Overview
Hi Class,
NO POINTS IF NOT SUBMITTED AS ONE FILE UPLOAD.
Here are the instructions for Lab 9 (last topo lab) dealing with Glacial and Arid climates.
Lab 9 starts on page 151 and we are starting with Deserts! Remember desert climate just means evaporation exceeds precipitation. So it does rain in the desert, but not a lot. So remember how erosion is the transport of rock/sediment by water, wind, and/or ice? The sediment doesn't get moved very far because there is not enough water to move it.
Page 152 Deserts:
- Answer questions #1-2
Page 153 Evolution of a Mountainous Desert Landscape:
Remember our evolution of a stream valley? This is much more straightforward. Look at Figure 9.2
[Image unavailable: arid landscapes.png]
In Early Stage there is a lot of "relief" meaning high mountains and low valley areas between the mountains. Remember there isn't a lot of rain here so every time it rains the rocks basically make it to the bottom of the mountain and stay there. That is an alluvial fan. Here I am on an alluvial fan in Death Valley National Park... Please don't laugh at the jean shorts... Notice the fan shape.[Image unavailable: alluvial_fan_closeup.jpg]Letter D on the topo map on page 155
In Middle Stage what happens is the rock/sediment that gets eroded from the high areas is deposited in the low areas. So see how the relief gets smaller. Remember relief is the highest point minus the lowest point. So middle stage there is less relief. Also remember there are no permanent streams here so that is why the sediment gets deposited in the low areas and just stays there. A Bajada is a bunch of alluvial fans that have joined together to make one huge feature.
Late Stage is where all the sediment from the mountains has been eroded and deposited in the low areas so see how it's FLAT. Remember flat is shown with closely spaced contours. And there would be very little relief (high point - low point). Sometimes these little isolated knubs (not sure if that's a word) or knobs of resistant bedrock stick up and they are called Inselbergs (letter C on the topo on page 155). Remember on a topo map hills are shown with concentric contour lines.
Page 154: Evolution of a Mountainous Desert Landscape: Use the above description and image below to answer the following questions:
- Question 3: use inside of your front cover in the lab manual
- Question 4: Highest point on the map - lowest point
- Questions 5-9 (use my map as a reference)
[Image unavailable: arid_map.png]
READY TO GET OUT OF THE DESERT AND GET COLD??? GLACIERS!!!!!
Page 157: Glaciers and Ice Sheets
Ok you have to read the paragraphs on page 156 to answer -
- Questions 1-3
I'm not going to sugar coat it - this glacial stuff isn't easy. There are a lot of definitions and features, but let's try - remember all of this is over at the end of July...
Page 158: Depositional Features of Glaciers. (AKA CONTINENTAL GLACIATION)
OK. I want you to think about how glaciers deposit sediment. I meet so many people that think around here in the Chicago area glaciers "carved out" the landscape we see today. Not quite. The ice that covered our area came down from Canada and it was thought to be about 3000 ft thick here in the chicago area. When it started to melt because of "climate change"- everything the glacier was carrying got dumped out. Think about how much sediment could be held up in a 3000 ft. glacier... a lot. And since glaciers are so thick they pretty much carry anything they want. A huge boulder or a small tiny piece of clay. They carry everything and when they melt - they dump it. Read through the definition on page 157-158 and use this image from Chapter 4:
[Image unavailable: depositional or continental glaciation.png]
- Questions 1-4: Use the above image or your textbook for reference
You will continue to use the above image when you look at a topographic map of Wisconsin so keep it handy.
Page 159-161 Depositional Features Associated with Ice Sheets
- Questions 4-12 (I'm going to explain on the map I provided below) And use the Figure 4.19 above or in your textbook
[Image unavailable: whitewater wisconsin.png]
I promise we are almost done. We have to look at Alpine or Valley Glaciers now. If you go to Alaska to look at Glaciers - this is what you see. Yes, we have a whole new bunch of vocabulary and definitions. Sorry!
Page 161 How Glaciation Effects Mountainous Topography
- Questions 1-3: (use my figure to answer)
[Image unavailable: alpine features.png]
Page 163: Identifying Glacial Features on a Topographic Map
This is it and then we're done with mega lab.
- Questions 1-4, 6,7
[Image unavailable: alpine topo.png]