Deck 18: Restless Realm: Oceans and Coasts

Question 1

Which trench includes the world's deepest sea floor (more than 11 km below sea level)?

A)Peru-Chile Trench
B)Puerto Rican Trench
C)Marianas Trench
D)Kamchatka Trench

Answer 1

C

Question 2

Compared to continental crust,oceanic crust is ____________.

A)denser
B)less dense
C)about the same density

Answer 2

A

Question 3

The two most abundant rocks within oceanic crust are ____________ and ____________.

A)granite;gabbro
B)basalt;gabbro
C)granite;rhyolite
D)limestone;shale

Answer 3

B

Question 4

What percentage of seawater,on average,consists of dissolved salt ions?

A)1.5%
B)3.5%
C)5.5%
D)6.5%

Question 5

On a bathymetric map,contour lines connect points of equal ____________.

A)surface salinity
B)surface temperature
C)temperature at the sea floor
D)depth of the sea floor below sea level

Question 6

The oldest oceanic crust is approximately ____________ years old.

A)1 billion
B)200 million
C)100 million
D)50 million

Question 7

A guyot is a(n)____________.

A)flat-topped seamount
B)large,counterclockwise ocean current in the northern hemisphere
C)isolated pocket of water with swirling currents
D)region of thick,floating seaweed that is abundant in the still waters within the central North Atlantic Ocean

Question 8

Compared to continental lithosphere,oceanic lithosphere is ____________.

A)thicker
B)thinner
C)approximately the same thickness

Question 9

The average depth of the abyssal plains below sea level is about ____________.

A)1 km
B)2.5 km
C)4.5 km
D)8 km

Question 10

The shallowest portions of ocean found along the margins of continents are the ____________.

A)abyssal plains
B)continental rises
C)continental shelves
D)continental slopes

Question 11

Which portion of the sea floor is most steeply sloped?

A)abyssal plains
B)continental shelves
C)continental slopes
D)continental rises

Question 12

The form and topography (depth profile)of the ocean floor is termed ____________.

A)orogeny
B)bathymetry
C)allocthony
D)aquitopography

Question 13

Approximately what percentage of Earth's surface is covered with water?

A)30%
B)50%
C)70%
D)85%

Question 14

____________ make up a majority of the ocean floor worldwide.

A)Abyssal plains
B)Continental rises
C)Continental shelves
D)Continental slopes

Question 15

The major oceans,such as the Atlantic,have been present since the Precambrian.

Question 16

Which type of coastline usually has a broader continental shelf?

A)a passive continental margin
B)an active continental margin

Question 17

Coastal processes are of interest to geologists,but affect relatively few people because less than 10% of the world's population lives within 10 km of a sea coast.

Question 18

At the equatorial ocean basins,sea surface temperatures may reach 30°C or greater;at the sea floor 4 km to 5 km below,the temperature is ____________.

A)slightly warmer (33°C)
B)about room temperature (25°C)
C)cool (10°C-15°C)
D)near freezing (1°C-2°C)

Question 19

Most of the igneous rocks within oceanic abyssal plains are ____________.

A)exposed at the surface of the sea floor
B)covered by sand and gravel introduced by rivers at deltas
C)covered by clay and the skeletal remains of microplankton
D)covered by limestones made up of the fragments of large invertebrate shells

Question 20

The deepest segments of the ocean floor are found ____________.

A)along mid-ocean ridges
B)in the geographic centers of abyssal plains
C)in trenches associated with passive margins
D)in trenches associated with subduction zones

Question 21

Bioturbation is the ____________.

A)generation of turbidity currents by sea creatures
B)mixing of sediment by plankton
C)mixing of sediment by burrowing organisms
D)formation of biochemical sedimentary rocks

Question 22

Waves ___________.

A)refract (bend)so as to impact the shore in a nearly parallel manner
B)refract so as to impact the shore nearly perpendicular to the shoreline
C)reflect directly backward from the angle at which they approached the shoreline
D)are reflected off the shoreline,but never refract

Question 23

For the Earth as a whole,ocean water temperatures vary more than surface-air temperatures.

Question 24

Locally tidal reach will be greatest during ____________.

A)full or last-quarter moon
B)full or first-quarter moon
C)full or new moon
D)first- or last-quarter moon

Question 25

The most prominent force inducing tides on Earth is the ____________.

