FORMATION OF CONTINENTS

The earth’ history is 4.5 billion years old when all the continents which we see today were not in this shape & position. Amazingly these continents were close to each other! By 750 million years ago the earth’s mass combined to ‘Supercontinent’. And surrounding this ‘Supercontinent’ there was also an extensive ocean. Roughly 750 Ma (million years ago), the earliest-known supercontinent Rodinia, began to break apart. The continents later recombined to form Pannotia, 600–540 Ma, then finally Pangaea which is “All Earth” in Greek.

Then about 200 million years ago the land began to drift apart. It broke into two pieces,
· Laurasia – the northern supercontinent- splits in Eurasia and North America
· Gondwanaland- the southern supercontinent which consisted
§ Antarctica,
§ South America
§ Africa
§ India and
§ Australia.

The two large continents continued to break apart into the smaller continents that exist today. Eduard Suess, an Austrian geologist named it ‘Gondwanaland’. The name based on a district in India where the fossil plant Glossopteris was found. Suess said that because this fossil plant could be found in India, South America, southern Africa, Australia, and Antarctica, then all the lands must once have been joined together. Gondwanaland was a hot and dry place with rainy seasons. The first tree ferns and coniferous trees appeared there. Dinosaurs lived there at one time too.
By the end of Cretaceous period, modern land masses were formed.

The Continental Drift Theory:
In 1915, the German geologist and meteorologist Alfred Wegener (1880-1930) first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. The fossil record supports and gives credence to the theories of continental drift and plate tectonics.

The top layer of the Earth's crust is made up of large sections called tectonic plates. Some are oceanic plates, located in the oceans, and some are continental plates carrying continents on top of them. The plates all move extremely slowly and in different directions. Where they meet is called a boundary. At some boundaries the plates move apart and liquid rock seeps into the valley that results. It hardens and becomes new crust. At some boundaries two plates collide, and one is forced up, forming mountains. The other is forced down and part of it goes into the Earth's core and melts. At other boundaries, the two plates grind together as they pass in different directions, but neither is changed. Earthquakes occur along the boundary as the plates grind each other.

See the development of Continents on the following link:

http://www.exploratorium.edu/origins/antarctica/ideas/gondwana2.html

Five Ways to Count Continents
#1 - Seven Continents Africa - Antarctica - Asia – Europe-North America - South America - Oceania

#2 - Six Continents Africa - Antarctica - Eurasia – Oceania - North America - South America

#3 - Six Continents Africa - America - Antarctica - Asia - Europe - Oceania

#4 - Five Continents Africa - America - Antarctica - Eurasia - Oceania

#5 - Four Continents Eurafrasia - America - Antarctica - Oceania

Now let’s play some game on Earth’s Geography. Go to the link below:
http://kids.nationalgeographic.com/kids/games/geographygames/geospy/