Earth and Life through time
Winter 203
Exam I - Study questions

The first exam will include, but will not be limited to, the following study questions. You will find that many of the exam questions are very similar in wording to these questions below, but some of the questions on the test may require a larger synthesis (i.e. several questions combined). The best way to study for the exam is to study the reading (i.e. read it, take notes, and re-read it) and study your class and lab notes. Note that this and all exams in the class include concepts from the lab.

An example of an old exam is here.

Chapter 1 - Time and Terrestrial Changes
What are some examples of catastrophic geologic change in the written history of humans?
What are examples of catastrophic geologic change that operated on times scales of less then 1 day? Greater than 1000yr?
With a series of beach terraces in an uplifted coast line, how could you determine the rate of uplift? What would you need to do this?
What is the difference between episodic change and gradual change? How can a process look gradual when actually it is catastrophic?
What is non-linear change? How can the concept be applied to seismic activity?
What is the difference between a catastrophic view and a uniform view of Earth's processes? Give examples of each in operation

Chapter 2 - Floods, Fossils, and Heresies
How did the Bible affect early geologic thought?
What are Steno's three "laws?" How are they important to the science of stratigraphy?
What is a fossil?
Early geologic though reasoned that geologic strata were laid down in The Flood. What are the main lines of evidence that Da Vinci used to suggest that this idea is wrong?
What is an unconformity?
What is stratigraphic correlation? How did Smith use stratigraphic correlation to construct his map in 1815?
Early in the science of stratigraphy, what role did fossils play in stratigraphic correlation?
What is an index fossil? What are the three basic criteria for a good index fossil?
What is Catastrophism and who was the founding scientist? How did evolution conflict with this idea.
What is Cosmogonies and how do you think this idea would later influence Kelvin?
What are the basic geologic units of A.G. Werner's "Neptunism?" How did each layer form (or originate).
Why was basalt such a problem for Werner? Do you think he ever got to Italy? He sould have gotten out more.
How did Hutton and Werner differ of how basalt formed?
According to Hutton, in the ideal cross section through a mountain range (caused by upheaval), what were the driving forces that resulted in the rock layers?
"Nothing but time" was Hutton's conclusion. Why? What actual observation influenced him?
Lyell's "Principles of Geology" was published in 1830 to 1875. What basic idea did this book forward?
What was the problem between Lyell and Kelvin?
What is Actualism and how does it differ from uniformitarianism?
Who would have said: "The present is a key to the past?"
What is "multiple working hypotheses?" Give an example?

Chapter 4 - Relative Geologic Time Scale
What was the big fuss about between Sedgwick and Murchison? How was this disagreement settled?
As it doesn't have any fossils, how is the age of the Old Red Sandstone known?
What is the difference between the Upper Cambrian and the Late Cambrian?
When was most of the Geologic time scale defined?
What is the "principle from cross-cutting relationships" and the "principle of included fragments?"
What is a "facies" - give an example of a "depositional facies"
What are the facies characteristics of a beach deposit?
How would transgression of a shallow marine facies leave a distinctive set of strata? How would these rocks change character if you looked at a stratigraphic section upsection?
What is regression and how is it caused.
What is Walther's Law (principle)?
How might facies affect the fossil content of a particular sequence?
What are different types of Biozones?
What are the different types of unconformities and what do they represent?
Aside for the "true" relative time scale, which is based on fossils, what are other types of relative time scales?

Chapter 5 - Numerical Dating of the Earth
What was the age of the Earth according to Kelvin? Where did he go wrong? What was he thinking>
What is a typical geothermal gradient on the planet?
What is an isotope? What are a couple of isotopes that are used for dating?
Uranium (238) decays to lead (206). In general, what happens along the way?
What is the half life (of U²³⁸ for example; or C¹⁴?)?
If you want to date a 100 Ma granite, why can't you use C¹⁴ dating?
If you want to date a rock using the U-Pb technique, what minerals do you need? (what minerals contain uranium)
If I date the rocks in the Adirondacks, I might get ages of 1110 Ma (U/Pb), 900 (K/Ar), 500 Ma (fossils in overlying strata), 100 Ma (fission-track). Why do the ages of these rocks and sediment vary?
What is Carbon-14 dating used for?
What is the "daughter" in fission-track dating?
If you get a granite from the Adirondacks and you get zircon crystals from that granite. Why would the U/Pb age be ~1100 Ma and the fission-track age be ~100 Ma (exactly the same rock, same zircon crystals)?
What are the oldest zircon grains ever dated?
What is closure temperature?
What are discordant dates?

Chapter 6 - Origin and early evolution of the Earth
How old is the Earth?
Why do meteorite and the Bulk earth have a similar composition?
What are the 4 main elements that make up both the Earth and Meteorites?
Why does the crust consist mainly of silicon, oxygen, aluminum, iron and calcium?
What does the nebular hypothesis suggest about the distribution of element sin the solar system.
Most cratering on the moon is inferred to have died down by about 3500 Ma. Why?
What is the difference between and Meteorite and a Comet?
What are the basic subdivision of the earth's interior?
What is the LVZ and why is it important to plate tectonics?
What is the Mohoroviviv discontinuity? What does it represent?
What causes the Earth's magnetic field?
How did the atmosphere and the hydrosphere form?
What does the Ozone layer do? Is it helpful?

Chapter 7 - Mountain Building and Drifting Continents
Who was really the first to proposal "continental Drift"? What was it opposed?
What is a Craton? Where is the nearest one to us?
What is the Shrinking earth hypothesis?
What are the observations that support a fit between SAM and Africa?
What is Gondwanaland? Laurasia? Pangea?
How does a rock retain its paleomagnetic signature of where it was formed?
What is a mid ocean ridge spreading center?
What doe s a triple junction represent? Where is one on earth?
What is a hot spot? What do they tell us about plate movement?
What are transform and transcurrent faults?
How do magnetic reversals in the earth's magnetic field get imprinted on the ocean floor?
What is a passive margin?
How does crustal cooling affect sedimentation on a passive margin?
Where does Salt Diapirs come from in passive margin sequences?
What are four possible mechanisms that drive lithospheric plates?
What is a subduction zone?
How does cooling subsidence affect oceanic crust?
What are the two steps in continental to oceanic rifting?
Subsidence can also be caused by loading. Where does this happen?

Sedimentary Rocks Lab (#1)
How are sedimentary rocks classified?
What is the relationship between rounding, sorting, and grain size with transport distance?
What are typical chemical sedimentary rocks that have economic uses?
What is a sedimentary structure?
What is a sedimentary structure that provides information about current direstions?

Fossils Lab (#2)
What is a fossil?
How are fossils formed?
What is the difference between sessile bentonic and vagrant bentonic?
If a fossil was nektonic or planktonic, what relationship do they have to the sediment that encases them?
What is an index fossil?

Life from the Sea (#3)
What do the Stromatolites from Shark Bay Australia have to do with early atmospheres?
What are “Black Smokers” and why are the life forms on them an analogy for early life?
We assume that early life clearly had two things: absence of oxygen and high temp. Why?.
Why is Carbon dioxide is tied up in limestone? Can this CO₂ be liberated?
Why is the atmosphere on Venus a good analogy for the atmosphere on early earth? Why is Venus different?
What is the Great Barrier Reef in Australia doing to CO₂ levels in the modern Atmosphere?

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© Geology Department, Union College, Schenectady N.Y. 12308-3107.All rights reserved. No part of the document can be copied and/or redistributed, electronically or otherwise, without written permission from J.I.Garver, Geology Department, Union College, Schenectady NY, 12308-2311, USA.

First posted: October 1996; Last updated: 3 January 2003