Welcome to Icelandia, a possible new continent

摘要

ICELAND could be the only exposed part of an entire continent, dubbed Icelandia, that is mostly submerged beneath the Atlantic Ocean. Gillian Foulger at Durham University in the UK and her team have published the idea in the book Footsteps of Warren B. Hamilton: New ideas in Earth science. Iceland (pictured) lies on the Mid-Atlantic ridge, where two tectonic plates are slowly moving apart. Magma wells up along the ridge, before cooling and solidifying into rock, forming more seabed. Earth's outer layer, the crust, is typically thinner - about 6 to 7 kilometres - under the oceans than it is under continents, but Foulger says Iceland is an anomaly at 40 km thick. In general, geologists argue that this can be explained by the presence of a so-called geological hotspot - an unusually hot region in the mantle under the crust that leads to greater volcanic activity.