I'm trying to imagine the forces required to inject the magma into the more solidified rock! Lassen must have put on quite a show. Thank you for this fascinating scenario!
It's too bad that you didn't get a chance to hike up the volcano, especially to Bumpass Hell. That place is so awesome to see, especially when the mud pits are full of water. Just be careful where you step.
I did hike to Bumpass Hell in a total socked in whiteout and rainstorm (thanks, remnants of Hurricane Hillary). I did videotape some sections but you literally couldn't see the steam rising from the fumarole because of the weather. I need to look at the footage, but I doubt it's that good so we'll see if I post it or not.
Thanks for the field trip Shawn! A campmate and I decided to hike the Lassen summit while the trail was closed for maintenance. We hit the trailhead at 12:30 am and got a half mile up the trail whereupon we saw a very large and wideset pair of yellow glowing eyes peering at us from the bushes above the trail. The other guy said, "Do you think that's a bear?" I said, "That's his friend Tigger I think." Needless to say, we turned around.
What time of year? Sounds like you were pretty high up. (My home turf.) Not much eatin' for bears in the high rocks. There are cougars, although personally in my 70 years I haven't seen one. Maybe "Tigger" was a good guess!
I love Lassen but so many people I've talked to didn't even know it exists. I've been there a few times, but my favorite was in the winter. My friend had hurt their foot, so I hiked in to Bumpass Hell and had the whole place completely to myself.
What a great experience! I went down a couple of times, 50 years ago. My baby bottles were warmed at "sulphur works" along the highway. Not being able to go where I want is sadness, now.
Lassen has no end of incredible areas to explore. The Devastated Area and the infamous Hot Rock boulder from the 1915-1916 eruption is easy to access. I highly recommend hiking to the summit of Mt Lassen, as well as the aptly named "Cinder Cone" just north of Lassen Peak.
After growing up spending Summers 11 miles downhill from the Park, only late in life have I gotten into the rich history of the area. Chico road to Silver City, Idaho! (2d greatest silver strike after Virginia City, Nevada.) Nobles Road easier than Applebee's Trail. The Modoc War. Timber boom on Shingletown Ridge. This educatiion about a landscape dear to my soul is dear to my heart. Thank you1
Excellent aerial and on-ground overview of this fascinating and geologically recent volcanic landslide. The only unfortunate incident is the appearance of an automobile at 6:17, an omen of what is soon to befall the earth's flora and fauna. Just like the lithosphere, the biosphere has limits too.
Yay, Lassen Volcanic National Park, even burned even up to the Peak, Dixie Fire relentless. But the creeks still flow, and the wildflowers still bloom.
I am a new subscriber and thank you for this easy to understand description. I have loved Lassen National Park and its surrounding area since my first visit in 1975. I was able to summit Lassen Peak on a different trip in the early 80s and take my son on a two day hike across the Painted Dunes past Cinder Cone in 2008. It is such a unique area that I suppose someone could study for a lifetime.
My Mom bought a place 11 miles from the Mountain in the middle of WW2. It has always been magic to me, yet to learn this geologic history is so great. But Lassen has been a notable human history crossroad: Noble's Trail, The Modoc War. Logging boomtown Shingletown. Chico Road to Silver City, Idaho; second richest silver strike next to Virginia City, Nevada. Important immigrant trail went past Cinder Cone, I envy you that you have been there, and I have not.
Thanks, Shawn-I learn something new about geology from all of your videos! I’m definitely going to look for inclusions here in the Oregon/Washington Cascades while out exploring.
Cool. I live on the outskirts of Lassen Volcanic Range in Westwood, CA. There are some awesome geological structures throughout the range. The Sulfur ponds and old magma flows make unique formations. There is usually too much snow to see much of anything, until the last few years.Mt. Lassen had deep snow year round. Now, Lassen and Shasta have lost most of the snow in the summer now. Love your videos. Your geology lessons are simple and enjoyable. Thank You 😊
When you visit Lassen, go explore Subway Cave Lava Tubes, which is north of LVNP. Take hwy 89 and the lava tube is just past the junction with hwy 44. It's great fun. Just bring a flashlight with you.
Cool video of one of my favorite places. Best bet on what triggered the jumbles rock avalanche is the Hat Creek fault just a few miles to the north. The wave forms of the jumbles are also fascinating. Lots of weird inclusions in a lot of our lavas at LVNP. Come see us again!
Great video. I’m a subscriber now and looking forward to viewing your past and future videos. I’m down the road in Shingletown on about 250 acres and it’s interesting all the volcanic rocks and boulders laying around from when Mt Lassen blew. Let’s hope there’s no future eruptions.
