1. A Simple Plate Tectonics Model
2. Mapping Plate Tectonics
3. The Rock Cycle
4. Virtual Field Site Questions
5. Checklist For Your Lab 4 Diagrams

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For parts II and III, Mapping Plate Tectonics and The Rock Cycle, you will make drawings. Mail your drawings to the instructor at

Ralph Dawes PNW
Wenatchee Valley College
1300 Fifth Street
Wenatchee, WA 98801

I. Plate Tectonics Model

In this section of the lab you will use a triangular paper cutout to represent a tectonic plate and the way it interacts with the plates along its boundaries. You will draw a plate tectonic map based on the model that shows all three types of plate boundaries. You will also use the triangle and plate tectonic map as a simplified model of the Plate Tectonics of the Pacific Northwest.

Use a ruler or straight edge to draw a triangle on a blank piece of paper. Make the triangle approximately 6 inches long on each side. Label the triangle A, the paper surrounding the triangle B, and number the sides of the triangle, as in the diagram below. Carefully cut the triangle out, leaving it and the paper it is cut out of with clean, straight edges. Do not cut through the paper around the triangle to get to the triangle. Leave the paper around the triangle intact.

The triangle, A (see diagram below), represents a moving plate. It is surrounded by one or more other plates, labeled B. To run the plate tectonic model, start with the triangular plate, Plate A, in place inside its triangular hole. Reach beneath the right side of Plate B to grasp the bottom right corner of the paper triangle. Slowly pull the triangle straight to the right, beneath the edge of Plate B at boundary 2.

Use the correct plate tectonic terminology in answering the following 6 questions. Answer each of the 6 questions with a single word.

1. What are the two plates doing at boundary 1?
2. What kind of plate boundary is boundary 1?
3. What are the two plates doing at boundary 2?
4. What kind of plate boundary is boundary 2?
5. What are the two plates doing at boundary 3?
6. What kind of plate boundary is boundary 3?

II. Mapping Plate Tectonics

7. Refer to the plate tectonic boundary map symbols in the Table of Plate Tectonic Boundaries. Refer to the triangular plate tectonic model that you cut out and ran in Part I of this lab assignment. Draw a plate tectonic map of the triangular plate and its surrounding plate(s). Use a ruler or straightedge to draw the plate boundaries as straight lines. In your drawing, use the proper map symbol for each type of plate boundary.
   
   Keep in mind that the tectonic map symbol for each type of plate boundary is not some symbol that goes on the map separate from the plate boundary itself. Wherever it is used on the map, the symbol for each type of plate boundary becomes the complete plate boundary itself.
   
   
8. The triangular plate (A) and the surrounding plate(s) (B) can be thought of as a simplified representation of the Juan de Fuca Plate and its surroundings. Label the following on your plate tectonic map (see previous question):
   
   * Juan de Fuca Plate
   * North American Plate
   * Pacific Plate
   * Juan de Fuca Ridge
   * Cascadia Subduction Zone
   * Mendocino Transform

• Also on your map, at the location of the Cascade volcanic arc, draw a sequence of triangles to represent the chain of composite cones.
  
• Note that you will not be mailing in the cut-out version of the plate triangle from Part I. You will mail in for grading the plate tectonics map you made and labeled for Part II.

III. The Rock Cycle

9. Draw a more detailed version of the rock cycle. Split the boxes for igneous rock, sedimentary rock, and metamorphic rock into two halves, and label the halves plutonic and volcanic (for igneous rock), clastic and chemical (for sedimentary rock), and regional and contact (for metamorphic rock).
10. Draw labeled arrows showing how geological materials are transformed from one box to another in the rock cycle. For example, draw an arrow going from magma to plutonic igneous rock labeled "slow cooling and crystallization within the earth," or "cools and solidifies slowly, underground," or something like that. Label all the arrows.
11. Refer to the numbers of the rocks in your Pacific Northwest Rocks kit. Write the number of each sample (numbers 1 though 9) in its appropriate box in the rock cycle. For example, the number for basalt would go in the volcanic igneous rock box in your rock cycle diagram.

IV. Virtual Field Site Questions

Tour the Tatoosh Range Virtual Field Site and answer the following questions.

12. What is the age sequence of the following three rocks (from oldest to youngest]): Tatoosh Pluton granodiorite, Mt. Rainier andesite, Stevens Ridge Formation dacite? Write the sequence from oldest (first) to youngest (last).

Think of the rock cycle as having six rock categories (along with magma and sediment, which are part of the rock cycle even though they are not categories of rock):

• plutonic igneous rock
• volcanic igneous rock
• clastic sediment
• chemical sediment
• clastic sedimentary rock
• chemical sedimentary rock
• regional metamorphic rock
• contact metamorphic rock
• magma

State which category each of the following three rock types are and state how each was transformed from its preceding category.

*Note: To describe how a rock was transformed from its preceding category, choose one of the following processes:

• cools and crystallizes slowly underground
• erupts and solidifies rapidly on the surface
• weathers, erodes into solid bits and pieces, is deposited
• weathers, dissolves, precipitates
• is lithified by burial, compaction, and cementation
• recrystallizes due to heat and pressure from deep burial and tectonic forces
• recrystallizes due to heat from a nearby body of magma

Tour the Hurricane Ridge Virtual Field Site and answer the following questions.

22. What type of plate tectonic boundary has caused rocks from the ocean floor to become mountains on the edge of the continent?

Think of the rock cycle as having six rock categories: plutonic igneous, volcanic igneous, chemical sedimentary, clastic sedimentary, regional metamorphic, and contact metamorphic, along with the categories magma and sediment. State which category each of the following three rock types are and state how each was transformed from its preceding category.

**Note: To describe how a rock was transformed from its preceding category, choose one of the following processes:

• cools and crystallizes slowly underground
• erupts and solidifies rapidly on the surface
• weathers, erodes into solid bits and pieces, is deposited
• weathers, dissolves, precipitates
• is lithified by burial, compaction, and cementation
• recrystallizes due to heat and pressure from deep burial and tectonic forces
• recrystallizes due to heat from a nearby body of magma

Checklist for Lab 4 Diagrams:

1. You are sending in a MAP of the triangular plate model, NOT the cut-out plate model itself.
2. The plate boundaries on your map are symbols. In other words, the symbols for plate boundaries on the map are not off to the side of the plate boundaries; the symbols ARE the plate boundaries.
3. You show the Cascade volcanic arc as extending only where subduction is occurring, parallel to the convergent plate boundary and not past the ends of the convergent plate boundary.
4. Your rock cycle is an advanced, detailed rock cycle with nine categories (including both types of sediment), NOT the simple rock cycle you can find on the Web with five categories. Your advanced rock cycle labels ALL processes, including:
   • how each of the two sub-categories of igneous rock form
   • how each of the two types of sediment form
     (both types of sediment turn into sedimentary rock the same way,
     so only one process is needed to get to the two types of sedimentary rock)
   • how the two types of metamorphic rock form.

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