Banded Iron Formations (IMAGE) Jacobs University Bremen gGmbH Caption A Banded Iron-Formation (BIF) with bands of iron-oxide (black) and quartz (white) that were deposited at the seafloor some 2700 million years ago. Credit Michael Bau/Jacobs University Bremen Usage Restrictions Jacobs University Bremen License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.