EQ1- Coats Flashcards
What is the littoral zone ?
The wider coastal zone, including coastal land areas and shallow parts of the sea offshore
What are the sub divisions of the littoral zone ?
Offshore
Nearshore
Backshore
What is offshore ?
Beyond the influence of breaking waves
What is nearshore ?
intertidal and within the breaker zone ;used for fishing, trade and leisure
What is backshore ?
above high tide and the influence of normal wave patterns; may have a storm beach further up
What are the characteristics of a rocky coast ?
- Subject to erosion
- steep or vertical in profile
- formed of resistant rocks
- attacked by weathering and mass
movement
-high energy enviroment
What are the characteristics of plain coasts ?
- deposited landscapes of sand,
shingle and mud - low, flat landscapes, often poorly
drained - dominated by processes of
accretion - coastline advances
seaward - often low energy environment
What is primary coastline ?
The land gradually slopes towards the sea across an area of deposited sediment dominated by land based processes (deposited from rivers or lava flows)
What is secondary coastline ?
dominated by marine erosion and depositional processes
What is an emergent coastline ?
where the coast is rising relative to the sea level - due to tectonic uplift
What is a submergent coastline ?
Areas flooded by rising sea levels and / or subsiding land
What is tidal range ?
Microtidal = 0-2m
mesotidal = 2-4m
macrotidal = over 4m
What is a low energy coastline ?
Sheltered coasts with limited fetch and low wind speeds
- small waves
What is a high energy coastline ?
exposed coasts facing prevailing winds with a long fetch
- powerful waves (destructive)
What are the elements of coastal geological structure ?
Strata- different layers of exposed rock
Deformation- degree of tilting and folding by tectonic activity
Faulting- factoring that rocks may have moved rocks from their original positions
What are two main types of coastline (caused by geological structure) ?
Concordant and discordant
What is a concordant coastline ?
When rock strata runs parallel to the coastline
What is a discordant coastline ?
When different rock strata intersect the coast at an angle so rock type varies along the coastline
What are examples of a concordant coastline ?
Dalmation coast in the Adriatic Sea
- limestone has been folded by tectonic activity into a series of anticlines and synclines that trend parallel to the coastline
- the syncline basins have been drowned by sea level rise
- the anticlines have produced long, narrow offshore islands
Haff coastline in the southern Baltic Sea
- long sediment ridges topped by sand dunes run parallel to the coast just offshore
- lagoons (haffs) are created between ridges ad the shoreline
What is the description of discordant coasts ?
dominated by headlands and bays
- less resistant rocks are eroded to
form bays
- more resistant rocks remain as headlands protruding into the sea
what is wave refraction ?
In deep water, wave crests are parallel. As water shallows towards the coast, waves slow down and wave height increases.
In bays wave crests curve to reflect their shape and wave height decreases
- wave action is concentrated on headlands
What are cliff profiles influenced by ?
- resistance to erosion of the rock
- dip of rock strata in relation to the
coastline
What else can influence cliff profiles ?
- Faulting to expose rocks to erosion
- natural cracks in the rock (jointing and fissures)
Describe the igneous rock type
Granite, basalt and dolerite
very slow recession (<0.1cm per year)
- the rocks are crystalline- strong and
resistant
- granite has few joints for erosion to
exploit
