Lava's plumbing system revealed! Beautiful dike carried lava up to surface in southwest Iceland
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- čas přidán 7. 09. 2022
- Check out this spectacular basaltic feeder dike with geology professor Shawn Willsey. This impressive geologic feature was the conduit that delivered lava to a surface eruption about 800 years ago, part of a series of eruptions on the Reykjanes peninsula known as the Reykjanes Fires. Learn how these dikes formed and then go up close to see how dikes affect the rocks they intrude.
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Shawn Willsey
College of Southern Idaho
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Video GPS location: 63.81689, -22.72657
I used this reference for this site: Jordan, B.T, Carley, T.L., and Banik, T.K., 2019, Iceland: The Formation and Evolution of a Young, Dynamic, Volcanic Island-A Field Trip Guide, GSA Field Guide 54. - Věda a technologie
Hi there, Shawn! It's great to see you in what is undoubtedly a geologist's dream. Before covid my daughter and I did a mother-and-daughters tour of Iceland, and our tour guide gave us this priceless piece of advise: "Don't piss off the elves!" We did NOT engage in any behavior that might have aggravated the elves, and they, in turn, left us strictly alone.
Very nice to see the guts of an eruptive feature.
That feeder dike is very interesting as you can easily see the differences between the core area and the outer area where it was in contact with the older tuffs through which it moved. Almost like looking at a textbook diagram.
I was going to say that, shit
I love how hands-on and up close you get with the rocks, its the next best thing to being in person. No other geology videos compare to yours Shawn!
Wow, thanks for the kind words, Colleen. Glad you enjoy my videos.
Dikes are so interesting!
Indeed, such a dramatic feature no matter where you see them.
Being able to see such a clear exposure of a feeder dike into older tuff, like this, really helps me visualize the process. Iceland's been a treasure trove of data and images since the Geldingadalir eruptions began and your visits to, and explanations of, regional geological events and features adds context to that, from an up close and personal perspective... much appreciated!
Remarkable. Appreciate how you give credit to other's work.
Standing on the shoulders of giants. The dyke is also lighter colored. It contains fewer of the mafic and ultramafic minerals that have already precipitated out of the melt (due to cooling and pressure change) before it ever reached this spreading point between plates.
Another highly informative video. Thanks Shawn. Found this information: "Chill margins are generally associated with igneous dikes - planer intrusive bodies, like veins, which cut through existing rock. If the dike is wide enough, it is common to have variations in the amount of time it took to cool. Along the edges, where the dike rapidly lost heat to the surrounding rock, cooling is relatively quick and the resulting texture is correspondingly fine grained. This fine grained edge, called a chill margin, then acts as an insulator, allowing the central core of the dike to cool much slower, resulting in a coarser texture. But chill margins aren't alone. The surrounding rock (called country rock) is also affected by the heat transfer which takes place as the dike cools. As the country rock heats up, metamorphic changes can take place, resulting in a metamorphic aureole extending into the surrounding rock. We call this metamorphic halo the baked zone."
Definitely more nicely written than my narration but basically the same I hope.
@@shawnwillsey Your narration was outstanding ....................
There are amazing examples of chilled margins and baked zones in feeder dikes and apophyses in the Henry Mountains, Utah, specifically on the south flank of Mt. Hillers. I was fortunate enough to have done part of my Field Camp with Dr. Vernor Johnson there in 2012 with a great group of other Colorado Mesa University students. A video on the Henrys would be wonderful, Shawn (hint hint). Clarence Dutton was the first geologist to map and study the area, 1880s I think. The Henrys used to be called the Unknown Mountains, and they were the last mountain range to be mapped in the Continental US. They were named the Henry Mountains by AH Thompson in honor of Joseph Henry, the first Secretary of the Smithsonian Institute in Washington, DC. (Joseph Henry was the first to discover magnetic inductance-credited later to Michael Faraday, the first to discover radio waves-credited later to Heinrich Hertz, and the first to invent the telegraph-credited later to Samuel FB Morse.)
Sounds very much like this stuff extruded from an ideal pizza oven with all that cooking and baking, and then brief cooling before my teeth engage talk.
What really fascinates me is the boundary between the hot magma dyke and the overlaying hot magma. We see how the surrounding rock and the underlaying rock has been cooked to for a different rock. I've seen this exact mechanism revealed in grand scale on the Yulludinida Crater on Mt. Kaputar, North West Slopes and Plains, New South Wales, Australia.
