View source for Earth:Windermere group

{{Infobox Rockunit
| name           = Windermere Group
| image          = 
| caption        = 
| type           = Geological group or supergroup
| age            = {{Long fossil range|1000|600|[[Earth:Neoproterozoic|Neoproterozoic]]}}
| period         = Proterozoic
| prilithology   = [[Earth:Conglomerate (geology)|Conglomerate]], [[Earth:Sandstone|sandstone]]
| otherlithology = [[Chemistry:Shale|Shale]], [[Earth:Carbonate rock|carbonate rock]]s
| namedfor       = Windermere map-area, British Columbia
| namedby        = J.F. Walker<ref name=Walker />
| region         = Montana, Idaho, {{wipe|Washington (state)}}; Alberta, British Columbia, [[Earth:Northwest Territories|Northwest Territories]], [[Earth:Yukon|Yukon]]
| country        = {{flag|United States}} {{flag|Canada}}
| coordinates    = 
| unitof         = 
| subunits       = Many
| underlies      = Various units
| overlies       = Purcell Supergroup ([[Earth:Belt Supergroup|Belt Supergroup]])
| thickness      = more than {{convert|8000|m|ft|-1}}<ref name="MF2426" />
| extent         = 
| area           = 
| map            = 
}}

Called the '''Windermere Group''' in the {{wipe|United States}} and the '''Windermere Supergroup, Windermere Series''', and '''Windermere System''' in {{wipe|Canada}},<ref name=Miller>Miller, F.K., McKee, E.H. and Yates, R.G. 1973. Age and correlation of the Windermere Group in northeastern Washington. Geological Society of America Bulletin, vol. 84, no. 11, p. 3723-3730.</ref> the Windermere sequence of North America is an extensive assemblage of sedimentary and volcanic rocks of latest [[Earth:Precambrian|Precambrian]] ([[Earth:Neoproterozoic|Neoproterozoic]]) age. It is present in the northern part of the North American Cordillera, stretching from Montana, Idaho, and {{wipe|Washington (state)}} in the northwestern United States, through Alberta, British Columbia, the [[Earth:Northwest Territories|Northwest Territories]], and the [[Earth:Yukon|Yukon]] in western Canada.<ref name="MF2426">{{cite web|last1=Miller, F.K. and Burmester, R.F. 2003|title=U.S. Geological Survey, Miscellaneous Field Investigations, MF-2426|url=https://pubs.usgs.gov/mf/2003/2426/bferry_met.txt|accessdate=12 April 2018}}</ref><ref name=Miller /><ref name=Mossop06>{{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|accessdate=11 April 2018}}</ref><ref name=Glass>Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. {{ISBN|0-920230-23-7}}.</ref> It was named for the Windermere map-area in the East Kootenay region of southeastern British Columbia by J.F. Walker in 1926.<ref name=Walker>Walker, J.F. 1926. Geology and mineral deposits of the Windermere map-area, British Columbia. Geological Survey of Canada, Memoir 148, 69 p.</ref>

The Windermere rocks include [[Earth:Ediacaran biota|Ediacaran]] [[Biology:Fossil|fossil]]s and [[Earth:Stromatolite|stromatolite]]s,<ref name=Mossop06 /> and host deposits of [[Chemistry:Base metal|base]] and [[Chemistry:Precious metal|precious metal]]s.<ref name=Walker />

==Lithology==
The Windermere consists primarily of coarse-grained [[Chemistry:Feldspar|feldspathic]] [[Earth:Conglomerate (geology)|conglomerates]] and pebbly [[Earth:Sandstone|sandstone]]s, with lesser amounts of [[Earth:Pelite|pelitic]] [[Chemistry:Shale|shale]]s, [[Earth:Dolomite (rock)|dolomite]]s, and [[Earth:Limestone|limestone]]s.<ref name=Glass /><ref name=Mossop06 /> [[Earth:Mafic|Mafic]] [[Earth:Igneous rock|igneous rock]]s are present in some areas.<ref name="MF2426" /><ref name=Miller /> In most areas the Windermere rocks are highly sheared, faulted, and [[Earth:Metamorphism|metamorphosed]].<ref name=Miller />

==Environment of deposition==
Most of the Windermere rocks were deposited as deep-water [[Earth:Turbidite|turbidite]] flows along a continental margin or in an active volcanic rift basin.<ref name=Mossop06 /> Glacial events such as the [[Earth:Sturtian glaciation|Sturtian]] and [[Earth:Marinoan glaciation|Marinoan glaciation]]s that occurred during Neoproterozoic time strongly influenced sedimentation,<ref name=Mossop06 /> and some of the Windermere conglomerates are believed to be [[Earth:Till|till]] or [[Earth:Diamictite|diamictite]] of glacial origin.<ref name=Miller /> 

==Paleontology==
[[Biology:Trace fossil|Trace fossil]]s, [[Earth:Ediacaran biota|Ediacaran]] fossils, and Ediacaran-like fossils have been described from the Windermere Suprgroup in the Mackenzie and Werneke Mountains of the eastern Northwest Territories, the Cariboo Mountains of British Columbia, and the Canadian Rockies near Jasper, Alberta.<ref name=Mossop06 /> Stromatolites are present in some of the [[Earth:Carbonate rock|carbonate]] beds.<ref name=Glass />

==Thickness and distribution==
The Windermere is both thick and extensive. It reaches thicknesses of more than more than {{convert|8000|m|ft|-1}},<ref name="MF2426" /> and is present parts of Montana, Idaho, and {{wipe|Washington (state)}} in the United States, and parts of Alberta, British Columbia, the [[Earth:Northwest Territories|Northwest Territories]], and the [[Earth:Yukon|Yukon]] in Canada.

==References==
{{reflist}}

[[Category:Geological groups]]

{{Sourceattribution|Windermere group|1}}