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Events That Made Lassen Volcanic National Park What it is Today

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Events That Made Lassen Volcanic National Park What it is Today

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Click on the links to jump to the post!

37 to 40 million years ago: Formation of The Cascade Range.

300/400,000 years ago: Formation and collapse of Mt. Tehama (also known as Brokeoff Volcano)

18 to 25,000 years ago: Glacial Erosion during the Last Ice Age

1,100 years ago: Formation of Chaos Crags and Chaos Jumbles

1914-1917: Lassen Peak Eruption

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1. Kohm Yah-mah-nee Visitor Center
2. Sulpher Works
3. Cold Boiling Lake
4. Fantastic Lava Beds and Painted Dunes
5. Devastated Area Trail
6. Chaos Crags
7. Subway Cave

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The Cascade Range is a series of mountains, dormant volcanoes, and active volcanoes, that line the Cascadia subduction zone that is caused by the sinking of the Juan de Fuca tectonic plate beneath the North American tectonic plate. The Juan de Fuca plate is made of oceanic crust and carries water with it beneath the continental crust of North America. As water-rich oceanic crust is crushed by the intense heat and weight of continental crust, the rock melts and water is released which lowers the temperature of the melting rock and creates magma that then rises to the surface and creates volcanoes. Over millions of years, the lava that has resulted from this tectonic activity has created the Cascade Range which has continued to change and develop even today. In the image above, that last little red triangle at the southern most point of the Cascade Range is actually Lassen Volcano!

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Before the rise of Lassen Peak, there was Mt.Tehama, a massive composite volcano that was about eight miles in diameter and elevated 11,000 feet above sea level. It was created out of layers of pyroclastic flows of volcanic ash, pumice, and andesitic (thick, sticky) lava. After years of eruptions, Mt.Tehama emptied its magma chamber, and collapsed on itself, creating a 2-mile wide caldera.

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When thinking of glaciation and ice ages, we tend to imagine insanely thick and massive slabs of ice that scrape across the land, however, the glaciation that occurred at Lassen Volcanic National park is a bit different. The ice sheet didn't stretch down as far south as northern California, but large glaciers still capped the mountains of dormant volcanoes and eroded them over time as they moved. Throughout the park lays evidence of glaciation in the form of rounded hills, glacial scarring, and U-shaped valleys.

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Formation of Chaos Crags and Chaos Jumbles

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Formation of Chaos Crags and Chaos Jumbles

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Similar to Lassen Peak, but much younger, are the six plug domes known as the Chaos Crags. Formed out of the remains of Mt.Tehama, these domes are made of a mix of rhyodactite volcanic rock as well as basaltic and andesitic rock, suggesting a mix within the magma chambers. After erupting for many years, the domes quieted down just before one of the domes collapsed on itself because of the instability among the settling volcanic rock. This collapse caused an avalanche known as the Chaos Jumbles that can still be seen today when hiking in Lassen Volcanic National Park.

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In May of 1914 Lassen Peak began to let off steam and began a steady eruption event that lasted for years. On May 22nd, 1915, the mountain finally erupted violently and released massive amounts of ash and pyroclastic flows in the area. Photos during this time show a lush forest at the base of Mount Lassen that was later decimated and carried away by the flow of lava.

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https://cityseeker.com/lassen-volcanic-national-park/1264708-kohm-yah-mah-nee-visitor-center

Kohm Yah-mah-nee Visitor Center: 21820 Lassen National Park Hwy, Mineral, CA 96063

Lassen Volcanic National park has one highway that runs through the park, with two visitor centers that function as entrances. Loomis Museum is the northwest entrance and Kohm Yah-mah-nee Visitor Center is the southwest entrance. Based on the stops on this field trip, I think the ideal starting point is the park's southwest entrance: the Kohm Yah-mah-nee Visitor Center.

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Sulpher Works: 40.4487° N, 121.5369° W

After arriving at Kohm Yah-mah-nee visitor center there is a short drive or walk to our first stop: Sulpher Works! Sulpher Works is a vent of the former Mt. Tehama. Volcanic vents are located around volcanoes and let out steam and pressure that is building underground in the magma chamber. Although Mt. Tehama became extinct thousands of years ago, Sulpher Works' current hydrothermal activity is proof of the pressure and magma that still sits beneath Lassen Volcanic National Park today. After seeing the awesome mud pots and volcanic activity at work, we’ll go back on the trail to drive up Highway 89 to the trail that leads to our next stop.

