The Fairholme Group is a

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

unit of

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding ...

(

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during ...

) age. It is present on the western edge of the

Western Canada Sedimentary Basin The Western Canada Sedimentary Basin (WCSB) underlies of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. This vast sedimentary ba ...

in the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

and foothills of

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

and

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. It was named for the

Fairholme Range The Fairholme Range is a mountain range east of the Bow River valley in the Canadian Rockies. The range is bounded on the west side by the Trans-Canada Highway as it passes through the towns of Exshaw and Canmore, while the northern section of t ...

near Exshaw in the Canadian Rockies by H.H. Beach in 1943. The formations of the Fairholme Group include

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

of marine animals such as

stromatoporoid Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Middle Ordovician to the Late Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. They can be cha ...

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

crinoid Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...

s, and

conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

Lithology

The Fairholme Group was deposited in marine environments and can be subdivided into three gross lithologic units: * The basal carbonate platform sequence of the Flume Formation, or in southern areas the

Hollebeke Hollebeke is a Flemish village in the Belgian province of West Flanders, now part of Ypres. History In World War I, it was the site of Allied heroism (like other neighbouring parts of Ypres, such as Klein Zillebeke) that won Khudadad Khan th ...

and Borsato Formations, which are composed of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

s and

dolomites The Dolomites ( ), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range in northeastern Italy. They form part of the Southern Limestone Alps and extend from the River Adige in the west to the Piave Va ...

. * The carbonate buildups (

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

al sequences) of the

Cairn A cairn is a human-made pile (or stack) of stones raised for a purpose, usually as a marker or as a burial mound. The word ''cairn'' comes from the (plural ). Cairns have been and are used for a broad variety of purposes. In prehistory, t ...

and Southesk Formations, also composed of limestones and dolomites. * The basin-fill clastic rocks of the Maligne, Perdrix, and Mount Hawk Formations, which consist primarily of

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

argillaceous Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay mineral ...

limestones, and

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

s. These are laterally equivalent to the reefal units.

Distribution and thickness

The Fairholme Group is present in the Canadian Rockies from the Kakwa Lakes area of northeastern British Columbia, south through Alberta to the

Flathead River The Flathead River (, , ), in the northwestern part of the U.S. state of Montana, originates in the Canadian Rockies to the north of Glacier National Park and flows southwest into Flathead Lake, then after a journey of , empties into the Cla ...

region of southeastern British Columbia, as well as in the subsurface beneath the immediately adjacent plains to the east. Where fully developed, the group reaches thicknesses from about 300 to 728 m (980 to 2400 feet).

Relationship to other units

The Fairholm Group overlies the Beaverhill Lake Group in the southern Alberta plains, and

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

overlies the

Middle Devonian In the geological timescale, the Middle Devonian epoch (from 393.3 ± 1.2 million years ago to 382.7 ± 1.6 million years ago) occurred during the Devonian period, after the end of the Emsian age. The Middle Devonian epoch is subdivided into two ...

Yahatinda Formation or pre-Devonian formations in the mountains. It is overlain by the Crowfoot Formation in the plains, and the Sassenach, Alexo or, rarely, the

Palliser Formation The Palliser Formation is a stratigraphic unit of Late Devonian (Famennian) age in the Western Canada Sedimentary Basin. It is a thick sequence of limestone and dolomitic limestone that is present in the Canadian Rockies and foothills of western ...

in the mountains. It is equivalent to the

Woodbend Group The Woodbend Group is a stratigraphic unit of Frasnian age in the Western Canadian Sedimentary Basin. It was first described in the ''British American Pyrcz No. 1'' well by Imperial Oil geological staff in 1950. Lithology The Formation is compo ...

and the lower part of the

Winterburn Group The Winterburn Group is a stratigraphic unit of Frasnian age in the Western Canadian Sedimentary Basin. It takes the name from Winterburn area located west of Edmonton, and was first described in well ''P.A. Pyrcz No. 1'' by Imperial Oil Limit ...

of the plains.

Lithology

Distribution and thickness

Relationship to other units

References

See also