12.4 Lab Exercise
Correct answer is letter ____
Correct answer is letter _____
3. Using Google Earth, search for the following area in Pakistan: 27 50 35.00N 67 10 03.70E. Zoom out to an eye altitude of approximately 25,000 feet. The inclined layers in these folded rocks can be easily seen. (You may find it helpful to tip your view; hold “shift” and hit the down arrow.) As you view them, in which compass direction are the beds dipping?
A. Northeast (NE)
B. Southeast (SE)
C. Northwest (NW)
D. Southwest (SW)
12.7 Practice with Block Diagrams
For each diagram, draw in the geological contacts on each side of the block. Add strike and dip symbols, and other symbols to document geologic features (like direction of movement on faults). Also state the name of the geology feature in the diagram (anticline, normal fault, etc.). If it is a normal fault or reverse fault, identify the hanging wall and footwall.
12.8 Lab Exercise
For each of the following block diagrams complete the following:
1. Complete the diagram drawing in geological contacts on each side of the block.
2. Add symbols indicating the strike and dip of each geological layer as well as symbols documenting any other geological features (include the direction of movement for any faults).
3. In the space provided under the block diagram write the specific name of the geology feature (normal fault, horizontal anticline, tilted layers, etc.) in the block diagram, and hanging wall and footwall (if appropriate). Please note that in several of the blocks the ages of the layers are provided.
Part C – Optional
At the end of the lab are two full-page block diagrams. Completing these are optional and you do not need to submit anything from this part.
The geologic map (page 307 of the lab manual) is from the Paleozoic rocks in the Northwest Georgia Mountains. Please refer to the key to rocks and their ages (page 306 of the lab manual) in order to answer the questions. Note that the rock key is in chronological order with the oldest rocks on the bottom (Conasauga shale) and the youngest rocks on top (Pennsylvanian Fm).
4. Examine the map and the ages of the rock layers. Based on your interpretation, label the structures and add appropriate symbols to the map to show the axis of the folds. What kinds of folds are present in this area? Explain how you came to this conclusion.
7. Search for 38 04 36.00N 109 55 26.61W and zoom to an eye altitude of 20,000 ft, make sure to note your geographic location.
a. You are looking at the surface expression of many fault lines (fault scarp) with the hanging wall occupying the valleys and the foot wall representing the plateaus. What kind of faults are they?
b. What would we call these paired features?
c. What type of stress created these features?
d. The amount of displacement (extension or shortening) in the area can be calculated by the following equation on the angle of the fault surface:
Amount of horizontal displacement = Vertical displacement along the fault surface (ft) / 5.67
Measure the change in elevation of one of these features to determine the amount of extension in the area. (Show your work, but feel free to use a calculator.)
e. How many of these faults would you need to make this area (Utah) a mile longer? (Remember these are 5,280 feet in a mile.)
8. Search for 22 48 45.63S 117 20 12.85E and zoom to an eye altitude of 25 miles. This feature is caused by the folding of rocks.
a. Imagine you are a geologist trying to determine what is going on in the area. How could you tell if this large bullseye structure is a dome or a basin? (State whether this is a dome or basin and give two different ways to tell them apart. Remember, this does not relate to if the elevation is raised or lowered in this area.)
a. Examine the feature ~10 miles southwest of the previous feature. Is this fold horizontal or plunging? How can you tell?