Question

Explain about the Continental Drift Hypothesis, the Seafloor spreading and Plate movements(plate tectonics theory).

Answer 1

Instructions:

• Explain each of them (1 x 3 = 3 Marks)

Solution:

• Continental Drift Hypothesis : Alfred Wegner argued that all the present-day continents were a single unit forming supercontinent named Pangea which was encircled by an ocean called Panthalassa. Wegener believed that over millions of years, the continental portions drifted over the ocean floor forming the present continents.
• Seafloor Spreading: New ocean floor is continuously being created as a result of magma that comes out through the divergent margins and solidification along the edges of the plates. This results in the phenomenon known as seafloor spreading.
• Plate tectonics theory: The lithosphere is not a continuous layer and there are seven major and several minor plates. The lithosphere tends to float on the asthenosphere which is in a semi-plastic state. This causes the movement of lithospheric plates