| A | B |
|---|
| normal polarity | a field with the same orientation as today's field |
| reversed polarity | a field that is opposite the present field |
| magnetometers | used to measure the ocean floor's magnetic field |
| results in a stronger than normal reading | when the ocean floor's magnetic reading matches the present field |
| results in a lower than normal reading | when the magnetic readings of the ocean floor are reversed compared to today's field |
| magnetic data of the ocean floor has been used to generate these | isochron maps |
| the ocean floor is younger near these | ocean ridges |
| the ocean floor is older near these | deep-sea trenches |
| geomagnetic time scale | constructed from data gathered from continental basalt flows |
| this type of line connects points on a map that have the same age | isochron |