A)Sun's gravitational pull
B)Moon's gravitational pull
C)electromagnetic attraction between the Earth and the Sun
D)gravitational attraction between ocean waters and the continents on Earth

Question 26

A wave will disturb the water to a depth equal to ____________.

A)its wavelength
B)its surface amplitude
C)the bottom of the sea floor
D)one-half of its wavelength

Question 27

The magnitude of tidal effect (lateral extent of the intertidal zone between low and high tides)is affected by the ____________.

A)steepness of the intertidal beach
B)position of the Sun
C)bathymetry of the region
D)A and C are correct.

Question 28

If currents are largely directed toward shore,the area is likely to experience ____________.

A)upwelling
B)downwelling

Question 29

High tides occur simultaneously at all coastlines around the world,except for minor effects on bays.

Question 30

The dissolved cations sodium,potassium,and calcium are ____________.

A)introduced to the ocean by volcanic gases coming into solution
B)emitted at hydrothermal vents in the deep sea
C)introduced to the ocean by the inflow of rivers
D)derived by the dissolution of salt deposits on the sea floor

Question 31

Rip currents flow ____________.

A)directly toward the shoreline
B)directly away from the shoreline
C)parallel to the shoreline

Question 32

Longshore currents flow ____________.

A)directly toward the shoreline
B)directly away from the shoreline
C)parallel to the shoreline

Question 33

The tidal range (difference in elevation between high and low tide)is approximately 3 m along all coastlines.

Question 34

As waves approach shore in shallow water their speed ____________.

A)increases
B)decreases

Question 35

Major oceanic surface currents travel ____________.

A)parallel to the prevailing wind direction in the region
B)in direct opposition to prevailing winds as a result of the Coriolis effect
C)at an angle to prevailing winds as a result of the Coriolis effect
D)at an angle to prevailing winds as a result of the Doppler effect

Question 36

The density of seawater increases with ____________ and ____________.

A)increasing temperature;increasing salinity
B)decreasing temperature;increasing salinity
C)increasing temperature;decreasing salinity
D)decreasing temperature;decreasing salinity

Question 37

Ripple marks in sediment caused by ocean waves are found ____________.

A)at all depths
B)only within the tidal range
C)only above the wave base
D)only below the wave base

Question 38

Gyres ____________.

A)rotate clockwise in the northern hemisphere and counterclockwise in the southern hemisphere
B)rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere
C)are partially caused by the Coriolis effect
D)A and C are both correct.

Question 39

Saline ocean water is ____________ than fresh water,and provides ___________ to objects floating in it.

A)less dense;more buoyancy
B)less dense;less buoyancy
C)more dense;more buoyancy
D)more dense;less buoyancy

Question 40

Rogue waves arise from constructive interference of multiple convergent waves,and can be more than 100 feet high.

Question 41

Water-filled coastal valleys that were excavated by glaciers are termed ____________.

A)deltas
B)tombolos
C)fjords
D)fords

Question 42

Because of wave refraction,erosion along an irregular coastline is ____________.

A)even along the length of the coast
B)greatest along headlands
C)greatest in bays

Question 43

When the sea level rises,the ocean may invade a river valley,producing a nearshore body of water of mixed and variable salinity termed a(n)____________.

A)atoll
B)lagoon
C)estuary
D)jetty

Question 44

The width of a beach in winter is typically ____________ its width in summer.

A)greater than
B)less than
C)equal to

Question 45

Which type of coastline would most likely contain estuaries or fjords?

A)subductive coastline
B)emergent coastline
C)submergent coastline
D)divergent coastline

Question 46

Which statement is NOT true about living coral reefs?

A)Coral reefs are generally restricted to water temperatures of 18°C or warmer.
B)Coral reefs are generally restricted to depths of 60 m below sea level.
C)The calcite reef skeleton is built by algae.
D)Algae provide oxygen that a key reef organism uses in order to secrete calcite.

Question 47

Estuaries most commonly have salinity that is ____________.

A)identical to normal marine salinity
B)identical to fresh water
C)hypersaline (greater than normal marine salinity)
D)brackish (between freshwater and marine salinity)

Question 48

Along beaches,groins have ____________.

A)solved the problem of beach drift
B)increased erosion rates immediately up current from the groin
C)increased erosion rates immediately down current from the groin
D)increased depositional rates immediately down current from the groin