Four Craters Lava Field
| Four Craters Lava Field | |
|---|---|
 Craters of the aptly named Four Craters Lava Field are seen here from the NW on Green Mountain. |
|
| Elevation | 4,924 ft (1,501 m) [1] |
| Location | |
| Location | Lake County, Oregon, USA |
| Coordinates | 43°21′40″N 120°40′08″W / 43.361°N 120.669°WCoordinates: 43°21′40″N 120°40′08″W / 43.361°N 120.669°W[1] |
| Geology | |
| Type | volcanic field |
| Age of rock | Holocene?[1] |
| Last eruption | < 50,000 years ago[2] |
Portions of this article include public domain text from the USFS Deschutes & Ochoco National Forests - Crooked River National Grassland.
Four Craters Lava Field is a basaltic volcanic field located south east of Newberry Caldera in the U.S. state of Oregon.[1] The volcanic field covers about 30 square kilometers. Four Pleistocene cinder cones are the source of the flows in the field and are aligned along a fissure trending N 30° W. The cones rise 75 to 120 meters above the flows and the distance between the northern most and southern most cones is about 3.5 kilometers.[2]
Closely related to the Four Craters lava field is Crack-in-the-Ground located at the southwest corner of the field. The eruptions from the field were accompanied by a slight sinking of the older rock surface. This shallow, graben-like sink is about 3 kilometers wide and extends to the south into an old lake basin. Crack-in-the-Ground marks the western edge of this small, volcano-tectonic depression and is nearly 9 meters deep and over a meter wide. The crack is the result of a tension fracture along a hingeline produced by the drapping of Green Mountain lava flows over the edge of upthrown side of the concealed fault zone.[2]
[edit] References
- ^ a b c d "Four Craters Lava Field". Global Volcanism Program, Smithsonian Institution. http://www.volcano.si.edu/world/volcano.cfm?vnum=1202-14-. Retrieved 2008-05-12.
- ^ a b c "Oregon Volcanoes - Four Craters Flows". Deschutes & Ochoco National Forests - Crooked River National Grassland. United States Forest Service. 2003-12-24. http://www.fs.fed.us/r6/centraloregon/geology/info/volcanoes/fourcraters.shtml. Retrieved 2008-05-12.
[edit] Further reading
- Peterson, Norman V.; Edward A. Groh (September 1964). "CRACK-IN-THE-GROUND, LAKE COUNTY, OREGON" (PDF). The Ore Bin (Portland, Oregon: State Of Oregon - Department of Geology and Mineral Industries) 26 (9): pp. 158–166. http://ir.library.oregonstate.edu/dspace/bitstream/1957/2741/1/vol26_no9_ocr.pdf. Retrieved 2008-08-21.
- Peterson, Norman V.; Edward A. Groh (March 1963). "RECENT VOLCANIC LANDFORMS IN CENTRAL OREGON" (PDF). The Ore Bin (Portland, Oregon: State Of Oregon - Department of Geology and Mineral Industries) 25 (3): pp. 33–45. http://ir.library.oregonstate.edu/dspace/bitstream/1957/2638/1/vol25_no3_ocr.pdf. Retrieved 2008-08-21.
