Geology 200 Preparation Questions

I will handout in class and list on the course web page a few questions for each lecture. These will serve as preparation for each class and be drawn from lectures and links. Please come to class with written answers to these questions, I may collect these on occasion as a quiz.

For 29 August 2001 (Wednesday)

1. What is the primary difference between the seismic "P-Wave" and the seismic "S-Wave"?

2. Why is there a seismic "S-Wave Shadow Zone"? What does it tell us about the Earth's internal composition?

For 31 August 2001 (Friday)

1. Write out the definition of a mineral.

2. What is it about the atomic structure of some minerals that gives them the property of cleavage?

3. What is Moh's harness scale? List the minerals with hardnesses of 1-10.

For 3 September (Monday)

1. Write out Bowen's Reaction series. How could a felsic rock be derived from a mafic melt (magma)?

2. Why do intrusive igneous rocks tend to have coarse crystals (phaneritic texture) and extrusive igneous rocks tend to have fine crystals (aphanitic texture)?

For 5 September (Wednesday)

1. Why are felsic melts more explosive than mafic melts?

2. How do melts migrate upward through the Earth's crust?

3. List ballpark (approximate) figures for the following:

a - average geothermal gradient

b - average density of Earth materials

c - average speed for seismic waves

d - temperature of a mafic melt

e - temperature of a felsic melt

For 7 September (Friday)

1. Sediments and sedimentary rocks. Think first about the breakdown of an igneous rock in some distant mountain, and then the minerals that are produced in the resulting sediment. Which igneous minerals are going to survive weathering and sediment transportation the longest. Why?

2. What are carbonate rocks? In what types of environments do they usually form?

3. How do most deposits of the mineral halite accumulate?

For 10 September (Monday)

1 - What is weathering? How does it differ from erosion?

2 - What are the factors that control the rates of weathering?

3 - What is a soil?

For 12 September (Wednesday)

1. Why do mudcracks appear in sediments which dry out?

2. What is a sedimentary facies? (Try the Web for this one)

3. What controls sea level change?

For 14 September (Friday)

After watching " In the Path of the Killer Volcano" answer the following questions. Prior to viewing reread sections in Chapter 4 in your text that describe volcanic processes.

1 - How might the Pinatubo volcano be classified based on the morphology of the volcanic landform?

2 - According to its location what would be the chemistry of the magma and the resulting extrusive rocks (felsic/mafic). Why?

3 - What is the Volcanic Explosivity Index (VEI) and how would Pinatubo fit within this classification.

4 - What is a pyroclastic flow and how would one recognize this deposit in the rock record?

 For 17 September 2001 (Monday)

1. How do geologists define a metamorphic rock?

2. What is the difference between lithostatic pressure and differential pressure? How can these differences be manifested in metamorphic rocks?

3. What are index minerals and how are they used to classify metamorphic rocks?

For 19 September (Wednesday) 2001

1. On the back is the geologic timescale that you already know something about. How are the absolute ages assigned to this timescale?

2. What error did the physicist Lord Kelvin make when he miscalculated the age of the Earth?

3. What is the Principle of Fossil Succession?

For 21 September (Friday)

1. Please see the diagram below. Your task before Friday's class is to develop the geological history for this block of crust. Follow the procedures outlined on pages 4494-497 of your text.. The units are not labeled, so use terms like "deposition of sediments", "folding", "faulting", "intrusion of dike", etc.

For 24 September (Monday)

1. What is the geological technique of stratigraphic correlation?

2. How can the fossil record be useful in correlating between different sedimentary facies?

3. Let's say you have found a stratigraphic sequence with a disconformity which you cannot actually see. How can the fossil record tell you it is there?

4. We return to some earlier reading for this lecture on absolute dating techniques. Let's start with a review of our most useful term: isotope. Please define an isotope below and give an example.

5. What is the difference between alpha decay and beta decay?

For 5 October (Friday)

1 - You want to radiometrically date a piece of wood approximately 25,000 years old. What will be your most useful technique?

2 - Radiocarbon dating (using 14C) has an effective range of only about 40,000 years under ordinary conditions. Why can't we use it for older materials?

3 - What is the difference between stress and strain in geological terminology?

4 - For that matter, what is the difference between brittle and ductile in geological terms?

For 8 October (Monday)

1. The concept of strike and dip of rock units is fundamental to an understanding of geological structures. Let's start with the first term: please define strike below. This will be very difficult to do without a little drawing!

2. OK, now what is dip?

3. While we're on these basics, please draw little labeled diagrams showing a normal fault and then a reverse fault. What forces (tension or compression) are involved in each?

