Is the Ocean expanding?

Sea floor spreading

Key words: Ocean ridges, magnetic reversal, magnetometer, paleomagnetism, seafloor spreading.

Magnetic patterns on the seafloor are symmetric in relation to ocean ridges, indicating that ocean crust on either side of the ridge is moving away from the ridge at almost the same rate. During seafloor spreading magma rises and hardens to form new crust which becomes part of the ocean floor. Each cycle of spreading and intrusion results in the formation of another small section of ocean floor, which slowly moves away from the ridge.

Questions: 

1. Are magnetic patterns symmetric in relation to oceanic ridges?
2. What happens during seafloor spreading?
3. What does spreading and intrusuion result in?

References:

Scelsi Hess F., Kunze G., LeslieS. A., Letro S., Millage C., Shrap L., Snow T. (2002). Earth Science: Geology, the Enviroment, and the Universe. New York: NY Glencoe.

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