At a very young age, we learnt that the Earth is not static but is revolving around the sun. It was perhaps the first ever Geography lesson for most of us. But what about the continents that we live in? Are they moving? If not then what are causing the earthquakes?
The first image is the supercontinent Pangea believed to have existed roughly 200 million years ago after which it started to break apart. The second image is the continents as they exist today. Alfred Wagner’s ‘Continental Drift Theory’ suggests that the continents drifted apart, formed new oceans (such as the Atlantic and Indian oceans) and became what they are today.
The most important proof for this theory lies in the boundary lines of the continents itself. Especially the southern continents of Africa and South America almost fit perfectly, though it may be a little rough around the edges.
Another proof is that similar fossils of flora and fauna were found in the southern continents of Africa, South America, Indian and Australia. Like the mesosaurs and other reptiles fossils found in the continents proving that the continents used to be a single landmass unless the reptiles learnt to swim across oceans. Though this theory had its popularity it was not considered plausible. There was no proper explanation as to what caused the breaking up of the Supercontinent Pangea.
The most agreeable theory to date is the ‘Plate tectonics Theory.’ Built on the same concept as the continental drift theory but instead of the continents, it’s the plates forming the outer most layer of the crust of the earth that is drifting. There are around 7 major plates and many other smaller tectonic plates forming the earth’s crust. The movement of these plates is causing the continents to rift and move apart.
Some of these tectonic plates are pushing land masses together and some of them are pulling them away from each other. When two plate boundaries are pulled away it’s called a divergent boundary and it is what causes the sea floors to spread.
A convergent boundary is when two plates are pushed together and one gets sunk under another. This process is called subduction. Some of the results of such an action are the formation of volcanoes, earthquakes and tsunamis. The ‘2004 Indian Ocean tsunami’ is a perfect example of this phenomenon. This also causes the formation of mountains. When the plate boundaries scrape against each other while moving horizontally it is a transform boundary.
The origin of this earth and every geological formation on it is fascinating. Hope you found this post useful. If you did please like, share and continue to read our posts.
1 thought on “Earth and Plate Tectonics – Beginners”
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