Ancient zircons may record the dawn of plate tectonics
Parts of the Earth’s crust may have started sliding around about 3.8 billion years ago
![a zircon crystal](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2022/04/042622_no_ancient-zircon_feat.jpg?fit=1030%2C580&ssl=1)
Zircons, such as this crystal unearthed in Italy, are hardy gemstones that can endure for eons. A chemical change 3.8 billion years ago in a cache from South Africa may mark the start of an early form of plate tectonics.
Matteo Chinellato – ChinellatoPhoto/Photographer's Choice RF/Getty Images