Final answer:
Conversion currents in the asthenosphere are mainly caused by heat transfer and density differences.
Step-by-step explanation:
Conversion currents in the asthenosphere
The asthenosphere is a semi-fluid layer located beneath the Earth's lithosphere. Conversion currents in the asthenosphere are mainly caused by two factors:
- Heat transfer: The heat from the Earth's core causes convection currents in the asthenosphere. As the mantle is heated from below, the hot material rises and moves towards the surface, creating a circular motion. This movement is known as a conversion current.
- Density differences: The solid rocks in the asthenosphere undergo temperature and pressure changes. These changes can cause rocks to melt, forming magma. Magma has a lower density compared to the surrounding rocks, which allows it to rise through the conversion currents.
These two causes, heat transfer and density differences, contribute to the formation of conversion currents in the asthenosphere.
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