Lynx Formation

{{Infobox rockunit

| name = Lynx Formation (Group)

| image =

| imagesize =

| caption =

| type = Formation or Group

| age = {{Fossil range|Late Cambrian|Late Cambrian|Dresbachian}}

| prilithology = Carbonate rocks

| otherlithology = Shale

| namedfor = Lynx Mountain

| namedby = C.D. Walcott, 1913

| region = Canadian Rockies

| country = Canada

| coordinates = {{coord|53.1407|-119.0492|display=inline,title|name= Lynx Formation}}

| unitof =

| subunits = Mistaya Formation
Bison Creek Formation
Lyell Formation
Sullivan Formation
Waterfowl Formation

| underlies = Survey Peak Formation

| overlies = Arctomys Formation

| thickness = up to {{convert|1220|m|ft|-1}}

| extent =

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}}

The Lynx Formation or Lynx Group is a stratigraphic unit of Late Cambrian (Dresbachian) age in the Western Canada Sedimentary Basin.{{Cite web|url=http://ags.aer.ca/reports/atlas-of-the-western-canada-sedimentary-basin.htm|title=The Geological Atlas of the Western Canada Sedimentary Basin (Mossop, G.D. and Shetsen, I., compilers), Chapter 8: Middle Cambrian and Early Ordovician Strata of the Western Canada Sedimentary Basin|author=Slind, O.L., Andrews, G.D., Murray, D.L., Norford, B.S., Paterson, D.F., Salas, C.J., and Tawadros, E.E., Canadian Society of Petroleum Geologists and Alberta Geological Survey|year=1994|accessdate=2018-07-13}} It is present in the Canadian Rockies of Alberta and British Columbia. It was originally described as the Lynx Formation by Charles Doolittle Walcott in 1913, based on and named for outcrops on the slopes of Lynx Mountain on the continental divide east of Mount Robson. It was subdivided into five formations and elevated to group status by J.D. Aitken and R.G. Greggs in 1967.Aitken, J. D and Greggs, R G., 1967. Upper Cambrian formations, southern Rocky Mountains of Alberta, an interim report. Geological Survey of Canada, Paper 66-49. The name Lynx Formation continues to be used in areas where some or all of the subdivisions cannot be distinguished. All of the formations in the Lynx Group include fossil trilobites and some contain the stromatolite Collenia.

Lithology and deposition

The Lynx Group is composed alternating zones of carbonate rocks, most of which are dolomitic, and shales.

{{Cite web|url=http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:008882

|title= Lynx Formation

|author=Lexicon of Canadian Geologic Units

|accessdate=2010-02-01}}

It was deposited in shallow marine environments along the western margin of the North American Craton during Late Cambrian time.Aitken, J.D. 1966. Middle Cambrian to Middle Ordovician cyclic sedimentation, southern Rocky Mountains of Alberta. Bulletin of Canadian Petroleum Geology, vol. 14, no. 6, p. 405-441. In many areas it is subdivided into the five formations listed below.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}}.{{cite web |last1=Alberta Geological Survey |title=Alberta Table of Formations, May 2019 |url=https://ags.aer.ca/document/INF/Table_of_Formations_2019.pdf |publisher=Alberta Energy Regulator |accessdate=24 March 2020}}

Subdivisions

Upper Lynx Group

class="wikitable"
FormationLithologyMax.
Thickness
Reference
Mistaya Formationcarbonate rocks, minor cherty layers{{convert|158|m|ft
1|abbr=on}}

|

Bison Creek Formationgreen and grey shales, argillaceous limestone{{convert|203|m|ft
1|abbr=on}}

|

Lyell Formationmassive cliff-forming carbonate rocks{{convert|519|m|ft
1|abbr=on}}

|

Lower Lynx Group

class="wikitable"
FormationLithologyMax.
Thickness
Reference
Sullivan Formationgrey, green, and brown shales, argillaceous limestone{{convert|424|m|ft
1|abbr=on}}

|

Waterfowl Formationcliff-forming carbonate rocks, minor siltstone and sandstone{{convert|183|m|ft
1|abbr=on}}

|

Distribution

The Lynx Group is present in the Canadian Rockies of Alberta and British Columbia. It is typically between 1068-1220 metres (3500-400 feet) thick in the front and main ranges. It extends as far north as the Monkman Pass area of British Columbia.

Relationship to other units

The Lynx Group overlies the Arctomys Formation and the contact is gradational. It is overlain by the Survey Peak Formation and the contact is concordant but abrupt.

References