For 10 October 2001 (Wednesday)

1. What was the contribution of the German meteorologist Alfred Wegener to the eventual Theory of Plate Tectonics?

2. How is Permian glaciation used to demonstrate the past existence of Gondwana?

3. What is the Curie Point?

For 12 October 2001 (Friday)

1. What is the Mohorovicic Discontinuity? (this is review)

2. How was the Moho discovered?

3. We'll cover them in detail later, but very briefly, what are ophiolites?

For 17 October (Wednesday)

1. Draw a diagram of a Convergent Margin. Label the subduction zone, forearc, backarc and magmatic arc portions of your cross-section.

2. What is the difference between autochthonous and allocthonous?

3. Why is an ophiolite often described as a pseudostratigraphy?

For 19 October (Friday)

1. Please name below three mountain ranges which have formed by collisions between two continental plates, and then name the two plates for each.

2. What is a microplate? These are sometimes called allochthonous terranes.

For 22 October (Monday)

1. What is the Red Shift?

2. Briefly outline what is meant by the Big Bang.

For 24 October (Wednesday)

1. What is the composition of most meteorites? What can they tell us about the origin of the planets, especially Earth?

2. Briefly, how does the internal structure of the Moon differ from that of the Earth?

3. It is called the "Big Splash Hypothesis". Briefly outline our current ideas about how the Moon formed.

For 26 October (Friday)

1. Almost 60% of Proterozoic rocks are quartzites, limestones and shale. What does this tell us about Proterozoic depositional environments? (Especially in comparison to the Archean and Phanerozoic.)

2. How do we define the Proterozoic/Phanerozoic boundary?

3. What was the Grenville Orogeny? How did it affect the region we now call Ohio? (see the ODNR web site for a review of the Precambrian history of Ohio).

http://www.dnr.state.oh.us/geo_survey/geo_fact/geo_f13.htm

For 29 October (Monday)

Monday's questions come from the Scientific American article entitled "Snowball Earth", by Paul Hoffman and Daniel Schrag. These questions are broad, so please just take enough notes so that you can discuss the questions in class.

1. What is the geological field evidence for the Snowball Earth scenario as outlined by Hoffman and Schrag?

2. How can the presence of glaciers slow down the process of extracting carbon dioxide from the atmosphere?

3. What is the mechanism that may have finally released the Earth from that enormous Neoproterozoic ice age?

For 31 October (Wednesday)

1. What is a mobile belt in terms of continental architecture?

2. For that matter, what are epeiric seas?

3. I don't think you'll find this one in your book, so to the web or a geological dictionary for you. What is an aulacogen?

For 2 November (Friday)

1. What was the primary cause of the Taconic Orogeny in eastern North America?

2. For that matter, what caused the Acadian Orogeny? Again, in simple terms.

3. The large clastic wedge formed from the Acadian Highlands in eastern North America is called the Catskill Delta. What was its equivalent from the Caledonian Highlands in Baltica?

For 14 November (Wednesday)

1. What do you think the climate was like in the interior of the supercontinent Pangaea in the Late Permian? Why?

2. The many orogenic uplifts associated with the development of Pangaea may have led to a decrease in the amount of carbon dioxide in the atmosphere. How can mountains affect atmospheric composition?

3. Name and briefly describe (one sentence) three groups of organisms which went extinct at the end of the Permian.

For 16 November (Friday)

This week's GEOCLUB presentation features Greg Wiles presenting work on Fish, Tree Rings, Climate and Glaciers in the North Pacific. The title: Pacific-Basin Climate Variability and Patterns of Northeast Pacific Marine Productivity.

1. On what timescales does climate change in the North Pacific?

2. What is meant by societal - relevant timescales?

3. How can climate affect salmon populations?

For 19 November (Monday)

1, What was life in the Mesozoic like? What organisms is the Mz known for?

2. Outline the current ideas on the evolution of birds.

3. What ws the climate like in the Cretaceous?

For 26 November (Monday)

1. In general, how do Mesozoic marine invertebrate communities differ from those of the Paleozoic?

2. Why is the element iridium significant for our catastrophic explanation of the Cretaceous extinctions?

3. What evidence do we have that the Chicxulub structure in Yucatan is really a buried impact crater?

For 28 November (Wednesday)

1. Briefly outline the evolution of the Gulf Coastal Plain.

2. What type of faulting is assocaited with the Basin and Range Province? Why?

3. Where and what is the Farallon Plate?

For 30 November (Friday) - refer to the reading handed out in class.

1. Outline how plate tectonics influences global climate.

For 3 December (Monday)

Read "What drives Glacial Cycles". Handout.

1. What are Milankovich cycles and how do they influence climate?

2. What and when was the Younger Dryas?

For 5 December (Wednesday) Ohio's Glacial World

See the ODNR website for the reading.

1. What was the Preglacial Teay's River?

2. Briefly ouline the geologic evolution of Lake Erie.