Please be sure to LIKE and SUBSCRIBE. You can support my educational videos by clicking on the "Thanks" button just above (right of Like button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Or: www.buymeacoffee.com/shawnwillsey
That basalt looks like if it cooled any faster it would have been obsidian. Thanks for posting. I envy you being in Iceland during an eruption event and hope to witness it personally someday.
That one layer of tuft is a good indicator that pyroclastic flows do happen in Iceland, though the majority of the rock layers seem to be of basalt, slower moving lava. Its that fast moving stuff you have to watch out for. scary.
"Welded Tuff." At last I understand what it is and what it can look like. Since I first heard this term about ten years ago it always has seemed funny, and I never quite understood it until now. Thanks.
Interesting and from Iceland. Perhaps you could do a video talking about the formation of Iceland ie, what areas formed first, oldest rocks, minerals ?
What a great road cut illustrating a couple different eruptive products-- the fused ash layer, the red and black basalts and the pinkish tuff. Any idea what gives the tuff layer its red color? Thanks so much for giving us a close up view of these rocks and this outcrop. Well done.
This seems to be the end of the mountainpass Öxnadalsheiði (if you're driving from Reykjavík direction). Öxnadalur valley is below along the ringroad(where you have Hraundrangar cliffs). The pass sometimes gets blocked by snow and the road closes. My dads brother died in a planecrash there up in the mountains a long time ago(a 20 year old medical student then). A memorial stone was put up by the side of the road last summer.
Good one Shawn. The small dikes you pointed out where magma made small cracks or filled voids I assume are much like the ones under the current eruption only with hot magma filling the cracks. I can now imagine what the magma chambers under the current eruption might look like at the margins. Perhaps like veins of magma running at various depths and thicknesses radiating from a central "pool" or column from deeper depths. Thanks for doing these roadcuts!
Not a lot of traffic in this part of Iceland, as a tour bus drives by. If ever there was evidence of Murphy's Law. 😂 Love these Iceland videos, what a fascinating island.
I'm 100% onboard with the pinkish layer being a welded tuff, but since Iceland is predominantly basalt, it would be interesting to know the geochemistry of the tuff layer. When you see the pinkish color you immediately think "rhyolite;" but I don't think rhyolite is a feature of Iceland's volcanism. Can it be a basalt tuff which just went through a lot of oxidation in the process of erupting and getting baked into place? _Really_ curious as to the chemistry of the tuff layer.
Yes, contact metamorphic zones can be very interesting from the mineralogical and geochemical perspective, depending on how different the chemistry of the two layers is.
I really enjoy the Random Roadcuts! I enjoy trying see if I can see what’s going on before you give your interpretation! 😃. After you finish one of these videos, particularly those in areas that are new to you, do you “hit the books” afterward to find out more about the rock units or the local geology?
This is in the northern part of Iceland so there is actually a good chance it could be Rhyolite as the volcanism of Northeastern Iceland tends to be bimodal involving both basalt and rhyolite. It is believed that there is actually buried continental material in this older section of Iceland likely derived from the break up of Laurasia between 60 and 58 Ma which formed the North Atlantic along with the North Atlantic Large Igneous Province responsible for or occurring contemporaneously with the separation of Greenland from what is today the British Isles. This old deep continental underbelly of material entrained within the plume may be the means where some rising magmas acquire additional siliceous/continental chemical affinities. A list of volcanoes in Iceland which from a brief google search can erupt or rather have erupted rhyolite in the past includes Askja, Bárðarbunga, Esjufjöll, Fremrinámar, Hekla(also erupts basaltic andesite, andesite and dacite all of a calc alkaline affinity unique for Iceland) Hengill(also erupts basalt, basaltic andesite and andesite) Hofsjökull, Katla(also erupts basalt, dacite and much less frequently andesite or basaltic andesite), Kerlingarfjöll, Krafla(Also erupts basalt andesite basaltic andesite and dacite), Kverkfjöll, Ljósufjöll(also erupts trachyte trachydacite trachyandesite trachybasalt and basalt) Oddnýjarhnjúkur-Langjökull, Öræfajökull, Prestahnúkur, Snæfell, Torfajökull, Þórðarhyrna Also while Basalt and secondarily Rhyolite are the two most common magma compositions in Iceland they are not the only magma types erupted. Additional notes for example Eyjafjallajökull erupts primarily andesite to basaltic andesite in addition to basalt trachyte and trachydacite and Hekla while primarily erupting basaltic andesite also erupts andesite dacite and rhyolite which appear to be derived from crystal fractionalization in that its eruptions progress from most siliceous and thus lightest before transitioning to lower silica melts as the eruption progresses. Vestmannaeyjar also apparently erupts basanite trachybasalt and trachyandesite. Katla and Krafla also erupt a wide assortment of other magma types beyond basalt and rhyolite. Icelandic rhyolites apparently also seem to generally have a more reddish coloration from chemical alteration so that is most likely what that layer was/is notably for most of these volcanoes it seems to be a bimodal composition of eruptive products with basalt being the dominant type of magma by far but rhyolite is surprisingly common. I was surprised to learn just how many different kinds of magmas there are in Iceland. Notably the volcanoes which only erupt basalt include those on the Reykjanes peninsula Grimsvotn and other ridge line volcanoes outside the central/eastern sections of Iceland. It is much clearer why volcanoes like Kalta Hekla Eyjafjallajökull and of course Bárðarbunga are so concerning when they show unrest so many things and ways they can erupt so it is not necessarily going to be basaltic effusive. In the case of Hekla it has only ever erupted explosively with virtually no warning time between the onset of unrest and a full blown magmatic eruption since the melts almost invariably move from 9 to 10 kilometers down to bursting out and erupting onto the surface in a span of several hours.