Interesting detail. Thanks
Thanks again, Shawn, for another fascinating video. My husband and I have watched the Iceland recent volcanic eruptions for months on the live cameras. It’s fascinating doubly because my brother lives in Monument Oregon where the “Monument dike swarm” came up. He and I have driven all around to find these dikes using guides to get us started then on our own. They look like dinosaur spines when you finally begin to see them. And one big one right in town. I will send you some photos as it is fascinating. None of these are marked!
Great to see the plumbing still connected like that. 👍
Just fascinating! Thank you again so much!
Super interesting up close
Damn, that is some beautiful geology, thanks!
Thanks so much for this video! Amazing stuff!
Love your enthusiasm
A great illustration of dike formation
Very cool imagining the dike pushing up to join the magma flow on top. Thanks.
Awesome it’s so easy to see. Before Mother Nature erodes it away
Thanks for the video. I enjoyed it a lot. Thank you for taking us viewers along to these fascinating geological field trips!
Very cool! (Some parts quicker than others :P)
Nice one!
That is really incredible, thank you! I had always wondered how these looked.
If you find a way to manage the production quality and get it increased, you'll likely have a well functioning, high value, high production value video education machine! You're a legend, thank you for providing this info!
Cool. Thanks for sharing.
With the 7 eruptions, and maybe 8th eruption on the way in the Svartsengi, Iceland, I'm digging in these wayback deep dives, refreshing memory to recall to get a good idea all that is happening at number 7 eruptions n Svartsengi. Thanks for the archived contents Doc.
I click and I'm like... eh well see....
Next thing I know I'm inches from my phone and haven't blinked in several minutes.
Captivating.
This is fascinating 😍. I grew up in Plovdiv where there are 6/7 hills right in the middle of a big plane. We knew as kids that they were some volcanic features but only recently I learned that they are like dikes and that they are actually part of a much bigger structure, which is yet to be revealed by erosion. That part of Europe doesn't have many volcanoes and a few more volcanic features so Iceland is very interesting to me and volcanoes as a whole of course. Thank you for the information you give us for free 👍
Wow Shawn, I aplaud your committment, your channel is now destined for greatness, I can assure of it! I hope you use your new wonderful education platform for forces of good
Thanks for citing the reference guide. This location is really showing the cooling effects clearly. Yes that clearly would be a good climbing hold. My ex was a rock climber. He would call that a bomb proof hold. These features are really interesting.
First time viewer. I'll be back!! This is ridiculously cool!!
Awesome. Welcome aboard and be sure to subscribe. You have lots of existing videos to work through while waiting for new ones.
Thanks again!
Contact lithification!! Thanks for the tour of a feature that I'm certain I'll never see in person. Much appreciated!
Geology rocks❣️😉
Fascinating. Thx for the interesting vid. Well done, as always 👏
Very cool. What a great example.
Fantastic!
Very interesting to see. Thank you.
Very interesting, thank you
Nice video.
Thanks!
Very interesting!
Awesome is right!
Fantastic!
Subscribed 👍
Thanks for the sub!
Wow
Thanks
VERY interesting.
Really enjoy seeing all these interesting spots, and the details covered explaining them, Thank You!
Are there any tells or details to estimate the depth of a dike when coming across one with no clear flow above or around? Possibly the vesicles are found more often higher in the column because of less pressure at the top of the column of fluid?
The dike's depth is related to the location of the magma system feeding it. With older dikes, the surface flow may be eroded or it is possible that the dike never propagated all the way the surface. So, not all dikes are feeder dikes. There are ways to estimate (crudely) how deep any portion of the dike was by looking at crystal size, mineralogy, and textures.
Your second question is spot on. Vesicles generally are larger as you approach the surface due to less pressure. Just like bubbles in your soda bubble accumulate on top.
Awesome
Interesting
WOW!
So this dike is basically the remains of an event very similar to the one occurring right now at the Reykjanes volcanic complex.
There are similar formation in Scotland, too: I only know about them as we had a book about volcanoes in Scotland, which has been mislaid and can't be found. The Author wrote about dike swarms, and he said each individual dike was only about two feet wide, but that the swarm consisted of dikes intruded into each other, to the point where it was almost impossible to match one side of each dike up with its other side...
Now that's cool.
Wow professor you’re in Iceland
Actually I returned a few weeks ago but filmed a dozen or so videos and have been slowly posting them. It was an awesome trip.
