Girish Mahajan

Fernie Formation

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Type  Geological formation
Province  British Columbia
Named for  Fernie
Country  Canada
Primary  Slate
Fernie Formation httpsuploadwikimediaorgwikipediacommonsthu
Sub-units  Nordegg Member, Red Deer Member, Poker Chip Shale, Lille Member, Rock Creek Member, Highwood Member, Pigeon Creek Member, Ribbon Creek Member
Thickness  up to 400 metres (1,310 ft)
Other  Sandstone, siltstone, limestone
Region  Alberta  British Columbia
Overlies  Schooler Creek Group, Montney Formation, Rundle Group
Underlies  Morrissey Formation, Nikanassin Formation, Monteith Formation

The Fernie Formation is a stratigraphic unit of Jurassic age. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. In some interpretations it has Group status. It takes its name from the town of Fernie, British Columbia, and was first defined by Leach in 1914.

Contents

Depositional historyEdit

The Fernie Formation consists of marine sediments that were deposited in the Western Interior Seaway. Deposition took place throughout most of the Jurassic period, starting during the Hettangian stage in some parts of northeastern British Columbia and continuing until the mid-Tithonian, as determined from its fossil assemblages, including ammonites, molluscs and microfossils.

The sediments were sourced from the east during the deposition of the lower and middle units of the Fernie, where the coarser facies occur in the eastern part of the formation. In the uppermost Fernie, the coarsest material is found in the west, however, indicating a shift to sources in the west and south.

LithologyEdit

The Fernie Formation is composed primarily of brown and dark gray to black shales that range from massive with conchoidal fracture to laminated and highly fractured or papery. Phosphatic sandstone and limestone, including cherty limestone, occur locally in the lower parts of the formation; siltstone, sandstone, coquinas and oolitic limestone interbeds can occur in the center; glauconitic sandstone and siltstone can be present in the upper parts.

DistributionEdit

The Fernie Formation reaches a maximum thickness of 400 metres (1,310 ft) near Mount Allan in Alberta, and typically is about 70 to 150m (230 to 492 ft) thick. It thins toward the east, disappearing at about the longitude of Calgary. The formation is exposed in outcrops in the Kootenay region of southeastern British Columbia, in the foothills and front ranges of the Canadian Rockies in southwestern Alberta, and as far north as the Peace River Country in northeastern British Columbia.

Relationship to other unitsEdit

The Fernie Formation is conformably overlain by the Morrissey Formation in the south, by the Nikanassin Formation in central Alberta and by the Monteith Formation in northeastern British Columbia. It rests disconformably on Triassic units in the west, and unconformably on upper Paleozoic units such as the Schooler Creek Group and the Montney Formation farther east.

SubdivisionsEdit

The Fernie Group has the following subdivisions from top to base:

References

Fernie Formation Wikipedia


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