GEO/OC 103
MIDTERM 1 Study Guide

To study for the test, please consider the following material, listed from highest to lowest priority:

PRIORITY 1 (HIGHEST): The concepts and specific examples presented during the lectures, which you can review by downloading and looking at the PowerPoint (PPT) files. Remember, you MUST have a copy of Microsoft PowerPoint installed on your computer in order to look at these files! And a word of warning about the PPT files: it's NOT a good idea to print them in slide mode because of the numerous graphics - just look at the slides on the computer and take notes from them, or select only a few slides to print (or change the background color to white and the text to black before printing).
The test will only cover the lectures on geological oceanography and closely-related subjects, hence only Lectures 1-9.
PRIORITY 2 (NEXT HIGHEST): The website notes in text format (but please keep in mind that the material emphasized in lectures might be somewhat different than the website notes. You are first and foremost responsible for taking your own notes on the concepts presented in lecture).
It doesn't hurt to look at the "Additional Resources" web links on the course lectures page as well.
LOWEST PRIORITY (OPTIONAL) Background material in the optional Invitation to Oceanography textbook by Pinet (Chapters 1-4).

It may also help to:

prepare for the exam by studying in a group with some of your classmates
Study Tip: When studying, "close the book, recall, then write it down." Put the PowerPoints, notes, and other resources aside. Then use the practice questions below as a guide and recall everything you can in order to answer the questions without the aid of your notes. Write your answers down, or say them out loud.

The following key concepts and questions should help guide your preparation for the exam, 70% of which will consist of multiple choice and true false questions, 30% of written extended answer questions.

The Growth of Oceanography

What is oceanography?

Make sure that you understand what the Challenger expedition (1872-1876) was.

The Shape of the Ocean Floor and The Earth's Structure

The contents of this lecture are extremely important.

Make sure that you know what multibeam mapping is.

Know what the major seafloor features are on the contiental margins and deep ocean floor (continental shelf, continental slope, abyssal plain, etc.).

The Shifting Crust, Plate Tectonics, and Creation, Aging, and Recycling of Ocean Floor

What are the three types of plate boundaries, and what features form at each?

What does the location of earthquakes tell us about plate tectonics?

How does the distribution of volcanoes relate to plate boundaries?

What is mantle convection, and how does it influence plate tectonics?

How old is the oldest ocean floor? Where can you find it?

What are hotspots? plumes? large igneous provinces?

What is the Wilson Cycle?

Why are subduction-related volcanoes the most dangerous on Earth?

What are "black smokers"?

How does the depth of the ocean floor change with age?

Nature & Distribution of Sediments

How are sediments classified? (size, composition)

What are the principal types of marine sediments? (terrigenous, biogenous, hydrogenous, cosmogenous)

What are biogenic oozes made of? (CaCO3 and SiO2 skeletons of plankton)

What are the main planktonic groups of animals and plants that produce biogenous sediments?

What river systems contribute the majority of sediments to the oceans?

What are "turbidites'? (submarine avalanche deposits)

What is ice-rafted debris?

What is the Carbonate Compensation Depth (CCD)?

Also:
Guest Lecture on Paleoceanography and Climate Change

What is Paleoceanography?

Why is climate change important?

What are oxygen isotopes? What do they tell us about ancient climates?

Example Questions: Multiple Choice/True-False

1. We have a reasonable idea of what the interior of the Earth is made of from:

A. the composition of manganese nodules

B. the abundance of elements in the Sun from analysis of sunlight

* C. seismic waves

D. all of the above

2. According to the plate tectonic theory, most new crust is formed as the result of:

A. plate convergence.

B. deposition of sediments along continental margins.

C. extrusion of lava from the liquid outer core.

* D. volcanism at mid-ocean ridges.

3. About _______ percent of the Earth’s surface is covered by the oceans.

* A. 71

B. 85

C. 97

D. 53

E. 68

4. The following was recognized early in the century as evidence for continental drift:

A. meteor impacts

B. El Niño

* C. diversity of species (fossil evidence)

D. none of the above

E. all of the above

5. On the map below, choose the letter labeling a site where you would expect to find ocean floor that is extremely deep ____A - Tonga Trench________.

