Physical Geography

First, download PlateTectonics Activity Data.zip from this week’s module in Canvas. Browse and find the downloaded zip file (by default it is in the “download” folder of your computer unless you saved it to your own folder). Single right-click on the file and choose “7-Zip”→ Extract to “PlateTectonics Activity Data\” to extract the data.

Go to https://earth.google.com/web using a Chrome Browser (Note, IE will not work for google earth web). Take a moment to familiarize yourself with the main interface. You will need to use the “Menu” button and the “Search” button at the upper-left corner.

Click on the “Menu” button and sign in with your student google e-mail account. You may also use other google account you have.

After signing in, go to “Settings” below your account name and turn on the “Enable KML file import (experimental)”. Click on “SAVE”.

Go to “Menu” → “My Places”. Click on “IMPORT KML FILE” and choose “Open file…”. Then browse to your “PlateTectonics Activity Data” folder and import the following files:

· Plate boundary model.kmz

· Volcanoes of the World.kmz

· Seafloor Age.kmz

When the files are successfully imported you can see them listed in the panel of “My Places”. You may turn ON/OFF the visibility of those layers by clicking on the “eyeball” button right beside the file name.

Part 1: Examine the seafloor age.

Seafloor age is a critical piece that has been used to reconstruct how ocean basins have developed over time and predict how they may evolve in the future. Go to “Menu” → “My Places”. Turn on the “Seafloor age” layer and keep the other two layers invisible. Your “My Places” panel should be like the screenshot shown below.

Minimize the “My Places” panel and you will see the legend of Seafloor Age at the upper-left corner. Navigate to the Atlantic Ocean and study the seafloor age pattern in the ocean:

1. What is the spatial (physical) relationship between the seafloor age bands (indicated in different color codes) and the Mid Atlantic Ocean Ridge?

2. How would you describe the change of seafloor ages as you move away from the central line to the margin of the Atlantic Ocean?

3. Given the pattern of the seafloor age, how would you explain the development of the Atlantic Ocean?

Patrich Physical Geography Activity | 2

Part 2: Examine tectonic plate boundaries and land features.

Go to “Menu” → “My Places”. Turn on “Plate Boundary Model” layer.

Expand the “Plate boundary model” folder under the layer name, and click on the info button “i” by the “Plate Boundaries” folder (Figure 2). You will see the color codes for plate boundary lines shown on your screen.

Navigate around the Earth, and identify the type of tectonic plate boundary, Convergent, Divergent, or Transform, at the following locations. Please circle the best answer. You may use the search tool to help navigation.

•

Aleutian Trench on the ocean floor near Alaska:

Converge/Diverge/Trans

•

Himalaya Mountains between Nepal and Tibet:

Converge/Diverge/Trans

•

Ryukyu Islands in Southeast Asia:

Converge/Diverge/Trans

•

Mariana Trench between the Pacific Ocean &

the Philippine Sea:

Converge/Diverge/Trans

•

Java Islands:

Converge/Diverge/Trans

•

Iceland:

Converge/Diverge/Trans

•

East Africa Rift Valley:

Converge/Diverge/Trans

•

Along the coastline of Peru-Chile:

Converge/Diverge/Trans

•

San Andreas Fault:

Converge/Diverge/Trans

Part 3: Volcanoes of the World

Go to “Menu” → “My Places”. Turn on the “Volcanoes of the World” layer. You may turn off the “Seafloor Age” if it is too overwhelming.

4. Study the spatial relationship between the locations of volcanoes and the tectonic plate boundaries. On which type(s) of tectonic plate boundary you may find active volcanoes?

Patrich Physical Geography Lab | 3

Connecting the Dots
Once data is collected and plotted, making a map is similar to connect the dots. Below is a sample diagram of elevations, some odd, some even. It is your job to connect the dots. Sometimes you will find that there may not be enough of the numbers you are looking for- that is where you have to figure out where that number belongs.

First- Dot the spot where the number belongs. The more dots you place, the better the accuracy of your map.

Second- Connect the dots of like elevation.

Below I have completed the 40ft contour, you need to next connect the dots. You will then repeat those steps for the following contour lines: 35, 30, 25, 20, 15, and 10.

How to Use an Auto Level

Terms:

· Backsight: A point of known elevation and location. Otherwise known as a BS, a backsight is recognized as a benchmark.

· Foresight: A point with no known elevation. Otherwise known as FS.

· Height of Instrument: The height of the Auto Level—found after the rod is placed on a BM, then adding the height read from the rod to the known elevation. Otherwise known as HI.

· Bearing: Degrees read from compass. EG 136*

Math Notes & Practice

PS. Check your math. BS values between the horizontal plane & stadia are always equal!

Formulae:

· HI=BM+BS

· Distance=(Stadia A – Stadia B) x 100

· Elevation= HI-FS

How to Make a Map

The next step in surveying—is putting it together as a map. With the data, we have a permanent station, the distance and direction of each ‘shot’, and plotting this data as a map simply requires the use of a paper, protractor, ruler and pencil. The data collected represents the perimeter of a sand sheet, (that is why the elevations are so constant).

For this activity, the cartographer decided that it would be best to convert the data as: 1 cm=2 meters. This will be helpful so that out map will not exceed that of the paper we are drawing on. I have completed stations 1, 4, 8 and 16. Your job is to complete the remaining stations—and then to ‘connect the dots’. Your final map will show the perimeter of a sand sheet within the Keeler dune complex, in Owens Valley.