Explain how continental drift is possible and why it happens?
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Under high pressure and elevated temperature, even seemingly solid rocks are able to flow and deform like cookie dough or wet clay.
Albeit to the tune of 1-5 cm or so per year. But over hundreds of millions of years, continents can drift apart due to such forces.
This is similar to the process of blacksmithing. When heated, iron can deform like clay, although it takes quite a bit of force to do it, in other words the force of hammer blows.
The outer core of the Earth is still molten. Periodically, hot molten material flows up through gaps and cracks, softening and liquifying certain minerals in the mantle which is otherwise largely solid. This hotter material slowly rises to the surface due to the pressure farther below. This effectively wedges continental plates apart, like using a wedge to split wood.
Because the rocks found in continents are less dense than those in the mantle, they “float” in a certain sense, while the denser rocks created in rift zones tend to be found lower in elevation…that is, in the mid-ocean ridges, underneath a few km of water.
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