Polyphasic carbonate precipitation in the shallow subsurface: Insights from microbially-formed authigenic carbonate beds in upper Miocene sediments of the Tertiary Piedmont Basin (NW Italy)

► We focus on the relationship of authigenic carbonate formation and microbial activity. ► We investigate the impact of biogeochemical processes on organic-rich sedimentary strata. ► Carbonates resulted from three microbially-driven processes: sulphate reduction, methanogenesis, and AOM.