GEL 1008: Lab 12 help

GEL 1008
PHYSICAL GEOLOGY

Physical Geology Helpful Lab Hints

Exercise 12: Arid Climate Landscapes

Problem 1

Alluvial fans are discussed on p. 231 in the lab book and in Section 13.12 in the textbook.
Use the figures and descriptions in the lab book to determine what these features would look like. Use the key to topographic maps (p. 104) to identify how those features would be depicted on the map.
Use this image to help find some of the features referred to in parts a, b, c, d

See lab book figure 12.5, p. 234
Observe what happens to a stream channel as it leaves the mountains.
- Hypothesis: Why does this happen?
- Test: How could you check your hypothesis? What kind of evidence or observation might support it?
- Hint: We did something in lab with sand and water...
Of the light, gray, and dark areas, which are old, middle-aged, or young? What will an area look like if it is freshly eroded or newly deposited?
Which areas are the most recently active? What color are they on the photo? (see 1.c.)

Problem 5

& b. See lab book figure 12.8, p. 232
Graphing! Click here for help with graphing.
- The graph and data table are on p. 243
- Set up the graph as indicated on this image (the first three dunes have been plotted).
- Does the data show a trend? If so, you should be able to imagine a "best fit line." Note: this is not "connect the dots;" it is a trend.
- The trend indicates a relationship between the two parameters; what is the relationship?
Fun with math!
- Rate = Distance/Time
  - Distance = 152 m (from the table on p. 243)
  - Time = 7 years
1. Measure the distance from dune 9 to the road in centimeters (see image)
2. Convert to ground distance using the scale. (1:20,000)
  - 1 cm = 20,000 cm
  - 1 cm = 200 m
3. Rate = Distance/Time so Distance = Rate X Time
  - Rate = (what you calulated for d.)
  - Time = 2000-1959
4. Rate = Distance/Time so Time = Distance/Rate
  - Distance = (what you measured and then calculated in parts 1 & 2)
  - Rate = (what you calulated for d.)
  - The year the dune reached the road is 1959 + the time you have just calculated.