Oceanography Chapter 10
What is a delta?
A deposit of sediment at the mouth of a river
Match the coast of the United States to its description.
Eastern: Passive continental margin; considered depositional Western: Active continental margin; considered erosional
Coasts classified as predominantly __________ lose sediments, whereas depositional coasts predominantly gain sediments.
erosional
A(n) _________ is a mound of sediment deposited by a glacier along its edge.
moraine
The region from the outer limit of wave action on the sea bottom to the upper limit of wave influence on the land is known as the ______.
shore
As bars along the coast accumulate enough sediment with time, they allow the establishment of __________ which in turns helps the bar grow even larger and possibly into a barrier island.
vegetation or grasses
A beach scarp is the product of ______.
wave erosion
The energy to transport beach sediment comes from _____ and the currents they produce.
waves
What is the direct source of energy for the transportation of beach materials?
waves
A summer berm is formed by gentle waves in spring and summer, whereas a(n) , or storm berm is formed higher up on the beach by strong storm waves.
winter
During what time of the year is it more likely for large storm waves to carry sand from the beach and deposit it in offshore bars?
winter
The majority of the world's population lives ______.
within 100 km of a coastline
Another word for the term eustatic is _______.
worldwide
Imagine that you are walking from land toward the ocean. In what order would you encounter the following three beach areas? Put the first area on top.
1. Backshore 2. Foreshore 3. Offshore
Match the area of the beach to its correct description.
Backshore: Dry region of the beach that is rarely submerged Foreshore: Extends from the dry beach area to the low-tide level Offshore: The shallow-water area seaward of low-tide level
Match the term to its correct description.
Delta: A deposit of river-borne sediment where the river meets the ocean Alluvial plain: A deposit created by surface runoff at the base of a mountain front
Which of the following describe beaches?
Dynamic Can be sand or gravel
True or false: Major changes that occur along coasts always do so rapidly, such as with a hurricane.
False; Significant change in coastal areas can occur over much longer periods and may not be perceived in a human lifetime.
Features that are found on primary coasts, are U-shaped narrow channels, and are formed by glacial erosion and, later, sea-level rise are ___________.
Fiords or Fjords
Choose all the factors that affect the width of a coast.
Geography Culture Vegetation Climate
Which of the following primary coasts are the result of erosion?
Ria coast
____________ coasts are created by the work of sea organisms.
Secondary
During this season, sand is frequently pushed back onto the beach from offshore bars.
Summer
Which statement correctly describes the relationship between the terms coast and coastal zone?
The coast is just land, whereas the coastal zone includes both land and the bays and estuaries that interrupt it.
How does building a dam on a river affect an associated beach?
The dam traps sediment carried by the river, which is then no longer supplied to the beach.
How are rip currents produced?
The water that piles up at the beach due to onshore transport returns to the ocean in these narrow, fast flows.
Fjords found along the coasts of Norway, New Zealand, and Alaska were formed by ______.
glacial scouring
If beach sediments at the depositional end of the drift sector are ______, it can also be said that they are accreting.
growing
Salt marshes are known for their ______, which provide sediment stability in this organically rich environment.
sea grasses
When breakwaters and jetties are built along a beach, sediment ______.
settles out in the quiet basin behind them, resulting in less material replenishing beaches further down the coast
Beaches are classified according to ______.
size of beach materials color shape and structure composition of beach materials
The ______ of the materials and the forces acting on a beach determine the composition and size of the materials found there.
source
Water rushing up onto the beach is called ______, and the resulting water moving back to the sea is called ______.
swash; backwash
The flat part of the foreshore that is located seaward of low-tide level is called the low-tide ______.
terrace
Match the component of a coastal circulation cell to its description.
Rocky headlands: Found at the beginning and the end of the cell Submarine canyons: Found in the offshore region of the cell; receive transported beach sediments Rivers: Provide the sediment that is transported within the cell
What two factors determine the composition and size of materials found on a beach?
The specific forces acting on the beach The source of the materials
Which of the following can be found at a coast?
Dunes Cliffs Bays River mouths Beaches
Which of the following describe a coastal circulation cell?
It is a series of drift sectors. Within the cell, sediment is transported permanently offshore.
How do researchers estimate sediment transport rates along beaches?
