Why isn't the fit perfect if the continents were once part of Pangaea?

Slipping and sliding under, over, bashing cracking, scraping, rising, sinking, eroding, pushing up mountain ranges, ..... Try breaking up an ice flow on the harbor and fitting it back together again.

The fit of the continents may not be perfect if they were once part of Pangaea due to several reasons:

1. Continental Drift: The continents have been moving continuously over millions of years due to the process of plate tectonics. This movement has resulted in the drifting apart of the continents from their original positions when Pangaea existed. As a result, the current positions of the continents may not perfectly match their geological fit.

2. Tectonic Forces: The Earth's crust is subjected to various tectonic forces, such as the collision of tectonic plates, subduction, and the creation of new oceanic crust. These forces cause the continents to shift and deform, leading to changes in their shape and overall fit.

3. Erosion and Geological Processes: Over time, erosion and other geological processes can modify the coastlines and features of the continents. The shaping of landforms, such as mountains, valleys, and coastlines, can alter the fit of the continents. Additionally, the deposition of sediment, like river deltas, can modify the shape of coastlines and further impact the fit.

4. Incomplete Geological Data: Our understanding of Earth's geological history is based on the available data and observations, which may not capture all the details accurately. Some areas, especially those covered by thick layers of sediment or areas under the oceans, may have limited data or mapping, making it challenging to precisely determine the fit of the continents.

To study the past positions of the continents and determine their fit when Pangaea existed, scientists rely on various geological evidence, including matching rock types, fossils, paleomagnetism, and the examination of continental shelves. By analyzing these pieces of evidence, scientists can reconstruct the positions of the continents and understand the changes over time. However, due to the factors mentioned above, the fit may not be perfect, and there might be some gaps or discrepancies in the puzzle of continental reconstructions.