Download Exam #2 Review `04

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GEOL 445 Review Sheet
Exam 2
The exam will commence at 12:30 p.m., Tuesday,
November 9th. Bring a calculator!
The exam will cover lecture topics from trace element partitioning to radiogenic isotopes
through solid Earth differentiation (crust-mantle-core), mainly drawing from lecture and
problem sets, but also including assigned reading.
What are D-values? How are they determined?
What are “bulk D-values”?
Be able to predict relative D-values by using Goldschmidt’s rules.
What is meant by the term “elemental fractionation”? What igneous processes
give rise to elemental fractionation?
Given the batch melting equation and a residual mineral assemblage, be able to
calculate the trace element content of both melt and residue for different degrees
of melting. Know the definition of Co, Cl, Cs, F, DRS.
What is the difference between batch melting and fractional melting?
Be able to predict how Cl/Co will change as a function of D value and F.
What are the main mineral phases in the upper mantle?
Why does the mantle melt? Be able to explain magmatism on Earth in the
context of its plate tectonic setting.
Which mantle phases contribute more to the melt? What is the likely mantle
residual assemblage going to look like after high degrees of melt extraction?
Be familiar with REE diagrams and be able to explain why the REE contents are
normalized to chondritic meteorites.
Be familiar with the three main types of radioactive decay and the resultant
changes in mass and/or atomic number.
Given D-values, be able to predict how parent/daughter ratios change during
mantle melting for radiogenic isotope systems.
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Be familiar with the decay equation, the equation for an isochron and the
relationship between half-life and decay constant.
Be familiar with the isochron plot and be able to determine the age of a suite of
cogenetic minerals or rocks given their isotopic compositions and decay constant.
What is the average composition of the continental crust (cast in terms of an
igneous rock type) and why is this composition problematic in understanding
crust formation?
What is a “Eu-anomaly”? The upper continental crust is observed to have a
negative Eu-anomaly. Explain how this might have been created.
What are the direct and indirect lines of evidence that the Earth has a Fe-rich
core?
How do we know that the core is not pure Fe-Ni, but contains a light element?
What geochemical imprint has core formation left on the Earth?
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