Pyrite-Rich Black Shale (IMAGE) University of California - Riverside Caption This photo shows pyrite-rich black shale containing MIF isotope signals, which could be later weathered at Earth's surface and transferred to the ocean. Credit Arizona State University 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.