COLUMBIA-ICEFIELD

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GEOLOGY

ALBERTA CANADA

 

The​ Columbia Icefields are the largest and most easily accessed Icefields in North America.

ROCK LAYERS

The

Palliser Limestone

The Palliser Limestone is a dark grey, finely crystalline limestone mottled with grey-brown dolomite, the estimated thickness is between 650 feet (200 meters) to 720 feet (220 meters). The limestone in the formation resembles exfoliating granite where thin slabs fall off resembling an onion, this is because the formation at Big Bend Peak has been tilted. 

 

The formation is split into two members: 

.Morrow Member

The lowest member is characterized by the massively bedded cliff-forming Morrow member and is 600 feet (180 meters) to 833 feet (254 meters).

.Costigan Member

The highest member is less resistant to weathering and is comprised of thinly bedded, argillaceous limestone (contains clay), and is 100-150 feet (30-45 meters).    

paleoalluvial fan deposits

The

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SUNwapta RiveR

Continued Rock Slides over the years eventually closed off the Sunwapta River and impounded a lake upstream, this forced the water to cut through the loose rock and talus. The river was and still is carrying glacial outwash which filled the upstream lake quiet fast with gravel and sand, continued downcutting of the river has formed terraces. 

River terraces are characterized by a bench or step that resides along the river valley and is formed by the rivers past flow. They form by a climate or hydrological change that forces downcutting, the terraces are usually the remnants of past floodplains and are cut through by the river as it extends deeper into the valley. 

Meltwater from other close glaciers cut smaller rivers into the terraces where the water then mixes as waterfalls into the Sunwapta River from smaller streams. 

Sunwapta in the Sioux/Dakota language means Stony or turbulent 

ATHABASCA GLACIER

The headwaters of the Sunwapta River start at the Athabasca Glacier and confusedly enough the Athabasca River begins at the 2-kilometre long Columbia Lake (Not its official Name) that is located at the base of the Columbia Glacier. The reason the name of the Columbia Lake is unofficial is that another 15-kilometre long lake by the same name exists to the south, and is the headwaters of the far larger Columbia River. Eventually, meltwater from the Columbia Icefields does end up in the Columbia River.

The Glacier as of 2007 was 6.2 kilometres long, this measurement is from the glacial toe to where it flattens out into the Icefield. In 1844 during the little ice age, the glacier was around 8 kilometres long. The loss of 5-10 meters each summer shows a rapid melt rate, at its highest, the upper end of the glacier is 2,800 meters while its lowest point is 1,980 with a difference of 820 meters. Its widest point is 1.3 kilometres located at its lowest icefall.

The Simpson Pass Thrust is located at the front of the current location of the glacier, some years it may be visible others not as meltwater covers the fault with sediment and water as the glacier melts. Below the fault in the footwall is the Eldon Limestone, the layer above in the hanging wall is either the Eldon or Snake Indian Formation and has been overturned from the Break-Thrust Anticline to the left on Mount Athabasca. 

  

Snow Dome

Snow Dome is one of two hydrographic apexes on the North American continent where water drains to three separate oceans, with the Triple Divide Peak in Glacier National Park Montana being the second. The three oceans where water drains to are the Arctic Ocean, the Pacific Ocean and the Atlantic Ocean. Further to the north is the Arctic/Pacific divide, which also crosses Snow Dome.

MOUNT ATHabasca

The

REFEreNCES

Environment Canada Parks service, Parks and People, Columbia Icefield, Ice Apex of the Canadian Rockies.

M. E. Holter: Limestone Resources Of Alberta Economic Geology Report 4, Alberta Research Council 1976.

 

Ben Gadd: Canadian Rockies, Geology Road Tours. Page 346 and 347, Corax Press. First printing: 2008, Second: 2009.

 

Scoon, Roger. (2019). Geotraveller 38: Geology of the Canadian Rocky Mountain National Parks. 10.13140/RG.2.2.19465.19047. 

Levson, V. M. British Columbia Geological Survey & Rutter, N. W. Department of Geology, University of Alberta, Edmonton, Alberta (1995). Pleistocene Stratigraphy of the Athabasca River Valley Region, Rocky Mountains, Alberta. Géographie physique et Quaternaire, 49 (3), 381–399. https://doi.org/10.7202/033061ar 

 

GHOST RANCH
NEW MEXICO, U.S.A
TROPICAL STORM ISAIAS
MARYLAND, U.S.A
BORAH FAULT SCRAP
IDAHO, U.S.A