>>21797588>>21797203i am a bit buzzed for this but when thinking about mineral vein formation, its good to not think in terms of something like molten rock (magma) being the primary carrier for mineralization. For many quartz hosted structures / veins, you have a super heated brine "fluid" (think more like a steam then liquid) that follows a magma plume or similar intrusive body up from the mantle into the upper crust. As the blob of molten rock is moving up, it causes immense pressure on the local host, which bakes or plastisizes. The super heated solution carrying precious metals travels along the rim of the plume, and anywhere a fault or a movement occurs this intensely pressurized solution shoots into these gaps, often instantly solidifying into a quartz vein due to the drop in pressure and heat. This especially happens where surface waters have reached deeper depths. During the vein making process the precious metals form minerals most often along the contact zone of the host and the vein, often these faults can reopen and get multiple injections of minealization, creating tree ring like patterns in the vein. You also can see brecciation occur, where veins are fragmented during new movement events, allowing newly injected fluid to create mineralized cement like features.
I ve got pages of photos for this sort of discussion but this boards bad for file size limits.
