Purcell Supergroup#Subdivisions

The Purcell Supergroup consists primarily of argillites, carbonate rocks (limestone and dolomite), and quartzites, and includes localized occurrences of igneous rocks (mafic lava flows, tuffs, pillow basalts, and gabbroic and dioritic sills and dykes). Sedimentary structures are well preserved in the Purcell rocks despite their great age.

In the southern Canadian Rockies (Waterton Park area), the supergroup is subdivided as follows:

In the southern Purcell Mountains (Cranbrook area), the supergroup is subdivided as follows:

The Purcell Supergroup was probably deposited in subsiding deltaic to marine environments along the margin of the North American craton,{{cite web|last1=Hein, F.J. and McMechan, M.E. 1994|title=Atlas of the Western Canada Sedimentary Basin (Mossop, G.D. and Shetsen, I., compilers), Chapter 6: Proterozoic and Lower Cambrian strata of the Western Canada Sedimentary Basin|url=http://ags.aer.ca/publications/chapter-6-proterozoic-and-lower-cambrian-strata|access-date=11 April 2018}} possibly in an intracratonic basin where North America and another landmass were joined in a supercontinent called Columbia/Nuna.Schieber, J., 1989. The origin of the Neihart Quartzite, a basal deposit of the mid-Proterozoic Belt Supergroup, Montana, USA. Geological Magazine, v. 126, p. 271-281. Deposition occurred during the Mesoproterozoic era, much of it probably between about 1470 and 1400 Ma (million years) ago.Evans, K.V., Aleinikoff, J.N., Obradovich, J.D. and Fanning, C.M. 2000. SHRIMP U-Pb geochronology of volcanic rocks, Belt Supergroup, western Montana: evidence for rapid deposition of sedimentary strata. Canadian Journal of Earth Sciences, v. 37, p.1287-1300.{{cite journal | last1 = Halpin| first1 = Jacqueline A.| last2 = Jensen| first2 = Torsten| last3 = McGoldrick| first3 = Peter| last4 = Meffre| first4 = Sebastien| last5 = Berry| first5 = Ron F.| last6 = Everard| first6 = John L.| last7 = Calver| first7 = Clive R.| last8 = Thompson| first8 = Jay| last9 = Goemann| first9 = Karsten| last10 = Whittaker| first10 = Joanne M.| year = 2014 | title = Authigenic monazite and detrital zircon dating from the Proterozoic Rocky Cape Group, Tasmania: Links to the Belt-Purcell Supergroup, North America | journal = Precambrian Research | volume = 250 | pages = 50–67 | doi = 10.1016/j.precamres.2014.05.025 | bibcode = 2014PreR..250...50H}}

In Canada, the Purcell Supergroup is present in an area of about {{convert|15,000|km2|sqmi|abbr=on}} that reaches from the southern Purcell Mountains in southeastern British Columbia to the southern Canadian Rockies in the southwestern Alberta. It extends southward into the United States (western Montana, northern Idaho, northwestern Washington, and western Wyoming) where it is called the Belt Supergroup.{{cite web|last1=Lori Tapanila and Paul Link|title=Mesoproterozoic Belt Supergroup|url=http://geology.isu.edu/Digital_Geology_Idaho/Module2/mod2.htm|website=Digital Geology of Idaho|publisher=Idaho State University, Department of Geosciences|access-date=16 September 2016}} It reaches a maximum thickness of more than {{convert|10,000|m|ft|abbr=off}} in the Purcell Mountains.

The Purcell Supergroup is equivalent to the Belt Supergroup of the northwestern United States. The base of the Purcell is not exposed in Canada, but it is inferred to rest unconformably on the Canadian Shield. The Purcell is unconformably overlain by the Neoproterozoic Windermere Supergroup in most areas, or by younger Cambrian or Devonian formations where the Windermere is absent.

The now-closed Sullivan Mine at Kimberley, British Columbia, worked a world-class sedimentary exhalative (SedEx) deposit that is hosted in the lower part of the Purcell Supergroup. During the life of the mine, the Sullivan ore body is reported to have yielded 8,412,077 tons of lead, 7,944,446 tons of zinc, and 9,264 tons of silver, as well as significant quantities of tin and other metals.

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Category:Western Canadian Sedimentary Basin

Category:Stratigraphy of Alberta

Category:Stratigraphy of British Columbia

Category:Geologic supergroups of Canada