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105 Cards in this Set
- Front
- Back
topographic map
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map showing the shape of the land
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map scale
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relation between distance on the map to the true distance on the Earth's surface
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Fractional Scale (map scale)
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1/24,000 or 1:24000 = distance of 1 unit on the map represents a distance of 24,000 of the same units on Earth
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Graphic/Bar Scale (map scale)
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bar divided into segments that show relation between distance on map to actual distance on Earth
- useful for measuring distance between points |
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latitude
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parallel lines to the N and S
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longitude
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meridians to the W and E
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measurements of longitude and latitude
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degrees, minutes, seconds
60 seconds = 1 minute 60 minutes = 1 degree |
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contour line
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line that connects all points of equal elevation
- usually measured from sea level - smallest interval possible |
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contour interval
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vertical distance in elevation between adjacent contour lines
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slope
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vertical change in elevation per horizontal distance
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steep slope
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contour lines that are close together
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relief
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difference in elevation between two points on a map
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total vs. local relief
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total = difference between highest and lowest points
local = difference between two specific points |
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contour lines crossing a stream
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peak upstream
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what do topographic map depict that normal maps do not?
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elevation of the land
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groundwater
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water that percolates through the ground
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surface water
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water that flows over the ground (streams and ponds)
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base flow
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grounwater that seeps into a stream via porous rock, fractures, springs (opposite of groundwater)
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perennial streams
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flow continuously throughout the year
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intermittent streams
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flow only at certain times
- rainy seasons - snow melts |
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flood
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when streams overflow their banks
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land erosion
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wearing away of the land
- streams do this more than anything else |
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alluvium
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gravel, sand, silt, clay deposited in floodplains, point bars, alluvial fans, etc.
- transported + deposited sediment |
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sheet flow
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water that flows over the ground before it can seep in
- flow downslope via gravity |
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stream drainage system
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tributaries to streams to rivers
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dendritic pattern
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branches of a tree
- tributaries - homogenous rocks |
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rectangular pattern
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right-angle bends that form pattern of interconnected rectangles + squares
- rocks fractured in 2 main directions |
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radial pattern
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flowing outward from a central area
- conical hills, volcanoes |
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centripetal pattern
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converge on center point
- lake |
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annular pattern
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incomplete, concentric rings of streams connected by short radial channels
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trellis pattern
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vine
- main stream is long + intersected at right angles by tributaries - alternating layers of resistant and nonresistant rock |
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deranged pattern
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random channels
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drainage basin
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entire area of land drained by one stream
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drainage basin divides
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linear boundaries separating basins
- usually hills |
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weathering
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streams physically erode + disintegrate materials or chemically decompose minerals
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transportation
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weathered materials transported downstream
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deposition
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velocity of stream drops so particles settle out or part of stream evaporates
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uplands
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highest elevation of streams
- head/source - erosion dominant process |
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differential erosion
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resistant = hard, chemically resistant form ridges or hilltops
nonresistant = soft, more easily weathered form valleys |
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mouth
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end of river valley
- enters lake, ocean, dry basin 0 alluvial fans or deltas |
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how geology affects rivers
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affects stream's ability to erode
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how gradient affects rivers
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steepness of slope (ft per mile)
- dividing verticle rise or fall between two points on slope by horizontal distance |
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how base level affects rivers
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lowest level to which a stream can theoretically erode
- mouth - deposition because velocity is zero |
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how discharge affects rivers
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rate of stream flow at given time + location
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how load affects rivers
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amounth of material that is transported by a stream
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change from headwater to mouth of stream
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- gradient decreases
- discharge increases - load increases - valleys widen |
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floodplains
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alluvium accumulates landward of river banks during flooding
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levees
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higher than the rest of the floodplain
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yazoo tributary
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tributary that can't breach a river's levee
- flows parallel to river |
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meandering channels
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winding rivers usually farther downstream
- cutbanks + points bars - ox bow lakes - migrate over time |
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cutbank
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erosion on outer side of meandering channels
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point bar
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depoits of gravel + sand along the inner edge of meanders
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oxbow lake
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outer edge of meader cut off by new path of river
- crescent shaped |
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braided stream patterns
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channels that are interconnected
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delta/alluvial fan
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stream drops its sediment load because velocity drops dramatically
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mass wastage
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downslope movement of Earth materials
- soil, rock - steep slopes |
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Where do streams generally carry a greater % load of sediment in terms of gradient?
