The Formation of Continents

Definition of continent and Pangea

We define continent as a huge landmass, and the joining islands. Today the existence of seven continents is obvious, however the formation took most of Earth's history. In the Earth's beginning there were no landmasses, just a burning gas orbiting the Sun. It took hundreds of million years before the first continents formed. We do not know exactly how they looked like, however it is confirmed that about 250 million years ago they joined together and formed a super continent- Pangea. Water life blossomed in the Panthalassa superocean, later also in rivers and lakes. First amphibians started living on-land, insects, plants and mammals joined them later. Climate was quite stable, until the super continent tore apart.

Pangea formation of continents
This is how Pangea might looked like

The Formation of Gondwana and Laurasia

Due to the plate tectonics movement, Pangea broke forming two huge continents- Laurasia and Godwana. Recent study suggests that this event may have started the Cambrian Explosion. Laurasia combined Asia, Europe, and North America, which broke off first. Godwana contained what we know today as India, Africa, South America, Australia, and Antarctica. However, the situation wasn't stable and Indian subcontinent broke from east coast of "Africa" and moved north, very fast for a huge landmass. On it's way it collided with Asia, forming the world's greatest mountain range- the Himalayas. However, plate tectonics did not stop moving, and the processes kept on going.

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Laurasia and Godwana

The formation of modern continents

Due to ongoing processes, 65 million years ago continents looked recognizable. North America broke off Laurasia, and kept drifting apart from them. Africa and South America also broke off, Madagascar formed during India's "escape". Antarctica also looked familiar, however Australia still was not very familiar. Due to the plate tectonics movement, continents kept on drifting apart. Later on, Greenland, the Antilles, and northern archipelagos disconnected from North America, which went a bit closer to the South America. Africa did not drift a lot, forming the Mediterranean sea with Europe and newly formed Arabian peninsula. Eurasia gained shape also with the formation of Indonesia and Philippines. Australia drifted apart from Antarctica for a very long time, small islands also disconnected with the main mass. During those 65 millions years world started looking as we see it today. However, plate tectonics never settle, so the continents may change in the future.

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formation of continents
Earth's continents today

Proofs on the formation of continents theory

The theory of super continent was formed by Alfred Wegner in the beginning of the twentieth century, and was very controversial at the time. The name Pangea, which means "Mother Earth" in Ancient Greek, appeared a bit later. The theory gained a lot of acceptance due to development in paleontology. Fossil records, as well as today's animals, show that similar species appear within great distances. The logical explanation is that they have a common ancestor, and later evolved due to environmental changes. The science that studies geographical distribution of species is known as bio-geography. Furthermore, modern mountain chains continuity indicates past processes. And finally, the polar ice cap, that covered the Pangea, exist both in South America and Africa, which gives the geological proof.

Biogeography proves, that all the continents were once a supercontinent
Credit: http://www.prism.gatech.ed

Continents impact on life

The formation of continents was a very long-lasting process, however it did impact evolution of life. When continents drifted apart, climate, terrain, and other factors changed, forcing adaptation. Structures similar to Earth's continents were not found anywhere else, moreover movements of plate tectonics may catalyzed life explosion events. The diversity of habitats and ecosystems may also impact biodiversity on our planet- more species could evolve separately. Though the exact impact of continents on life remains unknown, there are just too many clues to ignore it.

Also Read: How did life begin on Earth?

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