Assignment - Continental Scale Landscape Analysis

Continental Scale Landscape Analysis:
Introduction:
Landforms occur in patterns across the surface of the globe, and these landform complexes often
define geographic or landscape regions. One way of looking at landforms is through elevation
changes. A contour map is a useful two-dimensional representation of the surface and the most
common way we have of symbolizing the relief of the surface. However, a type of map called a
“shaded relief” map provides a more intuitive grasp of elevation.
Another way to understand landform regions or landscapes is to use a map that displays
information about the geology. A geologic map, has the following properties: It recognizes similarities and differences among materials that make up the Earth's crust
and classifies them by type of rock or surficial deposit; It places Earth materials into a specific environment or origin- for example, a volcano,
river deposit, windblown dune, limestone reef, alteration at depth by heat or pressure; It identifies rock formations of distinctive materials and ages that are the three dimensional building blocks of the Earth's crust; it further shows the relative position of
one formation to another at the Earth's surface; It arranges rock formations of different ages into a time sequence from which the
geologic history of the planet can be deciphered.
Can we use a map of elevation (and rock age) to identify large-scale patterns in the landscape?
What are the physiographic characteristics of North America?
Data and Methods:
You will need to:
1. Examine the maps in detail.
2. READ the materials that accompany the maps
3. finally (only after steps one and two are complete) Answer the questions!
The shaded digital relief map by Thelin and Pike is a classic map displaying a wide variety of
landforms. Thelin and Pike’s map uses digital elevation models to calculate the shadows that
would fall across the landscape. It is interesting to note that research has shown that the human
mind can most readily grasp the structure of the landscape when the digital sun is place in the
Northwestern sky (a condition that cannot ever happen in most of North America!).
Along with the maps, descriptive documents are provided. These documents are extremely
useful and several of the questions require you to read these documents.
The Thelin and Pike map is available on-line at:
http://pubs.usgs.gov/imap/i2206/
http://pubs.usgs.gov/imap/i2206/i2206_pamphlet.pdf
The 1974 Geologic Map of the US by King and Beikman has been merged with the Elevation
data in the Thelin and Pike map to form the geologic map we are using. This map, the
descriptive information about the map and various features (including a search function that
highlights various features) can be found at:
http://pubs.usgs.gov/imap/i2720/
Analysis:
Consider the following questions and answer them in your write up for this lab YOU WILL
NEED TO LOCATE AND USE AN OUTLINE MAP TO ANSWER THESE QUESTIONS. Some sort of coloring will also be useful to clearly identify the requested features. Please
indicate clearly in the text and on the map which questions are addressed where!
1. Examine BOTH maps, characterize the large-scale patterns. East/West? North/South
2. On your outline map, clearly identify areas of folding? How are folded ranges created?
3. In general, which direction do the rivers run?
4. Most of the Mountain ranges trend N-S. Identify on your map the mountain ranges that
trend E-W.
5. The Mississippi embayment is an area of flat land and very young sediments that show
where the Gulf of Mexico filled in much of the lower Mississippi valley. On your map
sketch and label the Mississippi embayment.
6. Crowley’s Ridge appears right through the heart of the Mississippi Embayment, label this
feature and suggest how it might have been formed?
7. Glaciers covered much of North America as recently as 11,000 years ago. Can you
identify landforms that are associated with the presence or melting of glacial ice?
Identify on your map the extent of the most recent continental glaciation.
8. How might the features of Coteau des Prairies be of interest to scientists trying to
understand Mars?
9. In general, where are the oldest rocks found?
10. On your map, locate the Michigan Basin and the Nashville Dome, do the ages of the
rocks have the same pattern in each feature (older-younger or younger to older?) Sketch a
profile of the structure of these features.
11. Locate the coastal barrier islands, what is the difference between east and west coasts?
(Mexico is not an ocean!)
12. Locate the Black Hills, describe their appearance, and speculate on the process that
created the Black Hills.
13. Identify on your map the basin and range province, how might it have been formed?
14. Sutter Buttes is plainly visible as a small but obvious ‘bump’ in the central valley of
California. What sort of event would produce an isolated and singular ‘bump’ like this?
15. Faults show up as straight lines, no other natural feature is as straight, identify on your
map what you suspect may be major fault zones, locate other linear features that may be
fault controlled structures.
Conclusions: Attach maps to your write up and label the features on the maps that help answer
the questions posed in this document.