Oceanography Midterm Study Guide – Chapters...

Oceanography Midterm Study Guide– Chapters 1-7

I. Introduction to Oceanography – Chapter 1

Vocabulary List - Chapter 1

Study the Terms and Concepts Lists Found at the end of theChapter

1) Attempt to remember them

2) Be ready to define many of these (at least the onesthat I have included in this study guide)

A. The Earth is a Dynamic Ever-changing System

1. Know the Earth's major subsystems

2. Be able to draw/ label the Earth's Cross-section

B. Be able to define Oceanography.

C. Oceanography and the Scientific Theory

1) Know the Scientific Theory approach to nature: the

basic foundation of all sciences.

· The basic steps

· Hypotheses and Theories

· Observations, Data and Evidence

· Methods of Testing

· Interpreting results

2) Understand the basics of how the approach works.

3) Find/create examples of the ST in the real world.

D. Be able to describe and explain the commonly-accepted

explanations for the Origin of Galaxies, the Solar System,

Earth, Ocean and Moon, and Life.

1) The Big-Bang hypothesis

2) The Solar nebula "cold" accretion hypothesis

3) Moltenization and differentiation periods of earlyEarth.

4) The origin and evolution of the Earth-Moonsystem.

5) The origin and evolution of Earth's earlyatmosphere,

oceans, and continental masses.

6) The origins of Life on Earth.

7) The “oxygen revolution”

E. Know what makes the Earth such a dynamic planet!

1) Generation of INTERNAL HEAT from two key sources

· Gravitational heat of accretion (core)

· Radioactive isotopes barbeque (mantle)

2) The presence of LOTS OF WATER on the surface.

3) Amazing set of balanced physical, chemical, andenergy

variables that allow water to exist in all three states.

5) SOLAR input.

6) Know and be able to describe the general physical and

chemical features of both, the Earth's interior and surface.

ü The Earth's subsystems

ü The global topographic and geographicsurface

patterns, e.g. layout of continentalmasses,

ocean basins, mountain ranges, trenches,

island arcs, mid-ocean rift valleys, etc.

F. Know what stimulated the voyages of the early seafaring

civilizations – compare and contrast the

intent and purpose for voyaging of the:

1) Polynesians and Vikings

2) Phoenicians and Greeks

3) Chinese and Europeans

G. List and describe the essential types of information

found in a marine chart (map)

1) Longitude and latitude

2) Scale

3) Coastlines

4) Bathymetry (water depths and contours)

H. Describe the important oceanographic contributions

of the most influential people and organizationsthroughout the

history oceanography

1) People like: Columbus, Megellan, Henry the

Navigator, Darwin, C. Maury, Captain Cook,and

John Harrison

2) Organizations within governments, military, andprivate/

public research institutions

I. List and Describe key technologic breakthroughs

that helped advance oceanographic research

1) Seaworthy ships

2) Compass

3) Sextant

4) Chronometer

5) Power winches

6) Electronic sensing devices (ex: for salinity,currents)

7) Sonar

8) Satellite

9) GPS

10) Computers and data software

II. Plate Tectonics and the Seafloor – Chapter 2





A. Know The Basics of the Earth's Rock Cycle -

1) What is it? The endless cycle of building-up and

wearing down of the Earth's crust.

§ Building up by magmatism andcrustal uplift.

§ Worn down by weathering anderosion.

§ Destroyed/recycled bysubduction.

2) A complex physical and chemical interplay of

processes between five major materialreservoirs:

magma, igneous rocks, sediments, sedimentary

rocks, and metamorphic rocks.

3) Series of related geologic processes occurbetween

two material reservoirs:

4) Three Major Rock Types

ü Each group defines a variety of rock types thathave a common origin.

1) Igneous Rocks - Formed by the cooling and

crystallization of either, magma deepbeneath

the Earth's surface, or lava extruded onthe

surface, or consolidation of volcanicejecta.

