ENVI 361 Oceanography

The greatest proportion of Earth's surface lies in this elevation/depth interval:

4,000 - 5,000 m below sea level

A ships' fathometer (an echo sounder) transmits a sound pule and records the return of an echo 7.4 seconds later. If the speed of sound in water is 1,500 m/second, what is the water depth in meters?

5,550 meters

Of the following items, which is/are associated with a passive continental margin?

A continental rise A wide continental shelf

Which of the following conditions allows for calcareous ooze to exist beneath the CCD?

A layer of clay buries the ooze before the sea floor subsides

The important contribution to navigation made by Eratosthenes in the third century BC was:

A reasonably accurate calculation of the circumference of our planet

Evidence shows that periodic reversals of Earth's magnetic field have resulted in:

A symmetrical pattern of normal and reverse magnetization in ocean crustal rocks

An oceanographic vessel is mapping a section of the ocean floor stretching for tens of miles in all directions. The seafloor is extremely flat, with a slope of less than one degree, and the water depth is about 4,500 meters. The area being mapped is most likely a(n):

Abyssal plain

Sediments deposited by the process of suspension settling produce the majority of sediment found on:

Abyssal plains

If the rate and direction of plate movement remains the same for the next 50 million years, an accurate prediction would then be:

Accretion of the California Terrane onto Alaska

Of the following statements about the density of seawater, which is/are true?

An increase in salinity increases seawater density A decrease in temperature increases seawater density An increase in pressure with depth has a negligible effect on density

The measurement of ocean depth and the charting of seafloor topography is called:

Bathymetry

Which is the most abundant ion in seawater?

Chloride

Of the following events, which occurred during the Age of Discovery in Europe?

Christopher Columbus made several trips across the Atlantic and discovered a 'new world' Ferdinand Magellan's crew completed the first circumnavigation of the globe

You take a sediment sample from the ocean floor at a depth of 5500 m. The area has a low biological productivity and the CCD is at 4500 m depth. Your sample will probably consist of:

Clay

From smallest to largest, which list of sediment particle sizes is in the correct order?

Clay, silt, sand, pebbles

Of the following statements about Earth's crust, which is/are true?

Continental crust is made of rock that is relatively light in color Continental crust is less dense than oceanic crust Continental crust and oceanic crust are both composed of igneous rocks

You add sand, silt, and clay to a jar of water, shake the jar vigorously, and allow the sediments to settle. The resulting sediment will most closely resemble that of a(n):

Continental rise

Which of the following is the main reason the Earth has a magnetic field?

Convection in the liquid iron-nickel outer core generates a magnetic field

Trenches are typically associated with:

Convergent continental margins

The lithosphere consists of Earth's:

Crust and uppermost mantle

There is a general trend of decreasing pH with increasing water depth in the ocean. What is the cause of this pattern?

Deeper, colder ocean water contains more dissolved carbon dioxide, which causes the pH to be lower

Of the following statements about density stratification, which is/are true?

Density stratification has caused the highest-density material to be found at Earth's core The origin of Earth's oceans and atmosphere are a result of density stratification Density stratification has caused Earth's internal structure to be layered Outgassing is a direct result of density stratification

Which of the following statements correctly interpret the environmental conditions associated with types of biogenous deposits?

Diatomaceous ooze on the sea floor indicates cool surface water above. Foraminifer ooze on the sea floor means warm water above. Coccolith ooze on the sea floor indicates the water is shallower than 4000 meters.

Which of the following microscopic, single-celled floating algae that accumulate to form biogenous sediment?

Diatoms Coccolithophores

Which of the following organisms are responsible for the creation of siliceous ooze?

Diatoms Radiolarians

Iceland is located on what type of plate boundary?

Divergent

Numerous small, shallow earthquakes tend to occur at:

Divergent plate boundaries

Of the following, which energy resource(s) can be extracted from marine sediments?

Gas hydrates Petroleum

Which of the following is an example of a nematath?

Hawaiian Islands - Emperor Seamount Chain

Salt beds of the US Gulf Coast are:

Hydrogenous sediments

Of the following statements about water's latent heat and changes in state, which is/are true?

In the solid state, all water molecules are connected by weak (hydrogen) bonds When water vapor condenses and forms a liquid, it releases heat to the environment Latent heat allows water to transfer energy from one place to another When water evaporates, its latent heat of evaporation absorbs heat In the vapor state, there are no weak (hydrogen) bonds between water molecules

A particle containing an unequal number of protons and electrons is called a(n):

Ion

Which of the following statements accurately describes a segment of the mid-ocean ridge spreading at a rate of 3 centimeters per year?

It would be classified as an oceanic ridge It would have a prominent and deep rift valley

The explorer who advanced oceanography by introducing systematic soundings, or depth measurements, was:

James Cook

Consider the geologic fate of the following seamounts and islands in the Hawaiian Island - Emperor Seamount chain. Assuming conditions remain favorable for coral growth, which would most likely be the next to form an atoll?

Kauai

What processes influence the shape and features of continental shelves?

