Iceland is a land of ice and fire. Not only is it one of the most breathtaking places in the world to visit, but it is also one of the most unique geological sites to study. I recently co-organized and participated in a field trip to Iceland and Sweden as part of our university’s Society of Economic Geologist Student Chapter (check out the video here!). In this multi-part series I will give a quick summary and self-guide on how to get the most out of a visit to Iceland by seeing the amazing country though the eyes of geologist in order to help you understand and appreciate just how (geologically) unique Iceland is! On our route we traveled clockwise around the island, and cut through the middle. Thus, the multi-part series is broken as follows.
- Part 1: A Land of Ice and Fire (Intro to Iceland, Reykjavík, the Golden Circle, Snæfellsnes Peninsula)
- Part 2: Volcanic Landscapes of the North (Mývatn, Dimmuborgir, Krafla, Námafjall, and Askja)
- Part 3: Glaciers and Volcanoes of the South (Nornahraun 2014/15 lava field, Central Highlands, Landmannaluagar, Laki, Vík)
Part 1: A Land of Ice and Fire
Brief geological setting of Iceland
The reason that Iceland is so unique is because it is centered on the Mid-Atlantic Ridge, which is an active spreading rift of two large continental plates; the North American Plate and the Eurasian Plate. As the tectonic plates move apart, magma rises up resulting in basaltic volcanism. The oldest rocks are 16 million year old (Ma), but most of rocks are less than 3 Ma (Moorbath et al., 1968).
From Reykjavík to the Golden Circle
The capital city of Iceland is Reykjavík, and from there the most accessible and popular destination is a tour of the Golden Circle. On the Golden Circle route is the impressive Gulfoss (foss = waterfall) and the geothermal field containing Geysir and Strokkur. This is actually where the word geyser comes from!
The water in the geothermal fields is alkaline, and the hot spring eruptions are driven by heat from a magma body ~ 2 to 3 km beneath the surface (Waltham, 2000). The hydrostatic pressure (i.e., pressure from the overlying water column) causes the water to boil at temperature over 100°C at depth, where it is converted to steam. The decreasing pressure with proximity to the surface results in flash production of steam from the superheated water which drives the explosive eruption every ~ 10 minutes!
Þingvellir
Next along the Golden Circle is Þingvellir National Park. This is arguably the most famous geological place in Iceland, as it is the northeast-elongated graben that represents the Mid-Atlantic ridge. It is the only above-water expression of the Mid-Atlantic Ridge, i.e., the rift that is pulling apart Iceland to this day! This area has been extensively studied and provides exceptionally clear evidence for continental drift and plate tectonics. It is also makes as neat photo as here you can “stand on” part of North America and Europe.
The Snæfellsnes Peninsula
The Snæfellsnes Peninsula is the western section of what is known as the Snæfellsnes Volcanic Zone. This is an intriguing area of island, as it is west-striking zone of intraplate alkalic volcanism that is off-rift to the main north-striking central volcanic axial rift system (Sigurðsson, 1970). On our trip we were joined by the Icelandic volcanologist Haraldur Sigurðsson (head of the Volcano Museum in Stykkishólmur which is definitely worth a visit). There are many interesting geological features to see, so I will just highlight several prominent ones we visited as we drove from Stykkishólmur counterclockwise toward the western end of the Peninsula.
Heading west from Stykkishólmur, a famous (and well photographed) mountain is Kirkjufell mountain. Differing from the volcanoes, this mountain is actually intermixed with glacial and interglacial-stage sedimentary rocks full of fossils, as well as layers of lava (Thordarson and Höskuldsson, 2002; Denk et al., 2011).
At the western edge of the Snæfellsnes Peninsula resides Snæfellsjökull. Snæfellsjökull is a stratovolcano located on the western tip of the peninsula; an infamous volcano featured in Jules Vernes’ Journey to the Centre of the Earth. This stratovolcano is 1446 km high and capped by the Snæfellsjökull glacier. It has produced both felsic and mafic volcanics. Products of the volcano shape the landscape on the western end of the Snæfellsnes Peninsula. The volcano has had several large eruptions that dispersed rhyolitic tephra over parts of the Snæfellsnes Peninsula, and well as smaller basaltic flows from fissures related to parasitic vents at the foot of the volcano (Kokfelt et al., 2009).
Lastly, a visit near the Djúpalónssandur is necessary to see some “magical” and bizarre rock formations.
The lavas here are a great example of the unique alkali lavas that compose the Snæfellsnes Peninsula. Alkaline rocks have an excess amount of alkali content (i.e., Na2O and K2O) over silica (SiO2). They are rarer than their sub-alkaline counterparts, which are the dominate lavas that make up the rest of Iceland, and most other igneous rocks in the world. The rock types seem at Djúpalónssandur and Hellnar are mugearite and benmoreite. Due to their higher silica content, beautiful flow banding can be seen in the grey lava. The dark (black) rocks represented parts of the lava that cooled very fast and are glassy, and the red lava represents oxidized lava that interacted with water.
Final thoughts:
From the moment you land in Iceland you can sense something is very special about this place. It is nice to be able to understand a bit more about the dramatic geological processes that shaped such a spectacular land. Because most people fly into Reykjavík, a tour along the Golden Circle is one of the easily accessible things to do, and definitely a good place to start your adventures in Iceland. The Snæfellsnes Peninsular is not too far away either (~2 hour drive north) and offers a beautiful landscape in the shadow of the mysterious Snæfellsjökull stratovolcano, and a landscape shaped by some odd geological processes compared to the rest of Iceland.
