Plate Tectonics Questions Medium
The theory of continental drift is supported by several lines of evidence. One of the key pieces of evidence is the fit of the continents. When the continents are arranged in a way that their coastlines match up, it suggests that they were once connected. For example, the east coast of South America fits perfectly with the west coast of Africa. This fit is particularly evident when looking at the continental shelves, which are submerged portions of the continents.
Another piece of evidence is the distribution of fossils. Fossils of the same species have been found on different continents that are now separated by vast oceans. This suggests that these continents were once connected and the organisms were able to freely move between them. For instance, fossils of the freshwater reptile Mesosaurus have been found in both South America and Africa, indicating that these continents were once joined.
Furthermore, the distribution of rock formations and mountain ranges also supports the theory of continental drift. Similar rock types and geological structures can be found on different continents that are now far apart. For example, the Appalachian Mountains in North America align with the Caledonian Mountains in Europe, indicating a shared geological history.
Additionally, paleoclimatic evidence provides further support for continental drift. Ancient glacial deposits and coal beds have been found in regions that are currently located in tropical or subtropical climates. This suggests that these areas were once located near the poles and have since drifted to their current positions.
Lastly, the discovery of mid-ocean ridges and the mapping of the ocean floor have provided evidence for seafloor spreading. These underwater mountain ranges and the symmetrical patterns of magnetic anomalies on either side of them indicate that new crust is being continuously formed at the ridges and spreading apart, pushing the continents along with them.
In conclusion, the theory of continental drift is supported by the fit of the continents, the distribution of fossils, the similarities in rock formations and mountain ranges, paleoclimatic evidence, and the discovery of mid-ocean ridges. These pieces of evidence collectively provide strong support for the idea that the continents were once connected and have since moved apart over geological time.