Komatiite Volcanic Rocks (IMAGE) Louisiana State University Caption Photomicrographs of fresh olivine (large green, blue and pink crystals) and glass inclusion (lower left inset). Komatiite volcanic rocks from the 3.3 billion-year-old Weltevreden Formation are the freshest yet discovered in from Earth's early Archean. Trace elements, radiogenic and stable isotopes from these rocks and olivine separates provide key evidence for evolution of Earth's mantle. Credit Keena Kareem, LSU 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.