2023年12月7日 · The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over 210,000 km2 of mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada.

2023年4月18日 · Columnar jointing is found in the Columbia River Basalts and Rattlesnake Tuff in and around John Day Fossil Beds National Monument. The Columbia River Basalts are flood basalts that were erupted from fissures in eastern Oregon, southeastern Washington, and Idaho, mostly between 16.7 and 15.5 million years ago.

Columnar jointing of volcanic rocks exists in many places on Earth. Perhaps the most famous basalt lava flow in the world is the Giant's Causeway in Northern Ireland, in which the vertical joints form polygonal columns and give the impression of having been artificially constructed.

The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. [1] The basalt group includes the Steens and Picture Gorge basalt formations.

THE COLUMBIA RIVER BASALT GROUP: The Columbia Basin of eastern Washington is plastered with deep layers of a fine grained black rock known as basalt. The basalt is lava that cooled and hardened after it flooded over the landscape. These astounding lava floods occurred on a scale unequalled anywhere else on the entire planet.

The Sheepeater Cliffs are a series of exposed cliffs made up of columnar basalt in Yellowstone National Park in the United States. The lava was deposited about 500,000 years ago during one of the periodic basaltic floods in Yellowstone Caldera , and later exposed by the Gardner River .

The study of the Columbia River Basalt Group has focused primarily on subdividing thousands of feet of undifferentiated volcanic deposits into different lava flows, fluvial deposits, and other types of volcaniclastic sediments.

Columbia River basalts. The Columbia River basalts were deposited between 17.5 and 6 million years ago and cover an area of approximately 210,000 km 2. Five main episodes of volcanism occurred in western Idaho, central and southern Washington, and northern Oregon. PDF slideshows: Columbia River basalts by Cash and Lewis

Columbia River Basalt Group Columbia River basalt is a series Of lava flows or flood basalts ranging in thickness from 5 to 45 meters, with a total thickness of about 300 meters (Schlicker and

2024年4月4日 · The term Columbia River Basalt had long been applied to extrusive volcanic rocks of the Columbia Plateau, Washington, Oregon, and Idaho, that are predominantly basaltic. This term was raised by Waters (1961, p. 607) to group rank, the Columbia River Group, when these basalts were subdivided into the Picture Gorge Basalt and the overlying Yakima ...