2) Sedimentary Rocks - Formed from thedeposited

layers of clastic and/or chemicalsediment via

compaction and cementation.

3) Metamorphic Rocks - Formed bymetamorphic

reactions of pre-existing solid rock via aunique

combination of extreme heat, pressure,fluids, and

deviatoric stresses.

5. Major rock-forming Processes

a. Heating (any rock) Partial MeltingMagma

b. Transport (magma) CoolingCrystallization Igneous Rock

c. Weathering (any rock) ErosionSediment

d. Deposition (sediment) CompactionCementation Sedimentary

Rock

e. Heating +/- Pressure +/- Fluids +/- Stress Metamorphic Rock

6. Be Able to Draw A Simple Rock Cycle Diagram

B. Know The Basics of Earth's Hydrologic Cycle

1) What is it?

· The endless cycling of water viaevaporation, precipitation,and runoff on Earth'ssurface.

· Major player in controlling Earth's climate

· Powers weathering and erosion.

· Plays a key role in mid-oceanhydrothermal systems

· Plays a key role in subduction zone.

2. Be Able to Draw/Label A Simple Hydrologic CycleDiagram

C. Wegener's Theory of Continental Drift (TCD)

1) Be able to explain the overall basic concept ofCD

2) Know the terms Pangaea, Gonwanaland, andLuarasia

3) List the major types of evidence supporting TCD

4) Know the major obstacle that discredited theTCD

5) Know the key scientists that developed/supportedTCD

D. Know All the Basics of the Plate Tectonic Theory --

1) Stiff, outermost shell of solid Earth consisting of

the crust and uppermost mantle called thelithosphere

Broken up into 6 major plates & 12minor plates –Move over the hot, plasticasthenosphere mantle.

2) Each tectonic plate moves independently: twoadjacent

plates can interact in one of three ways:

DivergeConvergeSlide past one another

3) Three types of plate boundaries and associatedprocess

· Divergent = rifting/ seafloor spreading;tensional· Convergent = subduction/ collision;compression· Transform = strike-slip faulting; shearing

4) Spreading centers and Continental rifts form atdivergent

boundaries, where two plates are movingaway from

each other, forming brand-new oceanic crust.

5) Subduction zones and magmatic arcs form atconvergent

boundaries, where an oceanic plate divesbeneath

either a continental or oceanic plate into themantle.

6) Continental collision zones also form at convergent

boundaries where two continental masses are

meeting head-on.

7) Great, transform strike-slip fault systems are created

where two plates slide sideways, past each other.

8) Three proposed driving mechanisms of plate tectonics

a. mantle convection

b. ridge push

c. slab pull

9) The plate interactions, over time, cause a

number of spectacular phenomena, includingmagmatic arcs,

mountain chains, terrane accretion and oceanbasin collapses and

openings.

· Describe the terrane accretion process

· Describe the Wilson Cycle

10) The plate tectonic theory unifies the observation andhypotheses

which attempt to explain most geologic phenomena.

11) The Earth's rock cycle is driven in large part by theperpetually moving plates

E. Seafloor Spreading (SS)

1) Be able to explain the basic concept of seafloorspreading

2) Know the key terms associated with seafloor spreading

3) List the major types of evidence/discovers behind SS

4) Know the key scientist that proposed

F. Subduction

1) Be able to explain the basic concept of subduction

2) Know the key terms related to subduction

3) List the major evidence/discovers for subduction

4) Know the key scientist that proposed

G. Important Points concerning Theory of Plate Tectonics -Know that:

1) Plate Tectonics is a unifying theory because it is able

to explain many geologic phenomena.

2) The so-called "Wilson Cycle" represents a plate tectonic

cycle of plate motions where an ocean basin is born,

grows, then shrinks, and finally collapses.

3) There are 500 million-year Supercontinent Cycles ofplate

motions and interactions that begins with the break-up of

an old supercontinent and ends with the formation ofa new

supercontinent.

