North America is 'dripping' into Earth's mantle

The oldest crust on Earth, known to be unchanging, is actually being altered in real time. The North American continent is "dripping" rock into the lower layers of the Earth, new research says, and in the process providing new information about how continents and landmasses evolve.

Between a rock and a hard place

The Earth's continents contain cratons, which are ancient and stable pieces of the crust that very rarely change and deform. Any changes to cratons happen over a long geologic timescale.