Observing the rate at which sand is deposited on the upstream side of an obstruction
Match the term associated with wave movement and sediment transport along the beach to its correct description.
Onshore current: Landward motion of water Onshore transport: Landward movement of sediment Longshore current: Motion of water parallel to shore Longshore transport: Movement of sediment parallel to shore
What two limits define the shore?
Outer limit of wave action on the sea bottom Limit of waves' direct influence on land
What is the main difference between primary and secondary coasts?
Primary coasts owe their character to land processes and secondary coasts to marine processes.
____ currents are narrow regions of water that are returning to the ocean after accumulating near the beach due to onshore currents.
Rip
What is the primary difference between runnels and ridges, and bars and troughs?
Runnels and ridges occur in the foreshore, and bars and troughs occur in the offshore.
This photo of ______ _________, California, is showing the dredging of sand necessary to keep the harbor open. The structures were built without considering the effect of the longshore current and drift.
Santa Barbara
What beach feature is indicated by the arrow in this image? (pointing to the arrow divot in the sand)
Scarp
Match the feature associated with secondary coasts to its description.
Spit: Connected to shore on one end; shifting sand deposit Sea stack: Found offshore; tall pinnacle of resistant rock Bar: Parallel but not connected to shore; sand deposit
The zone of transportation that sediments follow as they are moved by a longshore current is called the ______.
drift sector
Which of the following is not a primary coast? One that is formed ______.
due to alteration by marine plants and animals
A beach that appears not to change is likely in a state of ______ equilibrium, with the loss of sand equaling the gain of new sand.
dynamic
Recognize the effect of breakwaters along a beach by matching the area to the process or the structure involved.
A: Breakwater B: Deposition C: Erosion D: Wave direction
In the one circulation cell marked, match the correct feature to where it would be found in the cell.
A: Rocky headlands B: Sandy beaches C: Submarine canyon
Which of these can be correctly used to describe this beach? (Picture shows large rocks piled up)
Armored beach Lag deposit
The majority of beaches worldwide are light tan in color, as they are composed of resistant quartz sand. However, some beaches have distinct colors due to their source materials. Match the beach color to its most plausible source.
Black: Basaltic lava Green: The mineral olivine (olive) Pink: Shell materials White: Coral
Which of the following structures is used to protect beaches from wave energy and is built parallel to shore?
Breakwater
Match the type of primary coast to the correct example.
Dune coast: The Western Sahara grows westward by blowing sand toward the Atlantic Ocean. Lava coast: Flows from Hawaiian volcanoes produce black sand beaches. Fault bay/coast: Parallel movement of two tectonic plates creates a depression filled by seawater known as the Gulf of California. Ria coast: A river valley created during an ice age is drowned when sea level rises again; an example is Chesapeake Bay.
Why is it relatively risky to build a structure on a barrier island?
It will receive more storm wave energy than the beach inland. It is an inherently unstable feature.
Match each beach area with its corresponding shape and/or structure description.
Spit: Extends outward into the water and runs parallel to the shore Hook: Extends outward from the shore in a wide, sweeping arc Tombolo: Extends outward from the shore and connects to a rock or an island
Which of the following statements correctly describe how coasts can change over time?
Subtle change can occur during a human lifetime. Drastic change can occur over geologic time frames. Extreme change can occur very rapidly.
Which of the following statements correctly describe cusps?
Their size is related to wave energy. They are crescent-shaped depressions.
Which of the following statements correctly describe reef coasts?
They are created by sea organisms. They are a type of secondary coast.
What is the name given to a beach that connects the shore to an island, as shown in this image?
Tombolo
True or False: Because the amount of sand that is transported along a section of coast can measure up to 1,500,000 m3 per year, efforts to keep this material in place can be very expensive and may prove impossible.
True
True or false: The majority of the world's population lives within 100 km (60 mi) of a coastline.
True
How does the onshore movement of water result in a longshore current?
Waves usually approach the shore at an angle and return at a different angle, creating a resulting overall movement of water parallel to the beach.
Berms are low terraces found on the backshore area of beaches. Match the specific type of berm to its correct description.
