A snapshot of an Ediacaran microbialite assemblage from the Byng Formation (Neoproterozoic Miette Group, Alberta, Canada)

This study documents an extensive shallow-water boundstone facies within the Late Neoproterozoic aged Byng Formation of the Miette Group near Jasper, Alberta. The microbialites are densely packed and exceptionally well-preserved, ranging from stratiform to columnar and domal morphologies. They are restricted to an approximately 5 m thick boundstone that overlies ∼50 m of dolostone characterized by interbedded planar lamination and hummocky cross-stratification. Scanning electron imaging of thin sections reveals pervasive dolomitization, with distinct dolomite and quartz mineral phases preserved within the stromatolites. In this locality, we suggest that the Byng Formation was deposited under oscillatory flow conditions, punctuated by localized low-energy conditions fostering carbonate precipitation and the stabilization of a laterally extensive microbialite reef. Carbon and oxygen isotope compositions (δ 13 C carb : −7.3‰ to −0.1‰; δ 18 O carb : −18.6‰ to −4.3‰) are consistent with microbial mediated authigenic carbonate precipitation, with diminished meteoric influence and diagenetic overprinting, rather than recording the primary signatures of the global Ediacaran ocean. Together, these sedimentological and geochemical data demonstrate how coupled analyses of dolostone successions and associated microbialite reefs can constrain environmental variability during deposition of Ediacaran carbonate deposits.