So interesting! I have learned so much from these episodes. Thank you! Do you have a feel for when that explosive eruption might have taken place and where?
Hi Shawn. Commenting here randomly (figured a ‘random’ roadcut vid would be a good place!). I wasn’t able to find the video I commented on a month or so ago where I had mentioned you stopping in the Upstate NY region and said I didn’t think we had much to offer in terms of geology…but I was very incorrect in that thought. UA-cam has been suggesting geology-related videos for the Western NY and Finger Lakes regions, as well as a few that highlight my hometown area (suburbs of Rochester). Plus, NiagaraFalls is a 90-mile drive to the West, Finger Lakes within a couple dozen miles, Letchworth StatePark, the Genesee River Gorge I drive over twice a day getting to and from work! Plus, the Adirondack Mountains about 4-5 hours’ drive from me. You have really opened my eyes to my local geology…in my early 60s I’m reinvested in learning all I can about my area. Thank you. ❤
Thanks for the roadcut, very interesting. I wonder if, given the relatively small units involved, the dike jacked up the tuff layer on one side as it rose. The tuff was likely an e posed surface cap layer when the dike broke through, I would guess from all the recent Iceland reporting. That dike protrusion and spreading out may have been in the depth of an Icelandic winter, with a few feet of snow and howling freezing winds. Cold enough to make your freezer seem positively balmy. Very rapid cooling on the surface, in geo terms.
Hi, again. You said some of the basalt cooled quickly and dense and not crystalline. So are they between obsidian and basalt? And is there a term for the discoloration of the basaltic dike heating/melting/changing the color of the welded tuff, ??contact metamorphism? Thank you, professor!
Awesome! I love Iceland and I love your Random Roadcuts series! So what's better than an Icelandic Random Roadcut? Thank you for sharing this one, Shawn :) I recognized the basalt and spotted the dikes and (possible) fault so I guess I'm learning something ;) However I must say I'm a bit curious about the pinkish/reddish color of the tuff: is it due to iron oxide? And do you know what the flattened and elongated particles (fiamme) would be made of...?
Hi Shawn, love all your presentations. Can you give the geolocations with your location presentations in the video descriptions so if we ever get to go, we can find them, please?
Very interesting, thank you! If the upper layer of basalt may have formed under an ice cap, does that mean that the tuff is much older, pre ice age (whichever one)? Or can tuff also form under ice, and these layers may have been formed by two phases of one eruption?
Professor. One of the channels I watch, called Ants Pants, features an Estonian fellow. He found a large (1 tonne plus) pitted rock, not magnetic. He is wonder could it possibly be a meteorite? Pretty important if it is? Can you have a look, please?
Please be sure to LIKE and SUBSCRIBE. You can support my educational videos by clicking on the "Thanks" button just above (right of Like button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Or: www.buymeacoffee.com/shawnwillsey
Thank you for sharing your video! 😊 Very interesting!
I have stopped by two of your random road cuts, the unconformity by Laughlin, NV, and the Minnekhata Limestone at the sough entrance of Wind Cave.
That basalt looks like if it cooled any faster it would have been obsidian. Thanks for posting. I envy you being in Iceland during an eruption event and hope to witness it personally someday.
That one layer of tuft is a good indicator that pyroclastic flows do happen in Iceland, though the majority of the rock layers seem to be of basalt, slower moving lava. Its that fast moving stuff you have to watch out for. scary.
"Welded Tuff." At last I understand what it is and what it can look like. Since I first heard this term about ten years ago it always has seemed funny, and I never quite understood it until now. Thanks.
I must be learning something from your channel...in my head I had it all figured out before you crossed the road. Well done.
I've watched your volcano updates regularly but this is my first Random Roadcut.
I am hooked! 👍🏻 Gotta watch more, interesting!
