This is an online “virtual field trip” run by Arizona State University. Visit the following URL, click the Next button to find “The Mystery of Blacktail Canyon,” and hit the Explore button.
There will be a prompt to “Login as a Guest.” Then click the final link that says “Grand Canyon – The Mystery of Blacktail Canyon V2”
https://vft.asu.edu/migrated/iVFTLocations/GrandCanyon/GCoptions.html
This will take you to some 360-degree panorama views of Blacktail Canyon, a side branch of the Grand Canyon, with closeup photos and short YouTube clips.
You are now employed at the Grand Canyon National Park and are in charge of creating a sign for the public describing the history of the rocks at the bottom, with a focus on the Great Unconformity seen at Blacktail Canyon. “Consult” with Dr. Karlstrom and Dr. Semken to learn about the geology of the canyon.
Write a few paragraphs for a National Park sign (500 words) outlining the history of the rocks of Blacktail canyon for park visitors, incorporating the following:
• What type of rock is found below the Great Unconformity, and what would have happened to form a rock like this? What is the full name of the rock unit and how old is it? What is noteworthy about the age of this rock unit? (Geologists give rock units their own unique names, such as the “Acasta gneiss.”) [10 points]
• What type of rock is found above the Great Unconformity, and how does a rock like this form? What type of setting did this rock form in? What clue is present in this rock that hints at its original environment? What is the full name of the rock unit and how old is it? What is noteworthy about the age of this rock unit? [10 points]
• What is an unconformity, in general? Describe the Great Unconformity. How much time is missing here? [10 points]
• Write a final paragraph describing the geologic history of the rocks of Blacktail canyon, through the passage of time, from early on to the modern day. [10 points]