Add (with appropriate labels) the following features to the generalized cross section (note that the vertical scale below the sea level is not the same as the vertical scale above sea level):
1. A presently active subduction zone ( SZ). Indicate:

   a. the direction of motion within the subduction zone;

   b. the region where magma is generated and moves to the surface;

   c. the direction of motion of the Eurasian and Pacific Plates.

2. A midocean spreading ridge (MSR). Indicate the direction of motion of the two plate boundaries on either side of the ridge.

3. A back arc basin (BAB) and a deep sea trench (DST).

4. The boundary between oceanic crust and the upper mantle (OMOHO).

5. The boundary between continental crust and the upper mantle (CMOHO).

6. The boundary between the lithosperic plates shown and the underlying asthenosphere (L/A). Assume the plates are ~ 100 km thick.

7. A site of currently active basaltic volcanism (BV).

8. Two sites of currently active rhyolitic-dacitic-andesitic volcanism (DV).
   

Use the information in the generalized cross section and scheme of Appalachians evolution to answer the following questions.

9. Sandstone, shale, and limestone were being deposited on older continental basement in Minnesota during the Paleozoic. At the same time, as illustrated in the scheme of Appalachians evolution , an ancestral Atlantic Ocean was being subducted beneath the east coast of North America. Layeres of volcanic ash have been found in the Paleozoic limestones in Minnesota. If this ash came from volcanoes in eastern North America as illustrated in the generalized cross section, would you expect it to contain fragments of Ca-rich fieldspar (white) or potassium fieldspar (pink)? Using Handout 4 and Handout 7, explain your answer.

10. Based on your knowledge of the Archean and Proterozoic geology of Minnesota, what rock types would you predict would be intersected in drill core if deep drilling (10-20 km) were attempted in the middle of the North American continent? Indicate with cross section patterns and an appropriate legend the different rock types and their structural and stratigraphic relationships on the generalized cross section .

11. Note that the very large Eurasian Plate is found at both ends of your cross section (This could not be the case on a flat Earth!). Also, the Juan de Fuca plate is being squeesed in a northeasterly direction between the North American and Pacific Plates. Ignoring this complexity in the cross section, are the directions you indicated for the Eurasian Plate in questions 1 and 2 consitent with a continuous plate from Japan to the North Atlantic? Yes / No.