Problem 1
Would you expect all of the crystals in an intrusive igneous rock to be the same size? Explain why or why not.
Problem 3
Is it possible for two igneous rocks to have the same mineral composition but be different rocks? Use an example to explain your answer.
Problem 5
During a hike you pick up an interesting looking igneous rock. It is dark in color and has a fine, granular appearance with small, fairly round crystals of a glassy, deep green mineral scattered throughout. Answer the following questions about this rock: a. What mineral is the small, rounded, glassy green crystals likely to be? b. Did the magma from which this rock formed likely originate in the mantle or in the crust? Explain. c. Was the magma likely a very high temperature magma or a fairly low temperature magma? Why? d. What other minerals might make up the rest of this rock?
Problem 6
A common misconception about Earth's mantle is that it is a thick layer of molten rock. Explain, in your own words, why Earth's mantle is actually solid under normal conditions.
Problem 7
Describe two situations in which mantle rock can melt without an increase in temperature. How do these magma-generating mechanisms relate to plate tectonics?
Problem 9
Each statement describes how an intrusive feature appears when exposed at Earth's surface due to erosion. Name the feature. a. A dome-shaped mountainous structure flanked by upturned layers of sedimentary rocks. b. A vertical wall-like feature a few meters wide and hundreds of meters long. c. A huge expanse of granitic rock forming a mountainous terrain tens of kilometers wide. d. A relatively thin layer of basalt sandwiched between layers of sedimentary rocks exposed on the side of a canyon.
