Tag Geology

Banded rocks reveal early Earth conditions, changes

October 11, 2009

The strikingly banded rocks scattered across the upper Midwest and elsewhere throughout the world are actually ambassadors from the past, offering clues to the environment of the early Earth more than 2 billion years ago.

Lava flows reveal clues to magnetic field reversals

September 25, 2008

Ancient lava flows are guiding a better understanding of what generates and controls the Earth's magnetic field - and what may drive it to occasionally reverse direction.