
America's Oldest Rocks - Part 2 - The Unveil
About this episode
In this episode, we dive back into the bedrock of America to reveal which state holds the crown for the oldest rocks in the U.S.! Join us as we unravel the mysteries of ancient metamorphic formations. From the Morton Gneisses in Minnesota, to the Wyoming craton out West, and ending in Upper Michigan, you'll find out what the oldest rocks are, and how we know! Hit that subscribe button, because this episode rocks!
The paper that served as the basis for this episode is Frost, C.D., Mueller, P.A., Bickford, M.E., and Stern, R.J., 2025, USA’s oldest rock? A simple question with a complex answer: GSA Today, v. 35, p. 4–10,
https://doi.org/10.1130/GSATG613A.1.
00:00 Introduction and Episode Overview
00:50 Setting the Stage: America's Oldest Rocks
02:28 Understanding Metamorphic Rocks
05:18 The Importance of Rock Ages
09:55 Zircon and Uranium-Lead Dating
14:16 Metamorphism and Zircon Growth
22:05 Metamorphic and Igneous Rock Processes
23:32 Understanding Zircon Inheritance
24:32 Determining Rock Ages
27:21 Challenges in Identifying Rock Types
31:44 Oldest Rocks in the United States
36:52 Technological Advancements in Geochronology
42:51 Conclusion and Further Research
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