Chapter 6 · Try it yourself
Hotspot Conveyor
Deep under the western Galápagos, a plume of hot rock rises from the mantle and punches volcanoes up through the sea floor. The plume stays put. The sea floor does not: the Nazca Plate slides east over it, carrying each new island away like a suitcase on an airport belt. Run the clock and watch the islands get born, travel, wear down and sink.
The Galápagos, from above and from the side
Top: map view, north up, stretched east–west so the islands spread out. Bottom: the same strip seen from the side, cut along the equator, with height stretched about 60 times so the volcanoes show.
Today
Each step is 50,000 years. Arrow keys work too.
How fast is the belt?
About 5.9 cm a year (59 km per million years) toward the east, measured against the hotspot. That is a bit faster than your fingernails grow. Many guidebooks round it to “about 5 cm a year.”
Today
How far has Española moved since it formed?
about 190 km
Island ages at this moment
Simplified model: the plate moves due east at a steady 59 km per million years over a fixed plume, and each island is born when its spot on the plate passes over the plume, grows for a few hundred thousand years, then wears down and sinks. Island ages are the approximate emergence ages (oldest lavas above sea level) compiled by Geist and colleagues (2014, The Galápagos: A Natural Laboratory for the Earth Sciences, AGU); the plate speed is from the same work. Real islands form over a broad zone, not one point, and drowned older islands east of Española were found on the Carnegie Ridge by Christie and colleagues (1992, Nature). Positions and heights are approximate.