Page 399 - Laboratory Manual in Physical Geology

A CTIVIT Y 14.1 Dryland Inquiry

Name: ____________________________ Course/Section: _____________________________ Date: ______________

A. When most people think of drylands and deserts, they imagine hot sandy landscapes. Most of the southwestern United States
is desert, including the Sonoran Desert of southern California and Arizona. However, most of the Sonoran Desert is rocky

landscapes. Sandy areas are present, but limited, like the Algodones Dune Field in FIGURE 14.1 . This is the location where

Star Wars producers filmed desert scenes of the film’s planet Tatooine.

1. Notice the sand dunes of the Algodones Dune Field in FIGURE 14.1 . Why do you think there are no plants growing on

the dunes?

2. Winds in the Algodones Dune Field can reach velocities up to 60 miles per hour. This can create hazardous conditions and
the need for maintanence on the canal and Interstate Route 8. What would be the hazard, and what maintenance would
be needed periodically on the canal and Interstate Route 8 as a result of the hazard?

3. This region is managed by the U.S. Bureau of Land Management as Imperial Sand Dunes Recreation Area. Portions of the

dunes are available for operating off-road vehicles. What effect do you think the operation of off-road vehicles here would
have on plant growth and the hazards you described above?

B. Death Valley, occurs in the Mojave Desert. Analyze the images of the Death Valley region in FIGURES 14.2 and 14.3 .

1. Notice in FIGURE 14.2 that steep mountainous slopes occur on both sides of Death Valley. Also notice that there is

almost no soil or vegetation on the slopes. Describe what you think conditions would be like in the river valleys on these
mountain slopes when a heavy rain falls on them.

2. Notice the delta-like landforms that form at the mouths of the rivers in FIGURES 14.2 and 14.3 , where the rivers enter the

valley. Explain how you think these landforms form.

3. Notice that there is no standing water in Death Valley, even though you can see that water sometimes flows into the valley

from the mountains. It is a closed basin (meaning that water has no way to drain from it). It is also the hottest and driest
place in North America. When there is water on the floor of the vally, it is alkaline to salty and not potable (drinkable).
How do you think the water gets so alkaline and salty?

4. Suppose you could walk down to the white patches on the floor of Death Valley in FIGURES 14.2 and 14.3 and examine

them. Predict what materials and conditions you would find there.

5. Residents of Furnace Creek have grassy lawns, trees, and potable water to drink. Why do you think their water is potable?

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