A Brief Resumé of the Geology of Iceland

The current divergent plate boundary between North America and Eurasia across Iceland and the Iceland shelf is expressed by several segments between the submarine Reykjanes Ridge in the southwest and the Kolbeinsey Ridge in the north. Major elements of the present plate margin configuration were established at about 25 Ma, and Iceland occupies a complex plate boundary between the Reykjanes Ridge and the Kolbeinsey Ridge. Volcanic productivity is higher in Iceland than along the spreading axes to the south and north, indicating a mantle anomaly beneath the island, a hot spot. The area of the shelf around Iceland is larger than the subaerial island. Miocene lava sequences predominate in the far east and far west of Iceland, with Quaternary rocks occupying the central island. The geological structure is broadly symmetrical with gentle regional dips toward the volcanic spreading axes. Since the onset of the last Ice Age at about 2.6 Ma, Iceland has been periodically covered by an ice cap extending to the shelf. Today, Iceland is located directly in the path of high-altitude westerly jet streams. The climate is cold-temperate and maritime, and at present, c. 10% of the island’s area of 103,000 km2 is covered by glaciers.