Beaverhill Lake Group

The Beaverhill Lake Group consists of anhydrite and carbonate rocks at the base (the Fort Vermillion Formation), overlain by interbedded sequences of calcareous shale, argillaceous micritic limestone, limestone and dolomite. The group becomes thicker and more shaly to the west. ==Distribution and thickness==

The Beaverhill Lake Group is present beneath the plains of the southwestern Northwest Territories, northeastern British Columbia and Alberta. ==Stratigraphy==

;Central Alberta ;Swan Hills area In northern Alberta and northeastern British Columbia the unit has formation status and is not subdivided. ==Environment of deposition==

The formations of the Beaverhill Lake Group were deposited in an embayment that extended from an open ocean in the present-day Northwest Territories in Canada, to North Dakota in the United States. An extensive reef complex called the Presqu'ile Barrier had developed across the mouth of the embayment, blocking it from the open ocean and restricting the inflow of sea water. Low water levels and excessive evaporation led to the deposition of the anhydrite-rich Fort Vermillion Formation at the base of the group in northern areas. Water levels then increased throughout the embayment, and the overlying carbonate rocks were deposited in reefs (Swan Hills Formation), and in carbonate platform and basin environments (Waterways Formation). ==Relationship to other units==

The Beaverhill Lake Group is conformably underlain by the formations of the Elk Point Group. In most areas it is conformably overlain by the formations of the Woodbend Group, and in northwestern Alberta and northeastern British Columbia it is disconformably overlain by the Muskwa Formation. ==Paleontology==

The carbonate rocks of the Beaverhill Lake Group contain rich brachiopod faunas. There are also crinoids, ostracods and corals, and, in the Swan Hills Formation, stromatoporoids. ==Hydrocarbon production==

Since 1957 oil has been produced from the Swan Hills Formation of the Beaverhill Lake Group in the Swan Hills area of northern Alberta, where it includes Devonian reef structures similar to those of the Leduc Formation and the Rainbow Member in Alberta. ==References==