Four-billion-year-old rocks yield clues about Earth's earliest crust
Friday, May 30, 2014 - 05:06
in Earth & Climate
It looks like just another rock, but what researchers are examining is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth's first continents formed. Continents today form when one tectonic plate shifts beneath another into Earth's mantle and cause magma to rise to the surface, a process called subduction. It's unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play.