* Lack of a plausible mechanism: Alfred Wegener, the proponent of continental drift, proposed that continents plowed through the ocean floor like icebreakers. However, this explanation lacked a sufficient force strong enough to move such massive landmasses. The Earth's crust was thought to be too rigid for continents to move independently.
* No explanation for the driving force: Wegener couldn't provide a convincing explanation for what force could be powerful enough to move continents over such vast distances.
* Lack of supporting evidence: While Wegener presented compelling evidence like the fit of the continents, fossil distributions, and geological similarities, his theory was largely based on observation and correlation. The scientific community demanded more concrete, demonstrable evidence.
It wasn't until the 1960s, with the development of plate tectonics, that scientists found the missing piece of the puzzle. The theory of plate tectonics explains continental drift by proposing that the Earth's crust is divided into large, rigid plates that move on a partially molten layer beneath. This provided the mechanism (convection currents in the mantle) and driving force needed to explain how continents could move and shift over time.
In essence, the rejection of continental drift wasn't due to its lack of evidence, but rather the lack of a compelling explanation for *how* it could happen. The development of plate tectonics provided the missing link, bridging the gap between observation and mechanism, and leading to the widespread acceptance of the theory of continental drift.
