Iceland’s glaciers and features they create

Like other high-latitude locations on Earth, glaciers in Iceland have advanced and retreated many times during the past 2.5 million years, since we’ve been in a global Ice Age. The last glacial maximum was about 20,000 years ago, when ice completely covered the island and extended up to 200 km (120 miles) beyond the coastline to cover the marine shelf. Since then, glaciers have retreated at a rapid rate, especially during the past decades as climate change has accelerated.

This post will focus on existing Iceland glaciers. If you haven’t seen my previous Iceland posts, you can find information about the plate tectonic setting here—https://landscapes-revealed.net/standing-between-tectonic-plates-in-iceland/—and the variety of volcanoes here—https://landscapes-revealed.net/volcanoes-galore-in-iceland/.

This map shows existing Icelandic glaciers that cover ~10% of the country’s surface area. Almost 75% of this ice is contained in Vatnajökull (jökull=glacier), which is the largest glacier in Europe. These ice-covered areas would more properly be called “ice sheets” or “ice fields”, from which individual glaciers flow outward in all directions. Vatnajökull has at least 30 outflow glaciers—we walked on one of them in Skaftafell National Park. The highest mountain in Iceland is Öræfajökull, a volcano that reaches 2,110 m (6,920 feet) elevation and is covered by a glacier with the same name. The map is from: https://www.worldatlas.com/maps/iceland.

Iceland has changed much since the last glacial maximum when ice covered the island and extended far offshore. At that time, all of the island’s volcanoes would have been under ice. As the ice has melted, the island has been uplifted by a process called glacial rebound. Imagine putting the weight of your finger on an ice cube in your glass. When you release your finger, the ice cube moves upward in response. Similarly, Earth’s crust gets depressed by the weight of ice, and rises upward (rebounds) as the ice load melts. The uplift rate from glacial rebound along the southern edge of Vatnajökull is ~2.5 cm/yr (1 inch/year). The next six photos are from the coast on the southeast side of Vatnajökull.

Our group went to Skaftafell National Park, where there are many hiking trails, including this one that reaches the edge of a glacier flowing northward from Vatnajökull. The park once allowed walks on this glacier, but after retreat and lake formation, access became difficult. Now, park guides drive visitors a little farther northeast to a glacier that is easier to access.
Here is our geology group happily walking on one of Vatnajökull’s outflow glaciers. The guides provided us with crampons, ice axes and helmets for our safety. Photo is courtesy of our tour leaders—Tamie Jovanelly (in blue pants) and her husband Joe Cook (next to her).

A fascinating, and potentially terrifying, aspect of Iceland’s glaciers is that they cover active volcanoes. As you can imagine, when a volcano erupts under ice, it causes a lot of melting. This melt water flows outward, sometimes in catastrophic amounts and dangerously high speeds. These glacial outbursts are called jökulhlaups (=glacial run).

This photo overlooks the small town of Kirkjubæjarklaustur (locals just say “Klaustur”), located a short distance south of Skaftafell National Park. Between the town and the sea is Skeiðarársandur, a glacial outwash plain (sandur) that is the largest in Iceland. It was created by jökulhlaups—melt water carried seaward by the river Skeiðará from the glacier Skeiðarárjökull. On the map at the top of the post, sandurs are the lightest colored (tan) areas.
Because of frequent jökulhlaups along this part of the coast, this section of the “ring road” around Iceland was not constructed until after 1970. Prior to that, communities here were isolated from the rest of the country. The “ring road” was eventually completed, but in 1996 a particularly large jökulhlaup caused a flood with so much fast-flowing water and large ice blocks that it completely wiped out the road, including a 376-m-long (1233-feet-long) bridge that had been constructed over the outlet river. We stopped to see this piece of the bridge’s girding that has been retained along the road (since rebuilt) as a reminder of the hazards along this coast.

Continuing northeast along the edge of Vatnajökull (see map at top of post) are a series of sárlón (=glacial river lagoons) that formed since glaciers have been in rapid retreat. Glacial melt water is trapped behind terminal moraines and, with increased melting, the lagoons continue to expand.

