Field Trip to the Laramie Range, Vedavoo.

Leave parking lot to NE of Geology building at 9:35. Head out past Walmart to I-80, and go (east) up the freeway to Vedavoo exit. Go under the freeway and follow signs to Vedavoo glen rec area. First stop (mainly to get everyone together) will be at the information sign on the left, just after the cattle guard, just after the freeway underpass. From there we will go to Box Canyon area in Vedavoo.

Things to look at, on the way. (You travel from recent sediments in Laramie, to Limestones and Sandstones in the I-80 canyon, and finally to Granites and other igneous rocks at Vedavoo.)

As you go up the freeway, up the canyon to the Lincoln Memorial at the summit, look at the valley sides.

1. What is the angle of the valley slopes? Are they relatively straight, or are they convex or concave upwards?

2. Where do all the large blocks come from, that are lying on the slopes (most easily seen lower down the canyon)?

3. Look hard at the road cuts through the Casper Sandstone (red banded rocks). Look at the gradation from solid rock, to broken rock, to sand and then soil and organics as you look up through the profile from rock to ground surface. Is this depth from rock surface to ground surface approx. constant or does it vary? What determies the depth of the soil profile?

4. When you get past Lincoln, why do the trees end? Why is the land flatter and the curvature of the hills/valleys much less than in the canyon?

5. Look for surface changes that reflect the underlying bedrock changes.

6. Finally, on the drive across the high flats to the exit, try to see a pattern (on the scale of 10m or so) to the ground surface. Do you see a low relief pattern?

When we get to Vedavoo.

We will mainly be looking at small scale features, but you should also look at the rocks and ask a couple of big questions.

1)How did the formations get here? Why do they stick-up out of the ground?

2)What is the major erosion agent on the rocks? (And on what time scale.. 1 year, 100 years, 10,000 years? Are they the same?)

3)What makes "mushroom" rocks?

4)Why don't the balanced rocks fall? How steep a slope can rocks just sit on?

Small scale questions:

1. What is the soil made of?

2. Scrape the surface on both a small rise and in a micro valley. Is the soil different? Why.

3. Why is the surface of the soil coarser in many places.

4. Why is the upper surface of the rocks the least weathered and loose?

5. Note the subtle effects of vegitation on the erosion of the land surface. Why does the vegitation create high points in the local topography?

6. Look at the local slopes on the meter scale. What are the profile shapes, concave upwards or downwards? Symetric? What are the slope angles?

7. Look for some "alluvial fans"

On the way out of the Vedavoo area, on the straight section of road paralleling the freeway, you will some "rills" on the low road cut on the south side. Just look at them as you drive by.