Pretty crazy y'all can understand the difference between these and those greenish basement rocks from the Hawaii flow. I left the house with my shirt on backwards yesterday
I was there a dew years ago in a parking area with a rest stop and explanatory signs. One of the things that was demonstrated were cooled "lava bombs" that were also comprised of this Dacite/Andesite mixture. When they landed, they fractured along concave lines, making it look like huge rock flowers on the ground. The Chaos Jumbles area is massive, you don't really get the scale of the size of it til you are in the middle of it.
So is this a situation where the eruption clears out the rhyodacite in the upper portions of the chamber, and then later mafic magmas that were beneath the silicic magma are erupted up into the much cooler silicic lava subaerially -- or was an eruption triggered by an injection of mafic magma into the silicic magmas, _in_ the magma chamber?
I, Dave the RockSlayer, am a retired professional geologist; but never practiced in the field of volconology. Therefore, please take my "reply" with a grain of salt. I think I was wondering something along the same lines as you. I always thought "xenoliths" were older than the rock which contains them. It would seem to me that the widespread distribution and lack of significant evidence of "chill zones" around the mafic xenoliths suggest they represent pieces of older rock incorporated (or pushed) into the rhyodacite producing magma while it was still fluid; and that the presence of the xenoliths caused varying degrees of chemical weathering within the rock that resulted in producing the instability of the cone resulting in the rockfall.
Do you know about the Lava Tubes, north and above Paynes Creek? The small ones are strange, at about 50' above the creek bed and twist left and right with 10' drops.
No ash particles in the rock. It is lava that was extruded from the vent as thick, pasty lava not explosively along with ash. The rock is totally made of crystals (along with these inclusions).
When I think of a xenolith, I think of a chunk of country rock ripped from the wall of the magma tube. Whatever its makeup is, it was abruptly removed from the throat, and may be rough-edged. The heat of the magma might allow some of the country rock to melt or intermix with the magma, softening the boundaries between the two. What I think you’re saying is that the magma had cooled, and that the country rock (or something more fluid, later?) had intruded the stiffened magma and emplaced into it? Citations? Lava lamp analogy? 😂
I, Dave the RockSlayer, am a retired professional geologist; but never practiced in the field of volconology. Therefore, please take my "reply" with a grain of salt. I think I was wondering something along the same lines as you. I always thought "xenoliths" were older than the rock which contains them. It would seem to me that the widespread distribution and lack of significant evidence of "chill zones" around the mafic xenoliths suggest they represent pieces of older rock incorporated (or pushed) into the rhyodacite producing magma while it was still fluid. I'm sure I misunderstood Shawn; but, it seemed to me he was suggesting the mafic xenoliths were incorporated into the rhyodacite AFTER it cooled! Don't get me wrong, I'm not challenging him; I am just confused!
Great question and one that I don't have a perfect answer for. In reading definitions for both, they seem to appear the same. I used "quenched inclusions" because that was the name used in the reference I read: pubs.usgs.gov/publication/sir20175022K2 In looking at magmatic enclaves, this was a nice writeup with illustrations: geologyistheway.com/igneous/magma-mingling-and-mixing/
My family visited Lassen National park in 1952-3. One site, near where you were showing the rocks here, was what was called Hot Rocks. They were said to have tumbled down from Lassen in the last eruption c.1915. I would have liked you to have compared them with the rocks you were showing here.
The mafic magma being mixed into the rhyolitic-dacite could be the product of late-stage bi-modal volcanism, though we probably should not be seeing mafic rocks in a volcanic arc system, which the Cascades are. Perhaps it has something to do with fact that Lassen is on the far south end of the Juan de Fuca plate where the transverse fault extends east from Point Mendocino. Would need some geochemistry to confirm or refute hypotheses.
You say that the Chaos Jumbles rock avalanche occurred 300 to 350 years ago, "possibly triggered by an earthquake regionally" (4:45). If memory serves, thanks to Brian Atwater, we know that the Pacific Northwest experienced a very large Cascadia Subduction Zone earthquake in January of 1700, 320 years ago. Almost certainly any slope in the entire region that was on the verge a sudden mass wasting event would have been triggered by that earthquake, and it's doubtful that there would have been any major landslide events for decades after January of 1700 (anything that would have been about to fall, fell). It doesn't seem unreasonable to suggest, then, that the January, 1700, earthquake and Chaos Jumbles may be related.
So, I just discovered you while planning an October trip to the Oregon coast starting at Thor’s Well, traveling as south as Fern Canyon. Then Northward through Grants Pass on the way to, …..you guessed it, Cater Lake! Lastly Eugene 😮to Eugene to fly home to Florida. Question, while exploring the beaches on the Oregon and North California coasts, What are some rare treasures to hunt on those beaches. Do I have a smallest chance of finding obsidian or even Amber? Please advise me on must see geology, Oregon coast.
