Associated with a small Cretaceous-age granitic pluton that intrudes Devonian-age graywacke, mudstone, and siltstone of the Port Refugio Formation. Silicification and argillization of granitic rock. Drilled in the early 1970s.
Study area name
U.S. Geological Survey (2014a)
U.S. Geological Survey National Mineral Resource Assessment Team (2002)