Geologic dating exercise
View the above image, a cross-section (side-view of a cut-out through the crust) of the Grand Canyon.
Study this diagram carefully, noting the orientation of individual rock layers, as well as the type of rock in each layer, and the age of the rock in each layer. IS TO CLEARLY IDENTIFY FOUR MAJOR UNCONFORMITIES IN THE GRAND CANYON SEQUENCE.
Question 2: What is the sequence of events that can be inferred from the above cross-section?
The two intrusions are labeled as X and Z; the surrounding rock (called the "country rock") is labeled as D.
The various sedimentary layers are labeled as B, E, K and W.
The timing of the fault (break) in the rocks (labeled as Q) must be included in the sequence of events.
Part 2 ends with an application of the principles of relative dating to the rocks of the Grand Canyon.
To review our principles of relative dating as applied to such geologic cross-sections, we will make use of a neat learning tool available on the Internet.
"Athro Limited" is a private company which provides education modules on the Internet.
For each of the four major unconformities in the Grand Canyon, answer each of the following questions:2.
What evidence do you specifically see that allowed you to identify an unconformity at this location?