⚙️ how
How do geologists know how old Earth’s oldest rocks are?
Quick Answer
They date minerals like zircon with radioactive isotopes, revealing ages of more than 4 billion years.
The Full Story
Earth's oldest intact rocks are rare because plate tectonics recycles crust. To find very ancient ages, geologists often study tiny zircon crystals, which can survive erosion and metamorphism. Zircons from the Jack Hills in Western Australia have been dated to about 4.4 billion years old, making them some of the oldest known materials on Earth. These ages come from uranium-lead dating, which is especially reliable for ancient minerals.
Key Facts
1.Jack Hills zircons are about 4.4 billion years old
2.Uranium-lead dating is commonly used on zircons
3.Most very old crust has been recycled by plate tectonics
YouTube Angle
Suggested video title for this topic:
"The oldest surviving grains on Earth"
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