As a geologist with extensive experience in the study of plate tectonics and the geological history of the Earth, I can provide a detailed explanation for why the continents do not fit together exactly as they might be expected to if they were once part of a supercontinent like Pangaea.

Step 1: English Answer

Plate Tectonics and Continental Drift
The Earth's lithosphere is divided into several large and small tectonic plates that are constantly moving. This movement, known as continental drift, has been occurring for billions of years. The continents are essentially "rafted" on these plates, and their shapes have been influenced by this movement.

Erosion and Deposition
Over geological time, erosion has worn down the edges of continents, causing them to lose the sharp, jigsaw-puzzle-like edges they might have once had. Erosion is caused by various agents such as water, wind, ice, and biological activity. This process has altered the original shapes of the continents significantly.

Sea Level Changes
Fluctuations in sea levels due to factors like glaciation and deglaciation have also played a role in the shaping of continents. When large ice sheets melt, they can cause sea levels to rise, which may lead to the submergence of some continental shelves, altering the coastlines.

Tectonic Activity
The Earth's crust is dynamic, with tectonic activity such as earthquakes and volcanic eruptions continuously reshaping the land. This activity can cause the edges of continents to be broken or altered, preventing a perfect fit.

Biological and Chemical Weathering
In addition to physical erosion, biological and chemical weathering processes have also contributed to the change in the shape of continents. Organisms can break down rocks, and chemical reactions can dissolve minerals, both of which can lead to changes in the land's form.

Subduction and Mountain Building
At convergent plate boundaries, where one tectonic plate is forced under another, subduction occurs. This process can lead to the formation of mountain ranges and the destruction of the original continental edge, further distorting the fit.

Time and Geological Processes
The Earth is approximately 4.5 billion years old, and over this immense timescale, countless geological processes have acted upon the continents. These processes include but are not limited to folding, faulting, and the formation of new crust at divergent boundaries.

Human Activity
Lastly, it's important to note that human activity, while relatively recent in the grand scheme of geological time, has also had an impact on the shape of the continents, particularly through land reclamation and the construction of large-scale structures.

In summary, the continents do not fit together perfectly due to a combination of factors including plate tectonics, erosion, sea level changes, tectonic activity, biological and chemical weathering, subduction, time, geological processes, and human activity.

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There are several reasons due to which the present shapes of the continents will not fit perfectly into a super continent. The main reason can be attributed to erosion and rise and fall of the water levels. ... this never allows the continents to remain in the shape in which they were separated from one another.read more >>