The flows of Jordan Craters volcanic field are the youngest of a series of large Quaternary

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

fields in the eastern part of the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

. The field is thought to be approximately 3200 years old, based on findings of a lake sediment coring experiment in 1986. It was formed by basaltic

pahoehoe Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...

emanating from vents throughout the area. The most recent flows come from Coffeepot Crater, a large breached cinder cone. These flows show excellent examples of inflated lava. Historically, it is believed that Coffeepot Crater held a pond of lava that would occasionally breach the sides of the crater to flow freely into the field. Jordan Craters is approximately 120 miles (200 km) southwest of

Boise, Idaho Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown ar ...

and 18 miles (30 km) northwest of

Jordan Valley, Oregon Jordan Valley is a city in Malheur County, Oregon, United States. It is part of the Ontario, OR– ID Micropolitan Statistical Area. The city lies along Jordan Creek, a tributary of the Owyhee River; the creek is named for a 19th-century pr ...

. The craters are free and open to the public all year.

References

(archived) Volcanic fields of Oregon Landforms of Malheur County, Oregon Volcanoes of Oregon {{MalheurCountyOR-geo-stub

See also

References