Large fluctuations in sea level over geologic time Tectonic activity produced by offshore faults Trench formation at convergent boundaries Major climate changes, such as ice ages

Graded bedding provides evidence that:

Large, heavy particles settle out first as current velocity decreases

Earthquakes can only occur in the:

Lithosphere

Based on the concept of isostatic adjustment, which of the following would result in the uplifting in the uplift of Earth's surface?

Lithosphere that was made to be less dense lithosphere that was heated by hot atmosphere lithosphere that was thickened by mountain building

Of the following sediments, which one(s) is/are considered hydrogenous?

Manganese nodules Coatings of metal sulfides near black smokers

Which of the following techniques can be used to measure the salinity of seawater?

Measure the chlorinity of the water Pass electrical current through the water Evaporate the water sample and weigh the amount of solids that precipitate out

The water in Earth's oceans came:

Mostly from volcanic outgassing and partly from comets

Of the following statements about mapping the ocean floor, which is/are true?

Multibeam surveys from ships produce very detailed maps of the sea floor Measurements of sea surface elevation by satellites are used to produce maps of the sea floor Only about 20% of the sea floor has been accurately mapped in detail

Of the following statements about nemataths and volcanic arcs, which is/are true?

Nemataths and volcanic arcs are both the result of volcanic activity In a volcanic arc, any of the volcanoes can be active at any time Volcanic arcs are associated with convergent plate boundaries

Of the following statements about ocean crust, which is/are true?

Ocean crust is destroyed at deep sea trenches Ocean crust is created at the mid-ocean ridge

Marine sediment with more than 30% biogenous material is called:

Ooze

Stanley Miller's famous experiment demonstrated that:

Organic molecules could be produced from the mixture of gases comprising Earth's early atmosphere

Marine sediments provide valuable clues about which of the following Earth history events?

Past catastrophes, such as major extinction events The climate on Earth millions of years ago Previous ocean circulation patterns Movement of the ocean floor The ancient geographical locations of ocean basins

Earth's current atmosphere supports animal life because:

Plant photosynthesis provides oxygen that is critical for aerobic respiration

Most large ocean floor features owe their origins to:

Plate tectonic processes

Which of the following ideas support our current scientific understanding of the development of life on Earth?

Primitive life likely existed without the need for oxygen The 'prebiotic soup' of the primitive oceans provided favorable conditions for life to develop As life evolved it significantly changed Earth's environment Early organisms evolved into more complex organisms over geologic time

The most abundant mineral in lithogenous sediments is:

Quartz

Of the following statements related to the formation of a density-stratified Earth, which is/are true?

Rocky material of the mantle is less dense than the liquid outer core The layer of Earth with the greatest density is located at the deepest depth beneath Earth's surface Molten material will rise if it is less dense than the surrounding material

Sediment samples from deep beneath the ocean floor are recovered by:

Rotary drilling

Neritic sediments are most likely to be composed of:

Sand, silt, and gravel

Of the following processes, which increases the salinity of seawater?

Sea ice formation Evaporation

Measurement of ocean floor bathymetry from satellites relies on:

Sea surface elevation, which varies depending on the shape of the underlying sea floor

Of the following statements about seawater salinity, which is/are true?

Seawater salinity averages 3.5% The two most common dissolved components in seawater are sodium and chloride Seawater salinity averages 35 ppt

In comparison with other ocean basins, major sedimentary features such as continental rises and abyssal plains are relatively rare in the Pacific. The primary reason for their scarcity in the Pacific is that:

Sediment is trapped within the trenches of the convergent plate boundaries ringing the Pacific

Of the following techniques, which one(s) can be used to map the sea floor?

Sending sound through water (sonar) Recording many depths using a long cable Direct visitation of the sea floor Using satellites to measure the sea surface

A trench and a chain of volcanoes known generally as a volcanic arc are always present where there is:

Subduction

Of the following sediments, which one(s) is/are considered biogenous?

Tests of foraminifers Radiolarian ooze

Compared to the rest of the planet, an unusually high concentration of hot spots and rifting is located on the continent of Africa. A likely explanation for this is that:

The African Plate is essentially stationary with respect to Earth's interior and the thick continental crust acts as a 'heat blanket'

The largest geographic feature on the surface of Plant Earth is:

The Pacific Ocean

Which of the following statements is supported by the nebular hypothesis regarding the formation of our solar system?

The Sun became a star when its temperature and density became so great that nuclear fusion began

In which of the following environments would you expect lithogenous sediment to be the dominant sediment type?

The abyssal plains A sandy beach At the base of the continental slope

Of the following statements about the asthenosphere, which is/are true?

The asthenosphere is a highly viscous layer located beneath the lithosphere The asthenosphere is very hot and contains areas of partially molten rock

Oozes are uncommon on continental margins because:

The biogenous component tends to be overwhelmed by the amount of lithogenous material derived from the nearby continent

Which of the following lines of evidence did Alfred Wegener use to support the concept of drifting continents?

The distribution of species of fossils Evidence of glaciers in the areas that are now tropical The pattern of similar mountain belts on different continents The way the shapes of the continents fit together like pieces of a jigsaw puzzle

Of the following statements about Earth's hypsographic curve, which is/are ture?