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Cold Boiling Lake GPS Coordinates: 40.456469, -121.482933

After driving to Kings Creek Falls Trailhead parking we’ll head out on foot down Twin Meadows/Rice Creek Trail which takes us to our next stop which is Cold Boiling Lake! At this point in the trip, it might be a good time to take a break after all the hiking to refuel and rest and Cold Boiling Lake is the perfect place to do just that. This lake is a little less traveled than other lakes that have similar geothermal features, so it’s a great place to experience nature without the crowds.

As magma cools beneath the surface of the earth, it lets off gases that find their way out of the depths by any means possible. Beneath this small lake are cracks that allow an easy escape for the gases lurking beneath the park. This lake isn’t hot but it appears to be boiling as carbon dioxide gently bubbles up to the surface.

After a refreshing lunch and fun activity of who can spot the most bubbles, we’ll get back on the road and head to Summit Lake Campground.

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Third Stop: The Fantastic Lava Beds and Painted Dunes

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Third Stop: The Fantastic Lava Beds and Painted Dunes

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Painted Dunes/Fantastic Lava Beds GPS Coordinates: 40.5457° N, 121.3047° W

At summit lake campground we’ll go down the first trail on our way to The Fantastic Lava Beds and Painted Dunes: Echo Lake/Twin Lakes Trail. We’ll hike past several lakes before we reach the next trails: Rainbow Lake to Nobles Trail, and then Butte Lake to Snag Lake Trail where we’ll finally see the beautiful Painted Dunes right next to one of the many volcanoes located in Lassen: Cinder Cone Volcano.

As the name suggests, this is a cinder cone type of volcano that erupted mafic and andesitic lava around 350 years ago. The volcano’s ash and lava flows poured over the land destroying plant life for miles and even dammed up creeks which created two lakes that are still in the park. The Lava Beds at Lassen are the remains of this lava flow today. When looking at the Painted Dunes its hard to imagine that you're still on planet Earth because of the vivid pinks and reds against the black hardened lava flows. The vivid colors are actually fallen ash that landed on lava while it was still incredibly hot. The ash reacted to this heat similarly to what happens to a cut apple that's been left on a counter, by oxidizing into the colors we see today.

This will be the longest hike on the trip which is why on the way back there is the option of camping at Summit Lake Campground for the night and continuing on in the morning.

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Devastated Area Trail GPS Coordinates: 40° 29' 16'' North , 121° 30' 14'' West
Our next stop is the Devastated Area Loop Trail. For hundreds of years Lassen Peak remained calm and still, allowing a lush forest to develop at its base and around what is now Lassen Volcanic National Park. In May of 1915 when Lassen Peak erupted, this lush forest became the closest victim of its lava flows. In a short amount of time, the volcano launched massive boulders across the park and carried away the forest that took years to grow. Today there is a trail marking this area that showcases the destructive power of the now-resting Lassen Peak.

Hiking this trail is a really cool way to see how the Earth is ever changing and even though there’s evidence of destruction, the park is recovering that lush forest again. From this trail you can actually see the path of the lava flows that carried away trees and rocks that launched from the volcano. There’s also an amazing view of the star of the park: Lassen Peak. After this stop we get back on the highway and follow it northwest to our next stop.

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Chaos Crags GPS Coordinates: 40.5240° N, 121.5222° W

Our next stop is Chaos Crags. Like the name suggests, this area is quite chaotic and difficult to hike at the highest elevation with no trails leading to the center. However it’s one of the most interesting parts of the park and the trail on this field trip will take us to a great view of the dormant volcano. On the way to this trail there is also another smaller trail off the side of the highway that leads to the Chaos Jumbles. Either stop is a great way to view the long lasting impacts of the violent eruptions that once took place at Lassen Volcanic NP, and take in the awesome reality that there is still activity in this park. Next we get back on Highway 89 and head to our last stop.

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Subway Cave GPS Coordinates: N 40 41.126 W 121 25.141

As we head to Subway Cave, we’ll pass Red Lake Mountain, Table Mountain and many other peaks that line the highway. 20,000 years ago during a series of volcanic activities, lava flowed throughout the entire area. As it flowed, the lava that was exposed to the air cooled and hardened, protecting the molten lava from the elements and allowing it to continue flowing. Eventually, the lava reached its destination and left behind a long and empty lava tube that remains today. At this final stop on the trip we can actually get out and explore the lava tube.

As we head to Subway Cave, we’ll pass Red Lake Mountain, Table Mountain and many other peaks that line the highway. 20,000 years ago during a series of volcanic activities, lava flowed throughout the entire area. As it flowed, the lava that was exposed to the air cooled and hardened, protecting the molten lava from the elements and allowing it to continue flowing. Eventually, the lava reached its destination and left behind a long and empty lava tube that remains today. At this final stop on the trip we can actually get out and explore the lava tube.

