Final answer:
Magnetic stripes on the sea floor show the history of Earth's magnetic field reversals and provide insight into plate tectonics and geological events.
Step-by-step explanation:
Magnetic "stripes" of normal and reverse-magnetized rock on the sea floor reveal a record of Earth's magnetic field reversals and plate tectonics. The pattern of these stripes along mid-ocean ridges, like the mid-Atlantic ridge, indicates that new material is continuously being extruded as tectonic plates diverge. As lava solidifies at the ridge, it acquires the magnetic orientation of the Earth's magnetic field at that time.
Over time, due to the Earth's magnetic field undergoing reversals, these rocks capture a "magnetic signature" that, when paired with the known rate of tectonic plate spreading, allows scientists to develop the Geomagnetic Polarity Time Scale (GPTS). This scale is a valuable tool for learning Earth's past magnetic and geological events, such as plate movements and changes in climate or sea levels.