Lesson 10: Subduction Zones II: Sierra Nevada and Alpine Glaciation

This week's lesson, like lesson 9, focuses on parklands that give us windows into the processes that take place at subduction zones. This week, however, we'll consider the rocks formed by the roughly ninety percent of subduction zone magmas that do not reach Earth's surface. Instead of erupting to build volcanoes, these magmas cool and crystallize slowly underground to form bodies of coarse grained granite and diorite that may later be exposed by uplift and erosion. In many cases this erosion is accomplished in part by alpine glaciation, so we'll also examine this process and how it has shaped the landscapes of California's Yosemite and Sequoia-Kings Canyon National Parks.

As you read through pages 123-125 of chapter 5 and browse through the websites below please take careful notes so that you can keep track of major points and recall them more easily when we refer to them later in the semester. Be sure that you are prepared to meet the learning objectives outlined below before you move on to the exercise and quiz near the bottom of the page.

Weekly Learning Objectives

Upon successful completion of this week's lesson, a student is expected to be able to:

Reading and Browsing Assignment

Exercise 10 (Due by 9:00 AM on Monday, 29-Mar-2010)

After you have read about glaciers and glaciation, please load up your Hazard City CD and work through version 1 of the Snowpack Monitoring exercise. (Okay, we're only talking about snow and not glaciers in this exercise, but it's a start!) Pay careful attention to the approximate dates at which snowmelt begins and ends at each site when you review the SNOTEL records, and be sure to jot down any notes that might help you remember why you made the decisions you did. (I suggest printing the form provided, filling it in, and then adding any notes that might be helpful.) Finally, go to the Etudes "Assignments, Tasks, and Tests" tool to complete Exercise 10. There are 5 questions (just as in the report) and each is worth two points.

Quiz 10 (Due by 9:00 AM on Monday, 29-Mar-2010)

After you feel you have met the learning outcomes outlined above, please complete Quiz 10 in the Etudes "Assignments, Tasks, and Tests" tool. There are ten questions, each worth one point. If you can answer all of them correctly it means that you know your way around the "roots" of volcanic arcs and alpine glaciation pretty well and are ready to move on to learn about parklands formed at collisional convergent boundaries next week.