Can calcium carbonate scorch in a pan?
Like the comments have said, black residue is usually from organic material that has scorched.

If the pan somehow got to $840 ^{\circ}$C, then the calcium carbonate would decompose into calcium oxide and carbon dioxide, neither of which would lead to a black residue.

$$\ce{CaCO3 -&gt; CaO + CO2}$$

Organic materials are mostly made of hydrocarbons. When you burn the organic matter, you're left with pretty much all carbon. This occurs when there is not enough oxygen to completely burn all of the carbon - when there is enough oxygen, some of the carbon combines with it to form $\ce{CO2}$ and $\ce{CO}$ and the hydrogen combines with oxygen to form $\ce{H2O}$. When there is a lack of oxygen, some carbon is left over, and this is what we see as the black substance.