Hawaii Lava Flows are Look at Oregon Coast Millions of Years Ago

Published 06/17/2018 at 5:42 PM PDT
By Oregon Coast Beach Connection Staff

(Portland, Oregon) – If you want to get glimpse of what some parts of the Oregon coast looked like 15 million years ago, or maybe even 40 million years ago, look at the volcanic disaster in Hawaii right now. (Above: Rocky Creek / Depoe Bay pillow basalts).

It’s there where Mt. Kilauea is coughing up tons of hot molten rock every minute and gushing out rivers of lava that are marching their way across the land and into the sea. It’s here on the Oregon coast – which was actually part of a sea bed until about ten million years ago – where the same scene played out.

Especially fascinating to watch in Hawaii right now are the lava flows hitting the ocean with that rather acidic and dangerous steam - always grippingly dramatic. The heated masses explode upon contact with the sea water, which then in turn cool to become something you see in many places on Oregon’s coastline.

This is how the pillow basalts of Depoe Bay and Yachats were formed. In many ways, watching that gnarly lava take a dive into the sea is watching how those areas were formed. Those puffy, rounded and smoothed out shapes you see, especially in the Depoe Bay area, are called pillow basalts. There are some examples around Yachats – although some of these could just be wear and tear by 40 million years of tidal action.

Hawaii right now is like a live scene from these beaches millions of years ago, said Dr. Martin Streck, head of geology at Portland State University.

“When basalt lava flows into water, like a lake or into the ocean, that’s when it’s these so-called pillow basalts,” Streck said. “They make these nice forms that are really rounded.”

In other ways, those lava flows burning and disintegrating across Hawaiian forests and homes were just what you would’ve seen at other points in time inland from the coast. Silver Falls State Park and its basalts are a good example of that, while major landmarks on the beaches such as Tillamook Head or Cape Meares are the result of hundreds, maybe thousands of such flows.

Streck said what you see at Depoe Bay and in Hawaii may be similar in composition, in that it requires certain kinds of magma to form basalts. Other kinds of lava / magma won’t form that.

Also, the pillow basalts are much, much older than other black rocky areas of the region.

“One has to go back 40 million years ago, maybe 45 million years ago,” Streck said. “It depends on what you’re comparing with lava formations underwater.”

Photo USGS: Hawaii right now: this is how pillow basalt is formed.

One of the major factors along the prehistoric Oregon coast were the eruptions from what is now northeast Oregon some 18 million years ago. For several million years these raged across the landscape. Just like Kileuea, these flows were sometimes 10 to 20 feet high as they marched along.

Other basalts along the Oregon coast are much older and are locally derived, Streck said. These are usually the pillow basalts, but not always. A handful of local volcanoes – including Cape Perpetua – were responsible for much of the basalt in and around the Yachats area.

However, as an interesting side note, before all that something really surprising happened, adding to the volcanic action to come.

“About 50 million years ago an island like Hawaii was added to the North American continent, and this ocean plateau had a lot of similarity with the island of Hawaii,” Streck said.

Exactly how all this came together to create the Oregon coast we know is extremely complex. It goes far beyond even several million years worth of lava flows, set 20 million years apart. But you can see elements of it by watching the flows on television searing their way across Hawaii. Oregon Coast Lodgings for this - Where to eat - Maps - Virtual Tours

MORE PHOTOS BELOW

Above: Hawaii right now, courtesy USGS. Lava flowed like this covered Oregon 18 million years ago. Below: more pillow basalt from the Oregon coast.

More About Oregon Coast hotels, lodging.....

More About Oregon Coast Restaurants, Dining.....

LATEST Related Oregon Coast Articles

Back to Oregon Coast

Contact Advertise on BeachConnection.net
All Content, unless otherwise attributed, copyright BeachConnection.net Unauthorized use or publication is not permitted