I frequently hear and read that Wegener's theory was very controversial at the time it was suggested. Why was this so? Was it due to Wegener himself, to evidence that was erroneously interpreted at that time, or to something else?
Two primary reasons come to mind:
- At the time the crust appeared solid, and the mantle was not known to be fluid and convecting (although plastic deformation is implied by isostasy). Moving solid rock through solid rock was too strange a concept - especially without a fluid mantle.
- "Continental Drift" had no mechanism. Why did the continents appear to move? Today we think of it more as a symptom of plate tectonics.
Also, Wegener was a meteorologist by training. Proposing an extreme hypothesis is difficult at best, but proposing it in a field that is not your own only makes it easier to dismiss. Wegener was a distinguished meteorologist but he must have had the same problems as Agassiz and Glaciation Theory (Agassiz was a fossil fish expert not an alpine geologist!)