4) Plate tectonics is the cause of Earth's mountain building,

magmatism, and never-ending resurfacing of the planet.

5) The Earth's rock cycle is fueled by plate tectonics.

F. Be Able to Identify All Major Plate Tectonic Boundaries

On a Map or Globe

1) Circum-Pacific basin and adjoining continents

2) North and South Atlantic basin and adjoiningcontinents

3) Indian Ocean and adjoining continents

G. Be Able to Identify Elements of Plate Tectonics in a

Geographic Illustration (see online practice exam)

)1 Match plate processes (ex. seafloorspreading)

with associated geographic features (ex. mid-ocean ridges)

H. Understand and be able to explain the concept of isostacy.

III. Marine Provinces -- Chapter 3





A. Know the Geographic Significance of Seafloors

1) Oceans and seas cover over 70% of Earth's surface

2) Earth's seafloors constitute a global-scale topographic

region of low-lying relief that contrasts to the high-

standing relief of the continents

3) Seafloors represent the most vast (by far) depositional

environment on Earth

· Site of massive sedimentation and region ofsedimentary

rock production

4) The evidence used to establish and support the Theory

of Plate Tectonics was established from the scientific

study of seafloors and its sediments

B. Know Components and Nature of Continental Margins

· Shelf – flat portion nearest shoreline

· Slope – steep outer edge of shelf

· Rise – base of slope where continebt andoceanic crust meet

1) Shelf-slope break, Submarine canyons, Turbiditycurrents

2) Continental margin seafloors consist mainly of

Granitic crust = outer edges of continents

Covered primarily by Terriginous sediments

3) Water depths are shallow; up to 200 meters onshelves

4) Explain difference between Passive versusActive

continental margins

C. Know Components and Nature of Deep Ocean Basins

§ Abyssal plains and hills

§ Oceanic trenches

§ Oceanic ridge systems and fracture zones

§ Hydrothermal vents

§ Oceanic islands, atolls, guyouts, and seamounts

1) Ocean basins have rugged, variable topography

2) Oceanic basin seafloors consist of

· Basaltic crust = ophiolite package

· Pelagic clays and oozes (sediments)

Pelagic clays derived fromcontinents

Oozes consist mainly ofskeletons of microscopicmarine organisms

3) Water depth of deep ocean average 4,000 meters

IV. Seafloor Sediments - Chapter 4





D. List and Describe the Types of Seafloor Sediments

1) Four types of marine-based sediment - See Table 5.2

· Lithogeneous

· Biogenous

· Hydrogeneous

· Cosmogenous

2) Pelagic clays derived from primarily three land-based

sources

· Rivers

· Volcanic eruption (ash falls)

· Windblown material

· Consist mainly of quartz and clay

3) Describe the two main types of Biogenous Oozes

· Calcium carbonate oozes

· Siliceous oozes

· Constitute fecal pellets from larger animals

· Fine sand- to silt-size particles

4) Define the sources of calcium carbonate oozes

· Foraminifera

· Cocoliths

· Found on bottoms less than 4,500meters deep (CCCD)

5) Define the sources of siliceous oozes

· Tropical Radiolarians

· Polar Diatoms

6) Define types of hydrogenous sediments

· Manganese nodules

· Phosphate nodules

· Massive metal sulfide deposits

· Evaporites

E. Describe and Explain the Distribution of Seafloor

Sediments -

1) Study Table 5.3 very carefully

2) Study Figure 5.13 very carefully

3) Distribution of each sediment type controlled by several

environmental factors:

· Proximity to sediment source

· Rate of sedimentation (each specificsediment type)

