Coasts Flashcards
What is the littoral zone
the zone from the highest tide mark to the permanently submerged areas
What makes up the littoral zone
- in land
- backshore
- foreshore
- nearshore
- offshore
What are the types of coasts
- rocky coasts
- coastal plains
- high and low energy coast
- erosional and depositional coasts
- reef coasts
- deltaic coast (dominated by river sediment)
What are emergent coasts
when sea levels fall, leaving behind more land
What are submergent coasts
when sea levels rise, inundating the land
What are characteristics of igneous rocks
- crystaline
- resistant
- impermeable
- rate of recession = 1mm/year
- cooled and solidified magma or lava
What are the characteristics of sedimentary rocks
- jointed sedimentary (sand+limestone) are permeable
- porous (chalk)
- but shale is fine and compacted=impermeable
- recession rate = 1cm-1m/year
- formed in strata
What are the characteristics of unconsolidated material
- easily eroded
- if compacted an impermeable layer is formed in strata
- recession rate = 1m+/year
What are the characteristics of metamorphic rocks
- hard
- resistant
- impermeable
- recrystalization in a solid state
- formed when igneous or sedimentary rocks are either compressed or heated
What is a concordant/Pacific coastline
when strata is parallel to the coast
What is a discordant/Atlantic coastline
when strata is perpendicular to the coast
what is lithology
rock type:
1. composition
2. what minerals are inside
3. type of rock
what is geological structure
the arrangement of the rock
what is strata
the layers of rock
what are bedding planes
- natural horizontal cracks and breaks in strata
- caused by gaps in time formed during periods of rock formation
What are joints
- vertical cracks and fractures
- caused by either contraction as sediments dry, or earth movement during uplift
What are faults
- large cracks formed when pressure or stress is subjected to a rock
- this happens when the rock exceeds its internal strength, allowing the fault to move along the fault plain
What are folds
- curves in rock
- caused when pressure from tectonic activity buckles and crumples the rock
What is the dip of strata
the angle at which strata lies
What types of cliffs do horizontal strata produce
steep-sided cliffs
What type of cliffs do seaward dipping strata produce
steep-sided cliffs that are more susceptible rowards mass movement
What types of cliffs do landward dipping strata produce
stable, steep-sided cliffs
What are dalmatian coastlines
narrow lines of islands seperated by narrow sea channels