Coasts ch. 10 Flashcards
What is the coast
The land of the continent adjacent to the beach
Coast description
Land extending inland as far as marine influence is seen
Offshore
Extends from breakers to edge of continental shelf
Shelf
Continent that is submerged
Examples of places that get marine influence
La Jolla, Point Loma
Berm
The dry area at the foot of the coastal cliff (not part of the coast, part of the beach)
instances when the berm is submerged
Tsunamis, storm surges, high tides (spring tides)
wave cut platform
flat eroded bedrock at the beach, eroded by wave energy
Notch
Cave cut into sea cliff by wave energy
Where do you find offshore extending the farthest out
Passive Margins (longest cont. shelf)
Sources of sand on the beach
Erosion of the coastal cliff, rivers, cliff erosion
where is there more sediment
continental shelves
summertime beach
alot of sand, low energy, low tide, wide berm
Sandy beach
Wide Berm
Wintertime beach
wave energy is higher, short, high waves
Rocky beach…
Narrow berm
green algae
water is polluted
summertime vs. wintertime beach is b/c of
seasons
Longshore current ->
movement of water in surfzone, paralell to the shore
why is the longshore current parallel to the shore?
waves approach at an angle (from left to right)
drift->
net movement of sand grains
CA longshore current
N to S b/c of westerly winds
oceanside compartment
transports sediments (sand) from N to S
Classification of coasts
Depositional coast -> flat coast
why is it flat
because it is not active
Depositional coast-passive margin
the transition from land to sea is not associated with a plate boundary
Depositional coast-Subsidence
the gradual caving in or sinking of an area of land.
Depositional coast-Deposit sediment
the laying down of sediment carried by wind, flowing water, the sea or ice.
Depositional coast–Deltas
wetlands that form as rivers empty their water and sediment into another body of water (submergent coasts)
Depositional coast–barrier islands
thin ribbons of sand that line the US Atlantic and Gulf coasts and absorb the much of the force of storms like Hurricane Ian as they reach land
Erosional coasts
Eroding
Erosional coasts–coast is lifted
because it is tectonically active
Erosional coasts–active margin
A linear zone where tectonic plates either converge with one another (convergent margins) or shear past one another
Erosional coasts–tectonic uplift
the geologic uplift of Earth’s surface that is attributed to plate tectonics.
Erosional coasts–cliffs
erosion and weathering. Weathering happens when natural events, like wind or rain, break up pieces of rock.
Erosional coasts–Headlands, sea caves, arches, stacks
caused by erosion, when part of the coast separates from
Erosional coasts–marine terraces
erosional landforms that develop due to the landward retreat of the active sea cliff in response to erosion by ocean wave energy
Marine terrace
any relatively flat surface of marine origin, bounded by a steeper ascending slope on one side and by a steeper descending slope on the opposite side.
