USGS/Cascades Volcano Observatory, Vancouver, Washington
REPORT:
Guide to Geologic Field Trip Between Lewiston, Idaho, and Kimberly, Oregon,
Emphasizing the Columbia River Basalt Group
--
Swanson, D.A., and Wright, T.L., 1981,
Guide to Geologic Field Trip Between Lewiston, Idaho, and Kimberly, Oregon,
Emphasizing the Columbia River Basalt Group:
IN:
Johnston, D.A., and Donnelly-Nolan, J., (eds.), 1981,
Guides to Some Volcanic Terranes in Washington, Idaho, Oregon, and
Northern California:
U.S. Geological Survey Circular 838, 189p.
Introduction
The Columbia River Basalt Group comprises a tholeiitic flood-basalt
province of moderate size, covering an area of about 2x10^5 square kilometers,
with an
estimated volume of about 2x10^5 cubic kilometers (Waters, 1962).
The group is the
youngest assemblage of flood basalt known, with an age range from about
17 to 6 million years ago;
most eruptions took place between about 17 and 14 million years ago (Watkins
and Baksi, 1974; McKee and others, 1977). It is the only flood basalt province
of Phanerozoic age in North America.
Wide-ranging regional studies of the basalt, underway for the last 10 years,
have been devoted primarily to defining stratigraphic and chemical relations for
use in unraveling the history of the province and comparing the Columbia River
Basalt Group with flood basalt elsewhere. Recently, these studies have been
accelerated because of the need to know more about the stratigraphy and
structure of the basalt as related to potential storage of nuclear waste within
the basalt pile. A geologic map of the entire province is under preparation.
Reconnaissance geologic maps of the basalt in most of Washington and northern
Idaho have been completed (Swanson and others, 1979a) and eventually will be
published in color (for example, Swanson and others, 1980). Studies in 1978 and
1979 were conducted by full-time and temporary personnel of the U.S. Geological
survey under Interagency Agreement No. EW-78-I-06-1978 with the U.S. Department
of Energy in support of the Basalt Waste Isolation Program, administered by
Rockwell Hanford Operations, Richland, Washington. Personnel involved in this
mapping project have been: J.L. Anderson, R.D. Bentley, G.R. Byerly, V.E. Camp,
J.N. Gardner, P.R. Hooper, D.A. Swanson, W.H. Taubeneck, and T.L. Wright.
Return to:
[Report Menu] ...
[Circular 838 Menu] ...
URL for CVO HomePage is:
<http://vulcan.wr.usgs.gov/home.html>
URL for this page is:
<http://vulcan.wr.usgs.gov/Volcanoes/WesternUSA/Circular838/SwansonWright/introduction.html>
If you have questions or comments please contact:
<GS-CVO-WEB@usgs.gov>
06/20/02, Lyn Topinka