For the more information about the air resources of the National Park Service, please visit http://www.nature.nps.gov/air/.
Grande Ronde Feeder Dikes
The Grande Ronde Feeder Dikes is the best example of basalt dikes, the congealed feeder sources of the Columbia River basalt plateau. The site illustrates how these flows originated by eruption along multiple fissures.
Location: Asotin County, WA
Year designated: 1980
Please remember, National Natural Landmarks (NNLs) are not national parks. NNL status does not indicate public ownership, and many sites are not open for visitation.
Last Updated: June 28, 2012