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Websites:

https://www.volcanocafe.org/mount-tehama-brokeoff-mountain-and-the-lassen-volcanic-national-park/

https://www.nps.gov/places/sulphurworks.htm

https://northerncaliforniahikingtrails.com/blog/2018/12/11/subway-cave-hat-creek-trail-lassen/

https://www.summitpost.org/chaos-crags/309690

https://northerncaliforniahikingtrails.com/blog/2018/12/11/subway-cave-hat-creek-trail-lassen/

Books:

Secrets of The National Parks: The experts' guide to the best experiences beyond the tourist trail. Written by: Dan A. Nelson, Robert Earle Howells, Karen Carmichael, and more. 2014

Essentials of Geology. Written by Lutgens, Tarbuck. 2015

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This article began as a regular piece on Lassen Peak but quickly expanded as I discovered how incredibly complex the geology and history of the Lassen Volcanic Complex was. Unlike nearby Shasta, Lassen Peak is but a dacite lava dome, one of the largest lava domes on Earth but only one of the dozens of lava domes and peaks to be found within the Lassen Volcanic National Park. Before we begin to unravel the very complex history of eruptions, collapses and glacial erosion, it is a good idea to acquaint ourselves with the area and its main features:

Volcanic activity in the area goes back at least three million years. About 600,000 years ago, contemporary with the formation of nearby Mount Shasta, a series of large eruptions formed a huge volcano, Mount Tehama. Just to put it into perspective, the largest of these eruptions was about 50 times as powerful as the 1980 eruption of Mount St Helens or five times that of Mount Pinatubo. Mount Tehama was immense. At its base, it measured 18 km (11 miles) by 24 km (15 miles) wide and it stood more than 3,353 m (11,000 feet) tall. Its total volume must have been well in excess of 400 cubic kilometres, a rough calculation yields a volume of 425 cu km, comfortably larger than either present-day Mount Shasta or Mount Adams, both of which have volumes of about 350 cubic kilometres.

Activity at Mount Tehama continued for about 200,000 years and consisted mostly of pyroclastics and andesitic lava flows containing olivine. During the same period of time, other volcanic vents began to appear such as the shield volcanoes Raker Peak, Red Mountain, Prospect Peak and Mount Harkness. The distances from the central volcano, never more than eight miles, argues that they were satellite vents of Mount Tehama. As for the central volcano itself, there was a final, large lava flow on the north-eastern flank consisting of glassy dacite and further dacite flows formed smaller cones such as Mount Conard and Diamond Peak on the flanks of Mount Tehama.

Subsequent glaciation combined with extensive hydrothermal activity led to major erosion and to a subsequent collapse of Mount Tehama of which today the only visible, large remnant is Brokeoff Volcano, also known as Brokeoff Mountain. The collapse structure, a caldera about 3 km (2 miles) in diameter, was quickly infilled by debris and material from later eruptions. Further activity built more than thirty other cones which are sometimes referred to as the Lassen Domes.

As we have already seen, Mount Tehama began life as a rather typical andesitic stratovolcano, but subsequent activity became more and more silicic. After its collapse and disappearance, local volcanism shifted to what had been its northern flank. The last 400,000 years have seen at least three known lava flows, parts of which can be seen on or near Raker Peak and Mount Conard. There is also evidence of a very large explosive eruption which ejected an estimated 50 km ³ (12 cubic miles) of material and created a large crater which was soon obliterated by subsequent lava flows and emplacements. During this period, a further twelve lava domes were emplaced throughout the Park area. The next period of eruptive activity spanned some 50,000 years and ejected between 15 to 25 km ³ (3.5 to 6 cubic miles) in the form of pyroclastic flows, viscous lava flows and mainly dacitic lava domes.

About 27,000 years ago, Lassen Peak started to form as a mound-shaped dacite lava dome pushed its way through the shattered north-eastern flank of Mount Tehama. As the lava dome grew, it shattered overlaying rock, which formed a collar of angular talus around the steep-sided volcanic dome. Lassen Peak reached its present dimensions of nearly two km across at the base and prominence of 606 metres above the surrounding landscape in a remarkably short time, probably in just a few years or at most tens of years. From 25,000 to 18,000 years ago, during the last glacial period of the current Ice Age, the shape of Lassen Peak was significantly modified by glacial erosion. The bowl-shaped depression - cirque - on the volcano's north-eastern flank is the result of erosion by a glacier that extended some 11 km (7 miles) from the dome.

