7 1 14 COASTAL LANDFORMS Materials Rocky tons of rocks on the beach like no sand Sandy coasts beaches and sand dunes Muddy dominated by fine grain tidal flats Processes Primary coasts terrestrial processes rather than marine Ria coastline which is a coast that is dominated by drowned river valleys Irregular embayed coast with offshore islands Delta coastlines input of sediment from a river Fjord coastline long and narrow bays and deep Valleys here are glaciated with steep sides Secondary marine processes impacted them Wave cut cliff Large rock headland in water Kind of like a Ria but wave action is shaped the coast and cut back the headland and there s a wave cut platform and now there s a wave cut cliff from erosion Barrier islands marine deposition Coral reef coasts small volcanic island in middle sometimes barriers corals reefs Erosional landforms Wave cut cliffs and platforms are an example Tremendous force from wave on rock like in the middle and it erodes a notch deeper and deeper and the weight of the overlying material will be unstable and fall and have a huge pile of rubble at the bottom in the water and will be carried away and a new cliff is there and it starts over However less effective bc the cliff is now further from the shore Less energy each time and it ll just be a deep platform one day Coastal terraces platforms in the land Young volcanic islands that is uplifting Sea level is falling on the island Uplift period and sea level drops It attacks the cliff lower than the wave cut cliff from above and now that is a terrace Headland jets out in the water and will get cut away sometimes and it s now called an arch Erode the middle and cuts the middle and makes the cave thing As it gets larger the roof gets weaker and will collapse and will be pillars of rock called stacks Depositional landform Beaches highly dynamic and change rapidly Beach cycle annual sequence of change Fair weather storm cycle Occurs bc beaches adjust to wave energy Sand will be thrown around constantly and the beach will adjust to this sand moving around Storm weather conditions are during the winter usually The changes of it Beach with dune Bern where beach towels are and umbrellas and as you walk to the water the slope is steeper and this is the Bern crest and shows the foreshore During fair weather periods coast is dominated by swell waves that come from storms from thousands of miles away Long waves and low steepness travel faster reach deep to carry sediment and when swash comes back down it brings some sand back that was just carried in but it keeps some so we have net deposition and we build the foreshore up steeper until its steep enough that the backwash is strong enough to have equal sediment in and out with equilibrium Wide beach and Bern and steep foreshore Storm weather Large storm systems moving through and strong wind for long periods of time Shorter in length steeper so large wave height So we have our summer profile and now we have shorter and steeper waves coming in net transport is in the offshore direction Scoop up sand but they can t carry it super offshore so it s deposited to create a near shore bar Parallel to beach So like the water gets deep then all of a sudden it s shallow then deep again Narrow beach flatter foreshore along with the near shore bar next fair weather season long waves return and picks up materials from near shore bar and makes the equilibrium slope again by building the foreshore deep again spits ridge of sand that extends from the coastline following direction of the shoreline of that area Extension of the shoreline into the water spit out of the shoreline Tombolo also ridges of sand but instead of extending parallel to shoreline they are perpendicular Obstruction in nearshore like a huge ass rock Longshore currents coming in but the waves can t go through the rock so we have sand coming in but not out so we make a ridge between the shore and the rock Like a bridge barrier islands long but narrow deposits of sand Hundreds of miles long but not wide Separated from land coast from a shallow and small body of water called a lagoon or bay or sound Very common in gulf and up the Atlantic shoreline Sub environments On ocean side the waves are larger than the base side Open ocean means large fetch On lagoons they remain small On ocean side large and long beaches up Low and steep on lagoon side with low energy On beach side dune grasses and they are self tolerant to floods and stuff and abrasion by wind blown sand and are responsible for the foredune which is a ridge that is parallel to the shoreline and usually continuous and broken in occasional areas Behind the foredune lots more vegetation and maybe trees Sometimes there are more than one wave or hump in the island Like bigger dunes barrier island rollover is when the whole island moves in toward land and rolls over itself Peat soil is on the coast land side of the island The foredune is scarping The dune is obliterated and the sand is pushed landward as a result of a huge storm The salt march is buried in sand the peat soil Lots of viable plants in sand too and they will sprout Most barrier islands today are eroding or rollovering Peat outcrop overwash fan gap in dune where they have been breached waves go through and sand goes through and makes an overwash fan Over time a dozen pieces at a time are pushed landward barrier island formation Drown in place Period of low sea level Beach and dune at shoreline Period of sea level rise and island narrows and rollover starts and can t it hang so the barrier island is formed Spit extension Spit goes larger and larger and is breached by the storm Barrier Island is separated and then it s a barrier island Emergence theory idea that wherever you have a location where two marine currents run into each other they slow each other down and whatever they are carrying they drop and it builds up making barrier islands Biological landforms Coral reefs marine organisms called something maybe coral that extract calcium carbonate and solidify the form an exoskeleton which makes a coral reef Distribution and controls Human impacts Geography of them Basically all of them are between 30 N and S latitude so of the equator Needs to be warm tropics Also on the western side of ocean basins so like the eastern parts of the continents At each ocean basin there s a surface current called gyre also and they rotate across the equator getting warm then veers off toward or up the coast