Mid-ocean magnetic anomalies are not reversals (Talk.Origins)
From CreationWiki, the encyclopedia of creation science
- Plate tectonics became widely accepted when bands of reversed magnetic orientation were found mirrored on either side of the Mid-Atlantic Ridge. According to the theory, the sea floor spread gradually from the Mid-Atlantic Ridge, and periodic flips in the earth's magnetic field were preserved and recorded in the rocks as emerging magma cooled. But these bands of magnetism were misinterpreted; there are no magnetic reversals. Although magnetic intensities fluctuate, these are slight deviations around a high average. A compass needle would not change direction over these bands.
Source: Brown, Walt, 1995. In the Beginning: Compelling evidence for creation and the Flood, 6th ed., p. 79.
CreationWiki response: (Talk.Origins quotes in blue)
1. The magnetic field preserved in the rocks themselves does change direction. The magnetism measured in the 1950s was measured at the ocean surface, so the earth's present magnetic field was added to the magnetism from the rocks below.
Most creationists would agree with Talk Origins here, however the most it shows is that the claim is out of date. That's fine because the truth is far more interesting.
2. The main significance of the data was that the pattern was mirrored on either side of the midocean ridge. This is just the pattern one would expect from sea-floor spreading.
The problem is that there is no mirrored pattern. While the rocks do show magnetic reversals, they are not even close to being a mirrored pattern. There are bands along the Mid-Atlantic Ridge but they are not the nice neat mirrored bands predicted by Plate tectonics. The actual reversal patters are quite chaotic. The same thing occurs in the Pacific Ocean. The chaotic nature of the pattern is even more evident when one looks at other areas of the ocean floor such as the North Atlantic. The fact is that there is no objective relationship between the pattern predicted by Plate tectonics and what is actually found on the ocean floor.
- Reference: Magnetic stripes: look again
- Reference: Problems with Plate Tectonics
- Reference: Introduction to Plate Tectonics
3. There is a great deal more evidence for plate tectonics.
None of which stand up to objective scrutiny. Most of them are readily explained by other models and the other one is just a Plate tectonics' interpretation of the data.
- Reference: Claim CD740