The hypsographic curve shows that the average depth of the ocean is about four times the average height of the continents The hypsographic curve shows that a majority of the ocean floor is more than 4 kilometers deeps The hypsographic curve shows that a majority of the exposed land is below 1 kilometer in elevation The hypsographic curves shows the percentage of Earth's surface area is covered by ocean waters

Of the following statements about Earth's magnetic field, which is/are true?

The lines of the magnetic force are perpendicular relative to Earth's surface at the magnetic south pole The lines of the magnetic force are parallel with Earth's surface at the equator The magnetic north pole may reverse so that it is located near the geographic south pole The lines of the magnetic force are perpendicular relative to Earth's surface at the magnetic north pole

Of the following statements about the internal structure of Earth, which is/are true?

The magnesium-silicate rocks of Earth's mantle exist in both solid and molten form The mesosphere and the asthenosphere have the same chemical composition

Of the following statements about the age of the ocean crust, which one is true?

The oldest ocean crust is about 200 million years old and is located near an ocean trench

Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge?

The polarity of Earth's magnetic field experiences reversals The ocean floor is spreading apart and new sea floor is forming The igneous rock of the ocean floor preserves Earth's existing magnetic field as the rock cools

The flat top of a guyot or tablemount in deep water is evidence that:

The seamount was once at the surface of the ocean, but is now submerged due to plate movement and erosion when it was near sea level

Of the following statements about seawater properties in high and low latitudes, which is/are true?

There is a thermocline in low latitudes There is a halocline in low latitudes There is a halocline in high latitudes There is a pycnocline in high latitudes

What do all plate boundaries have in common?

They are all associated with zones of earthquakes

Of the following statements about sea floor magnetic anomalies, which is true?

They are oriented parallel to the mid-ocean ridge

Compared to continental crust, oceanic crust is generally:

Thinner, denser, darker in color, and at lower elevations

Which of the following would best describe the principle goal of science?

To explain the causes and effects of observable natural phenomena

Where a mid-ocean ridge is offset, the linear feature connecting and between the crests of the ridge segments is called a:

Transform fault

According to the Geographic Time Scale, which selection lists the correct order of coexistence, from earliest to latest?

Trilobites and amphibians, insects and dinosaurs, dinosaurs and birds, flowering plants and fishes, humans and reptiles

Of the following statements about turbidity currents, which is/are true?

Turbidity currents are highly erosive and carve submarine canyons Turbidity currents move sediment down the continental shelf and the continental slope to be deposited on the continental rise The material carried by turbidity currents is what builds deep-sea fans Turbidity currents are episodic events (they don't occur all the time, but ever so often, like a flash flood)

The majority of ocean trenches are associated with:

Very deep ocean water depths The Pacific Ring of Fire Volcanic arcs and active continental margins Subduction zones and associated faults Narrow or no continental shelves

Of the following types of lithogenous sediment, which one(s) would you expect to find very far from the location of origin?

Volcanic ash Quartz silt

Nearly all oceanic islands are:

Volcanic in origin

Which of the following features is/are associated with the mid-oceanic ridge?

Volcanoes A central rift valley Basalt volcanism and pillow lavas Hydrothermal vents

Of the following properties of water, which is/are caused by the unusal geometry of water molecules?

Water has the ability to dissolve just about anything Water molecules have polarity Water has cohesion and surface tension Water molecules from hydrogen bonds

Of the following statements about the density of freshwater and the formation of ice, which is/are true?

Water's maximum density is at 4*C As the temperature of water decreases from 4*C to 0*C, its density decreases Water at 2*C is less dense that it is at 4*C Ice is less dense than liquid water, which is why ice floats

In science, which of the following would be considered an observation?

Waves are seen to approach the beach at an angle

Sediments with all grains of about the same size are classified as:

Well sorted

The principal reason that oil and water do not mix, even when shaken, is that oil molecules:

are nonpolar whereas water molecules are polar

If you were an explorer stranded in the Arctic Ocean, what method(s) could use use for creating fresh drinking water?

boil seawater; catch and condense the water vapor catch and melt fresh falling snow heat sea ice that formed a long time ago

We would expect the salinity of surface waters to be higher in regions where:

evaporation is much greater than precipitation

We might expect to encounter brackish ocean surface water __.

off the coast of Washington and Oregon

The pH of surface seawater usually has a value of around 8.0. That means that water is:

slightly basic (or alkaline)

Of the following statements about the pH of seawater, which is/are true?

the carbonate buffering system stabilizes the pH of seawater dissolving carbon dioxide in seawater decreases the pH of seawater the pH of seawater is higher than that of pure water

The primary difficulty that must be overcome in the use of desalination plants to provide fresh water is __.

the high cost of energy involved

By measuring only chlorinity (concentration of the chloride ion, CI-) in seawater, we can then calculate the total salinity. This is the application of:

the principle of constant proportions

Of the following, which requires the greatest amount of heat energy?

vaporizing one gram of water