Geoscience Reference
In-Depth Information
C H E C K y O U R U N D E R S T A N D I N G
1.
What is the difference between an ocean and a sea?
Name the oceans of the world and at least five major
seas.
9.
How are sea caves, sea arches, and sea stacks part of
a geomorphic continuum that indicates shoreline ero-
sion is occurring?
2.
What does the term
salinity
mean, and how is it related
to the chemical composition of ocean water?
10.
What is the difference between an erosional and a dep-
ositional coastline?
3.
In the past approximately 150,000 years, what has been
the primary cause of eustatic sea-level change? Why
have these changes occurred, and what are some prom-
inent landscapes that indicate such fluctuations?
11.
Name and describe the depositional landforms associ-
ated with the longshore current.
12.
Why are coastlines a good place for dune fields to
evolve?
4.
With respect to tides, what is the difference between
centrifugal and gravitational forces, and how do they
produce tidal bulges?
13.
How is the shape of river deltas influenced by coastal
processes?
14.
How do coral reefs form, and why is this process funda-
mentally different from other geomorphic processes?
5.
Compare and contrast spring and neap tides.
6.
Describe the formation and movement of waves. What
happens to waves when they approach the shore?
15.
What are the various ways that people attempt to protect
beaches and bluffs from erosion? Why do these approach-
es also cause problems in nearby parts of the coast?
7.
Describe the processes associated with littoral drift.
How are they related to the approach of waves to the
shore?
16.
How does a groin take advantage of the longshore current
to cause beach growth? Why are groin fields common?
8.
How does a marine terrace indicate that (1) a period of
coastal erosion occurred, and (2) sea level fell or tectonic
activity transpired?
17.
Name and describe the two ways in which global warm-
ing may cause sea level to rise.
ANSWERS TO VISUAL CONCEPT CHECKS
V I S U A L C O N C E P T C H E C K 1 9 . 1
Assuming that the axis of this part of Australia's coast aligns north and south, the wave-forming winds
must be out of the southeast. These winds are causing swells to move slightly toward the northwest
before they break as waves and strike the coast. This oblique approach causes the force of the water
to be deflected toward the north, resulting in the formation of a longshore current flowing in that direc-
tion. In association with this current and swash/backwash of the surf, littoral drift is toward the north
along the shore.
V I S U A L C O N C E P T C H E C K 1 9 . 2
Sea stacks and arches are indicative of a retrograding coastline. These landforms are bodies of rela-
tively resistant rock that have, until now, withstood the force of erosion caused by waves.
V I S U A L C O N C E P T C H E C K 1 9 . 3
Assuming north is at the top of the photograph, this landform indicates that the longshore current is
flowing slightly from northwest to southeast. The spit has formed because the longshore current en-
countered the relatively still water in the open ocean, causing deposition of sediment and progradation
of the landform. The spit is curved because waves are moving sediment landward at the same time
that it is being deposited at the tip of the feature.
