Most major gold deposits are related to orogenic events (mountain building). A significant subset of these are related to fluids associated with felsic magmatism. However, the majority of orogenic gold deposits are linked to fluids that escaped during wide-spread regional metamorhpism, as opposed to volcanic activity. In other words, they're not related to igneous activity, but rather with burial and heating of large regions of rocks. (Note - Metamorphism is not melting.)

That aside, my main gripe is with using "center of the earth".

Yes, many gold deposits are linked to igneous activity. However, even if it is volcanic, what does that have to do with "the center of the earth"? Volcanoes don't source anything from that deep. Nothing comes from the core.

The metorite bombardment I was referring to is an early phase in Earth's history. After the core and mantle segregated, most of the heavy elements should have wound up in the core and been unable to escape. However, we see relatively high concentrations of many heavy elements in the crust and mantle. The leading hypothesis is that the heavy elements were added during the meteorite bombardment phase of the planet's formation. Because the core had already segregated, the heavy elements added this way were able to remain in the mantle and crust.

At any rate, sorry to go on a rather technical rant. It distracts from the main point of the article.