Lacustrine stromatolites and algal laminites in a Pennsylvanian coal-bearing succession near Sydney, Nova Scotia, Canada
Stromatolitic limestone units in the Pennsylvanian Morien Group near Sydney, Nova Scotia occur within mudstones in repetitive fining-upward, coal-bearing sequences, interpreted as meandering fluvial cyclothems. The fluvial association, presence of a non-marine fauna, and the lack of marine fossils indicate a lacustrine environment for the algal units. Horizontally laminated and domal forms are present, the latter encrusted on oncoids, which are attributed to moderate wave agitation. The stromatolites occupy a position analogous to the marine bands in paralic coal sequences and represent repetitive lacustrine development within the fluvial cyclothems of the Sydney Basin.