Unusual Geology
Rocks and mountains in the Hoffell region are unique in that they are made up of gabbro. In contrast to basalt found throughout much of the rest of Iceland, an igneous rock formed by the lava cooling quickly, gabbro is formed by lava cooling slowly. The slow cooling process causes large crystals develop, creating a course-grained, durable rock, that is dark-green in color. Gabbro is often found in deep oceanic crust or ancient mountains, but glacial erosion and uplift, caused when the massive weight of glaciers is removed as they retreat, have made gabbro now visible on the surface around Hoffell.