Plate Tectonics?

Question

The theory of Plate Tectonics was not widely accepted until the discovery of the magnetic
striping of the ocean floor. In light of earlier observations, the jigsaw puzzle fit of the
continents, the occurrence of fossils of the same life-forms on both sides of the Atlantic,
and paleoclimatic conditions, why is the magnetic striping such a key piece of evidence?

Answer 1

Because it proves that the seafloor is spreading. You have mirror images on both sides of the Atlantic ridge.

Answer 2

Mainly because it provides a MECHANISM to explain how the plates separate. Prior to their discovery and interpretation, it was difficult to concieve how the continents could move around in such a manner -- many explanations resorted to, or were understood to be, blocks of continents floating through the crust.

With the interpretation of seafloor spreading as the mechanism for driving the continents apart, the explanations could be properly understood as upwelling "new crustal material" driving the plates apart and replacing the "old crustal material" that was being subducted where the plates were colliding.

Therefore, seafloor spreading resolved several problems with global interpretations: 1. what caused the mid-ocean ridges; 2. what caused the deep ocean trenches; 3. what generated the heat and material for the island arcs; 4. why the continents fit like jigsaw puzzle pieces; 5. why the isolation of some species (especially related to those in Australia); 6. why the similar (often same) species on continents separated by wide oceans; 7. evidence of similar paleo-climates.

One piece of evidence therefore simplified a lot of theories.

Answer 3

I would say the first answer is good. I would add that I think there is an underlying arrogance that scientists practice far too often. They often ignore evidence which goes against a current theory and exaggerate the evidence with helps prove the theory. Mapping of the sea floor was relatively new as was the discovery of the mid ocean ridge. As magnetic minerals in basalt cool, they retain the direction of the prevailing magnetic field and the earth's polarity shifted quite often. Since the magnetic anomalies were so perfectly matched on both sides of the mid ocean ridge, the overwhelming weight of evidence did not allow those the old die hards to hang on to the old orthodoxy of geologic theory.

Answer 4

the striping is more about the magnetic fields in the earth, and how they change, but since they are formed only as the rock cools, and they have a reflection on the other side of the ridge, it helps show the spreading.

Answer 5

One could argue that those first things are just coincidences. But the magnetic striping is far more convincing evidence that the plates are separating.

Answer 6

Because of the changing of the poles of the striping does it indicate a movement or change from one point to another.
Example: A = North but now A = South, movement or replacement accounted for the change.