Final answer:
The asthenosphere enables tectonic plates to move by providing a lubricating layer through which convection currents in the mantle occur. Without the asthenosphere, the plate tectonics mechanism that drives geographical transformations on Earth would likely cease to function.
Step-by-step explanation:
The asthenosphere contributes to the movement of tectonic plates by acting as a soft, plastic-like layer on which they can move, facilitated by mantle convection currents. Without the asthenosphere, tectonic plate movements would likely be impossible due to the lack of a lubricating layer.
As part of the earth's upper mantle, the asthenosphere is essential for plate tectonics. It extends to about 60 kilometers in depth and consists of semi-molten rock that behaves plastically, allowing the lithospheric plates to move over it. These movements are driven by the convection currents within the asthenosphere, resulting from the heat escaping from the planet's interior. This heated material rises, while cooler material sinks, creating a flow that drags the plates along. When plates interact at their boundaries, they can diverge, converge, or transform, leading to various geological phenomena such as earthquakes, volcanic activity, and mountain formation. If the asthenosphere were removed, these convection currents would become inactive, resulting in the hardening of the mantle and halting the mechanism that allows the plates to glide over the Earth's surface, ending the dynamic geological processes that shape our planet.