At what depths in Earth do metamorphic rocks form? What happens if temperatures get too high?
Why are there no metamorphic rocks formed under natural conditions of very low pressure and temperature, as shown in Figure 6.1?
How is slaty cleavage related to tectonic forces? What forces cause minerals to align with one another?
Would you choose to rely on chemical composition or type of foliation to determine metamorphic grade? Why?
You have mapped an area of regional metamorphism, such as the region in Figure 6.9a, and have observed a series of metamorphic zones, marked by north-south isograds, running from sillimanite in the east to chlorite in the west. Were metamorphic temperatures higher in the east or in the west?
Draw a P-T path for shock metamorphism of country rock during a meteorite impact.
Which kind of pluton would produce the highest grade of metamorphism, a granitic intrusion 20 km deep or a gabbro intrusion at a depth of 5 km?
Draw a sketch showing how seafloor metamorphism might take place.
Subduction zones are generally characterized by high pressure–low temperature metamorphism. In contrast, continent-continent collision zones are marked by moderate pressure–high temperature metamorphism. Which type of plate boundary has a higher geothermal gradient? Explain.