Geology of the Northwest Territories province from dikes and mafic lava flows, overlain by deep ocean turbidite deposits. These rocks are believed to be the remains of oceanic crust that ended up preserved, surrounded on all sides by felsic volcanic rocks and granitoid plutons. In the area of Snofleld Lake in the northern part of the Slave Province, the remains of Archean stromatolites are preserved in a dolomite unit between felsic volcanic and greywacke-mudstone turbidites, some of the earliest evidence of life, forming in the shallows around volcanic islands. Around 1.27 billion years ago in the Proterozoic, a series of major magmatic events affected the
Whim Creek Copper Mine exhausted of copper oxide ore within early 2009. An option exists for the operation to continue as a sulphide operation thereafter. The Whim Creek Copper Mine extracts two volcanogenic massive sulfide ore deposits, namely Mons Cupri (lit. "copper mountain") and Whim Creek, which are located within the Cistern Formation and Rushalls Slate sedimentary members, which are part of a series of rift-related felsic, intermediate and mafic volcanic rocks known as the Whim Creek Group. The Whim Creek Group is approximately 2.9 to 2.8Ga old and lies unconformably upon an older basement of Portree Granite. The ore deposits are classified as