Iceland straddles the Mid-Atlantic Ridge where the Eurasian and North American tectonic plates meet. This unique geographical setting has led to some fascinating geological features and dynamic landscapes.
In this episode, I go over the geology a little bit, the main reason why Iceland does not split in two even though the tectonic plates are slowing moving apart, and where in the country you can enjoy seeing the Mid-Atlantic Ridge in the country.
The Mid-Atlantic Ridge and Iceland’s Unique Position
The Mid-Atlantic Ridge is a submarine mountain range that runs down the center of the Atlantic Ocean, marking the boundary between the Eurasian and North American tectonic plates. In most places, this ridge lies deep underwater, but in Iceland, it rises above the sea, creating a rare opportunity to observe tectonic activity on land.
Iceland owes its existence to this tectonic setting. The ridge is characterized by divergent boundaries, where the plates are moving away from each other. As these plates diverge, magma rises from the mantle to fill the gap, creating new crust. This process is responsible for the volcanic activity that has shaped Iceland’s rugged terrain.
The Nature of Tectonic Plates
The movement of tectonic plates is a slow and gradual process. The Eurasian and North American plates are drifting apart at an average rate of about 2.5 centimeters (.9 inches) per year. While this may seem significant, it’s important to put it in perspective. Over millions of years, this movement will indeed widen the Atlantic Ocean, but the effect on Iceland is much more subtle.
The divergence of these plates does cause fissures and rift valleys, such as the Þingvellir National Park, where the rift between the plates is visible. However, this does not mean Iceland will split in half. Instead, the country is constantly being reshaped and reformed by volcanic activity and the upwelling of magma, which fills in any gaps created by the diverging plates.
Volcanic Activity and Land Formation
One of the key factors that prevent Iceland from splitting is its volcanic activity. Iceland is one of the most volcanically active regions in the world, with eruptions occurring roughly every four to five years. In most recent years, we have seen an increase in volcanic eruptions with them happening multiple times in a year just in 2024. These eruptions are part of the same process that forms the mid-ocean ridges.
When magma from beneath the Earth’s crust reaches the surface, it cools and solidifies, forming new land. This continuous creation of new crust compensates for the divergent movement of the tectonic plates. Instead of splitting apart, Iceland is actually growing larger over time as new volcanic material is added to its landmass.
The Role of the Icelandic Mantle Plume
Adding to the volcanic activity is the presence of the Icelandic mantle plume, a column of hot, molten rock that rises from deep within the Earth. This plume provides a steady supply of magma, which fuels Iceland’s numerous volcanoes. The mantle plume is thought to be responsible for the high levels of volcanic activity and the formation of Iceland itself.
The mantle plume’s upwelling helps to reinforce the island’s structure. As magma rises and cools, it forms new rock that acts to fill in and stabilize any fractures or rifts caused by the diverging plates. This process ensures that while fissures and rifts are part of Iceland’s landscape, they do not lead to the island splitting apart.
Geophysical Studies and Predictions
Extensive geophysical studies have been conducted to monitor Iceland’s tectonic activity. Seismologists and geologists use a range of tools, including GPS measurements, seismographs, and satellite imagery, to track the movement of the plates and the activity of the mantle plume. These studies provide valuable insights into the dynamics at play.
The data shows that while there are indeed rifting events and volcanic eruptions, the overall structure of the island remains stable. The creation of new crust through volcanic activity outpaces the divergent movement of the tectonic plates, maintaining the integrity of the landmass.
Where to Experience the Mid Atlantic Ridge in Iceland
There are two well marked areas where you can experience the rift valley in Iceland. The most well known place is Thingvellir National Park, which is part of the famous Golden Circle route. Here, you can walk in the rift valley, which is the valley between the Eurasian and North American Tectonic Plates.
I shared in a recent episode about snorkeling between these plates and how incredibly fun it is. If you plan to do that, you can use my code Iceland10 to save 10% when you book with Arctic Adventures.
If you are curious about all of the stops on the Golden Circle, including some fun extras, check out my Ultimate Golden Circle episode that I shared on the podcast.
The other place is on the Reykjanes Peninsula. In fact, there is a Bridge between Continents attraction there. It is a symbolic bridge named after Leifur Eriksson that shows that you cross between continents. Technically, it is that you can cross between plates but because most of North America is on the North American tectonic plate and most of Europe is on the Eurasian tectonic plate, it is advertised as between continents.
Random Fact of the Episode
A unique feature of Iceland is that it is only inhabited island in the world where the Mid-Atlantic ridge is visible on land.
Icelandic Word of the Episode
Atlantshafshryggurinn – Atlantic Ridge
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