A SEDIMENTARY-EXHALATORY BARITE DEPOSIT AND ASSOCIATED CHEMOSYNTHETIC BIOHERM, AGUATHUNA QUARRY, PORT AU PORT PENINSULA, NEWFOUNDLAND, CANADA

Previous research has described Mississippian age barite deposits on the Port au Port peninsula of Newfoundland as near-shore evaporites. This research documents that the barite is actually a sedimentary-exhalatory deposit, coming to the surface in conjunction with hydrocarbons. This is evident in thin section and hand specimen, showing hydrocarbons closely associated with barite and other sulfide minerals such as pyrite and galena. Associated with this deposit is a community of serpulid tube worms, bivalves, and bacterial mats theorized to have thrived by chemosynthesis, relying on the hydrocarbons for energy. This research attempts to draw a closer link between the exhalation of the barite solution, its associated hydrocarbons, and the fossil community that they fueled. These data benefit current oil exploration projects on the peninsula, helping to define the nature and timing of hydrocarbon flow within faults that rise to the surface. These Mississippian sedimentary-exhalatory deposits are an ancient analog to the modern hydrocarbon seeps, as well as their associated communities. Through the Aguathuna deposits we may understand what fuels modern seeps and how they aid in the sustenance of unique life in an otherwise hostile seafloor environment.