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The landscape in North America remains more or less unchanged at this location until the Permian period (late Paleozoic Era~300-250 Ma). Use the stratigraphic column below to help you answer the following questions. 

What likely caused this unconformity? Tip: think about what kind of rocks these are and their corresponding depositional environments.

If you laid out geologic time as if it occurred in a single calendar year, when would you expect human history to be recorded?

The rock identified in problem #1 is 3.06 Ga. However, the zircons encased in it are not the same age (see Question 3). What is the reason for this?

Select the Global Paleogeographic Model folder. Double click to zoom out. Also select the placemark labeled “Question 30” and navigate to where it is in view. Toggle through the beginning of the Permian (~300 Mya) through its end (~250 Mya). What significant event happens at the placemark during this time?Tip: Check out Figure 11.11 in your book to help orient where the modern continents were at this time as you explore the model on Google Earth Pro. Mark all that apply.

Fly to “Hermit Formation, Grand Canyon” to explore this formation. Click the name of the placemark to see three images of the red-brown, nonresistant clastic rock. What rock type makes up the Hermit formation?

What does this outcrop tell us about the Earth at this time in the late Proterozoic?

Paleozoic Era

We can extract the zircons from these rocks to obtain an age of the zircons, thereby providing the age of the first preserved material on Earth.Within the zircons in this rock sample, the ratio of parent to daughter isotopes is 8.5:7.5. Using the chart below, determine how many half lives have passed.

What is responsible for the ridge at AL 3?