25: The Oldest Rock on Earth
How old is the oldest rock, where was it found, and what type of rock is it?
To answer that question, we'll journey into Canada's Northwest Territories, deep underground to the breaking point of rocks, and we'll run into a shrimpy friend from Episode 10.
26: The Magma Forge
What did the oldest rock look like 4 billion years ago, before it was pressure-cooked?
Today, we'll answer that question by melting chocolate chip ice cream, meeting one of granite's less famous cousins, and returning to our old friends: zircon crystals.
Extra credit: Eat some ice cream, go on a skiing trip, or both!
27: Rare Earth
Is there any place today that resembles the Earth 4 billion years ago?
Surprisingly, the answer is yes... ish. Today, we'll learn a secret recipe for continents, one that made the very oldest rocks on Earth and is still making the island of Iceland today.
Along the way, we'll freeze a magma chamber solid, meet some politically contentious metals, and cross a real bridge from one tectonic plate to another.