Continents rest on huge slabs of rock that we call tectonic plates. They move and interact with each other. Mountains are formed where plates have collided. One theory is that the land on earth was once connected all together and at some point broke off and the continents floated away to their current positions. Many scientists say this couldn’t happen because what would make them move and go to a certain place? Some Christian scientists believe it is possible that this happened.
Here’s an explanation from GotQuestions.org:
Pangea is the concept that all of the land masses of the earth were at one time connected as one giant super-continent. On a world map, some of the continents look like they could fit together like giant puzzle pieces (Africa and South America, for example). Does the Bible mention Pangea? Not explicitly, but possibly. Genesis 1:9 records, “And God said, ‘Let the water under the sky be gathered to one place, and let dry ground appear.’ And it was so.” Presumably, if all the water was “gathered to one place,” the dry ground would also be all “in one place.” Genesis 10:25 mentions, “…one was named Peleg, because in his time the earth was divided…” Some point to Genesis 10:25 as evidence that the earth was divided after the Flood of Noah.
While this view is possible, it is most definitely not universally held by Christians. Some view Genesis 10:25 as referring to the “division” that occurred at the Tower of Babel, not the division of the continents via “continental drift.” Some also dispute the post-Noahic Pangea separation due to the fact that, at the current rates of drift, the continents could not possibly have drifted so far apart in the time that has transpired since the Noahic Flood. However, it cannot be proven that the continents have always drifted at the same rate. Further, God is capable of expediting the continental-drift process to accomplish His goal of separating humanity (Genesis 11:8). Again, though, the Bible does not explicitly mention Pangea, or conclusively tell us when Pangea was broken apart.
The post-Noahic Pangea concept does possibly explain how the animals and humanity were able to migrate to the different continents. How did the kangaroos get to Australia after the Flood if the continents were already separated? Young-earth creationist alternatives to the standard continental drift theory include the Catastrophist Plate Tectonics Theory and the Hydroplate Theory, both of which place accelerated continental drift within the cataclysmic context of Noah’s Flood.
(There’s more at the link.)