Earth Sciences

Alaska

Denali from the west across Wonder Lake (photo by David Thompson, 2004).

Bergschrund crevasses at the head of glaciers east of Denali’s summit. (David Thompson, 2004)

Bedrock: Unnamed Granodiorite
Late Cretaceous

Stocks of granodiorite intruded into a synclinorium of Cretaceous sedimentary and volcanic rocks. The area was uplifted along the Denali fault on the north side of the range.

Kantishna, a ghost town within Denali Park north of Mt. McKinley, was the center of a 1905 stampede for placer gold, followed by lode mining for gold, silver, lead, zinc, copper and antimony.

Surfical Geology: The summit was eroded by glaciers in the Pleistocene, at the northern limit of the North American ice sheet. The summit is covered by snow year-round, and there is no vegetation above 7500 feet. Present-day valley glaciers include Muldrow Glacier to the north, Traleika and Ruth Glaciers to the east, and Kahiltna Glacier on the west side. Kahiltna provides the common route followed by Highpointers toward the summit.

Selected References:

• Harris, Ann G., 1977, Geology of National Parks, 2nd Edition: Kendall/Hunt.
• Zumwalt, Paul L., 2002, Fifty State Summits: Guide with Maps to State Highpoints, 8th Edition: Jack Grauer, Publisher, Vancouver, WA.

Other suggested sources of information:

• Glossary: http://www2.nature.nps.gov/geology/usgsnps/misc/glossaryAtoC.html
• Time scale: http://www.ucmp.berkeley.edu/help/timeform.html
• Alaska Volcano Observatory: www.avo.alaska.edu
• Denali National Park: http://www.nps.gov/dena/