Gabbros (igneous rock type) are host to many types of precious metals. Some are barren. Shear zones can also host gold. Shear zones are a local or regional deformation of the rock. Gold can be emplaced in the the shear. As for Quartz carbonates they are present in every major Greestone gold deposit and from my reading over the years and in my opinion are usually present in any Archean deposit that is mineable. Red Lake has carbonates and so does Timmins. Carbonates usually involve sediments and hydrothermal environments which precipitate gold.