Consider a melt that has cooled to a temperature such that olivine, pyroxene, amphibole, and calcium-rich plagioclase feldspar have crystallized. which elements will be enriched in the melt, and which will be depleted in the melt?

Calcium is enriched, while they are depleted of carbon.

Explanation:

It should be understood that during the process of volcano eruption, carbon is liberated as the molten magma is coming out , this is due to the heat that is being evolved. And calcium will be the molecules that will make the molten solidified after wind has cooled it down.

That is why they are depleted of carbon, and enriched with calcium.

your spelling is a little off : ]