Florissant Fossil Beds National Monument Stratigraphy is the study of rock layers (called beds) and their ages in relation to each other. The law of superposition (one of the Principles of Geology) tells us that any rock layer lying underneath another must be older than the one above. And any layer lying above another must be younger than one under it. Basically, the oldest rock sits at the bottom and the youngest is at the top. You will need:
You can replace any of the food items you don't have or don't like with something else. Just make sure that you have different items to represent each rock layer. In order to study formations (groups of related rock layers found in an area) in detail, geologists make a stratigraphic column. A stratigraphic column is a diagram of the different rock layers and how they are stacked on top of one another. In this activity you will make your own "stratigraphic column" with your sandwich. 
Florissant Fossil Beds National Monument InstructionsAt Florissant Fossil Beds, geologists a stratigraphic column of the Florissant Formation to help them understand the sequence of geologic events that happened 34 million years ago. The Florissant club sandwich starts with the Wall Mountain Tuff. 37 million years ago a caldera collapsed about 50 miles away from Florissant. This sent a cloud of super-heated ash, gas, and debris like a hurricane rushing through the valley. This created the welded tuff. Step One:Put a slice of wheat bread (or whatever you are using instead) on the plate. This represents the Wall Mountain Tuff. The Wall Mountain Tuff is the oldest rock layer in the Florissant Formation so it is represented at the bottom. The rest of the layer will be stacked on top of it with the youngest layer at the top. Fossils can be incredibly helpful to geologists finding the relative age of rocks. Paleontologists can often develop an idea of how old a rock layer is by identifying the fossil types found in it. A few of the next rock layers we look at can be identified and their age estimated by the fossils found within them. Step Two:Put the lettuce on the first slice of bread. This represents the fossil plants found in the Lower Shale Unit. The Lower Shale Unit is the oldest of the shale deposits. It lies well beneath the other shale units because it was deposited well before them. Step Three:Use the diagram of the Florissant club sandwich and the stratigraphic column of the Florissant Formation to make the rest of the sandwich. Keep reading for the story of each layer and how it was deposited. As you make your sandwich remember, the oldest goes at the bottom and the youngest goes on the top. The first Ancient Lake Florissant was formed in the Florissant Valley. This lake deposited the Lower Shale Unit. The lettuce represents the various fossil plants found in this unit. Later on, the lake drained out and giant redwood trees took root. These massive trees grew along a creek that ran through the valley. Then a volcanic mudflow, called a lahar, covered the bottoms of the trees. Over time this preserved the giant petrified stumps now found on the Petrified Forest and Ponderosa loops at Florissant Fossil Beds National Monument. Step Four:Look at the Florissant club sandwich diagram to see how the layers should be ordered. Once the sandwich is made use the plastic knife or popsicle stick to carefully cut it in half. Now you have a cross section of your sandwich. Take a look at the layers inside. Can you relate each layer in your sandwich to the rock layers in the stratigraphic column? Step Five:Time to take a core sample. Take the plastic straw and push it through the top of one half of the sandwich. Push it all the way through to the other end of the sandwich and then pull the straw out. You now have a core of your sandwich. You should be able to see the different layers stuck in the straw. Step Six:Enjoy you sandwich! New Words!
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Last updated: August 16, 2022