Origin of the New Brunswick Gypsum Deposits
The New Brunswick gypsum and anhydrite deposits make up part of the Windsor group in the Upper Mississippian. The present deposits were formed by surface hydration of the underlying anhydrite beds. The subhydrate, hydrate, and di-hydrate stages of gypsum are formed from the anhydrite by this hydration. The anhydrite was precipitated from sea water in embayments that were separated from the sea by a reef or baymouth bar. The anhydrite is the original form of the calcium sulphate precipitate.