| 词条 | Beaver Mines Formation |
| 释义 |
| name = Beaver Mines Formation | image = | caption = | type = Formation | age = Early Cretaceous (Albian) | period = Albian | prilithology = | otherlithology = | namedfor = Beaver Mines, Alberta | namedby = G.B. Mellon, 1967[1] | region = {{flag|Alberta}} {{flag|British Columbia}} | country = {{flag|Canada}} | coordinates = | unitof = Blairmore Group | subunits = | underlies = Ma Butte Formation | overlies = Gladstone Formation | thickness = up to {{convert|455|m|ft|-1|abbr=on}} | extent = | area = | map = | map_caption = }} The Beaver Mines Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin[2] that is present in southwestern Alberta and southeastern British Columbia, Canada. It was established by G.B. Mellon in 1967 who named it for the hamlet of Beaver Mines, Alberta.[1] It contains a variety of plant fossils.[4] LithologyFine- to coarse-grained greenish grey sandstone interbedded with greenish grey mudstone and siltstone, and lesser amounts of conglomerate, bentonite and tuff. Some conglomerate beds contain pebbles of volcanic origin. Minor argillaceous limestone is present at the top in some areas. The sandstones are feldspathic, in contrast to the quartzoes sandstones of the overlying Ma Butte Formation.[3] Environment of deposition and paleontologyThe Beaver Mines Formation was deposited in floodplain and fluvial channel environments by meandering river systems.[4] It contains a variety of plant fossils including remains of ferns, cycads, cycadeoids, Ginkgos and extinct conifers, but remains of flowering plants do not appear until the overlying Ma Butte Formation.[5][6] Distribution and thicknessThe Beaver Mines Formation is present in the southern foothills of southwestern Alberta and southeastern British Columbia, and extends as far north as the Clearwater River where it grades into the Gates Formation of the Luscar Group.[7] It reaches a maximum thickness of about {{convert|455|m|ft|-1|abbr=on}} at Ma Butte north of the Crowsnest Pass.[3] Relationship to other unitsThe Beaver Mines Formation is part of the Blairmore Group. It disconformably overlies the Gladstone Formation and grades into the Gates Formation of the Luscar Group north of the Clearwater River. It is disconformably overlain by the Ma Butte Formation in the southern foothills and by the Blackstone Formation north of the Red Deer River. To the east it is correlated with the upper part of the Mannville Group.[3] See also{{Portal|Earth sciences|British Columbia|Paleontology|Cretaceous|Mesozoic}}
References1. ^1 Mellon, G.B. 1967. Stratigraphy and petrography of the Lower Cretaceous Blairmore and Mannville Groups, Alberta foothills and plains. Alberta Research Council, Bulletin 21. 2. ^{{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, Chapter 19: Cretaceous Mannville Group of the Western Canada Sedimentary Basin|others=Compiled by Mossop, G.D. and Shetsen, I.|author= Canadian Society of Petroleum Geologists and Alberta Geological Survey|year=1994|accessdate=2016-06-20}} 3. ^1 2 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}}. 4. ^Taylor, D.R. and Walker, R.G. 1984. Depositional environments and paleogeography of the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines Formations, Alberta. Canadian Journal of Earth Sciences, vol. 21, p. 698-714. 5. ^1 Bell, W.A. 1949. Lower Cretaceous floras of western Canada. Geological Survey of Canada, Memoir 285, 331 p. 6. ^McLean, 1980. Lithostratigraphy of the Lower Cretaceous coal-bearing sequence, foothills of Alberta. Geological Survey of Canada, Paper 80-29. 7. ^Langenberg, C.W. and McMechan, M.E. 1985. Lower Cretaceous Luscar Group (revised) of the northern and north-central foothills of Alberta. Bulletin of Canadian Petroleum Geology, vol. 33, p. 1-11. 7 : Geologic formations of Canada|Western Canadian Sedimentary Basin|Stratigraphy of Alberta|Cretaceous Alberta|Stratigraphy of British Columbia|Cretaceous British Columbia|Albian Stage |
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