Interesting and from Iceland. Perhaps you could do a video talking about the formation of Iceland ie, what areas formed first, oldest rocks, minerals ?
What a great road cut illustrating a couple different eruptive products-- the fused ash layer, the red and black basalts and the pinkish tuff. Any idea what gives the tuff layer its red color? Thanks so much for giving us a close up view of these rocks and this outcrop. Well done.
This seems to be the end of the mountainpass Öxnadalsheiði (if you're driving from Reykjavík direction). Öxnadalur valley is below along the ringroad(where you have Hraundrangar cliffs). The pass sometimes gets blocked by snow and the road closes. My dads brother died in a planecrash there up in the mountains a long time ago(a 20 year old medical student then). A memorial stone was put up by the side of the road last summer.
Interesting. I like this random roadcut series. Thanks!
Really appreciate your presentations!! Thanks!
Thanks so much for taking time to post a Road Cut from Iceland! I know you had LOTS of items on your to-do list!
That's a great view of what is going on in Iceland ATM near the Blue Lagoon.
That was great, and also understandable with all I have learned from you over the past six months! Thank you and enjoy your vacation 😊
Very interesting to understand what the rocks can tell us about the geological history of the places. Thank you Shawn!
ありがとうございます！
❤❤❤Thank you, Shawn! Fun...and a new perspective forming.
wow, something very new. Thanks Shawn!
Good one Shawn. The small dikes you pointed out where magma made small cracks or filled voids I assume are much like the ones under the current eruption only with hot magma filling the cracks. I can now imagine what the magma chambers under the current eruption might look like at the margins. Perhaps like veins of magma running at various depths and thicknesses radiating from a central "pool" or column from deeper depths. Thanks for doing these roadcuts!
Thanks!
Beautiful road cut!
Not a lot of traffic in this part of Iceland, as a tour bus drives by. If ever there was evidence of Murphy's Law. 😂 Love these Iceland videos, what a fascinating island.
I'm 100% onboard with the pinkish layer being a welded tuff, but since Iceland is predominantly basalt, it would be interesting to know the geochemistry of the tuff layer. When you see the pinkish color you immediately think "rhyolite;" but I don't think rhyolite is a feature of Iceland's volcanism. Can it be a basalt tuff which just went through a lot of oxidation in the process of erupting and getting baked into place? _Really_ curious as to the chemistry of the tuff layer.
Yes, contact metamorphic zones can be very interesting from the mineralogical and geochemical perspective, depending on how different the chemistry of the two layers is.
I really enjoy the Random Roadcuts! I enjoy trying see if I can see what’s going on before you give your interpretation! 😃. After you finish one of these videos, particularly those in areas that are new to you, do you “hit the books” afterward to find out more about the rock units or the local geology?
This is in the northern part of Iceland so there is actually a good chance it could be Rhyolite as the volcanism of Northeastern Iceland tends to be bimodal involving both basalt and rhyolite. It is believed that there is actually buried continental material in this older section of Iceland likely derived from the break up of Laurasia between 60 and 58 Ma which formed the North Atlantic along with the North Atlantic Large Igneous Province responsible for or occurring contemporaneously with the separation of Greenland from what is today the British Isles. This old deep continental underbelly of material entrained within the plume may be the means where some rising magmas acquire additional siliceous/continental chemical affinities.
A list of volcanoes in Iceland which from a brief google search can erupt or rather have erupted rhyolite in the past includes Askja, Bárðarbunga, Esjufjöll, Fremrinámar, Hekla(also erupts basaltic andesite, andesite and dacite all of a calc alkaline affinity unique for Iceland) Hengill(also erupts basalt, basaltic andesite and andesite) Hofsjökull, Katla(also erupts basalt, dacite and much less frequently andesite or basaltic andesite), Kerlingarfjöll, Krafla(Also erupts basalt andesite basaltic andesite and dacite), Kverkfjöll, Ljósufjöll(also erupts trachyte trachydacite trachyandesite trachybasalt and basalt) Oddnýjarhnjúkur-Langjökull, Öræfajökull, Prestahnúkur, Snæfell, Torfajökull, Þórðarhyrna
Also while Basalt and secondarily Rhyolite are the two most common magma compositions in Iceland they are not the only magma types erupted.
Additional notes for example
Eyjafjallajökull erupts primarily andesite to basaltic andesite in addition to basalt trachyte and trachydacite and Hekla while primarily erupting basaltic andesite also erupts andesite dacite and rhyolite which appear to be derived from crystal fractionalization in that its eruptions progress from most siliceous and thus lightest before transitioning to lower silica melts as the eruption progresses. Vestmannaeyjar also apparently erupts basanite trachybasalt and trachyandesite.
Katla and Krafla also erupt a wide assortment of other magma types beyond basalt and rhyolite.
