GLY306 Petrology
Various amount of points. Plots - Be prepared to plot or interpret some of the following information on a petrogenetic grid like to one pictured below:
20 point questionsA. Selected geothermal gradients.
B. Melting curves for granite and basalt.
C. Various facies of metamorphic rocks
D. Anhydrous metamorphic reactions.
E. Decarbonation reactions.
F. Dehydration reactions.
1. Discuss the concept of metamorphic grade as developed by Barrow in the Scottish Highlands. Define the concept of isograd and plot the minerals used by Barrow on a sketch map of his study area.
2. Identify the metamorphic facies associated with various minerals plotted on an ACF diagram.
3. Show how a tie-line flip can explain a paired metamorphic reaction that occurs at an isograd.
(10 point) questions
1. Compare the mineral sequence in Barrows isograds with those of the Buchan type of metamorphism. Explain what controls the difference of these sequences.
2. Plot some metamorphic minerals an ACF triangular diagram.
3. Write the Gibbs phase rule. Answer questions on a diagram showing the kyanite-sillimanite-andalucite P-T relationship to explain the relationship of phases to degrees of freedom in this system.
4. Balance a metamorphic reaction given the minerals involved. (Only
simple mineral compositions will be given.)