Obsidian is quite brittle and unlikely to be found on beaches. I doubt there would be amber either. More likely to find quartz based material such as jasper, agate, chalcedony. A bit north of Yachats is Beverly Beach which has nice fossils (sometimes in rounded concretions). Great geology all along coast. Coos Bay area is nice. Sunset Bay State Park (southwest of Coos) has some nice strike slip faults at beach. Maybe get the Roadside Geology of Oregon book as a good reference.
@@shawnwillsey so much for that information. I had hoped to make it to glass beach but when doing a bit of research, it appears as though so much of it has been taken that there’s only white and green glass.
One spring, my son and I took an Amtrak from Denver to Salt Lake City. We got off at the Glenwood Springs stop. We stayed a couple of days. We enjoyed a splendid surprise in our rental car,on the way to Colorado’s best kept ski secret, Sunlight. Back on the train around every bend is a new, unique outcropping. Again, I stress enjoyment of this trip .
Northern California is the place to be ! Before camping at crater lake . I love 💗 this stuff . Thanks Shawn 🎉
I'm trying to imagine the forces required to inject the magma into the more solidified rock! Lassen must have put on quite a show. Thank you for this fascinating scenario!
It's too bad that you didn't get a chance to hike up the volcano, especially to Bumpass Hell. That place is so awesome to see, especially when the mud pits are full of water. Just be careful where you step.
I did hike to Bumpass Hell in a total socked in whiteout and rainstorm (thanks, remnants of Hurricane Hillary). I did videotape some sections but you literally couldn't see the steam rising from the fumarole because of the weather. I need to look at the footage, but I doubt it's that good so we'll see if I post it or not.
Thanks for the field trip Shawn! A campmate and I decided to hike the Lassen summit while the trail was closed for maintenance. We hit the trailhead at 12:30 am and got a half mile up the trail whereupon we saw a very large and wideset pair of yellow glowing eyes peering at us from the bushes above the trail. The other guy said, "Do you think that's a bear?" I said, "That's his friend Tigger I think." Needless to say, we turned around.
Rubbish.
Eyes do not "glow". That implies a source of light inside the eye itself.
What time of year? Sounds like you were pretty high up. (My home turf.) Not much eatin' for bears in the high rocks. There are cougars, although personally in my 70 years I haven't seen one. Maybe "Tigger" was a good guess!
@@daphnewilson7966 Summer at 9000’ ft. Just below tree line.
I love Lassen but so many people I've talked to didn't even know it exists. I've been there a few times, but my favorite was in the winter. My friend had hurt their foot, so I hiked in to Bumpass Hell and had the whole place completely to myself.
It's a really great park.
What a great experience! I went down a couple of times, 50 years ago. My baby bottles were warmed at "sulphur works" along the highway. Not being able to go where I want is sadness, now.
Lassen has no end of incredible areas to explore. The Devastated Area and the infamous Hot Rock boulder from the 1915-1916 eruption is easy to access. I highly recommend hiking to the summit of Mt Lassen, as well as the aptly named "Cinder Cone" just north of Lassen Peak.
After growing up spending Summers 11 miles downhill from the Park, only late in life have I gotten into the rich history of the area. Chico road to Silver City, Idaho! (2d greatest silver strike after Virginia City, Nevada.) Nobles Road easier than Applebee's Trail. The Modoc War. Timber boom on Shingletown Ridge. This educatiion about a landscape dear to my soul is dear to my heart. Thank you1
Excellent aerial and on-ground overview of this fascinating and geologically recent volcanic landslide. The only unfortunate incident is the appearance of an automobile at 6:17, an omen of what is soon to befall the earth's flora and fauna. Just like the lithosphere, the biosphere has limits too.
Photobomb courtesy of my truck.
Thanks, Shawn for this overview and explanation of this exciting jumble. Lassen is one of my faves and I never knew of this area/event before-
Yay, Lassen Volcanic National Park, even burned even up to the Peak, Dixie Fire relentless. But the creeks still flow, and the wildflowers still bloom.
I am a new subscriber and thank you for this easy to understand description. I have loved Lassen National Park and its surrounding area since my first visit in 1975. I was able to summit Lassen Peak on a different trip in the early 80s and take my son on a two day hike across the Painted Dunes past Cinder Cone in 2008. It is such a unique area that I suppose someone could study for a lifetime.
Welcome aboard my channel. Glad you liked this one and hope you enjoy perusing the other existing videos.
