Fig. 2.6 The continents are formed from light material of granitic composition drifting on top of
the asthenosphere. Early records show that the continents once formed a unique block that started
to fragment under the effect of convection currents in the mantle. The continents become a giant
puzzle that assembled themselves periodically, such as 200 million years ago. A unique ocean
called Pantalassa surrounded the original continent called Pangaea
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2 Our Haven, Planet Earth