Icelandic rhyolites apparently also seem to generally have a more reddish coloration from chemical alteration so that is most likely what that layer was/is notably for most of these volcanoes it seems to be a bimodal composition of eruptive products with basalt being the dominant type of magma by far but rhyolite is surprisingly common.
I was surprised to learn just how many different kinds of magmas there are in Iceland. Notably the volcanoes which only erupt basalt include those on the Reykjanes peninsula Grimsvotn and other ridge line volcanoes outside the central/eastern sections of Iceland.
It is much clearer why volcanoes like Kalta Hekla Eyjafjallajökull and of course Bárðarbunga are so concerning when they show unrest so many things and ways they can erupt so it is not necessarily going to be basaltic effusive.
In the case of Hekla it has only ever erupted explosively with virtually no warning time between the onset of unrest and a full blown magmatic eruption since the melts almost invariably move from 9 to 10 kilometers down to bursting out and erupting onto the surface in a span of several hours.
So interesting! I have learned so much from these episodes. Thank you! Do you have a feel for when that explosive eruption might have taken place and where?
Interesting and educational 👍. Thanks Shawn
Great geo-adventure Prof. Thx ✌🏻
Neat outcrop!
Hi Shawn. Commenting here randomly (figured a ‘random’ roadcut vid would be a good place!). I wasn’t able to find the video I commented on a month or so ago where I had mentioned you stopping in the Upstate NY region and said I didn’t think we had much to offer in terms of geology…but I was very incorrect in that thought. UA-cam has been suggesting geology-related videos for the Western NY and Finger Lakes regions, as well as a few that highlight my hometown area (suburbs of Rochester). Plus, NiagaraFalls is a 90-mile drive to the West, Finger Lakes within a couple dozen miles, Letchworth StatePark, the Genesee River Gorge I drive over twice a day getting to and from work! Plus, the Adirondack Mountains about 4-5 hours’ drive from me. You have really opened my eyes to my local geology…in my early 60s I’m reinvested in learning all I can about my area. Thank you. ❤
Good to hear.
Another outstanding Geology educational video. Thanks Shawn. 338 Like ...................
Thanks for the roadcut, very interesting. I wonder if, given the relatively small units involved, the dike jacked up the tuff layer on one side as it rose. The tuff was likely an e posed surface cap layer when the dike broke through, I would guess from all the recent Iceland reporting. That dike protrusion and spreading out may have been in the depth of an Icelandic winter, with a few feet of snow and howling freezing winds. Cold enough to make your freezer seem positively balmy. Very rapid cooling on the surface, in geo terms.
thats a good point, they have been talking about meters of bouyant uplift recently with the magma activity going on
Very nice thanks for sharing
Hi, again. You said some of the basalt cooled quickly and dense and not crystalline. So are they between obsidian and basalt? And is there a term for the discoloration of the basaltic dike heating/melting/changing the color of the welded tuff, ??contact metamorphism? Thank you, professor!
Interesting color, surprised to see that.
Thx! Good job!
These are so interesting!
Awesome! I love Iceland and I love your Random Roadcuts series! So what's better than an Icelandic Random Roadcut? Thank you for sharing this one, Shawn :) I recognized the basalt and spotted the dikes and (possible) fault so I guess I'm learning something ;) However I must say I'm a bit curious about the pinkish/reddish color of the tuff: is it due to iron oxide? And do you know what the flattened and elongated particles (fiamme) would be made of...?
Not your average cut, but very cool thank you ALL stay safe
Wonder what peak hour looks like 😅 interesting to see the layers!
Hi Shawn, love all your presentations.
Can you give the geolocations with your location presentations in the video descriptions so if we ever get to go, we can find them, please?
He's given the GPS coordinates -- which he typically does at each of these roadcuts.
It's in the description.
Thanks, Shawn! Stupid question: Where there is grass in Iceland, is there also topsoil?
Gorgeous and fascinating! Thanks for showing and describing! I love the smaller dikes! Have a wonderful rest of your Iceland trip!
Haven't made it to N Iceland yet!
Very interesting, thank you!
If the upper layer of basalt may have formed under an ice cap, does that mean that the tuff is much older, pre ice age (whichever one)? Or can tuff also form under ice, and these layers may have been formed by two phases of one eruption?
How many rocks did you take home from Iceland? I got a rock from my grandmothers farm, in Saudarkrokur, Iceland..
How old do you think this is? Really interesting RRC thanks Shawn
Professor. One of the channels I watch, called Ants Pants, features an Estonian fellow. He found a large (1 tonne plus) pitted rock, not magnetic. He is wonder could it possibly be a meteorite?
Pretty important if it is?
Can you have a look, please?
♥
Thanks!
Thank you for supporting geology education videos.