My Mom bought a place 11 miles from the Mountain in the middle of WW2. It has always been magic to me, yet to learn this geologic history is so great. But Lassen has been a notable human history crossroad: Noble's Trail, The Modoc War. Logging boomtown Shingletown. Chico Road to Silver City, Idaho; second richest silver strike next to Virginia City, Nevada. Important immigrant trail went past Cinder Cone, I envy you that you have been there, and I have not.
Thanks, Shawn-I learn something new about geology from all of your videos! I’m definitely going to look for inclusions here in the Oregon/Washington Cascades while out exploring.
Awesome! Thank you!
Thx Prof for another geo-ed adventure.
Well done Sir. ✌🏻
Glad you enjoyed it
Cool. I live on the outskirts of Lassen Volcanic Range in Westwood, CA. There are some awesome geological structures throughout the range. The Sulfur ponds and old magma flows make unique formations. There is usually too much snow to see much of anything, until the last few years.Mt. Lassen had deep snow year round. Now, Lassen and Shasta have lost most of the snow in the summer now. Love your videos. Your geology lessons are simple and enjoyable. Thank You 😊
Thanks for sharing. Glad you enjoyed this.
05:39 Wow. Not what I imagined from the GE map. Quenched inclusions, interesting.
Always interesting, Thank You Shawn!
When you visit Lassen, go explore Subway Cave Lava Tubes, which is north of LVNP. Take hwy 89 and the lava tube is just past the junction with hwy 44. It's great fun. Just bring a flashlight with you.
I did go there. It was a great lava tube. Thanks!
Cool video of one of my favorite places. Best bet on what triggered the jumbles rock avalanche is the Hat Creek fault just a few miles to the north. The wave forms of the jumbles are also fascinating. Lots of weird inclusions in a lot of our lavas at LVNP. Come see us again!
Only 300 years ago! Been driving this road for 70 years, had no idea this event so recent.
thanks... i enjoy getting around...
Great video. I’m a subscriber now and looking forward to viewing your past and future videos. I’m down the road in Shingletown on about 250 acres and it’s interesting all the volcanic rocks and boulders laying around from when Mt Lassen blew. Let’s hope there’s no future eruptions.
Welcome aboard. Hope you enjoy the existing videos along with more to come.
Pretty crazy y'all can understand the difference between these and those greenish basement rocks from the Hawaii flow. I left the house with my shirt on backwards yesterday
Holy Cow what a shocking landscape.
I was there a dew years ago in a parking area with a rest stop and explanatory signs. One of the things that was demonstrated were cooled "lava bombs" that were also comprised of this Dacite/Andesite mixture. When they landed, they fractured along concave lines, making it look like huge rock flowers on the ground. The Chaos Jumbles area is massive, you don't really get the scale of the size of it til you are in the middle of it.
My new favorite geology term: "quenched inclusions." It joins my other favorite term "entrenched meander."
All about the buzzwords....
So is this a situation where the eruption clears out the rhyodacite in the upper portions of the chamber, and then later mafic magmas that were beneath the silicic magma are erupted up into the much cooler silicic lava subaerially -- or was an eruption triggered by an injection of mafic magma into the silicic magmas, _in_ the magma chamber?
I, Dave the RockSlayer, am a retired professional geologist; but never practiced in the field of volconology. Therefore, please take my "reply" with a grain of salt. I think I was wondering something along the same lines as you. I always thought "xenoliths" were older than the rock which contains them. It would seem to me that the widespread distribution and lack of significant evidence of "chill zones" around the mafic xenoliths suggest they represent pieces of older rock incorporated (or pushed) into the rhyodacite producing magma while it was still fluid; and that the presence of the xenoliths caused varying degrees of chemical weathering within the rock that resulted in producing the instability of the cone resulting in the rockfall.
Very interresting, but you failed to mention the 1914-17 volcanic eruptions!
Yes, so much to cover. I videotaped more stuff around Bumpass Hell and such but the weather was so socked in that I am not sure it is worth posting.
Thanks!
Thank you for your support.
Thanks Prof, love your videos…xenoliths, huh?
very careful engineering and patience
Do you know about the Lava Tubes, north and above Paynes Creek?
The small ones are strange, at about 50' above the creek bed and twist left and right with 10' drops.
Quenched Inclusions....still trying to wrap my head around that. 🤔
Why isn't that a welded tuff or pyroclastic breccia? Just wondering what the 'tell' is to differentiate them.
No ash particles in the rock. It is lava that was extruded from the vent as thick, pasty lava not explosively along with ash. The rock is totally made of crystals (along with these inclusions).
