Recent volcanic activity on Iceland serves as a reminder that the Mid-Atlantic Rift continues as a very active plate tectonic boundary zone, with spreading first beginning about 200 million years ago. The rift has produced an easy route for magma to break through the crust, which has caused volcanic activity along the mid-Atlantic ocean floor. The volcano island of Iceland is a product of this volcanic activity, but because of its northern location, Iceland is also known for its glaciers.
The Tectonic Setting of Iceland
The Mid-Atlantic Rift is a divergent plate boundary, where the Atlantic Ocean floor is spreading at an average rate of about 2.5 centimeters per year. In the northern part of the rift, North America and Europe are being pushed away from each other and in the southern part of the rift, South America and Africa are being pushed away from each other. The Atlantic Ocean started out as a tiny inlet between the continents of Europe, Africa and the Americas, but during 200 million years of rifting and sea floor spreading, it has become the massive ocean it is today.
Iceland stradles the Mid-Atlantic Rift and provides a natural laboratory at the surface of what is occurring thousands of feet below the Atlantic Ocean. The island itself is being split apart right down the middle, with the eastern zone of the island being the most volcanically active throughout history. Iceland's volcanism is manifested in two ways: large volcanoes that explosively erupt lava and ash clouds into the atmosphere, and fissure systems that passively erupt tons of sulfur dioxide gas and basaltic lava flows.
The Geology of Iceland - Geothermal Activity and Glaciers
The rift system that passes through Iceland is responsible for the geothermal and volcanic activity on the island, but its geographic location high in the Northern latitudes is responsible for its glacial geology. Both of these types of geology are a valuable energy resource for the country. Citizens of Iceland use geothermal energy to their great advantage, with almost 70 percent of their energy needs being met by tapping into geothermal resources.
In Iceland, about 11 percent of the islands surface is covered by glaciers, which provides a substantial hydroelectric resource as the glaciers melt and release massive amounts of running water. Iceland has come to depend on glacial melt as a major source of hydrolectric power for the island. About 20 percent of their energy consumption in 2008 came from hydroelectric power. However, if the pattern of global warming continues at its current rate, Iceland will lose 40 percent of its glaciers by 2100, and virtually all of them by 2200. This will have a significant detrimental impact on Iceland's ability to meet future energy demands.
Sources
- "Understanding Plate Motions", USGS.gov
- "Sea Level and Climate", USGS.gov
Alexandra Matiella Novak - With a PhD in Geology and expertise in science education, Alexandra is passionate about increasing the public's Earth science literacy.
