Lab 9 Exercises
Today, you will be learning the basic principles of geological mapping. In this activity you will learn to identify layers of rock, group them into mappable layers, and identify dip direction using satellite imagery in Google Earth Pro. The take-home assignment you will complete aims to link together all the topics covered in this lab to introduce you to geological mapping using satellite imagery.
Before you get started, download Google Earth Pro (free) for desktop. Web or Mobile versions are also available but they do not have all the features you will be required to use in this activity.
Instructions
Download the 1101 Lab 9.kmz file provided by your instructor. In Google Earth Pro, click File, Open and navigate to wherever you saved the downloaded .kmz file.
In the left panel you should see a list of places in this kmz file, double click on “Raplee Anticline”. We will begin by examining the Google Earth satellite imagery only, so uncheck the box next to “Mexican Hat Topographic Map”.
1. Examine the area around Raplee Anticline from an altitude of ~5 km. Write down any observations you have about this area.
2. Notice the different colours. What might these different colours represent?
3. Why are we examining this area to study bedrock geology? Why not look around Calgary? Why not look around Vancouver, BC?
Turn on the “Mexican Hat Topographic Map” layer by checking the box next to it in the Places sidebar. Make sure the map is 100% opaque (not transparent at all).
- To adjust the transparency, right click on the name of the layer in the Places sidebar, and select Properties.
- A dialogue box should appear. Click and drag the bar to adjust the transparency of the topographic map overlay.
Now that you are examining a topographic map draped over the 3D landscape in Google Earth, let’s review some concepts about topographic maps from Lab 8.
4. What units are used to show elevation on this topographic map?
5. What is the contour interval on this topographic map?
6. What do topographic contour lines do when they cross a stream? If you’re not sure, examine one of the streams to the northwest of the Raplee Anticline, but still on the east side of the San Juan River.
Adjust the transparency of the topographic map such that it is almost transparent but the topographic contour lines are still visible.
7. Examine the immediate area around the Raplee Anticline in plan view (remember, you can press r on your keyboard to return to plan view). What do you notice about the contour lines relative to the contacts? Hint: the contacts are the planes between layers of rocks of different colours.
8. Rotate the view to examine the area in 3D. Circle the correct answer: do these layers in the immediate area around Raplee Anticline appear to be horizontal, vertical, or dipping?
9. If you were to walk 500 m from Raplee Anticline, heading due west, would you be walking over progressively younger or older rocks? What principle of stratigraphy did you use to