Next up in my “How to explore Iceland through the eyes of a geologist” series is Part 2 – Volcanic Landscapes of the North. Here resides ominous volcanic landscapes and features that look truly out of this world!
-Stephanie
Table of Icelandic Geology Terms
| á (s) ár (pl), fljót (large river) | River |
| askja | Caldera |
| aur (glacial outwash) | Sandur |
| bergkvika | Magma |
| berg | Rock |
| bjarg (s), björg (pl) | Cliffs/Rocks/Crags |
| borg (s), borgir (pl) | Rocky hill |
| bunga | Rounded hill |
| dalur | Valley |
| díabas | Dolerite |
| eldar (pl) | Fires/Eruptions |
| eldborg (s), eldborgir (pl) | Lava ring |
| eldgjá | Lava fissure |
| fjall (s), fjöll (pl) | Mountain |
| gjall | Scoria |
| hellir | Cave |
| hraun | Lava flow |
| jökull | Glacier |
| móberg | Tuff/Hyaloclastite |
| vatn (s), vötn (pl) | Lake |
| víti (also used for explosive volcanic craters or maars) | Hell |
| völlur (s), vellir (pl) | Field/plain |
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[…] Si algo distingue a Islandia es su extraña geología. Quien quiera profundizar en su conocimiento, puede visitar http://exploringtheearth.com/2016/07/05/geological-journey-iceland-land-fire-ice-part-1/ y https://pubs.geoscienceworld.org/books/book/2192/chapter/122608249/Iceland-The-Formation-and-Evolution-of-a-Young. […]
[…] Si algo distingue a Islandia es su extraña geología. Quien quiera profundizar en su conocimiento, puede visitar http://exploringtheearth.com/2016/07/05/geological-journey-iceland-land-fire-ice-part-1/ y https://pubs.geoscienceworld.org/books/book/2192/chapter/122608249/Iceland-The-Formation-and-Evolution-of-a-Young. […]
[…] Si algo distingue a Islandia es su extraña geología. Quien quiera profundizar en su conocimiento, puede visitar http://exploringtheearth.com/2016/07/05/geological-journey-iceland-land-fire-ice-part-1/ y https://pubs.geoscienceworld.org/books/book/2192/chapter/122608249/Iceland-The-Formation-and-Evolution-of-a-Young. […]
[…] la lave du Quaternaire. Au sommet se trouve le tuf (un profil géologique est disponible en bas de cet article en anglais).Et puis pendant la dernière période glaciaire, l'érosion l'a modelé. Ses flancs […]
[…] “How to explore Iceland through the eyes of a geologist“ […]
[…] et la lave du Quaternaire. Le dessus est en tuf (un profil géologique est disponible au bas de cet article).Puis, au cours de la dernière période glaciaire, l'érosion a façonné le paysage. Son flanc […]
Hi Stephanie.
Thanks for your blog. I have been reading and enjoying your blogs for a few years and always look forward to seeing what you have to reveal to us.
Ininitally, I discovered your blogs when I was trying to work out (Internet search) the geology of a farm my wife and I bought in Northern NSW.
It is quite an interesting situation. About 200km west of Byron Bay we are at 600m AHD and are on the western edge of the Great Dividing Range (GDR). Just to the East of us (1 km) are volcanic basalt soils. We have, what I think are metamorphic rock (sedimentaries, locally termed Traprock) and Granites.
Our property is 3km East to West. On the East side is, what I think is Turbidite and on the West site is (again I think) wave rippled metamorphised sandstone. It may be that we have, on our property, the uplifted coastine of the Permian Era Australian plate. The sandstone being the ancient beach / dune area and the turbidite would have formed just off shore. The GDR to the East, having been pushed up by subduction of the Pacific Plate.
I find this quite exciting but no one else I speak to is interested. Maybe, if you are interested I could send you some pics for your consideration and opinion.
Best wishes for your studies and thanks again.
Jim Barber
Hi Jim,
Thanks for following along and reading my blog, I am glad you enjoy it 🙂
The geology around your farm sounds interesting, I would be happy to take a look if wanted to send me some pics (my email is sykorastephanie@gmail.com).
In the meantime, have you had a seen the geological map of the area? If you are ~200 km from Byron Bay your farm might be on this one (http://www.resourcesandenergy.nsw.gov.au/__data/assets/image/0003/287202/NewEngland_500k.jpg).
Cheers,
Stephanie
Iceland’s tourism companies and officials have long promoted the potential for an adventurous stopover on the island. There are even itineraries available for travelers who only have a few hours to explore.
Yes, in the last couple years Iceland has been trying to increase its tourism so you will probably seen lots of “adventurous stopovers” being advertised. Not a bad place for a stopover I reckon!
Regards,
Stephanie
I really enjoy reading your blogs. My background is Geology/Physical Geography and despite being an astronomer my ‘closet’ passion is landforms and their evolution. At the present time I’m working with around 130 Science Teachers in a NASA event called Sally Ride’s EarthKAM Mission. All this coming week the teachers will be able to request pictures of the Earth during daytime orbits. If you have the time, ie. sit still for a while!, I could add you to the list and send you the log-in info and the ‘codewords’ needed to request images. Check out the web site (earthkam.org) and get back to me if you are interested.
Hi Bob,
Thanks a lot, I’m glad you enjoy my blog 🙂 I had a look at the EarthKAM site, it sounds like a neat event and I would love it if you could add me to the list. I already have a couple of areas in mind if I can manage to sneak in a request or two. Would you be able to please send me more information in an email regarding it? My address is sykorastephanie@gmail.com. Thank you again for following along with my blog and informing me of cool opportunities like this. Cheers!
Stephanie