Comment: 14:36 - 15:43 (01:07)
Source: Annenberg/CPB Resources - Earth Revealed - 5. The Birth of a Theory
Keywords: "Scott Bogue", geologist, paleomagnetism, ocean, oceanographer, "lava flow", "Cambridge University", "Frederick Vine", "Drummand Matthews", intensity, "magnetic reversal", "sea floor", "magnetic field", polarity
Our transcription: By the early 1960s, geologists were mapping the magnetization of rocks worldwide.
One startling discovery came from the ocean bottom where oceanographers discovered an unusual pattern of strong and weak magnetic stripes in sea floor lava.
Cambridge University student, Frederick Vine, and his advisor, Drummand Matthews, were especially intrigued.
Two questions fascinated them.
What causes the strong and weak parts of the magnetic patterns, and why is the pattern striped?
They soon realized that the changing intensity of the pattern was caused by the reversal of Earth's magnetic field.
The evidence we have that the Earth's magnetic field has been reversed in the past is simply that we find rocks, old rocks, that are reversely magnetized; that is to say, they are magnetized pointing south rather than pointing north.
Geology School Keywords