Question.
How are the convectional currents in the mantle initiated and maintained?
Answer.
Convectional current theory was given by Arthur Holmes in the 1930s and he expressed the possibility of convection current operating in mantle portion.
Presence of Radioactive elements in mantle portion cause thermal differences and convection currents are generated due to these thermal difference. Convection currents moved in a cyclic manner.
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| convectional cell |
The horizontal movement of convection currents is happening due to thermal differences caused by radioactive elements.
Vertical movement of convection currents happens due to thermal differences caused by depth. Hot magma at greater depth has higher temperatures as compared to shallower's depth magma. Comparatively cooler magma from shallow depth sink and comparatively hotter magma from greater depth rise; by this way convectional currents in mantle initiated and maintained.
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