· Chemical stability at site of deposition

4) Unique distribution pattern for each sediment type

Study Distribution Map shown in Figure 5.13

· Lithogeneous -

· Biogenous

· Hydrogeneous

· Cosmogenous

F. Define the Rates of Seafloor Sedimentation

1) Deep ocean sedimentation rates are very low

2) Each type of deep seafloor sediment has specific rate

· Lithogeneous - 2 millimeters per 1000 years

· Biogenous - 1 to 6 centimeters per 1000years

· Hydrogeneous - 1 to 10 millimeters per 1million years

· Cosmogenous - Negligible

G. List and Describe Methods of Seafloor Sediment

Sampling

· Piston Coring samplers

· Drag bucket and Clamshell samplers

H. List and Describe Types of Seafloor Mineral Resources

1) Continental Margins

§ Oil and gas (hydrocarbons)

§ Sand and Gravel

2) Deep Ocean basins

· Manganese nodules

· Massive metal-sulphide deposits

· NO gold and silver

Essay Questions - A super effective means ofreally “getting” the science terms and concepts is

to answer questions in essay form (usuallyrequire answers of about 3 to 8 sentences inlength). The following are key questions fromChapters 5 through 7 concerning the materialcovered for this midterm exam:

IV. Seawater Properties - Chapter 5





1. What is salinity? How is it measured?

2. List the two ions with the highest concentrations in seawater.Indicate which ion is a cation and which is an anion. Which saltconsists of a combination of these two ions (spell out the name, notjust the chemical formula)?

3. Explain what oceanographers mean when they say that a dissolvedion or salt is conservative in seawater.

4. Give an explanation for the observation, based on evaporitecomposition, that sea salt concentration and composition havebeen nearly constant for about the last 1 billion years.

5. Why are oxygen concentrations higher in ocean surface waters andlower in the deep ocean?

6. Why are carbon dioxide concentrations lower in ocean surfacewaters and higher in the deep ocean?

7. What are nutrients? Give the names of two nutrients and brieflydescribe their importance in the ocean.

V. Question on Atmospheric Circulation - Chapter 6





1. The energy that the Earth receives from the sun is returned to spaceby two processes, reflection and re-radiation. Describe, briefly, whathappens to the sun's energy when it is reflected and when it is re-radiated.

2. In the heat budget of the Earth, which two things must balance (orbe equal to one another)? What would be the consequence if thisbalance did not exist?

3. Why are the equatorial regions of the Earth, on average, hotter thanthe polar regions?

4. How does evaporation of water from the oceans result in a transferof heat to the atmosphere?

5. Why is carbon dioxide called a "greenhouse gas"?

6. Why is the concentration of carbon dioxide in the Earth'satmosphere increasing?

7. It is difficult for scientists to predict how much the Earth's climatewill warm, if the concentration of carbon dioxide in the Earth'satmosphere doubles over the next 50 years. Describe one of thereasons for this difficulty.

8. Explain why a parcel of air which was originally moving directlynorthward from the equator is displaced to the east, so that ittravels to the northeast of its original position. (Note that it is not

sufficient to name the effect responsible (Coriolis effect); you mustexplain what causes this effect (Coriolis effect)).

9. Unusually large amounts of rainfall occur near the equator. Why?

10. Between the equator and 30° N, the winds generally blow from thenortheast (the Northeast Trade Winds). How do atmosphericconvection and the Earth's rotation produce this wind pattern? Adiagram may be helpful in answering this question.

11. Between 30°S and 60°S latitude, the winds generally blow from thenorthwest (the Westerlies; this wind band includes the "RoaringForties" and "Furious Fifties" of sailors' lore). How do atmosphericconvection and the Earth's rotation produce this wind pattern? Adiagram may be helpful in answering this question.

12. Why is low atmospheric pressure generally found over the oceansof the Northern Hemisphere in winter?

13. Why do winds in the Northern Hemisphere generally blowcounterclockwise around low pressure areas? A diagram may behelpful in answering this question.

14. What causes the wet, or summer, monsoon found along the westcoast of India ? How is this related to the onshore breeze that oftenoccurs in coastal areas during the afternoon?

15. Although El Niño was first noted along the west coast of SouthAmerica , it is actually a global phenomenon. What are 3 unusualocean or weather conditions associated with El Niño, either in theeastern tropical Pacific or elsewhere?

