User:Sedith7/Columbia River Basalt Group

The transition to flood volcanism in the Colombia River Basalt Group (CRBG), similar to other Large igneous province s, was also marked by atmospheric loading through the mass exsolution and emission of volatiles, via the process of volcanic degassing. Comparative analysis of volatile concentrations in source feeder dykes to associated extruded flow units have been quantitatively measured to determine the magnitude of degassing exhibited in CRBG eruptions. Of the more than 300 individual flows associated with the CRBG, the Roza flow contains some of the most well chemically preserved basalts for volatile analysis. Contained within the Wanapum formation, Roza is one of the most extensive members of the CRBG with an area of 40,300 square kilometres and a volume of 1,300 cubic kilometres With magmatic volatile values assumed at 1 - 1.5 percent by weight concentration for source feeder dykes, the emission of sulphur for the Roza flow is calculated to be on the order of 12Gt (12,000 million tonnes) at a rate of 1.2Gt (1,200 million tonnes) annually, in the form of sulphur dioxide. However, other research through petrologic analysis has yielded SO2 mass degassing values at 0.12% - 0.28% of the total erupted mass of the magma, translating to lower emission estimates in the range of 9.2Gt of sulfur dioxide for the Roza flow. Sulfuric acid, a by-product of emitted Sulfur dioxide and atmospheric interactions, has been calculated to be 1.7Gt annually for the Roza flow and 17Gt in total. Analysis of glass inclusions within Phenocryst s of the basaltic deposits have yielded emission volumes on the magnitude of 310 Mt of Hydrochloric acid, and 1.78 Gt of Hydrofluoric acid, additionally.