Glacial erratic boulders of King County are large glacial erratic boulders of rock which were moved into King County, Washington by glacial action during previous ice ages.
The Pleistocene ice age glaciation of Puget Sound created many of the geographical features of the region, including Puget Sound itself, and the erratics are one of the remnants of that age. According to Nick Zentner of Central Washington University Department of Geological Sciences, "Canadian rocks [are] strewn all over the Puget lowland, stretching from the Olympic Peninsula clear over to the Cascade Range." Erratics can be found at altitudes up to about 1,300-1,600 feet (400-490 m) in the Enumclaw area, along with kames, drumlins, and perhaps also the unique Mima mounds. The soil of Seattle, the county's (and state's) largest city, is approximately 80% glacial drift, most of which is Vashon glacial deposits (till), and nearly all of the city's major named hills are characterized as drumlins (Beacon Hill, First Hill, Capitol Hill, Queen Anne Hill) or drift uplands (Magnolia, West Seattle). Boulders greater than 3 meters in diameter are "rare" in the Vashon till, but can be found, as seen in the table below.
Video Glacial erratic boulders of King County, Washington
List of boulders
Maps Glacial erratic boulders of King County, Washington
References
- Notes
- Sources
- Booth, Derek B.; Troost, Kathy Goetz; Shimel, Scott A. (2008), Geologic Map of Northeastern Seattle (Part of the Seattle North 7.5 X 15-minute Quadrangle), King County, Washington: Geologic Summary, United States Geological Survey
- Bretz, J Harlen (1913), Glaciation of the Puget Sound Region (PDF), Washington Geological Survey .
- Dolan, Maria (2004), "Tiger Mountain: Talus Rocks", Outside Magazine's Urban Adventure: Seattle, W. W. Norton & Company, ISBN 9780393323979
- Goldstein, Barry (1994), "Drumlins of the Puget Lowland, Washington State, USA", Sedimentary Geology (91): 299-311, doi:10.1016/0037-0738(94)90136-8
- Hutton, Jane (December 2012), "Distributed Evidence: Mapping Named Erratics", in Ellsworth, Elizabeth; Kruse, Jamie, Making the Geologic Now;Responses to Material Conditions of Contemporary Life, pp. 99-103, ISBN 978-0-9882340-2-4
- Livingston, Vaughn E. (1971), Geology and Mineral Resources of King County, Washington (PDF), State of Washington Department of Natural Resources in cooperation with United States Geological Survey, Bulletin 63
- Morgan, Bruce (June 2012), "Part 6 of the Series: Living with Your Next Door Wildlife Neighbors: Memories of Beaver Lake Wildlife" (PDF), The Beaver Lake Monitor, Sammamish, Washington: Beaver Lake Management District Advisory Board, 13 (1), archived from the original (PDF) on 2015-09-24
- Ray, Robert C., ed. (1891), The Coast of British Columbia: Including the Juan de Fuca Strait, Puget Sound, Vancouver and Queen Charlotte Islands, U.S. Government Printing Office, Issue 96 of US Navy Bureau of Navigation, Hydrographic Office; Volume 15106 of CIHM/ICMH Microfiche series
- Stekel, Peter (2009), "Chapter 18: Cougar Mountain", Best Hikes Near Seattle, Rowman & Littlefield, p. 152, ISBN 9780762755813
- Troost, Kathy Goetz; Booth, Derek B. (2008), Geography of Seattle and the Seattle area, Washington, Geological Society of America, doi:10.1130/2008.4020(01)
- Waterman, T.T. (1922), "The Geographical Names Used by the Indians of the Pacific Coast--Indian Place Names About Seattle", Geographical Review, American Geographical Society, 12
- Weber, Andrew; Stevens, Bryce (2010), 60 Hikes Within 60 Miles: Seattle: Including Bellevue, Everett, and Tacoma, Menasha Ridge Press, ISBN 9780897328128
Further reading
- John Figge (2008), The Glacial Origins of the Puget Basin: The Evolution of the Modern Lowland Landscape (PDF), The Northwest Geological Institute - via North Seattle Community College
- Hannah Holmes (March 2012), "Rock ... And Roll: How a glacier pushed a boulder to a place near you", National Geographic
External links
- Washington glacial erratics project at University of Washington dept. of earth and space sciences
Source of article : Wikipedia
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