16. Why do hurricanes form only in the tropics?

17. From 0° to 30° N latitude, the Northeast trade winds blow from thenortheast; between 30° and 60° N latitude, the Westerlies blow fromthe southwest. Explain how this wind pattern, in along with theEarth’s rotation (Coriolis effect), causes the clockwise flow ofcurrents circling the North Pacific Ocean , the North Pacific Gyre.

18. Describe the Earth’s heat budget. It is not necessary to give aquantitative answer, but your answer should include a description ofthe major processes affecting the sun’s energy after it enters theEarth’s atmosphere. How will increasing carbon dioxideconcentrations in the Earth’s atmosphere affect the Earth’s heat

budget? Indicate the specific processes affected as well as theoverall effect on the budget.

IV. Ocean Circulation - Chapter 7





1. Why is the salinity of ocean water greater near 30° N than it is near60° N latitude?

2. List two processes that increase the salinity of seawater, and twoprocesses that decrease the salinity of seawater.

3. List two properties of water that affect water density, and, for each,indicate whether density would increase or decrease if that propertyincreased.

4. Define the terms thermocline and halocline, and pycnocline.

5. What condition exists when a water column is unstable? Brieflydescribe one way in which a water column can become unstable.

6. Define thermohaline circulation.

7. Explain thermohaline circulation's role in ocean circulation.

8. In which regions of the ocean do deep and bottom waters form?Why is the formation of deep and bottom waters confined to theseregions?

9. A hypothesis has been proposed that states there is a link betweenthe climate of northern North America and Europe (especially ice

ages) and the rate of formation of North Atlantic Deep Water. Howcould North Atlantic Deep Water formation rates affect climate?

10. Oceanographers say that the deep and bottom waters of the NorthPacific Ocean are "old". Why are these waters said to be old?

11. Define the term water mass.

12. What is the Ekman Spiral? How is it related to Ekman Transport?(A diagram may be helpful in answering this question.)

13. How does Ekman Transport cause coastal upwelling? (A diagrammay be helpful in answering this question.)

14. What is an ocean gyre?

15. What are eddies? How do they form?

16. Define and explain the terms divergence, convergence, upwelling,and downwelling.

17. Describe how the divergence and convergence of ocean currentscan cause upwelling and downwelling, respectively.

18. Describe how prevailing winds blowing parallel to a coastline cancause either, upwelling and downwelling.

19. List the five common water masses found in the temperate andtropical latitudes.

20. Illustrate a general temperature-salinity (T-S) diagram, and showhow different sets of T-S values for different water masses can haveidentical densities.

21. Name, describe, and elaborate on the origin and activity of the threemajor deep-water masses.

22. Describe and illustrate the classic model of pure thermohalinecirculation.

23. What is the process of “caballing”?

24. What is the vast global-scale ocean circulation system currentsystem termed the “global conveyor belt for heat transport”?

25. What are the two traditional types of methods for measuringcurrents?

26. Which type of current measuring method works best for each typeof water mass?

27. What is “acoustical tomography”, and what is its usefulness instudying ocean currents?

28. Describe the changes in water density in the upper ocean layer overthe annual cycles at tropical, temperate, and polar latitudes and thecorresponding changes in water temperature. Indicate at which timesof year, in each region, that the water column is unstable and mixingwith underlying water occurs. Diagrams may make this easier.

29 Describe the circulation of the Atlantic Ocean below 1000 m depth.Discuss the sites of formation of water masses, how they form (e.g.,cooling at the ocean surface, mixing of other water masses), andtheir paths of flow. Include the following water masses in youranswer: North Atlantic Deep Water (NADW), Antarctic IntermediateWater (AAIW), Antarctic Bottom Water (AABW), and MediterraneanWater (MW).

30. Define and discuss in adequate detail the vast global-scale oceancirculation system current system termed the “global conveyor belt forheat transport”. Also discuss how it has primary importance inmoderating and shaping Earth’s climate

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