Isua in Greenland (IMAGE) University of Cambridge Caption At first glance the rocks that make up Greenland's Isua supracrustal belt look just like any modern basalt you'd find on the sea floor. But this outcrop, which was first described in the 1960s, is the oldest exposure of rocks on Earth. It is known to contain the earliest evidence of microbial life and plate tectonics. Credit Hanika Rizo 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.