landforms Flashcards
rias- submerged landform
formed through a combination of geological and hydrological processes. a ria is a costal inlet formed by the partial submergence of an unglaciated river valley. firstly a v-shaped valley is formed through erosion, this process is influenced by factors such as a rivers velocity and load. following the erosion if sea levels rise the valley becomes flooded. as the sea rises, the base and lower parts of the valley become submerged. the areas that were once river banks are now the side of the ria, creating a wider, deeper, and often more irregular shape. during the flooding deposition of material carried by the river can create mudflats and esturine environments.
fjords - submerged landform
fjords are formed through a series of geological and glacial processes. a fjord is a deep, narrow sea or lake drain. the formation begins with the action of glaciers. which created u-shaped valleys as the glaciers eroded the landscape through plucking and abrasion. plucking is the processes where glaciers scrape along the surroundings pulling out rock. in addition to this the weight of glacier exerts pressure allowing it to erode even hard rock beneath it. as climate warms and glaciers melt, sea levels rise, and water floods the glacially carved valleys. the flooded u-shaped valley is known as a fjord, which are characterised by steep cliffs on earth side, which are ruminants of the original valley walls
tombolo’s - costal landforms
tombolo’s are formed through a series of transportation and depositional processes. a spit is formed through the deposition of sediment carried y longshore drift. if a spit continuous to grow seawards through the deposition of material from longshore drift in low energy zones. a tombolo can be formed if the spit continuous to grow and join an island, connecting the mainland and island . the growing of vegetation on tombolo’s help to stabilise the structure and influences further growth.
salt marshes - costal landforms
saltmarshes form in intertidal zones where saltwater and freshwater mix. they typically develop in sheltered areas such as estuaries and bays. the formation begins with the deposition of sediment , which is carried by the river flow and tidal movement. the sediment settles in the intertidal zone. as the sediment accumulates salt tolerant plants such as cord grass begin to colonize the area. the presence of the vegetation stabilizes the sediment by reducing erosion. as well as this the roots of the plants trap more sediment allowing the salt marsh to grow vertically. salt marshes are characterised by vegetated areas of deposited slits and clays
spits - costal landforms
spits are long, narrow beaches of sand or shingle that are a attached to the land at one end and extend across a coastline. they are formed through a combination of sediment transport and deposition. the primary mechanism for spit formation is longshore drift, which occurs when a prevailing wind causes waves to approach the coastline at an angle. this causes the sediment to be carried in a zig zag pattern. as sediment is moved along the coastline it begins to accumulate at areas where wave energy is low. over time as more sediment is deposited a narrow landform known as a spit begins to extend out. the end of the spit may become recurved due to refractory waves and a second prevailing wind. vegetation may begin to grow on the spit further stabilising it and promote further growth.
onshore bars - costal landforms
onshore bars form in areas where there is a strong wave action. waves approach the shore and break, causing sediment to be transported. similar to spits longshore drift transports the sediment in a zigzag pattern along the shore in the direction of the prevailing wind. as waves loose energy sediment is deposited. over time the accumulation of sediment begins to form a onshore bar. this bar extends parallel and joins the other side of the coast. vegetation can grow and cause stabilize the bar. the onshore bar will also create a lagoon on the landward side.
