The Iron Range

Title: Drawing of Iron Bearing Rocks
Type: Art
Date: 1894
Source: Josiah Spurr

Description: This drawing came from The Iron-Bearing Rocks of the Mesabi Range in Minnesota, a book that Spurr wrote in 1894.

Activities:

1. In the first image, the iron is in the outer layer of the rock. Why isn't it in the middle too?
   
   
   
   
   Answer: In this example the iron soaked into the rock, probably because the rock was in iron filled water. But the water couldn't soak through all of the rock.
2. In the second image the iron has spread to some parts of the rock, but not to other parts. How might this have happened?
   
   
   
   
   Answer: In this case the iron-rich water has seeped into small cracks in the rock and left the iron inside.
3. The last image has many layers of iron and rock. How might this have occurred?
   
   
   
   
   Answer: This is probably a piece of a much larger rock. Here layers of sediments like sand and iron ore took turns covering each other. Over a long period of time the weight of the sediments pressed the layers together to form rock.
4. From the answers above, what are some of the things that you need to have in order to form rocks with iron in them?
   
   
   
   
   Answer: You need iron dissolved in water, and then rocks or sand. Of course, if all you had was iron, then the rocks would be made totally of iron powder.