How did scientists calculate spreading rates at the Juan de Fuca Ridge?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Earth's lithosphere and upper mantle — oceanic crust A cross section of Earth's outer layers, from the crust through the lower mantle.

Scientists calculated the spreading rates at the Juan de Fuca Ridge by applying a established time scale of Earth’s magnetic field reversals to the marine magnetic anomalies mapped over the ridge.

By correlating these anomalies with known ages of magnetic reversals, researchers were able to date the oceanic crust. The spreading rate was then computed by dividing the distance of a specific anomaly from the spreading centre by the age of that anomaly. This method allowed geologists to determine that the crust at the Juan de Fuca Ridge was moving away from the ridge crest at a rate of approximately 30 mm (1.2 inches) per year.1