Cadillac Gold Ore (3.8 cm across) - this is a hydrothermal quartz-gold vein from the Precambrian of Cadillac in southwestern Quebec, Canada. In this sample, native gold is emplaced only in fractures in the quartz. The gold blebs you see at center & at right are lining a fracture that's been split (you’re facing the plane of the fracture). Published research on Cadillac auriferous quartz veins indicates that most of the gold there is along late-stage fracture faces. Quartz veins in this area intrude Archean rocks (Cadillac Group & Pontiac Group turbiditic continental shelf type sediments & Piche Group mafic and ultramafic volcanics).

Age of gold-quartz hydrothermal mineralization: late Neoarchean, ~2.7 billion years.

Gold occurrences in the Cadillac and adjacent areas of southwestern Quebec are in proximity to the Larder Lake-Cadillac Fault Zone (a.k.a. Cadillac Break, Larder Lake-Cadillac Deformation Zone, Cadillac Tectonic Zone). This regional shear zone in the Superior Province has been identified by geologists as the principal conduit for auriferous fluids during the ancient Kenoran Orogeny (late Neoarchean).