Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

60 Cards in this Set

  • Front
  • Back
What is the main difference between erosional and depositional coasts?
The primary features of an erosional coasts are caused by wave action or glaciers, while those of depositional coasts are laid down by rivers, currents and waves.
What are five features of depositional coasts?
deltas, mangrove swamps, salt marshes, barrier islands, and sand dunes
What is the difference between primary and secondary coasts?
Primary coasts are formed by terrestrial processes like rivers, glaciers, volcanoes, and plate movement, while secondary coasts are formed by waves, currents, and marine organisms.
What are two tectonic processes that can create new coasts?
Hot spots can build new islands, and action at plate boundaries can lift some the continental crust above the oceanic crust.
What are three ways coasts can be destroyed?
Continents can collide, landslides can dump land into the sea, and sea level can rise.
What is the difference between eustatic sea level changes and isostatic sea level changes?
Eustatic changes occur worldwide and mainly involve the ocean, while isostatic changes occur regionally and mainly involve the continents.
How do fjords form?
Glaciers cut deep valleys with a lower sea level, deposit sediment as a moraine at the mouth; when sea level rises as the glacier retreats, the moraine becomes a sill and the valley a fjord.
Why do few rivers actually transport sediment to the continental shelf and change the coastline?
They deposit their sediment on the coastal plains that make up the end of the river.
What is ironshore?
dead coral reefs that were raised out of the water, forming a jagged surface and much of the Cayman Islands
What kind of rock is eroded the fastest?
What effect does wave action generally have on a shoreline?
It straightens the shoreline.
What effect does wave action generally have on the slope of the shore?
It flattens it between high tide and low tide and creates a sea cliff on the land side.
What are three features of coastal headlands?
sea stack (isolated mound), sea arch (tunnel thru rock), and sea cave (indentation)
What is the area between low tide and high tide called?
foreshore, or low tide terrace
What is the area between high tide and the highest point storm waves have reached?
What size tidal range favors erosion?
small, because it concentrates the energy
What do tides do to wetlands?
Tides drain mudflats and recycle sediment.
How are sand dunes formed above the backshore?
Winds carry the sand upland.
What kinds of vegetation protect the soil from erosion?
grasses, seagrasses and mangroves
What is the area between low tide and the farthest out that waves touch bottom?
What are the two definitions of the littoral zone?
Geologists say it's from the backshore to the nearshore, while biologists label it just as the foreshore.
What are berms?
beach-long "speed bumps" on the backshore, formed by storm waves with the stronger storms making higher, more permanent winter berms
What is required for a greater foreshore slope?
larger sand particles
What are scarps?
berms formed in the foreshore by high (spring) tides rather than by storm waves
What are longshore bars?
speed bumps in the nearshore where sand eroded from the coast is deposited, sometimes becoming barrier islands or detected by early wave breakage
What colors of sand are found in Hawaii?
white, black, green, red, maybe more
What is one of the most resistant rocks?
What organisms can deposit calcareous shell fragments that make up many tropical coasts?
foraminifera, mollusks, echinoderms, and some algae
In general, where do sand grains come from?
How does longshore drift happen?
Waves come in at an angle, and the swash brings suspended sand toward the shore and in the direction of the wave, but the backwash is driven by gravity, so it goes straight out away from land, with a net drift of sediment parallel to the shore.
What is another name for longshore drift?
littoral drift
What two factors influence the volume of sand transported by longshore drift?
height and frequency of the waves
What is the range of speeds for longshore drift?
a few meters to a kilometer per day
Which way does longshore drift generally go in the US?
south, because storms come from the north
What are the components of a longshore drift cell?
Rivers bring sediment to the beach, longshore transport carries it along the beach, and it empties into a submarine canyon at the end.
What causes concern about California's beaches?
The damming of rivers has depleted the sediment delivered to the beach, leaving more of the backshore exposed to wave action and erosion.
Why are smaller sand grains brought farther out to sea than larger ones?
Wave velocities are higher for the swash than the backwash, so smaller sand grains are pulled out to sea by the backwash, while larger ones are left on the beach.
Why are beach sands relatively well sorted?
They must be small enough to be carried by longshore drift but big enough to remain on the beach when backwash and rip currents pull them out.
What are the differences between beaches in the summer and winter?
Beaches experience more erosion in winter, so they are left with larger sand particles, larger offshore bars, and a flatter beach.
Why do larger sand particles mean steeper beaches?
Backwash can percolate through the gaps in larger particles, reducing the amount of sand pulled out to sea.
What is a lagoon?
the sheltered area between a barrier island and the mainland
What are the zones of a barrier island, from the ocean to the lagoon?
ocean, beach, dune, barrier flat, high salt marsh, low salt marsh, lagoon
What happens to barrier islands as sea level rises?
They migrate landward.
How were most barrier islands formed?
As sea level rose after the ice age and more land was eroded, spits formed downdrift from headlands, which developed into barrier islands.
Name four famous US developed barrier islands.
Miami Beach, Palm Beach, Galveston, and Corpus Christi
What are seawalls, and what do they do?
Hard walls built parallel to shore to break up storm waves, they work for a while, but concentrate erosion on either side and eventually are undermined by wave action, quickening coastline erosion. They also narrow the beach and withhold sand from longshore bars, making wave erosion more powerful.
What are groins, and what do they do?
Groins are walls built perpendicular to shore to stop longshore drift; often in a series, they redistribute sand in a zigzag pattern with erosion on one side of the groin and accretion on the other side.
What are jetties, and what do they do?
Jetties are pairs of walls built perpendicular to the coast to protect an inlet between them from waves, but often end up redistributing sediment with accretion on one side and erosion on the other.
What are breakwaters, and what do they do?
Walls built out to sea to protect a harbor from waves, breakwaters keep sediment in the harbor, making it shallower and only fixable by expensive dredging projects.
What do reef-building corals require?
warm water >18°C, medium/high salinity, low turbidity, and symbiotic photosynthetic dinoflagellate zooxanthellae
What are the three types of coral reefs?
fringing reefs, barrier reefs, and atolls
How do barrier reefs form?
When sea level rises relative to the land they are near (isostatically or eustatically), the ideal growth region is offshore but not too deep, so the reef grows off the shore.
How do atolls form?
Volcanic islands sink after becoming inactive, and the barrier reef keeps growing upwards as the land disappears.
What are the differences between fringing reefs, barrier reefs, and atolls?
Fringing reefs are next to the coastline, barrier reefs are off the coast, with a lagoon in between, and atolls have no coastline.
What are the two types of tidal wetlands and the emergent plants in them?
Salt marshes have marsh grasses, and mangrove swamps have mangroves.
Where are mangrove swamps found?
in the tropics, between 30°N and 30°S
How do mudflats accumulate organic matter?
Detritus has low density, so it accumulates on the top of the mudflats and is not lost through the bottom.
Why do most eastern US rivers carry little sediment?
They often go through former glacial valleys, which themselves have not filled with sediment.
When do deltas get their sediment?
when rivers flood or change their course
What are levees and what do they do?
Levees keep a river from flooding, saving lives but starving the surrounding soil of its nutrients. The surrounding land is eroded such that flooding can cause mass devastation (New Orleans).