Columbia River Basalt Group
Columbia River Basalt Group is a vast province of Miocene to Pleistocene flood basalt flows that cover much of the Columbia Plateau and Pacific Northwest.
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Geography
| Continent | North America |
|---|---|
| Region | Northern Rift Zone |
| Subregion | Pacific Northwest |
| Country | United States |
| State | Oregon |
| County | Multnomah and Hood River counties |
| District | Gorge of the Columbia River |
| City | Portland and The Dalles |
| Timezone | AmericaLos Angeles |
| Latitude | 45.7 |
| Longitude | -121.2 |
| Maps |
11:51 AM LOCAL TIMEColumbia River Basalt Group is a large and geologically significant province of flood basalt flows that erupted during the Miocene to Pleistocene epochs. Spanning over _20,000 square kilometers across eastern Oregon, southern Washington, and parts of Idaho, these basalts are responsible for defining much of the region's **geology**, **soil**, and **landscape**. The flows originated from a series of ** fissure vents and volcanic complexes**, resulting in wide, relatively thin sheets of basalt that often flood valleys and carve dramatic escarpments. Key features and landforms shaped by these basalts include the Columbia River Gorge, Snake River Plain, and extensive basalt plains of the Lower Columbia and Puget Sound_ areas. The basalts are typically dark gray to black and are critical habitat for native fish species; they also influence groundwater flow and sediment transport. Visitors and researchers explore this region to understand igneous processes, regional tectonics, and hazard history.
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