Slave cratonとは 意味・読み方・使い方

The Slave craton is a Canadian geological formation located in the Northwest Territories and Nunavut. This craton is approximately 300,000 square kilometres (120,000 sq mi) in size and forms part of the Canadian Shield. It is dominated by ca. 2.73-2.63 Ga greenstones and turbidite sequences and ca. 2.72-2.58 Ga plutonic rock, with large parts of the craton underlain by older gneiss and granitoid units. The cratonic block extends from the Great Slave Lake at about 61 °N to Coronation Gulf on the Arctic Ocean at 69 °N. It covers longitudinally the area between about 105 °W to 117 °W. The Slave includes the Acasta Gneiss which is one of the oldest dated rock units on Earth at 4.03 Ga.