Graded Assignment
Lab Report: Interpreting Geologic History
Answer the questions below. When you are finished, submit this assignment to your teacher by the due date for full credit.
In this laboratory experiment, you will write a narrative history of a rock section found in the Grand Canyon. You will describe and explain the events starting with the Vishnu Schist forming and ending with the unconformity above the Red wall Limestone in the Mississippian. Your description should include environmental changes.
Example:

• Sea level lowered, and the Esplanade Sandstone was deposited in a beach environment.
• Erosion, and the sea level rose.
• Hermit Shale deposited in a deeper sea.
• Sea level drops, returning the area to a beach environment where the Coconino Sandstone was deposited.
Total score: of 25 points
(Score for Question 1: ___ of 20 points)
1. Interpret the bottom half of the cross section below. Start with the Vishnu Schist and end with the Red wall Limestone.
Scoring:
Correct order (8 points):
Proper environmental changes (8 points):
Attention to detail and completeness (4 points):


(Score for Question 2: ___ of 5 points)
2. There is one of each type of unconformity in this diagram. Name at least one of each of them by indicating the layers that they are between.
Nonconformity:

Type your answer here.
Angular unconformity:

Type your answer here.
Disconformity:

Type your answer here.
Symbol Name Environment
Sandstone Beach or nearshore environment
Limestone Forms in warm shallow seas
Shale Deep sea
Igneous Rock (Granite) Formed when rocks melt and then recrystalize
Metamorphic Rock (Schist) Formed when rocks are severely deformed without melting; in this cross section, the Vishnu Schist represents the original surface in the area
Igneous intrusion Magma melting and rising from deeper levels
Hint: How can you tell the difference between an intrusion and rocks melting in place? Rocks melting in place usually appear as a large mass, whereas intrusions seem to have risen up from a source.