Very interesting and clearly described. Is the center section an analog of a lava tube with liquid flowing through the insulated core?
Thanks for watching. Yes, I suppose the comparison is broadly similar except for the orientation of the conduit. Also, lava tubes eventually drain out as lava supply wanes and so they leave a hollow tube or cave, whereas lava remaining in the conduit solidifies to form the dike.
@@shawnwillsey Thanks so much. My uneducated guess is that the relatively small diameter and them mass of the lava in the dike does not allow for the draining seen in lava tubes. Thanks again from new subscriber.
cool!
Great informative video ❤ could you tell me if it is on festarfjall where you find this feeder dike. Hard to tell from the video. Festarfjall is an interesting little mountain on the edge of the coast near grindavik that has an exposed feeder dike on it due to sea erosion. Im wondering if its the same one. I only live a few miles away and would like to look at this myself at some point :)
Hi there Lava Lady (great name). Glad you enjoyed the video. The GPS coordinates for this video are under the description. The location is west of the parking area at Valahnukur (near the Reykjanesviti lighthouse). I have also been to Festarfjall when I came to Iceland in 2018 with students. It is also an impressive feeder dike that cuts through a classic tuya section of pillow lava, hyaloclastite tuff, and subaerial lava. I chose this one for the video because its a little easier to get up close to it for video purposes. Have fun exploring your amazing country. I'll be back next summer.
That's really incredible to see! How fast would the lava have flown in that dyke? I would imagine relatively high to prevent it from cooling to rapidly and cause it to clog up.
Shawn, to the right of the dyke and above it are rocks with lighter coloured really weird squiggly lines on the surfaces and probably running through them. I've never seen rocks like them before. Any idea what they are?
Good observation and question. My best guess is stress fractures caused by the injection of magma into the surrounding tuff.
Without having been there, my guess is calcite veins? Groundwater effects?
Do you only do videos on places you travel?
So many things I'd like to say and ask, but I'll just leave it with thank you.
Thank you for sharing the coordinates of this location, i hope to make it there this weekend. Is there a trail that leads down to the site along the water? What is the best way to reach it as it looks like a bit of a tricky place to get to. Thank you so much for any info!
No real trail to speak of. Follow coastline or you can cut inland a bit. If you end up above the cliff, go east a bit to where you can scramble down soft sand to base. It's really worth the 15 minutes or so it takes to get there.
I chase Dikes local in my own backyard geology.
How I imagine such a dike to develop during an eruption is that in areas where the lava can flow more freely, more heat from the deep will get transmitted to the surrounding rock and melt the immediate surroundings there. This should allow for even more flow, more heat, more melting. So I expect a greater cross section of the flow would establish there and a more circular shape of the dike.
Is that a realistic idea?
👍👍👍👍👍👍
❤
does basalt become harder over time in the same way concrete cures and becomes harder? Like is 5k yr old basalt stronger than the 800-1k yr old stuff you just showed us?
On your relatively easy beachside amble from your previous location there to this one, did you see any chunks of deadfall boulders or other debris hurtle down from above or is that a rare enough event to discount - my brain would like to believe that as your camera looks straight up.
The walk over is along the beach with large wave-tossed boulders.
What camera are you filming with?
GoPro hero 8
I am a bit surprised by how small that dike is. Is that Dacite? The ones I have found are over a meter wide and are comprised of columnar basalt with a horizontal separation.
Yes, it is small but dikes can occur at a variety of scales. Very large ones can be tens or maybe hundreds of meters thick. Smaller ones can be centimeters thick. This dike is basalt. Some dikes do exhibit columnar jointing if cooling rate is uniform. Joints will form perpendicular to walls of dike (cooling surfaces).
So was the crumbly stuff bentonite? Otherwise how would such an easily crumbled rock still be there after even a few good rains?
The crumbly material is tuff (mostly ash with some larger lapilli sized particles). This cliff face is capped by a 5-8 meter layer of basalt, which is hard and resistant to erosion. So the basalt above keeps the tuff from weathering as quickly as it would otherwise.
This is the stuff that, through diagenetic alteration, ends up becoming bentonite.
Has that greenhouse showing up in the livestreams been abandoned or is it a secret scientific laboratory growing cloned Viking warriors.. lol?
That tuff is weak..
pls hold the camera steady. Filming something is not the same as looking at something.
Thanks!
Thank you.