Cascade Volcanoes Tour from Space: Oregon

The Oregon Cascade Range is… complicated. From the surface, it looks like a series of volcanoes that we just started exploring. british columbia It stays the same. But once you start looking at the deep geological processes that give rise to volcanoes in Oregon, you quickly realize that there is a lot going on.

“How many?” do you say Here’s a short list:

• The Juan de Fuca plate still dominates the North American continent just off the Pacific coast.

• Much of the basin along the Columbia River is filled with basaltic lava from the greatest flood basalt age of the past 50 million years.

• The high waterfalls from Hood to Three Sisters are located in faulted grabens (valleys) bordering both sides of the mountain range.

• Several major fault zones intersect the Cascade Range.

• To the west, the High Lava Plains, a chain of rhyolite and basalt volcanoes about 10 million years old that become younger, intersect the Cascade Range near Bend, Oregon.

• The Basin & Range, a region of mountain ranges and valleys in western North America, begins in southern Oregon just east of the Cascade Range.

We won’t get into the “why” of all this, but volcanic activity in the Oregon Cascade Range is certainly influenced by a cluster of these tectonic factors. Another fun thing about the Oregon Cascade Range is that I do a lot of research there. many About them.

As usual, you can find: high resolution version of these Sentinel-2 images here.

Mt Hood (Wy’East*)

Mt Hood Mount Rainier in Portland is like Mount Rainier in Seattle. It’s the ever-present sentinel that makes for a beautiful setting and ominous neighborhood. Few people in the Portland area would know that Hood exploded. As recently as 1865! If you’ve ever spent time at Mt. Hood and its famous Timberline Lodge, you’ve seen some of the action. on Over the past 250 years, it has climbed to near the summit. Additionally, the river channels leading from Hood, especially those to the south, are blocked by volcanic debris transported there. pyroclastic Flows and volcanic advection.

All of this adds up to Hood. Land at #6 Most Potentially Ranked by USGS dangerous America’s volcanoes make it the 4th most dangerous volcano in the Cascade Mountains. Earthquake swarms are relatively common near Mt. Hood, but are typically associated with: a series of defects A place running south of the volcano. Hood is also home to two small glaciers. Potential threat from volcanic mudflows baby face between eruption.

Mount Jefferson (Seekseeksqua)

mount jefferson, a remote volcano in the central Cascades of Oregon, was once one of the largest volcanoes along the west coast of North America. The last ice age had many impacts on Jefferson, leaving behind a lumpy mass of lava flows and volcanic debris. Jefferson’s own eruption may have last occurred during the last Ice Age. About 15,000 years ago. The eruption was large and sent volcanic ash as far east as present-day Idaho.

Even if the main volcanic eruption did not occur generation For thousands of years, associated concrete cones have exploded south of Jefferson. Most recently in 950 AD. Because Jefferson is covered in snow all year round, volcanic mudflows are always present. potential dangerThis is especially true if you go down to a reservoir like Detroit Lake or Billy Chinook Lake.

Belknap Crater and Collier Cone

The Central Oregon Cascades are filled with basaltic shield volcanoes, lava flows, and scoriacones. That’s strange. In fact, some of the most extensive activity The mountains along the Cascade Range are not large volcanoes like Mount St. Helens, but rather Lava flow fields in central Oregon. Over the past 3,000 years, lava has flowed from numerous small volcanoes and fissures in the McKenzie Pass area, sending lava nearly 10 miles down the McKenzie River valley.

Volcanic activity like we see Belknap Crater Collier cones (cinder cones of the North Sister Slope formed about 1,500 years ago) are uncommon in continental subduction zones such as the Cascades. One idea is that faults across central Oregon, as part of the complex structures mentioned above, allowed this basaltic lava to rise to the surface more easily than in other subduction zones, such as the Andes.

Belknap Crater’s most recent activity occurred only 1,500 years ago, and you can explore this strange, lunar-like landscape by crossing the McKenzie Highway. vicinity Sand Mountain Volcanic Area It exploded just 1,050 years ago.

Three Sisters (Clarkane)

that much Three sisters from central Oregon It’s one of my favorite places. Few places on Earth are richer in volcanic diversity than the Three Sisters region. You’ll find basaltic andesite lava flows and cinder cones, massive composite volcanoes (three of them!), rhyolite domes, massive pumice and ash deposits, glaciers, and more.

Sentinel-2 images capture most of the Three Sisters region. In fact, the Three Sisters (North, Middle, and South Sisters) themselves are large arc volcanoes that (generally) get younger the further south they go. Just east of South Sister is Broken Top, an ancient volcano that was active 150,000 years ago. What looks like strange pancakes just south of South Sister are Devils Hills and Rock Mesa. Just 2,000 to 2,200 years ago.

Interestingly, although the Three Sisters have seen eruptions just north and south of the Three Sisters over the past few thousand years, there has yet to be a confirmed eruption from the main sister peaks. For at least the last 20,000 years. That said, South Sister is one of the only volcanoes in the Cascade Mountains. Deformation associated with magma intrusion is shown. Under a volcano in the 21st century.

Newberry Caldera

Newberry Caldera It may not be in the same lineup as the Cascade Range, but its eruption shaped the area around Bend. Newberry, so close to the Three Sisters, has actually erupted more recently and more frequently over the past 10,000 years than the neighboring Cascade Range.

The large gray mass south of Newberry Caldera is “large obsidian flow” is an event that erupted only 1,300 years ago. has been one of Largest source of obsidian Targeted at Native Americans living in the Pacific Northwest.

Newberry Caldera’s twin lakes, Paulina Lake and East Lakes, are separate. Another small obsidian flow and cinder cone. There are still hot springs on the shore of the lake.

Newbury has more, too. Much of the area around the caldera is covered by basaltic andesitic lava flows associated with the Newbury magma system, which erupt into fractures and cinder cones along faults that cross the region. that much northwest rift zone Newberry created a volcanic landscape of dark lava flows that includes Lava Butte, a small concrete cone just off Highway 97.

Newberry is one of the following sites: Striking “hot rock” geothermal energy prospects The same goes for the US. Altarock Energy has been working on: improved geothermal system Development that breaks up rock to allow easier fluid flow underground.

Crater Lake (Giiwas)

Until about 7,600 years ago, there was a place like Mount Hood in southern Oregon. It now has one of the most beautiful lakes in the world. crater lake It is the product of the largest known eruption in the Cascade Range. Cataclysm of 5,680 B.C. Mt. Mazama (referring to a mountain in the past). This eruption was large enough to empty the interior of the volcano, leaving no ash behind. base as it were.

all things folded Like a piston, maybe for a few days. This transformed the ~11,000-12,000 foot volcano into a caldera over 2,000 feet deep (or ~5,000 feet above sea level). That’s an altitude loss of 7,000 feet! More than 50 cubic kilometers of ash and debris exploded during the eruption. bay 7 It is an eruption of the same scale as the Tambora volcano eruption in 1815.

Wizard Island is a small concrete cone. formed inside the caldera Several hundred years after a massive explosion. There were several other explosions. happened It lies below the surface of the lake, following an eruption in 5,680 BC. Although Crater Lake has not likely seen any eruptions in the last ~6-7 thousand years, some of the residual heat from the magma system below is still leaking into the lake. Vents in the bottom of a lake.

Next time, we’ll look at the Cascades in Northern California and consider what the future holds for the Cascade Range.