City of Mesa, AZ

Removing a Fossil

 

This series of drawings demonstrates the process of removing a typical large fossil from the field. In this case the fossil is a partial mammoth tusk.

Image of Step 1

1. The fossil is discovered. Erosion has removed enough surrounding rock or soil to partially expose our fossil.

Image of Step 2

2. Scientists carefully expose the fossil using a variety of hand tools. They take measurements, record spatial data, and make a map. Although not shown in the drawing, the fossil may be given a protective “cap” of plaster at this point to prevent damage as excavation continues.

Image of Step 3

3. Paleontologists expose the tusk even further, in preparation for plaster jacketing. Excavators have dug a trench around the fossil and it now sits on a pedestal of rock.

Image of Step 4

4. Excavators cover the fossil tusk with moistened tissue paper, which will act as a barrier between the fossil and the plaster.

Image of Step 5

 

5. Excavators wrap burlap soaked in plaster around the fossil. When dry, the plaster hardens into a shell that protects the fossil during transport.

 

Image of Step 6

6. Next, one carefully tunnels under the fossil and quickly flips it off its pedestal. This is usually the most delicate and dangerous part of the excavation.

Image of Step 7

7. After excavators flip the fossil, they apply plaster burlap strips to the exposed rock matrix to completely encase the fossil. We have successfully made a plaster jacket.

Image of Step 8

8. After the plaster has hardened, we can prepare our fossil for transport. We can now move the fossil by sling, sled, or, if we are lucky, by vehicle.