Slave Craton

The Slave craton is an Archaean craton located in the north-western part of the Canadian Shield, spanning Northwest Territories and Nunavut. It is famous for containing the 4.03 billion-year-old Acasta Gneiss, one of the oldest dated rocks on Earth. Despite its small size—covering around 300,000 square kilometers—it holds great importance in understanding Earth's early history.

The visible part of the Slave craton, known as the Slave Province, stretches about 680 kilometers from Gros Cap on the Great Slave Lake to Cape Barrow on the Coronation Gulf. It is mostly made up of rocks formed between 2.73 and 2.63 billion years ago, including greenstones, turbidite sequences, and plutonic rocks. Older gneiss and granitoid rocks also lie beneath much of the area.

The Slave Craton is one of the ancient building blocks of North America, contributing to the foundation of the palaeocontinent Laurentia. It is split into two main parts: the Central Slave Basement Complex in the west-central area and the Hackett River Terrane, or Eastern Slave Province, in the east. These two parts are separated by a 2.7 billion-year-old boundary that runs north to south across the craton.

Subdivisions

Central Slave basement complex

The Central Slave basement complex is the base under the middle and western part of the Slave Craton. Along the Acasta River, it includes very old rocks called the Acasta Gneisses, which are about 4.03 billion years old—one of the oldest rock units known on Earth. These rocks have gone through many changes and have a specific type of composition.

Scientists study how the Slave Craton formed by looking at its shape and the rocks. Some think it crashed into another land area long ago, while others believe it broke away and changed shape. Later, the area stretched out and formed a large basin. Eventually, it collided with a much bigger land area, and later joined with another area called the Rae Craton. These events helped shape the Slave Craton into what we see today, as part of Laurentia.