Sunday, January 20, 2013

Beacon Rock

One last short stop on my loop (bridge-of-gods-landslide-and-history and icy-multnomah-falls) up the lower Columbia River Gorge was Beacon Rock. The rock was named by Lewis and Clark. They must have been feeling good when they saw this rock as it was at this location in the gorge that they first noted tidal influences on the river.

Beacon Rock
Beacon rock is the remains of a volcano. The rock is the hard solidified magma that once was the core of the small cinder cone. The rest of the mountain was eroded away by the huge ice age floods that surged down the river. The United States Geological Survey recently determined the age of this volcano to be approximately 57,000 years old. It was one of several associated with a dike of magma extending to the north several miles. Perhaps there were others to the south that were completely eroded away by the river. The rock was almost eroded during the Anthropocene. The US Army Corp of Engineers considered using the rock for jetties at the mouth of the Columbia River.
Given the cold, wind and icy conditions as well as my needing to get to a job site I passed on taking the trail to the summit hence no details. But the remnant of a small volcano of such a young age is a reminder that the Cascade volcanic range consists of more than a series of large strato volcanoes. Another eruption like the one at Beacon Rock in the vicinity would make for an interesting alteration of the landscape and the flow of the Columbia River.

1 comment:

Garry Hayes said...

One of my favorite hikes when I have the rare opportunity to get up that way!