About 150 million years ago, a massive tectonic mega-plate stretched across the Earth, spanning roughly a quarter of the size of the Pacific Ocean. Its jagged contours ran all the way through the ...

For millions of years, Earth’s moving plates have sculpted continents, carved oceans, and built massive mountain ranges. Yet some of these giant structures vanished deep into the mantle, hidden from ...

This piece is part of a special project on deep time examining what the Western U.S. was like thousands, millions and even billions of years ago, and how that history is still visible and ...