Microbial-stromatolitic carbonate units are a characteristic feature of carbonate-evaporite successions throughout the stratigraphic record, and, commonly being dolomitized and porous, can form important hydrocarbon reservoirs. Here, Perri et al. describe with an Upper Permian (Zechstein) stromatolitic deposit (the "Crinkly Bed") that is closely associated with evaporites in northeast England. The results reveal that this ~ meter-thick unit exhibits a range of cm-scale structures, from stromatolitic domes and cones through to ripple-like features. Despite a complex diagenetic history, it preserves grains and microbial remains, and retains some original geochemical signatures. This distinctive meter-thick stromatolite is interpreted to result from syn-sedimentary and post-sedimentary physical and microbial processes. These results, describing the features, extent and geometry of these stromatolites, highlights numerous challenges in distinguishing the abiotic precipitates from microbialites.
Biotic and abiotic processes in the formation and diagenesis of Permian dolomitic stromatolites (Zechstein Group, NE England) by Edoardo Perri, Maurice E. Tucker, and Mike Mawson