Magnetic History

Clindor Cacho, a crewmember on R/V Knorr handles a tag line to steady the autonomous underwater vehicle (AUV) Sentry while recovering the vehicle in 2013 near Barbados. Sentry carried a suite of sensors on its deployments that included a magnetometer so that scientists could trace the history of seafloor spreading in the region. In the 1960s, magnetometry data helped bring together seafloor spreading and continental drift into the theory of plate tectonics. (Photo by Henry Dick, Woods Hole Oceanographic Institution)