Predicting Weathering!

Name_______________

Period_____

Date_______

Objectives:

• To compare and contrast chemical and mechanical/physical weathering.

• To determine the factors which promote chemical weathering.
• To predict where chemical weathering will occur on a specific continent.

Procedure:

1.      Internet Research!  Use the following links to answer the following problems.  You can complete your own Internet search, but these links will provide you with enough material to answer all the questions.  Some links are basically the same:

http://www.gpc.edu/~pgore/geology/historical_lab/weathering.php

http://grunwald.ifas.ufl.edu/Nat_resources/weathering/weathering.htm

http://www.soils.wisc.edu/courses/SS325/weathering.htm

http://geoweb.tamu.edu/courses/geol101/grossman/Weathering.pp.html

http://www.tulane.edu/~sanelson/geol111/weathering.htm

http://www.stonecaretechniques.com/8_m.htm

http://ruby.colorado.edu/~smyth/G101-6.html

http://www.geog.ouc.bc.ca/physgeog/contents/11b.html

http://lists.uakron.edu/geology/natscigeo/Lectures/weath/weath.htm

http://courses.smsu.edu/ejm893f/creative/glg110/Weathering.html

http://pasadena.wr.usgs.gov/office/ganderson/es10/lectures/lecture11/lecture11.html

http://www.geosci.unc.edu/faculty/glazner/Images/Weathering/weathering.html

·              Briefly describe weathering.

·              What is the difference between mechanical/physical and chemical weathering?

·              How is weathering related to erosion?

·              What is the difference between erosion and weathering?

·              Describe the types of chemical weathering. 

·              Give an example of a chemical weathering reaction.

·              What are some landscapes associated with chemical weathering?

·              How are soils and weathering related?

·              What are the controlling climatic factors for chemical weathering?

·              What two climatic conditions would be necessary for high amounts of chemical weathering?

2.      GIS Project!  ****Important:  Save your project often!!!!!!!***********

·        Choose a continent to predict weathering (do not choose Antarctica)

·        Open ArcCatalog and connect to your data location.

·        Browse through your data.  Use the preview tab.  Describe the data you have.

·        Create a “Weathering” Folder on your G Drive.

·        Copy and paste any data that you might need to your newly created “Weathering” folder.  ***it is important to copy, paste, or move GIS data using ArcCatalog.  Each file has associated files that need to be included or ArcMap will not be able to read them.  ArcCatalog automatically transfers all necessary files when you copy, paste, or move any GIS data from one location to another.

·        What data do you need to predict where weathering might occur or not occur?

·        Open ArcMap using the toolbar in ArcCatalog.

·        Once ArcMap opens, create a “new empty map.”

·        Under “tools” go to “extensions” and make sure 3D Analyst and Spatial Analysis are checked.

·        Under “view” and “toolbars,” make sure 3D Analyst and Spatial Analysis are checked.

·        Add your desired maps by clicking “Add Data”.

·        Select the data you want to view.

·        You will notice that any new map you add is placed over your previous map.  You can change the order of your maps by dragging and placing your maps.  You can also turn the layers off by unchecking the box to the left of the layer. 

·        Make sure you are comfortable checking an unchecking layers as well as dragging and moving layers above others.

****Important:  Save your project often!!!!!!!***********

·        Select the  button and click on any portion of your map.  You will get an “Identify Results box that will tell you any data at that point.      In this example you can view data such as the area, perimeter, low temperature, and high temperature.  Make sure you know how to do this.

·        Practice using the “zoom in” tool to zoom in on a selection of your map.  You will be able to see areas that might be too cluttered at your current scale.

·        Select the  or back arrow to return to the full or previous scale of your layer.

·        You now should have your layers in your desired order.  Now you need to manipulate the layers to predict where weathering might occur.  You should have already come to the conclusion that high precipitation and temperature are your two qualifiers for high rates of chemical weathering, but where are those places?  You can visually look for those places or you can mathematically determine those locations.  Your layers are known as “features.”  Each polygon or area has attributes that are unique to that specific area.  There will be locations with high temperatures, but low precipitation.  What is better?  Low temperature and high precipitation or high temperature and medium temperature?  Create a mathematical model to determine this.

·        You will need to “reclassify” your layer to a raster layer that only represents certain numbers based upon your number of divisions.  To do this, click on  “Spatial Analysis, Convert, and then Features to Raster.       

·        You will then need to  make sure your input feature is the layer your desire to convert, make sure the field is the field you wish to convert (probably temperature or precipitation, not area), do not mess with the output cell size yet, and then make sure your output raster will be saved in the right location.  Press OK and the computer will take a while, but convert your layer to a raster layer.

·        Uncheck your other two layers so you can see your new layer.       

·        You will see that your new layer is now color coded into divisions according to the criteria you selected.

****Important:  Save your project often!!!!!!!***********

·        You will want to choose three divisions instead of the multiple divisions that ArcMap gave you.  To do this, right click your layer and choose properties. 

·        You will then need to select the tab “Symbology “ and then show “Classified.”  Choose three classes and the color scheme you want and then select apply. 

·        Your new map will only have three colors representing three ranges of temperature or precipitation.                                                                                               

·        Repeat those steps for your other layer. 

****Important:  Save your project often!!!!!!!***********

·        In order to use your mathematical model, you will need to reclassify your divisions into the same numbers for your precipitation and temperature layers.  To do this, select spatial analysis and then reclassify.

·        You will want to assign new numeric values to your former values. 

·        Press OK and you will get a new layer called “reclass. of polygonx.

·        Do the same for your other layer and uncheck all other layers that are not reclassified.

·        You are just about done!  Now you need to do a simple calculation using spatial analysis.

·        Double-click the layers you want to calculate and click the function and then select evaluate.

·        You will get a new layer that assigned numerical values for areas of high through low chemical weathering.   You can expect that chemical weathering will not occur in areas with a value of zero and more than likely occur in areas that have values of four.

·        Change the colors and make the layer aesthetically pleasing (eye candy).

·        Now you are ready to publish your new map.  To do this, select “view” and then “layout.” 

·        Use the “Draw” toolbar to add text and other features (such as your name)

·        You can insert legends, scales and other labels to make your new map complete.

·        When your project is complete, print it.  But make sure the paper size is correct and it is printing to the correct printer.