Galápagos Hydrothermal Mounds: Stratigraphy and Chemistry Revealed by Deep-Sea Drilling

Abstract
The Galápagos mounds sea-floor hydrothermal system is at least 300,000 years old and once produced manganese-poor sediments, which nearly blanketed the area of the present mounds field. Present-day mound deposits are limited manganese-rich exposures, suggesting that the system has changed from rock- to water-dominated and has diminished in intensity with time.