Type Geological formation Other Shale, anhydrite Primary Limestone Overlies Rundle Group | Underlies Golata Formation Province Alberta Named for DeBolt Unit of Rundle Group | |
Sub-units Upper Debolt
Lower Debolt Thickness up to 366 metres (1,200 ft) Region Alberta, British Columbia | ||
The Debolt Formation is a stratigraphical unit of Meramecian age in the Western Canadian Sedimentary Basin.
Contents
It takes the name from the hamlet of Debolt, Alberta, and was first described in the Amerada Crown GF23-11 well near Debolt by G. Macauley in 1958.
Lithology
The Debolt Formation is commonly subdivided into a lower and upper unit. Lower Debolt rocks are bioclastic limestones deposited on a stable carbonate ramp. These lower Debolt rocks are rarely dolomitized and therefore have little porosity or commercial use. Upper Debolt sedimentation is characterized by a number of shallowing upwards facies. At the base of the Upper Debolt is distal and medial ramp argillaceous limestone facies with limited laminations and thin bedding. These argillaceous facies rarely contain clean carbonate interbeds in the medial ramp setting, predominately wackestones and packestones. These facies are followed by a capping proximal ramp/shoal facies with abundant skeletal packstones and grainstones.
Distribution
The Debolt Formation is present in the sub-surface in the Peace River Country in northern Alberta and north-eastern British Columbia. The formation is 366 metres (1,200 ft) thick close to the Rocky Mountains, and thins out northward and eastward. It has a thickness of 244 metres (800 ft) at its type locality near Debolt, Alberta.
Relationship to other units
The Debolt Formation is the upper most component of the Rundle Group. It rests conformably on the Shunda Formation, resting on shale and carbonates. It is overlain conformably by the Golata Formation of the Stoddart Group in the west, and the upper contact becomes unconformable with gradually newer formations to the east and north (Permian, Triassic, Jurassic and Cretaceous beds).