Actvity Summary: Explain how a paleomagnetic record is recorded in rock and obtained by scientists.

Once a core is brought on deck of the JOIDES Resolution, it is cut into manageable sections and labeled for a variety of analyses and descriptions in the laboratory. One group of scientists, the paleomagnetists, study the Earth’s history by looking for magnetic (polar) reversals in the layers of the core. Magnetic reversals can be measured in two ways, inclination and declination. Declination is the same as a handheld compass showing 0-360° on a horizontal plane, while inclination, the more important component, measures magnetic dip (angle of magnetization into or out of the Earth’s surface). A reversal of the magnetic field is observed as an abrupt change in direction. Paleomagnetists are able to determine the age of layers in the core by recording, analyzing, and comparing the timing of the reversals to those in cores of known ages from around the globe