Why do rocks at the bottom of the mantle spread out and move higher when they heat up?
The core heats the bottom of the rocky mantle. The hottest rock near the bottom of the mantle becomes slightly less dense than the somewhat cooler rock above it, so buoyancy forces try to push the hottest rocks upward.
What causes convection currents to move within the mantle?
Convection currents are the result of differential heating. Lighter (less dense), warm material rises while heavier (more dense) cool material sinks. It is this movement that creates circulation patterns known as convection currents in the atmosphere, in water, and in the mantle of Earth.
Does convection occur in the lower mantle?
The temperature difference between the upper and lower boundaries of the mantle requires heat transfer to occur. While conduction seems the more obvious method for heat transfer, convection also occurs in the mantle.
What is the cooling source for convection in the mantle?
The primary sources of thermal energy for mantle convection are three: (1) internal heating due to the decay of the radioactive isotopes of uranium, thorium, and potassium; (2) the long-term secular cooling of the earth; and (3) heat from the core.
Where does heat come from that drives this convection current in the mantle?
Question One: Where does the heat come from that drives this convection current in the mantle? The heat driving the convection current in the mantle comes from the extreme temperature in the earth’s core, and the heat from the mantle itself.
Which of the following best explains convection current in the mantle?
Answer. Answer: Convection currents within the mantle provide one potential driving force for plate movement. The plastic movement of the mantle material moves like the flow of mountain glaciers, carrying the lithospheric plates along as the convection movement in the mantle moves the asthenosphere.
What is constructive force caused by the convection in the mantle?
Answer: convergent margins. Explanation: Mantle convection causes the phenomenon of plate tectonics on the earth surface. From plate tectonics, we understand that the earth surface is broken into several giant slabs made up of the crust and upper part of the mantle.
What is special about the lithosphere?
The lithosphere is the rocky outer part of the Earth. It is made up of the brittle crust and the top part of the upper mantle. The lithosphere is the coolest and most rigid part of the Earth.
What is the driving force for the movement of the lithospheric plates?
Lithospheric plates are part of a planetary scale thermal convection system. The energy source for plate tectonics is Earth’s internal heat while the forces moving the plates are the “ridge push” and “slab pull” gravity forces. It was once thought that mantle convection could drive plate motions.
What really happens when plate moves?
When the plates move, they will eventually collide. These collisions cause earthquakes, tsunamis, and volcanoes. Earthquakes usually happen when two plates slide past each other. Volcanoes form when one plate sinks under the other plate allowing lava/magma to seep through and build up to form a volcano.