Galápagos volcanoes ride a hotspot toward South America
Ecuador’s Galápagos sit on the equator about 898 kilometres west of South America, named for giant tortoises—galápagos. They perch on a triple junction and hotspot as the Nazca plate slides east-southeast under the continent at roughly 6.4 centimetres a year.
Bishop Tomás de Berlanga’s accidental landing in 1535 is the first firm record, and a lack of fresh water probably kept earlier people away. The buccaneer Ambrose Cowley in 1684 and naval captain James Colnett in 1793 named islands after British monarchs, nobles, and admirals, names later replaced by Spanish ones. Ecuador annexed the archipelago in 1832, and the 1892 Columbus anniversary briefly popularised the name Archipiélago de Colón.
Straddling the equator roughly 1,000 km from mainland Ecuador, the islands hold about 8,000 km² of land spread over 45,000 km² of sea: 127 islands, islets, and rocks, of which 19 exceed one square kilometre. Volcanism has run for at least 20 million years. Some magma rises from the mantle plume, some from shallower rock, and the nearby Galápagos Spreading Center weakens the young, thin crust. Western volcanoes are taller, younger, and caldera-crowned; eastern ones are lower, older, and more varied in chemistry.
The small islands have their own stories. Daphne Major, north of Santa Cruz, appears unnamed on Cowley’s chart and hosts Peter and Rosemary Grant’s decades-long finch studies. South Plaza, named for Ecuadorian president Leónidas Plaza, covers just 0.13 km² and rises 23 metres, carpeted red by Sesuvium beneath Opuntia cactus. Herman Melville gave two sketches of The Encantadas to Roca Redonda, about 25 km northwest of Isabela.
Champion islet, only 1.64 km long, shelters some of the last Floreana mockingbirds, and the Galápagos fur seal breeds only here. Beneath it all, the Nazca plate carries the islands east-southeast toward South America at about 6.4 cm a year.
Source: Galápagos Islands
