Continent-size blobs in Earth's mantle are a billion years old, ancient crystals reveal

Internal structure of the Earth, cutaway computer illustration. From the centre outwards, the four layers shown in the image are: inner core, outer core, mantle, and crust.

Continent-size islands deep inside Earth's mantle could be more than a billion years old, a new study finds.

Known as large low-seismic-velocity provinces (LLSVPs), these blobs are both hotter and older than nearby areas of the mantle. The findings, published Jan. 22 in the journal Nature, shed light on Earth's deep interior and could help explain how the mantle moves over time.