Which term refers to a piece of lithosphere that moves slowly on the asthenosphere?

Which term refers to a piece of lithosphere that moves slowly on the asthenosphere?

• A. Tectonic plate
• B. Crust
• C. Mantle
• D. Core

Answer: (A)

Plates are chunks of the Earth's lithosphere that drift slowly on the partially molten layer beneath called the asthenosphere. The term for a piece of lithosphere that moves on that layer is tectonic plate. Each plate includes the crust plus the rigid part of the upper mantle, riding on the underlying mantle as convection currents push and pull. This slow movement, a few centimeters per year, shapes the surface at plate boundaries—causing earthquakes, volcanoes, and mountain formation. The crust is just the outer skin, the mantle is a much thicker layer beneath, and the core is the Earth’s center, so those terms don’t specifically describe a moving piece of lithosphere on the asthenosphere.

Plates are chunks of the Earth's lithosphere that drift slowly on the partially molten layer beneath called the asthenosphere. The term for a piece of lithosphere that moves on that layer is tectonic plate. Each plate includes the crust plus the rigid part of the upper mantle, riding on the underlying mantle as convection currents push and pull. This slow movement, a few centimeters per year, shapes the surface at plate boundaries—causing earthquakes, volcanoes, and mountain formation. The crust is just the outer skin, the mantle is a much thicker layer beneath, and the core is the Earth’s center, so those terms don’t specifically describe a moving piece of lithosphere on the asthenosphere.