places on earth where you can see
the full spectrum of the magma
Fogo Island’s 420-million-year-old geologic history is in evidence everywhere and includes stunning and fascinating contortions of rock formed by ice, fire, and sea. For geology enthusiasts, it is one of the few places on earth where you can see the full spectrum of the magma chamber exposed – and for much of the year there is a geologist-in-residence on the island to guide you to the secrets the rocks hold.
The geological story of Fogo Island and the neighbouring Change Islands begins 420 million years ago in a time geologists call the Silurian Period of the Paleozoic Era. At that time, the ancient continent of Gondwana, which included Africa and South America, had started to collide with the North American Continent, Laurentia, to form the Appalachian Mountain Belt along the eastern margin of North America. As the two large continents of Gondwana and Laurentia started to collide in the late Silurian Period, melting within the Earth’s mantle resulted in the creation of hot molten magma which rose into the earth’s crust forming large magma chambers.
As this hot magma continued its rise to the earth’s surface, volcanoes formed and erupted on top of the sedimentary basin with massive and destructive forces. The magma also intruded into the sedimentary basin, resulting in the destruction, consumption, and metamorphism of the sedimentary rocks. The magma chamber which remained below the surface eventually cooled, forming igneous rocks such as granite and gabbro.
During the final formation of the Appalachian Mountain Belt, all of the key geological components resulting from the continental collision including the Sedimentary rocks, the Volcanic rocks, and the Intrusive igneous rocks became tilted, faulted, folded and uplifted by the tectonic forces resulting from continental collision. This was followed by 400 million years of erosion to expose all these rocks at or near the surface of the earth in the distribution pattern which we observe on Fogo Island today.
The Geology At The Edge Residency Programme was established to add to the body of geologic knowledge on and about Fogo Island. The rocks know all, and their lessons are of great value in keeping community with the past and in navigating the often stormy waters of modernity.