sand