At Fjallsárlón we were treated to a rafting trip on the glacial lagoon—the Fjallsjökull (glacier) is in the background. Surprisingly, our driver/guide was from Eastern Europe. Indeed, we found that most guides, and often restaurant and other employees, were from other countries in Europe. Our two glacier-walk guides were from France and Belgium, attracted to these jobs by their enthusiasm for outdoor adventure. One of the guides had earlier in the year trekked across the whole icy expanse of Vatnajökull.
A little farther northeast along the coast is a popular stop—Jökulsárlón, another glacial lagoon crammed with glacier-blue icebergs. Notice that some of the icebergs appear to be leaning to one side. This is because, as they melt, their balance changes and they can roll over.

We’ll next go to the north side of the island, near Akureyri (see location on map at the top of the post). On the map, notice the long indentations in the northern shoreline. Like other high-latitude locations during the glacial maximum, glaciers carved valleys that later filled with ocean water when the glaciers melted and sea level rose.

This valley is along the road near Akureyri. Notice the volcanoes with flat tops. This tells us that ice completely filled the valley and even buried the volcanoes. Throughout Iceland, these flat-topped mountains provide evidence of an island completely covered with ice.
I took this photo in the Eyjafjörður (fjord) where I did a whale watching trip from Akureyri, located at the fjord’s southern end (the direction of the photo). Notice the flat-topped mountains, and the U-shaped valley, both hallmarks of glacier action. This is a humpback whale in its summertime feeding ground. On this trip we saw four humpbacks and one minke whale.

This is my last Iceland post, at least for the July 2022 trip, and so I’ll end with a few photos I like.

Ólafsvík is a quaint coastal fishing village on the west side of Iceland, on the Snæfellsnes Peninsula near Grundarfjordur (see location on map at top of post). Although he has lived in Paris for many years, I was amazed that Iceland’s most famous artist (Erró—look him up!) is from this village.
This photo was taken on the southwest coast, on the Reykjanes Peninsula near Grinkavik (see location on map at top of post). I had never seen such large boulders on a beach before. Their imbrication (consistent tilting toward the sea) indicates they were placed there by waves. This is the North Atlantic Ocean, and clearly the waves here can be extremely large and powerful. Looking at the camera is Nancy, me, and Tamie, trip co-leader. Photo is courtesy of her husband Joe.
With the extremely long days at this latitude in July, and the frequently cloudy conditions, we did not see many sunsets. But I got lucky during a last day back in Reykjavik, when a clear evening took me out to explore the town at 11 PM! This view is to the northwest, across the bay (Reykjavik=smoky bay). It seems an appropriate image to end my post about this geologically-fascinating country.

Resources

Iceland, the formation and evolution of a young, dynamic, volcanic island—a field trip guide: Geological Society of America Field Guide 54, 2019, by Jordan, Carley, and Banik.

Iceland: tectonics, volcanics, and glacial features, 2020, by Tamie Jovanelly.

Iceland, Third Edition (Classic Geology in Europe series), 2022, by Thordarson & Höskuldsson.

Posted in

8 Comments

  1. Jane Gill-Shaler on August 21, 2022 at 2:30 am

    Thanks for a great tour for us stay-at-homes, Karen!

    • Landscapes Revealed on August 21, 2022 at 2:01 pm

      Thanks Jane. I always appreciate your comments!

  2. Thompson on August 21, 2022 at 9:36 am

    wow, great photos, and of course geo info! thanks for sharing. and greetings back from foggy SMP!!

    • Landscapes Revealed on August 21, 2022 at 2:01 pm

      So glad to see you’re still reading my posts! Hope to see you here or there soon.

  3. Joan Lamont on August 21, 2022 at 5:06 pm

    Thanks for enduring the rain and cold for us!! Beautiful photos, very informative and interesting commentary. What a great trip. Thanks Karen!!!

    • Landscapes Revealed on August 21, 2022 at 5:25 pm

      Thanks so much Joan!

  4. Earle Sloan on August 26, 2022 at 4:09 pm

    Thanks for a great tour, Karen. Fascinating to imagine the entire island covered in ice. Never seen a flat volcano before.
    Earle

    • Landscapes Revealed on August 27, 2022 at 12:18 am

      Thanks Earle! It is a fascinating place.

Leave a Reply

Subscribe to Blog

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Archives