The Icelandic landsmass is alive, constantly expanding and changing shape. It may seem daunting at first, but we‘re going to explain 16 million years of hard, volcanic work with a 4 minute read in layman‘s terms.

Iceland's geology
Iceland on the Mid Atlantic Ridge with the plates on each side.

No land without fire

Iceland sits right where the North American plate and the Eurasian plate meet. These 2 continental plates sit either side of the Mid – Atlantic Ridge (MAR) and are moving away from each other, creating a microplate between them. As they move apart, it creates space between them for lava to move up from inside the earth and spread outwards through volcanoes and deep cracks called fissures.

This is what happens at the bottom of the ocean along the MAR. If you took all the water away, you would see a line of volcanoes and cracks along it, with lava occasionally coming out.  Iceland is unique as you can see this magnificent process happening here above sea level. This part of the MAR is above sea level due to large plume of lava right below Iceland, pushing up from the center of the earth like a big balloon. The East and the West fjords are the oldest parts of Iceland, at up to 16 million years old. They were the original landmass of Iceland, which has continued to grow from the centre and spread outwards.

Informational video explaining the plume of lava under Iceland which is pushing it up above sea level. 
Iceland‘s Geology Explained in 4 Minutes
Ísafjörður – U-shaped valleys in West Fjords. Photo by Golli.

Rise and shine, Iceland

Iceland was completely covered by a huge ice sheet in the last Ice Age. The ice movement of massive glaciers eroded the landscape shaping it into the flat topped mountains (tuyas) and huge u-shaped valleys you can see today. The higher mountains rose from volcanic activity that provided enough force to get them above the ice level.

The weight of all that ice, over 2km thick in places, pushed low lying areas of Iceland below sea level.  This gave sediments a chance to accumulate on the land sitting underwater, where populations of small seashell creatures thrived. As the ice slowly melted, the weight on the island decreased, so Iceland has been rising back up out of the ocean. These beds of sediment rose as well, so you‘ll find marine fossils dotted around the country.

Iceland's geology
Basalt columns at Reynisfjara. Photo by Ian Funk

Basalt and not pepper

Iceland is mostly composed of basalt lava flows which erupted from volcanoes and fissures. All around the island, you‘ll find staggering basalt columns, where cracks are formed when lava quickly cools. These columns twist into amazing shapes (known as hackley) once they‘ve cooled in the presence of water. As you drive around the Icelandic countryside, the rhyolite mountains stand out with their very light colour compared to the dark brown basalt. There‘s also a lot of beautiful rocks to be found such as Jasper in all colours, beautiful zeolites, Icelandic spar (calcite), obsidian, as well as amethyst.

Iceland's geology
Photo by Páll Stef

Whether you love all nature, or if you‘re simply fond of hard hitting geology – there‘s plenty for you to discover.

We recommend also reading: 13 facts you (probably) didn’t know about Icelandic Volcanoes
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