Boulder Park

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Coordinates: 47°52′43″N 119°48′06″W / 47.87861°N 119.80167°W / 47.87861; -119.80167
Source: Wikipedia, the free encyclopedia.
For the community in Imperial County, California, see Boulder Park, California.
For the community in Charlevoix County, Michigan, see
Boulder Park, Michigan
.
glacial till
on Waterville Plateau, Washington, USA

Boulder Park National Natural Landmark, of Douglas County, Washington, along with the nearby McNeil Canyon Haystack Rocks and Sims Corner Eskers and Kames natural landmarks, illustrate well-preserved examples of classic Pleistocene ice stagnation landforms that are found in Washington. These landforms include numerous glacial erratics and haystack rocks that occur near and on the Withrow Moraine, which is the terminal moraine of the Okanogan ice lobe.[1][2]

Geomorphology

Boulder Park is located on the Waterville Plateau of the

glacial deposits.[1][2]

This park lies about 6 kilometers (3.7 mi) northeast and 17 kilometers (11 mi) north of the arcuate ridge of the Withrow Moraine. It marks the southern, 17,000 year-old

Spokane Floods at a time prior to when the Okanogan ice lobe partially covered the Waterville Plateau during most of the last of the Last Glacial Maximum. At its maximum extent, this ice lobe was up to 300 meters (980 ft) thick and 40 kilometers (25 mi) wide. It effectively blocked most of the Columbia River Valley and created Glacial Lake Columbia.[2][3][4]

The

haystacks. Some haystack rocks, e.g. Yeager Rock, are the size of large houses. The boulders provide important evidence for glacial erosion and transport, as well as marking the direction of movement and the terminus of the Okanogan ice lobe and the southern margin of the Cordilleran ice sheet during the Last Glacial Maximum.[2][4][5]

Underlying the glacial deposits of the Okanogan ice lobe and outcropping, where it is absent, is the middle

United States of America. It forms a large igneous province that covers an area of 163,700 km2 (63,000 mile2) of the Pacific Northwest with an estimated volume of 174,300 km3 of basalt lava and other volcanics. Eruptions were most vigorous between 17 and 14 million years ago, when over 99% of the basalt was released. Less extensive eruptions continued between 14 and 6 million years ago.[2][3]

See also

  • List of National Natural Landmarks in Washington State

References

  1. ^
    ISBN 0-89301-206-8
    .
  2. ^
    ISBN 978-1879628397
  3. ^ a b Gulick, C.W., and M.A. Korosec (1990) Geologic map of the Banks Lake 1:100,000 quadrangle, Washington. Open File Report 90-6. Seattle, Washington, Washington Division of Geology and Earth Resources. 20 p., 1 pl.
  4. ^ a b Easterbrook, D.J. (2003) Cordilleran Ice Sheet Glaciation of the Puget Lowland and Columbia Plateau, and alpine glaciation of the North Cascade Range. in Swanson, T.W., ed., Western Cordillera and Adjacent Areas. Field Guide 4, Boulder, Colorado, Geological Society of America. p. 137-157
  5. ^ Cheney, E.S. (2009) Floods, Flows, Faults, Glaciers, Gold and Gneisses, From Quincy to Chelan to Wenatchee, June 13–14, 2009. Society Field Trips in Pacific Northwest Geology Field Trip Guidebook 24. Seattle, Washington, Northwest Geological Society. 44 p.

External links

Photo gallery

  • Mixed erratics located near Sims Corner. The nearest is basalt, which the ones behind it are granite.
    Mixed erratics located near Sims Corner. The nearest is basalt, which the ones behind it are granite.
  • A kame among the glacial drift on the terminal moraine.
    A kame among the glacial drift on the terminal moraine.
  • Terminal moraine (Withrow Moraine) of the Okanagon Lobe
    Terminal moraine (Withrow Moraine) of the Okanagon Lobe
  • Multiple erratics on the terminal moraine of the Okanagon Lobe. Cascade mountains in the background.
    Multiple erratics on the terminal moraine of the Okanagon Lobe. Cascade mountains in the background.
  • Multiple erratics on the terminal moraine of the Okanagon Lobe.
    Multiple erratics on the terminal moraine of the Okanagon Lobe.

47°52′43″N 119°48′06″W / 47.87861°N 119.80167°W / 47.87861; -119.80167

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