coasts Flashcards
Faulting?
Stress or pressure exceeds the rocks internal strength causing it to fracture. Rock then moves along fault planes
Folding?
Pressure during tectonic activity makes the rocks buckle and crumple
Jointing?
Vertical cracks caused by contraction (from rocks drying out) or by earths movements during uplift
Dip?
Angle that the rock strata lies (horizontal, vertical, sea-ward dip etc)
Dalmation Coastline?
Folds formed parallel to coast create concordant coastline. The layers of soft rock have been eroded and flooding creating parallel islands
Haff coastline?
Parallel islands to the coast created by sandy bars and lagoons. (low energy coastal environments)
Igneous rocks?
Randomly arranged interlocking crystals (formed by magma solidifying)
Examples of igneous rocks…
Granite
Diorite
Basalt
Obsidian
Sedimentary rocks?
Broken rocks transported and deposited at the bottom of lakes. Builds up layers and is compressed, has weak bedding planes
Examples of sedimentary rocks…
Limestone, chalk, sandstone (PERMEABLE)
Shale, clay (IMPERMEABLE)
Metamorphic rocks?
Formed from other rocks that are changed under heat and pressure
Examples of metamorphic rocks…
Marble
Schist
Slate
Igneous recession rates
1mm/year
Sedimentary recession rates
Up to 1m/year
Metamorphic recession rates
1-3mm/year
Wave refraction?
Wave energy converges at headlands and diverges at bays due to the shallower water around headlands creating friction
Pros and cons of groynes?
PROS: builds up beach, protects beach and increases tourist potential, cost effective
CONS: ugly, starves areas downwind of sediment
Pros and cons of rock armour?
PROS: cost effective
CONS: rocks sourced from elsewhere so do not fit the local geology, hazardous if climbed on
offshore breakwater…
…forces waves to break before reaching the shore
PROS: effective
CONS: ugly, hazard for boats, impacts longshore drift
HALOPHYTE
salt tolerant
XEROPHYTE
tolerant of dry conditions
Cliff regrading and drainage…
…makes cliff angle less steep and less vulnerable to collapse
PROS: cost effective
CONS: may look unnatural, can cause cliff to collapse as it is drier
Dune stabilisation…
…planting of marram grass
PROS: cost effective and provides habitats
CONS: planting is time consuming
Beach nourishment pros and cons?
PROS: builds up beach, protects cliff and increases tourist potential. Cot effective and looks natural
CONS: needs constant maintenance, dredging for sediment may have negative impacts on local coastal habitats
What is the littoral zone?
Area of shoreline that is subject to wave action (offshore, nearshore, foreshore, backshore)
