Slave Craton
The rest of the CSBC is younger with a central core <3.5 Ga and the remaining craton with detrial and protolith ages ranging from 3.4 to 2.8 Ga.[2] The basement complex is overlain by Neoarchaean supracrustal sequences and intruded by plutonic suites.
[9] The Back River volcanic complex is an Archaean stratovolcano preserved in an upright position surrounded by four sedimentary sequences reflecting the volcano's magmatic history.
[11] This fuchisitic quartziite sequence seems to be characteristic of many other cratons between about 3.1 and 2.8 Ga and marks a global peak in quartzite production.
[11] A quartz pebble conglomerate found at the base of the Central Slave Cover Group marks a distinct unconformity that is laterally continuous over much of the CSBC.
[13] The lower Kam group consists of the Chan Formation which contains flows of pillowed basalts intruded by a series of gabbroic sills and dikes that were produced in an extensional back-arc basin setting.
[13] It is composed mainly of intermediate and basaltic volcanic rocks with thin intercalated rhyolite tuff layers and minor komatiite flows.
The deposit consists of polymict conglomerates and fluvial sandstones that have been subjected to a major metamorphic event as evident by similarly oriented vertical dips and lineations found in older groups.
[15][14] Trace isotope analysis show that these early granite rocks originated from a highly depleted mantle and suggest that large scale differentiation occurred before ~4.0 Ga.[14] These zircon crystals may be important in furthering the understanding of the earliest crustal formation processes, as little is yet known.
[14] The overall stability of a craton is highly correlated to the presence of a strong and deep continental lithospheric mantle because it protects the crust from thermal erosion and mitigates the effects of tectonism.
[13] The oldest diamonds derived from the mantle were between 3.5 and 3.3 Ga, which suggest that the Slave Protocraton would have formed a thick crustal root by this time.
The presence of a collisional suture suggests the CSBC collided with an island arc terrane along a boundary directed north–south before 2.69 Ga. Alternatively, the Eastern Slave may be an attenuated and modified Mesoarchaean lithosphere which developed during rifting at 2.85–2.70 Ga.
Following the 2.7 Ga rifting or accretion event, the Slave underwent large scale extension at 2680 Ma resulting in the formation of the > 400x800 km Burwash Basin, widespread mafic sills, and other younger turbidites along the northwestern margin.
[17][11] The Burwash Basin consists of metamorphosed turbiditic sandstones and slates interspersed with thin felsic tuff layers.
[17] At 2634 Ma the Slave switched to a compressional regime and the Burwash Basin started to close, possibly due to shallow subduction from the NW or SE.
[15][18] The Wopmay fault zone consists of thin skinned thrust belts that mark the suture between the Hottah terrane and Slave Craton.
