Why Huge Bands of Iron Formed Billions of Years Ago on Earth's Surface
Monday, November 16, 2009 - 12:49
in Astronomy & Space
No one knows why massive formations of banded iron -- some ultimately hundreds of kilometers long, like a sleeping giant's suspenders -- mysteriously began precipitating on Earth's surface about 3.5 billion years ago. Or why, almost 2 billion years later, the precipitation ceased.