THE CALAPAGOS ISLANDS 3 THE VOLCANOS

Mid-ocean islands like the Galapagos are formed from basalt, the most basic of all types of lava. Basalt has a very different chemical composition from the lavas that erupt from continental volcanoes, and is much more fluid. Consequently, as the lava flows build up to produce a volcanic cone, the island cones have a much shallower slope than those on the mainland. These shallow-sloped volcanoes are called shield volcanoes and in the Galapagos, they are often compared to over-turned soup bowls. Such shield volcanoes can clearly be seen in the younger western islands of Isabela and Fernandina. To the east, the volcanoes are lower and more eroded.
read more..