Winter berm: Formed during severe storms; closer to the coastline Summer berm: Formed by gentle waves; closer to the water
The result of swash and backwash is ______.
a zigzag movement of water along the swash zone
If beach sediments at the depositional end of the drift sector are growing, it can also be said that they are ______.
accreting
Building on a(n) _______ island, such as those off of North Carolina, is risky because they are inherently unstable and receive the brunt of the energy from ocean storms.
barrier
Sand ______ are created along secondary coasts as material is carried by waves and currents away from the beach and deposited offshore yet parallel to the coast. These features may grow to break the surface and form ______.
bars; barrier islands
Some beaches have distinct colors due to their source materials. For example a black beach's source material is most likely ______, and a white beach's source material is most likely ______.
basaltic lava; coral
An accumulation of sand along the shore is called a(n) _______.
beach
The part of the foreshore that is alternately exposed and covered by water is called the _____.
beach face
__________ are described and classified according to shape and structure, and the size, composition, and color of materials.
beaches
A coastal _______ cell links together drift sectors, forming a system that moves sand along and then permanently away from the beach.
circulation
Both natural and human factors determine the width of a coast. The natural factors include geography, _________, and ________________.
climate; vegetation
The land edge that is affected by marine processes is known generally as the ______.
coast
These crescent-shaped depressions are _______. Their size is related to wave energy.
cusps
The construction of a ______ on a river results in the loss of sediment and erosion of the associated beach.
dam
A beach that is in dynamic equilibrium ______.
does not appear to change
Beach sediments transported by a longshore current are moved from their source area to an area of deposition; this zone of transportation is called a(n) _____ sector.
drift
The higher water levels associated with sea-level rise allow waves and currents to move farther up the beach profile and expend more energy there, result in more _______.
erosion
Match the word to the correct blank in the phrases describing the four types of primary coasts.
erosion: Formed through ______ by water, wind, or ice glacier: Formed from river, ______, or wind deposits volcanic: Created through ______ activity subsidence: Created by crustal movements causing either land ______ or uplift
Match the word to the correct blank in the phrase describing one of the three types of secondary coasts.
erosion: Formed through ______ by waves, currents, or the dissolving action of seawater tide: Formed from wave, ______, or current deposits animal: Created through marine plant or ______ activity
During periods of glaciation, the oceans experience a(n) ______ change in sea level, as the water is tied up in ice. Subsequently, when the ice melts, worldwide sea levels go back up.
eustatic
Which of the following is not a secondary coast? One that is formed ______.
from river, glacier, or wind deposits
The study of coastal landforms and the processes that create them is called coastal ______________.
geomorphology
Coastal geomorphology considers many processes that form and shape the coasts. These processes include the influence of all of the following except ______.
humans
A beach composed of pebbles and boulders, known as ______ deposits, can become a(n) ______ beach if these large particles accumulate in quantities significant enough to protect the beach from further erosion.
lag; armored
The large yellow arrow labeled "A" in this image represents the ________ current, created from the waves approaching the shore at an angle.
longshore
An erosional coast ______ sediments, whereas a depositional coast ______ sediments.
loses; gains
Found in Florida, Australia, and the West Indies, ______ provide shelter along a coast for other plants as well as animals.
mangroves
Bars along the beach ______.
may accumulate sediment to the point of breaking the water's surface, where they may become stabilized by vegetation and change into a barrier island
Both Long Island and Cape Cod are ______, a mound of rubble created by a glacier as it paused in motion and deposited a ridge of sediment.
moraines
The eastern coast of the United States is a passive continental margin, which means it is ______; the western coast is an active margin.
not located on or near a plate boundary
The movement of water and sediments toward the shore is called _______ current and transport, whereas the resulting movement of water and sediments parallel to the shore is called _________ current and transport.
onshore; longshore
A coast that is formed predominantly by land processes is known as a(n) ___________ coast, whereas a coast that owes its character to predominantly marine processes is known as a(n) ________________ coast.
primary; secondary
At low tide and in the foreshore, runnels and __________ are found as a series of low and high regions, respectively. Similar features are also found in the offshore and are known as _____________ and bars.
ridges; troughs
Individuals build _________ along beaches in order to protect their property from wave energy and erosion, but these structures often make conditions worse and concentrate wave energy in a neighboring location.
seawalls or bulkheads
As opposed to the term coast, a coastal _____ is one that incorporates not just land but also water areas, and it is used in legal and legislative documents.
zone