To inject a piece of human history, Lassen Peak was named after the Danish blacksmith Peter Lassen (most likely an Americanisation of Larsen), who guided immigrants in covered wagons past this peak into the Sacramento Valley during the 1830s. The trail that Lassen blazed never found general long-term use because it was considered to be unsafe.

Just over 1,000 years ago, a major period of activity resulted in the extrusion of five dacite lava domes that form the 177 metres high Chaos Crags. Initially, they must have been considerably higher as a major rockslide occurred just 300 years ago. Riding on a cushion of compressed air, the sturzstrom landslide travelled 20 to 30 times the vertical fall height and resulted in the formation of beautiful Lake Manzanita, 3 km (2 miles) from the Chaos Crags.

The most recent period of activity at Lassen Peak took place between 1914 and 1921. After 27,000 years of dormancy, Lassen Peak was shaken by a steam explosion on May 30 th, 1914. By mid-May 1915, more than 180 steam explosions had gouged out a 300 metre-wide (1,000 ft) crater near the summit. On the evening of May 14 th, 1915 the character of the eruption changed dramatically as incandescent blocks of lava could be seen bouncing down the flanks of Lassen Peak from as far away as the town of Manton, 30 km to the west. Next morning, the crater had been filled by a rapidly growing dacite lava dome.

Late in the evening of May 19 th, the lava dome was fragmented by a large hydrothermal explosion. Glowing blocks of lava fell on the summit and snow-covered upper flanks of Lassen Peak and launched an 800 metre (half mile) wide avalanche of snow and volcanic rocks that roared 10 km (6 miles) down the volcano's steep northeast flank, over a low ridge at Emigrant Pass and into Hat Creek. The lahar was deflected north-westward at Emigrant Pass and flowed more than 11 kilometres (7 miles) down Lost Creek. During the night of May 19-20 th, dacite lava slightly less viscous than that which erupted on the night of May 14-15 th, welled up into and filled the new crater at Lassen's summit, spilled over low spots on its rim, and flowed 300 metres (1,000 ft) down the steep west and northeast flanks of the volcano.

At 4:30 p.m. on May 22 nd 1915, Lassen Peak exploded after two quiet days in what is referred to as "the Great Explosion". The eruption column rose more than 10,000 metres (30,000 ft) and was visible from as far away as the Pacific coast 240 km (150 mi) to the west. The blast created the larger and deeper of the two craters seen near the summit of the volcano today. Pyroclastic flows devastated an area of 8 km ² (3 sq miles) below the volcano, and melting snow created a series of lahars that rushed nearly 16 km (10 miles) down "Lost Creek" to the Old Station. The lahars released large masses of water that flooded the lower Hat Creek Valley a second time. A layer of volcanic ash and pumice was traceable for 25 miles (40 km) to the northeast and fine particles of ash rained down as far away as 320 km (200 mi) to the east.

For several years after the main eruption, rainfall triggered steam explosions indicative of fresh lava just below the surface, and in May 1917, a series of vigorous hydrothermal explosions obliterated the two older craters and dug out the second of the two summit craters visible today. It was not until 1921 that the eruptive period was officially declared over.

Mount Tehama today. Activity at the Lassen Volcanic complex is far from over. There are several areas of hot springs and fumaroles of which the Sulphur Works and the hot mud springs at Bumpass Hell on the Lassen trail are the most well known. With major eruptive activities during the Holocene, the area around Mount Lassen, which more accurately ought to be referred to as Mount Tehama, and the nearby Mount Shasta are considered to be the most likely volcanoes in the Cascade Range to erupt during the coming decades and centuries. Should they do so during our lifetimes, it is not inconceivable that we might see a repeat of the rapid growth of Mount Shastina, Black Butte, Lassen Peak or the Chaos Crags. I for one would much rather see this volcanic creation process than a truly huge eruption that has a "human impact", to put it euphemistically...

Henrik

For further stunning views of the Lassen Volcanic National Park, please visit
http://www.astropics.com/Lassen-Volcanic-National-Park-Pictures/ http://vibadirect.com/photos/lassen-volcanic-trip.html http://www.shltrip.com/Northern-California_Part_1.html

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Mount Tehama, Brokeoff Mountain and the Lassen Volcanic National Park

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This article began as a regular piece on Lassen Peak but quickly expanded as I discovered how incredibly complex the geology and history of the Lassen Volcanic Complex was. Unlike nearby Shasta, Lassen Peak is but a dacite lava dome, one of the largest lava domes on Earth but only one of the dozens of lava domes and peaks to be found within the Lassen Volcanic National Park.