Boulder with bands of light and dark minerals.

In the last three units, you've learned about crustal deformation and its effects on the rocks of the crust: deforming them into folds and faults. You know about the impact of movement along faults, making earthquakes, and the destruction they cause. In this unit, you'll learn about another consequence of crustal deformation: making metamorphic rocks. Metamorphic rocks form through metamorphism, transforming an existing rock, called the protolith, into a rock with a different mineral composition or texture. This happens when the protolith is subjected to intense heat and pressure but without the rock melting - If it melts, it would become magma and eventually igneous rock.

Like deforming the crust into mountains or making volcanic arcs through subduction, metamorphic rocks generally form along convergent plate boundaries where rocks are subjected to high pressure and temperatures. They always form underground, where temperatures and pressures are high enough to drive metamorphism.

Goals

Master the Learning Objectives

Students can explain the rock cycle, differentiate among the three types of rocks, and use texture and composition to identify common rocks and their origins
Illustrate the interrelationship among the three types of rocks using the Rock Cycle
Describe the processes that form metamorphic rock
Determine the grade of metamorphism based on grain size and possible index minerals
Classify metamorphic rocks based on their texture and mineral content
Recognize metamorphic environments (origins of metamorphic rocks) and types of metamorphism

Complete the Module

Complete each page of this module in order (no skipping) using the "Next" button in the lower right corner of this page
Submit each assignment by the due date to avoid late penalties
Consider your understanding of the learning objectives for each assignment
Submit all assignments by the module closing date, next Sunday at 11:59 pm (this module closes a day earlier so you can prepare for final exams)
Use Pronto to talk with your classmates
Contact your instructor or TA with questions, concerns, suggestions, etc.