Complete Lab 9 before you attempt this assignment.
After completing this take-home activity, you should be able to:
- Draw a geological map from satellite imagery, including all required cartographic elements and symbols to indicate dip direction.
Geological Map of Sheep Mountain
As a take-home assignment, create a hand-drawn geological map of the northern part of Sheep Mountain in Wyoming. This map area has been outlined in the 1101 Lab 9.kmz file for you to examine in Google Earth Pro, and is located on the homelands of Arapaho, Arikara, Bannock, Blackfoot, Cheyenne, Crow, Gros Ventre, Kiowa, Nez Perce, Sheep Eater, Sioux, Shoshone and Ute tribes. Sheep Mountain was selected for this activity because of the clear colour contrasts in the rocks, and because this area has very little vegetation to obscure your view of the rocks. Both of these features make it possible for you to actually map the bedrock geology based solely on satellite imagery.
The purpose of your geological map is to show your reader where different geologic units are exposed at the surface of the Earth. These units will be defined by you based on differences you observe in the satellite imagery.
Instructions for creating your geological map
1. Examine the area you will be mapping (Sheep Mountain Map Area).
2. In Google Earth Pro you can navigate to this area, saved as a polygon called “Sheep Mountain Map Area” in the 1101 Lab 9.kmz file. Spend some time examining the features of this area using the 3D capabilities of Google Earth Pro.
3. Attach a piece of tracing paper to your printed satellite imagery with a paper clip or piece of clear tape. Be gentle; tracing paper tears easily! Be very careful when erasing!
4. Set up your map area. Make sure that you have enough space on your tracing paper set aside for your legend and other cartographic elements (review the checklist below). You may also format your legend on a separate piece of paper.
5. As you examine the base image and explore the map area in 3D using Google Earth Pro, decide how many different units you wish to include on your map. Remember, any geological map requires some degree of “lumping” (grouping together layers of rocks with something in common) or “splitting” (separating layers of rock into distinct units to be mapped separately). Your map must have at least four, distinct units. Think about how you would briefly describe each of your units in the legend of your map. In this case because you are working only from an image and cannot reliably identify lithology, your description will likely focus on the colour of the rocks.
6. With a pencil, lightly and neatly draw in the contacts that you see between different units in the satellite imagery. The contacts (lines) that you draw around a particular area will delineate a polygon that contains a rock unit. Once you are confident with the contacts you have drawn, trace over them in black pen.
7. Colour in and write a map code inside each polygon. Keep track of the colours and map codes that you use on a spare sheet of paper to help format your legend once you have finished your map.
8. Review the checklist below and ensure that your finished map contains all the required information.
9. Scan OR take a clear photograph of your finished map to submit. It is your responsibility to ensure that your submission is legible. If your instructor cannot read your work, they cannot mark it!
10. Submit your finished map on Blackboard.
|At least four distinct units mapped and neatly coloured
|Rivers or streams
|Legend (includes the colour, map code, and a brief description of each of your units. Remember that the legend on a geological map always list the oldest unit at the bottom and the youngest unit on top! How can you determine which of your units is the oldest?)
|Contacts between units drawn in black pen
|Roads (if any)
|Black arrows to indicate dip direction on the NE and SW sides of the mountain
|Scale as representative fraction
|Reference point in UTM coordinates
|Date of satellite imagery and source of satellite imagery
|Author’s name (your name)
- 1101 Lab 9.kmz file © Siobhan McGoldrick. CC-BY-NC-SA 4.0. Derivative of Kmz file of placemarks for other structural mapping examples © Barbara Tewksbury, Locations in Google Earth for teaching geologic mapping and map interpretation, used under CC-BY-NC-SA 3.0.
- Sheep Mountain Map Area satellite image used under the following Google Maps and Google Earth guidelines.