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gentle gradient
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stress
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force thta acts on a rock unit to change its shape or volume
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compressional stress
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shorten a rock body
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tensional stress
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elongate or pull apart a rock body
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shear stress
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bend or break a rock
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plastic deformation
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stress applied exceeds rock's strength
- high temperatures + pressures - permanent change in rock |
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fold
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wavelike undulation
- produced by plastic deformation |
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fault
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movement of rocks on either side of fracture
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joint
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break in rock but not displacement
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strike
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trend
- compass direction of line produced by intersection of inclined rock layer with horizontal surface plane - angle relative to N - N 10 degrees E |
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dip
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angle of inclination of surface of rock from horizontal plane
- angle + direction of inclination - 90 degree angle to strike - teeny line in correct direction and degree marking |
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folds
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formerly flat rocks compressed into series of waves
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anticlines
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arch
- rock layers dip away from axial plane - erosion -> oldest rock layers exposed |
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synclines
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downfolds/troughs
- layers dip toward axial plane - erosion -> youngest rock layers exposed |
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axial plane
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imaginary plane drawn through long axis of fold that divides it as equally as possible
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limbs
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two halves of axial planes
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symmetrial folds
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limbs are mirror images
- same angle |
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asymmetrical fold
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limbs have different angles of dip
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overturned fold
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fold where one limb is tilted beyond vertical
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dip-slip fault
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vertical movement of rock layers
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strike-slip fault
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horizontal movement
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hanging wall
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- dip-slip fault
- angle sticks out on top - workers would hang tools |
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footwall
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- dip-slip fualt
- angle sticks out on bottom - worker would stand here |
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normal fault
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hanging wall drops down
- tensional forces |
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reverse fault
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hanging wall pushed upwards
- compressional forces |
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right-lateral vs. left-lateral stirke-slip faults
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depends on relative motion of blocks
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submergent coastline
- retrogradational - transgression - subsidence |
caused by rising sea level
- flooding + receding (retrogradational) - water level actually rising (transgression) - land getting lower (subsidence) |
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emergent coastline
- progradational - regression - uplift |
caused by falling sea level
- elevated about sea level and buildign out into the water (progradational) - water level falling (regression) - land rising (uplift) |
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barrier island
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long, narrow island that parallels the mainland coastline
- separated by lagoon, tidal flat, salt marsh |
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beach
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gently sloping deposit of sand or gravel along edge of shoreline
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berm crest
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highest part of beach
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washover fan
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fan-shaped deposit of sand moved landward of beach during storm or very high tide
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estuary
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river valley flooded by rise in level of ocean
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longshore current
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water current in surf zone
- flows parallel to shoreline driven by waves caused by wind |
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delta
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sediment deposit at mouth of river where it enters an ocean or lake
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headland
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projection of land that extends into ocean or lake
- cliffs |
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spit
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sand bar extending from end of beach into mouth of adjacent bay
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tidal flat
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muddy or sandy area covered with water at high tide but exposed at low tide
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saltmarsh
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marsh that is flooded by ocean water at high tide
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wave-cut cliff
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seaward-facing cliff along steep shoreline
- caused by wave erosion |
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wave-cut platform
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bench at sea level along steep shore
- caused by wave erosion |
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marine terrace
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elevated platform that is bounded on its seaward side by cliff or steep slope
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stack
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isolated orcky island near headland cliff
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tombolo
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sandbar that connects island with mainland or other island
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tied island
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island connected to mainland by tombolo
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sea wall
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boulders etc. constructed against a shoreline to prevent erosion
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breakwater
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offshore wall constructed parallel to shoreline to break waves
- sand accumulates + beach widens because no longshore current |
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groin
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short wall perpendicular to shoreline that traps sand
- up-current side accumulates sand |
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jetties
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long walls etending from shore to protect inlets + harbors
- come in pairs |