page_title: Banff National Park
section_title: Geology
hierarchical_section_title: Banff National Park / Geology
caption_attribution_description: English: Water reflection at Two Jack Lake, a subsidiary part of Lake Minnewanka, with Mt. Rundle in the background.Deutsch: Im Two Jack Lake, einem Seitenarm des Lake Minnewanka, spiegelt sich der Mount Rundle.
context_page_description: Banff National Park is Canada's oldest national park, established in 1885. Located in Alberta's Rocky Mountains, 110–180 kilometres west of Calgary, Banff encompasses 6,641 square kilometres of mountainous terrain, with many glaciers and ice fields, dense coniferous forest, and alpine landscapes. The Icefields Parkway extends from Lake Louise, connecting to Jasper National Park in the north. Provincial forests and Yoho National Park are neighbours to the west, while Kootenay National Park is located to the south and Kananaskis Country to the southeast. The main commercial centre of the park is the town of Banff, in the Bow River valley.
  The Canadian Pacific Railway was instrumental in Banff's early years, building the Banff Springs Hotel and Chateau Lake Louise, and attracting tourists through extensive advertising. In the early 20th century, roads were built in Banff, at times by war internees from World War I, and through Great Depression-era public works projects. Since the 1960s, park accommodations have been open all year, with annual tourism visits to Banff increasing to over 5 million in the 1990s. Millions more pass through the park on the Trans-Canada Highway.
context_section_description: The Canadian Rockies consist of several northwest–southeast trending ranges. Two main mountain ranges are within the park, each consisting of numerous subranges. The western border of the park follows the crest of the Main Ranges (also known as the Park Ranges), which is also the continental divide. The Main Ranges in Banff National Park include from north to south, the Waputik, Bow and Blue Ranges. The high peaks west of Lake Louise are part of the Bow Range. The eastern border of the park includes all of the Front Ranges consisting of from north to south, the Palliser, Sawback and Sundance Ranges. The Banff townsite is located in the Front Ranges. Just outside of the park to the east lie the foothills that extend from Canmore at the eastern entrance of the park eastward into the Great Plains. Well west of the park, the Western Ranges of the Rockies pass through Yoho and Kootenay National Parks. Though the tallest peak entirely within the park is Mount Forbes at 3,612 metres (11,850 ft), Mount Assiniboine on the Banff-Mount Assiniboine Provincial Park border is slightly higher at 3,618 m (11,870 ft).
  The Canadian Rockies are composed of sedimentary rock, including shale, sandstone, dolomite and limestone. The vast majority of geologic formations in Banff range in age from Precambrian to the Jurassic periods (600–145 m.y.a.). However, rocks as young as the lower Cretaceous (145–66 m.y.a.) can be found near the east entrance and on Cascade Mountain above the Banff townsite. These sedimentary rocks were laid down in shallow seas between 600 and 175 m.y.a. and were pushed east during the Laramide orogeny. Mountain building in Banff National Park ended approximately 55 m.y.a.
  The Canadian Rockies may have rose up to 8,000 metres (26,000 ft) approximately 70 m.y.a. Once mountain formation ceased, erosion carved the mountains into their present rugged shape. The erosion was first due to water, then was greatly accelerated by the Quaternary glaciation 2.5 million years ago. Glacial landforms dominate Banff's geomorphology, with examples of all classic glacial forms, including cirques, arêtes, hanging valleys, moraines, and U-shaped valleys. The pre-existing structure left over from mountain-building strongly guided glacial erosion: mountains in Banff include complex, irregular, anticlinal, synclinal, castellate, dogtooth, and sawback mountains.
  Many of the mountain ranges trend northwest to southeast, with sedimentary layering dipping down to the west at 40–60 degrees. This leads to dip slope landforms, with generally steeper east and north faces, and trellis drainage, where rivers and old glacial valleys followed the weaker layers in the rocks as they were relatively easily weathered and eroded.
  Classic examples are found at the Banff townsite proper: Mount Rundle is a classic dip slope mountain. Just to the north of the Banff townsite, Castle Mountain is composed of numerous Cambrian age rock formations. The uppermost section of the peak consists of relatively harder dolomite from the Eldon Formation. Below that lies the less dense shales of the Stephen Formation and the lowest exposed cliffs are limestones of the Cathedral Formation. Dogtooth mountains, such as Mount Louis, exhibit sharp, jagged slopes. The Sawback Range, which consists of nearly vertical dipping sedimentary layers, has been eroded by cross gullies. The erosion of these almost vertical layers of rock strata in the Sawback Range has resulted in formations that appear like the teeth on a saw blade. Erosion and deposition of higher elevation rock layers has resulted in scree deposits at the lowest elevations of many of the mountains.
caption: Two Jack Lake and Mount Rundle
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