- Columbia River Basalt Group Stretches from Oregon to Idaho (usgs.gov)
The thick, layered lava flows of the CRBG erupted as flood basalts, which originate as some of the most highly effusive eruptions in the world. The CRBG sequence a classic example of flood basalt activity that erupted more than 350 lava flows from about 16.7 Ma to 5.5 Ma. The eruptions originated from a series of generally north-northwest-trending linear fissures, ranging from tens to hundreds of kilometers in length, located along the Washington/Oregon/Idaho border. The magma that fed these massive eruptions may have come from a plume-like upwelling from the mantle called a hot spot. Since the time of the CRBG eruptions, the North American plate has moved in a west-southwestwardly motion, and that hot spot is now believed to reside beneath Yellowstone volcano in northwest Wyoming.
- Panthalassa (Wikipedia)
Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek πᾶν “all” and θάλασσα “sea”), was the superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During the Paleozoic–Mesozoic transition c. 250 Ma it occupied almost 70% of Earth’s surface. Its ocean floor has completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific (“old Pacific”) or Proto-Pacific because the Pacific Ocean is a direct continuation of Panthalassa.
