#high cascades

[bettergeology]

(Lava) Bomb on the Mountain (volcano)

South Sister is Oregon's 3rd tallest peak. It's a stratovolcano 10,363 ft (3,158 m) tall, part of the Three Sisters complex which includes dozens of smaller volcanoes and several older eroded mountains.

The upper 2,000 feet or so (~650 m) is a 20,000 year-old cinder cone, the result of a fire-fountain-type eruption of lava. One of the common features of that style of eruption are lava bombs - chunks of liquid lava flung through the air that cool in streamlined and elongated shapes. The upper flank of the mountain is very steep, and makes for slow climbing through cinders. Slope pitches average 30˚ in this area, and get as high as 58˚!

Perched at random on this slope is probably the largest lava bomb I've ever seen! It's probably about a meter across and shows the streamlined, elongated nature of a bomb very well. I'm not sure why it's still sitting at that precarious location, but up close you can see the vesicular texture of erupted lava (basaltic andesite). This might be classified (yes, there are sub-classifications of lava bombs - geologists love classifications!) as a breadcrust bomb because it looks almost like a crusty bread with cracked crust. These are very common on volcanoes like this. It's hard to see in this picture, but amidst the vesicles (bubbles) in the rock are numerous plagioclase feldspar crystals ~0.5-1 mm across.

Anyway, volcanoes are cool.

[rabbitcruiser]

West Diamond Lake Highway, OR (No. 2)

Mount Bailey is a relatively young tephra cone and shield volcano in the Cascade Range, located on the opposite side of Diamond Lake from Mount Thielsen in southern Oregon, United States. Bailey consists of a 2,000-foot (610 m)-high main cone on top of an old basaltic andesite shield volcano. With a volume of 8 to 9 km3 (1.9 to 2.2 cu mi), Mount Bailey is slightly smaller than neighboring Diamond Peak. Mount Bailey is a popular destination for recreational activities. Well known in the Pacific Northwest region as a haven for skiing in the winter months, the mountain's transportation, instead of a conventional chairlift, is provided by snowcats—treaded, tractor-like vehicles that can ascend Bailey's steep, snow-covered slopes and carry skiers to the higher reaches of the mountain. In the summer months, a 5-mile (8 km) hiking trail gives foot access to Bailey's summit. Mount Bailey is one of Oregon's Matterhorns.

Native Americans are credited with the first ascents of Bailey. Spiritual leaders held feasts and prayer vigils on the summit.

Source: Wikipedia

[rabbitcruiser]

West Diamond Lake Highway, OR (No. 4)

The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as many of those in the North Cascades, and the notable volcanoes known as the High Cascades. The small part of the range in British Columbia is referred to as the Canadian Cascades or, locally, as the Cascade Mountains. The highest peak in the range is Mount Rainier in Washington at 14,411 feet (4,392 m).

The Cascades are part of the Pacific Ocean's Ring of Fire, the ring of volcanoes and associated mountains around the Pacific Ocean. All of the eruptions in the contiguous United States over the last 200 years have been from Cascade volcanoes. The two most recent were Lassen Peak from 1914 to 1921 and a major eruption of Mount St. Helens in 1980. Minor eruptions of Mount St. Helens have also occurred since, most recently from 2004 to 2008.The Cascade Range is a part of the American Cordillera, a nearly continuous chain of mountain ranges (cordillera) that form the western "backbone" of North, Central, and South America.

Source: Wikipedia

[bettergeology]

Mount Hood

Mount Hood is the tallest peak in Oregon, over 11,240 feet. It's an active stratovolcano covered in glacial ice that last erupted about 240 years ago (in the 1780s, exact years unknown). The large crater that opens to the south near the summit was formed about 1,500 years ago, and the pinnacle standing in the middle - Crater Rock - was squeezed out like toothpaste in the most recent eruption (~240 years ago). The crater contains many active fumaroles and steam vents, hinting at the heat still within. The eruption that formed the crater is called the Timberline Eruptive Period. The collapse of the south face of the volcano deposited a huge debris fan that now appears as a gentle slope to the summit area. Timberline Lodge, a 1936 Works Progress Administration (WPA) project owned by the US Forest Service, is built on this debris fan and offers tremendous views of the southern glaciers, the summit cliffs, and the ski slopes that remain open to skiing through August most years.

These photos were taken in early August, 2022 on Kodak Gold film. Find more at my Flickr!

[rabbitcruiser]

West Diamond Lake Highway, OR (No. 3)

Odell Lake is located near Willamette Pass in the northwest corner of Klamath County, Oregon, United States. It is one of several lakes in the Cascade Range in Central Oregon, and lies within the Deschutes National Forest. It was named for Oregon Surveyor General William Holman Odell by Bynon J. Pengra, in July 1865, while they were making a preliminary survey for the Oregon Central Military Road, which would later become Oregon Route 58. The lake fills a basin carved by a glacier, and the resulting terminal moraine confines the water along the lake's southeast shore.

Source: Wikipedia

[rabbitcruiser]

West Diamond Lake Highway, OR (No. 1)

Mount Thielsen (Klamath: hisc’akwaleeʔas), is an extinct shield volcano in the Oregon High Cascades, near Mount Bailey. Because eruptive activity ceased 250,000 years ago, glaciers have heavily eroded the volcano's structure, creating precipitous slopes and a horn-like peak. The spire-like shape of Thielsen attracts lightning strikes and creates fulgurite, an unusual mineral. The prominent horn forms a centerpiece for the Mount Thielsen Wilderness, a reserve for recreational activities such as skiing and hiking. Thielsen is one of Oregon's Matterhorns.

Thielsen was produced by subduction of the Juan de Fuca Plate under the North American Plate. Volcanism near the Cascades dates back to 55 million years ago (mya), and extends from British Columbia to California. Thielsen is part of the High Cascades, a branch of the main Cascades range that includes several Oregon volcanoes less than 3.5 million years old; it is also a member of a group of extinct volcanoes distinguished by their sharp peaks.

The area surrounding the volcano was originally inhabited by Klamath Native Americans, and was later encountered by settlers. One of the visitors was Jon Hurlburt, an early explorer of the area who named the volcano after the engineer Hans Thielsen. Later explorers discovered nearby Crater Lake. The volcano was not analyzed until 1884, when a team from the United States Geological Survey sampled its fulgurite deposits.

Source: Wikipedia

[bettergeology]

Studying and mapping the recently discovered Twin Lakes Fault on Mount Hood, Oregon. This segment bounds Frog Lake, and the lake is being dropped down while the mountain is being uplifted. This is called a normal fault. In most places, the scarp is about 1.5m high. The downed tree crosses the scarp.

[bettergeology]

Mt. Jefferson is Oregon’s second highest point, at 3,199 meters, it isn't a giant, but the relatively low-lying mountains and plains around it ensure the volcano stands out. It is far more heavily glaciated than Mt. Hood, and creates a fantastic climbing challenge, as well as dramatic spires around its summit.To the original inhabitants, it is known as Seekseekqua. 

Here, the volcano (last erupted about 950 A.D.) is seen from the more iconic Oregon symbol of Mount Hood, above the Timberline Lodge (about 1,950 meters), and it is difficult to imagine the fire that brews below. After over 1,000 years of quiet, it is difficult to say how active the volcano is now, though it would be irresponsible to call it dead. Cascade volcanoes are on their long-term dying as their source of magma (the subjecting Juan de Fuca plate) plunges ever-deeper into the mantle. Eventually the crags shall be forever silent, and crumble away into eternity.

If you like these photos, please look at more from this trip over at my Flickr page.