Question

Lab7GEOL1330 x

GEOL

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330 Name:

Global Warming

Lab #7 Due November 1

1. (40 points) Refer to the figure below (Zachos et al., Nature, 2008). The top panel shows δ13C values for ocean sedimentary materials. The middle panel shows a δ18O record from benthic (bottom-living) foraminifera. The bottom panel shows the calcium carbonate content (shells) material found in ocean sediment. Consider the large spike in data appearing in all three panels about 55.5 million years ago. Reading pages175-178 in your textbook (or going over our lecture slides) and comparing this figure to Figure 6.23 in your textbook will help you to answer the following questions.

What is the name of the event around 55.5 million years ago and what happened to the atmospheric CO2 levels at that time?

What can you infer from the top panel (13C record) in the figure?

How did deep ocean temperatures change (based on the middle panel)?

Based on the lower panel, what happened to the amount of shelled life at this time? What might have caused this large change?

2. (10 points) The figure below shows a plot of past benthic δ18O values vs. time.

What has happened to long-term global temperatures since about 50 million years ago? Provide at least two likely causes of this global temperature change.

3. (50 points) Very interesting climatic events in the Earth’s past that we have not covered in class are the so-called “Snowball Earth Events”. Go to the following website in order to answer the questions below:

http://www.snowballearth.org

. You are welcome to use (and cite) other sources as well.

What is “Snowball Earth” (why has this name been chosen, and who came up with this name)?

When did the “Snowball Earth events” occur?

What is the evidence for “Snowball Earth events”?

What may have caused the events?

How did the events terminate?

Teamwork in the lab is encouraged. However, each student must provide his/her own answer. Copying of answers results in a grade of zero for all students involved.

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