When I think of a xenolith, I think of a chunk of country rock ripped from the wall of the magma tube. Whatever its makeup is, it was abruptly removed from the throat, and may be rough-edged. The heat of the magma might allow some of the country rock to melt or intermix with the magma, softening the boundaries between the two.
What I think you’re saying is that the magma had cooled, and that the country rock (or something more fluid, later?) had intruded the stiffened magma and emplaced into it? Citations? Lava lamp analogy? 😂
I, Dave the RockSlayer, am a retired professional geologist; but never practiced in the field of volconology. Therefore, please take my "reply" with a grain of salt. I think I was wondering something along the same lines as you. I always thought "xenoliths" were older than the rock which contains them. It would seem to me that the widespread distribution and lack of significant evidence of "chill zones" around the mafic xenoliths suggest they represent pieces of older rock incorporated (or pushed) into the rhyodacite producing magma while it was still fluid. I'm sure I misunderstood Shawn; but, it seemed to me he was suggesting the mafic xenoliths were incorporated into the rhyodacite AFTER it cooled! Don't get me wrong, I'm not challenging him; I am just confused!
Thank you for the nice video. Are there any differences between quenched inclusions and magmatic enclaves?
Great question and one that I don't have a perfect answer for. In reading definitions for both, they seem to appear the same. I used "quenched inclusions" because that was the name used in the reference I read: pubs.usgs.gov/publication/sir20175022K2 In looking at magmatic enclaves, this was a nice writeup with illustrations: geologyistheway.com/igneous/magma-mingling-and-mixing/
My family visited Lassen National park in 1952-3. One site, near where you were showing the rocks here, was what was called Hot Rocks. They were said to have tumbled down from Lassen in the last eruption c.1915. I would have liked you to have compared them with the rocks you were showing here.
I'm not familiar with the Hot Rocks area.
The mafic magma being mixed into the rhyolitic-dacite could be the product of late-stage bi-modal volcanism, though we probably should not be seeing mafic rocks in a volcanic arc system, which the Cascades are. Perhaps it has something to do with fact that Lassen is on the far south end of the Juan de Fuca plate where the transverse fault extends east from Point Mendocino.
Would need some geochemistry to confirm or refute hypotheses.
You say that the Chaos Jumbles rock avalanche occurred 300 to 350 years ago, "possibly triggered by an earthquake regionally" (4:45). If memory serves, thanks to Brian Atwater, we know that the Pacific Northwest experienced a very large Cascadia Subduction Zone earthquake in January of 1700, 320 years ago. Almost certainly any slope in the entire region that was on the verge a sudden mass wasting event would have been triggered by that earthquake, and it's doubtful that there would have been any major landslide events for decades after January of 1700 (anything that would have been about to fall, fell). It doesn't seem unreasonable to suggest, then, that the January, 1700, earthquake and Chaos Jumbles may be related.
So, I just discovered you while planning an October trip to the Oregon coast starting at Thor’s Well, traveling as south as Fern Canyon. Then Northward through Grants Pass on the way to, …..you guessed it, Cater Lake! Lastly Eugene 😮to Eugene to fly home to Florida.
Question, while exploring the beaches on the Oregon and North California coasts,
What are some rare treasures to hunt on those beaches. Do I have a smallest chance of finding obsidian or even Amber? Please advise me on must see geology, Oregon coast.
Obsidian is quite brittle and unlikely to be found on beaches. I doubt there would be amber either. More likely to find quartz based material such as jasper, agate, chalcedony. A bit north of Yachats is Beverly Beach which has nice fossils (sometimes in rounded concretions). Great geology all along coast. Coos Bay area is nice. Sunset Bay State Park (southwest of Coos) has some nice strike slip faults at beach. Maybe get the Roadside Geology of Oregon book as a good reference.
@@shawnwillsey so much for that information. I had hoped to make it to glass beach but when doing a bit of research, it appears as though so much of it has been taken that there’s only white and green glass.
One spring, my son and I took an Amtrak from Denver to Salt Lake City.
We got off at the Glenwood Springs stop. We stayed a couple of days. We enjoyed a splendid surprise in our rental car,on the way to Colorado’s best kept ski secret, Sunlight.
Back on the train around every bend is a new, unique outcropping.
Again, I stress enjoyment of this trip .
i believe i can understand why half that mountain fell down... it was already fractured to bits....
Is this what Yellow Stone has processing underneath going on...?
Extrapolate please...
Rock hound in texas...
Phenocrysts are aka xenocrysts, and in aggregate are called xenoliths. Encylcopedia Brittanica, xenocryst.
How did it happen? Well, I know I didn’t do it.😂