Tiger Eye FIB Rock (IMAGE) Georgia Institute of Technology Caption This tiger eye BIF (banded iron formation) rock shows layers of iron that settled as compounds out of oceanic solution. Before oxygen became more plentiful, the oceans were likely full of iron that could have made nitrous oxide that entered Earth's early atmosphere to keep it warm. Credit Georgia Tech / Allison Carter Usage Restrictions None License Licensed 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.