ISBN: | 978-5-5126-9147-2 |
High Quality Content by WIKIPEDIA articles! The Acasta Gneiss is a rock outcrop of Hadean tonalite gneiss in the Slave craton in Northwest Territories, Canada. Located on an island about 300 kilometres north of Yellowknife, the Acasta River rock deposit, believed to be 4.031 to 3.58 billion years old, is the oldest known intact crustal fragment on Earth.