Wernecke Mountains Group
They have provided important wildlife habitat for animals such as grizzly bears and caribou as well as trapping and hunting land for the indigenous people of the Yukon for many centuries.
[4] At least three cycles of basin formation and extension at the western edge of Laurentia resulted in 22 kilometers of sediment deposited in the early Proterozoic through to the Paleozoic eras.
[3] Extension and crustal thinning associated with basin development during the Paleoproterozoic suggests separation of Laurentia from another continent to the west, thought to be ancient eastern Australia.
[3][5] These rocks are hypothesized to be a thinned continuation of the granitic Fort Simpson terrane exposed to the East based on aeromagnetic and gravity anomalies combined with drill-hole analyses in NWT.
[3] The Fairchild group, the oldest and most deformed member of the Wernecke Supergroup is characterized by about 4.6 km of upward grading siltstone to shale with carbonates, representing a low sediment input environment and a shallow basin.
[8] These sediments have since been metamorphosed to slate, phyllite, or fine-grained chloritoid- or garnet-porphyroblastic muscovite-chlorite-quartz schist by the Racklan orogeny at 1.6 Ga, as well as magmatism and hydrothermal activity.
[3] The Quartet group records a time of increasing sediment input beginning with shales and coarsening upward to siltstone and carbonates.
[3] The Gillespie lake group is characterised by wavy and plane bedding and preserved cross laminations, algal mats, stromatolites, pisolites, intraclasts, and mud-cracks, indicating a shallow water depositional environment.
[3] The period of rifting and crustal extension embodied by the Hart River volcanics was followed by basin sedimentation represented by the Pinguicula group.
[3] The Pinguicula group is separated from the Wernecke Supergroup by an angular unconformity, representing an erosional stage after the Racklan orogenic event.
[3] Sediment supply for the Hematite Creek basin formation has been tentatively attributed to the Grenville orogeny of approximately the same time period through U-Pb dating of zircon grains.
[8][3]) This theory is sustained by the similar cooling age of the white mica in the Wernecke supergroup and the timing of Corn Creek orogeny, dated using 40Ar–39Ar methods.
[3] The Laramide orogeny is associated with the accretion of exotic superterranes on the West Coast of North America, as well as the subduction of the Farallon and Kula plates.
[13] In central Yukon, these rocks were deformed in a northerly-directed, fold-and-thrust belt in the Jurassic to Cretaceous possibly due to more accretion on the West coasts.