6. On the map below, choose the letter labeling a site where you would expect to find ocean floor that is extremely young. ____D - Mid-Atlantic Ridge (not C, C is on land, Iceland!)________.

7. On the map below, choose the letter labeling a site where you would expect to find very, very thick crust ___B - continental crust_________.

8. On the map below, choose the letter labeling a site where you would expect to find very deep earthquakes _____A - Tonga Trench, or B is ok too (Himalayas)____ .

9. A plate capped by oceanic crust subducts beneath a plate capped by continental crust because:

A. oceanic crust is thicker than continental crust.

* B. oceanic crust is thinner than continental crust.

C. oceanic crust is older than continental crust.

D. oceanic crust is younger than continental crust.

10. The term bathymetry refers to:�

A. submarine mineralogy

* B. submarine topography

C. submarine biology

D. submarine currents

E. submarine waves

11. According to plate tectonic theory, the Mid- Atlantic Ridge should be:

A. the same age as the east coast of the United States.

B. older than the east coast of the United States.

* C. younger than east coast of the United States.

D. the theory is not specific enough to address this issue.

12. The oozes on the seafloor in the deep ocean consist mostly of:

A. terrigenous sand and clay deposited by turbidity currents

B. bones and teeth of bottom-dwelling fish

C. small glass spheres reaching the Earth from outer space

* D. microscopic shells of single celled plants and animals that live near the surface of the ocean

13. Which materials listed below, found in deep- sea sediments, are composed of calcium carbonate (CaCO₃)?

A. diatoms

* B. foraminifers

C. pteropods

* D. radiolaria

14. The oldest sediments in the ocean

A. date back billions of years, to when the oceans first formed

* B. date back to about 200 million years, the age of the oldest ocean floor

C. are about 100,000 years old, deposited during the Ice Ages

D. are only 6,000 years old

15. The carbonate compensation depth (CCD) is

A. the ocean depth below which calcium carbonate sediments are not preserved

B. is largely controlled by the rate at which carbonate dissolves in sea water

C. explains why calcareous oozes are limited to the shallower depths of the oceans such as the tops of ridges and rises

* D. all of the above

16. There is a record in deep-sea sediments of long-term changes in the orbital motions of the Earth around the Sun, because the orbit affects the climate of the Earth.

* A. True

B. False

17. Oxygen exists as three isotopes__________, which can help us to reconstruct the climates of the past

A. 2O, 3O and 4O

* B. 16O, 17O and 18O

C. 19O, 20O and 21O

18. The lava that erupts in the Hawaiian Islands is thought to be the result of a:

A. divergent plate boundary.

B. convergent plate boundary.

C. transform plate boundary.

* D. hotspot.

19. The science of oceanography is customarily divided into four categories, which

are:

A. coast, sea cliff, nearshore, and offshore

B. wetland, estuary, lagoon, and bay

* C. physical, geological, chemical, and biological

D. shelf, slope, rise, and basin

E. epipelagic, mesopelagic, bathypelagic, and abyssalpelagic

20. "Climate" and "weather" mean the same thing.

A. True

* B. False

Example Questions: Extended Answer

Briefly explain how SONAR works.
SONAR is an acronym for sound navigation and ranging. It is based on the simple relationship of sound (acoustic) velocity = distance/time. A SONAR instrument on the bottom of a ship or from an underwater vehicle sends pulses of sound to the seafloor and determines the amount of time it takes for them to return to the instrument. Knowing this along with the average velocity of sound in seawater yields a distance or depth. That distance or depth is used to produce a map of the ocean floor showing its topographic features.

What exactly is oceanography (i.e., briefly define its FIVE subfields), AND how does it differ from other fields of science?
Refer to the notes and PowerPoint file for Lecture #2, "The Study of the Oceans." Oceanography is considered to be uniquely more interdisciplinary and collaborative than other sciences. It also requires going to sea in ships!

Others:
Explain and illustrate the basic plate tectonic mechanism that has created the Cascade Mountain Range.

How does the Earth's mantle differ from its and crust? What is the relationship of the mantle to the lithosphere and the asthenosphere?

http://dusk.geo.orst.edu/oceans/guide1.html

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