What natural process occurring in the semi-solid Asthenosphere causes the Lithospheric Plates to break apart and move?
A. Gravity
B. Continental Drift
C. Uneven heating of the Earth from the sun
D. Convection Currents
The correct answer is D. Convection Currents.
To understand why convection currents in the semi-solid asthenosphere cause the lithospheric plates to break apart and move, let's break down the process:
1. Convection currents: Convection is the transfer of heat through the movement of a fluid. In the case of the Earth's asthenosphere, which is a semi-solid layer beneath the lithosphere, convection currents occur due to the heat generated from the Earth's core.
2. Heat source: The Earth's core is extremely hot, creating heat that rises towards the surface. This heat causes the rock material in the asthenosphere to become less dense and rise.
3. Rising material: As the heated material rises, it pushes against the overlying lithospheric plates.
4. Shearing forces: As the rising material pushes against the lithospheric plates, it creates shearing forces along the edges of the plates, causing them to break apart.
5. Plate movement: Once the lithospheric plates break apart, the convection currents continue to drive the plates in different directions, resulting in plate motion - a phenomenon known as plate tectonics.
In summary, convection currents in the semi-solid asthenosphere cause the lithospheric plates to break apart and move due to the rising of heated material and the resulting shearing forces along the plate boundaries.