We often say all the continents used to be one large landmass called Pangaea, but especially if the shape of continents changes with the sea levels, even though all the landmasses seem to fit together like a jigsaw puzzle, what causes scientists to conclude it was all one landmass at one time?

Question

My friends debate this all the time. I’m not sure their angle, but they often say “just because all the landmasses can fit together doesn’t confirm they did come together”, often using the analogy of how actual jigsaw puzzles might have pieces that fit perfectly fine with the pieces of other puzzles, or how a generic phrase might unintentionally fit as a haiku format.

Side note, I noticed there’s no geology flair.

In: 0

Answer 1

– it’s not the coastlines that fit together, it’s the continental shelves which aren’t affected by sea levels.

– it’s not only the shape, there’s also geological formations and the distribution of fossils that fit together.

– we have proof that the oceanic ridges are expanding because they record the history of Earth’s magnetic field.

– today, we can directly measure how the continents are moving.