Plankton from Early Cambrian black shale series on the Yangtze Platform, and its influences on lithologies

Blackshalesandcherts ,containingnodularphosphoritesandorelayers1] arecommonintheEar lyCambriandeeperwaterfaciesoftheYangtzePlat form2 ] andoffera goodchanceformicropaleonto logicalresearchusingtechniquesofchemicaldissolu tion ,peelingandsectioning .Wetriedtoseparateandinvestigateoceanicplanktoncommunitiesfrombitu minous,“deeperwater”chert ,blackshale andphosphoritelithologies ,andtodocumenttheirpreser vationandinfluencesonthecompositionofthesedi ments .Thepresentpaperaimsatgivingareportof…

Plankton from Early Cambrian black shale series on the Yangtze Platform, and its influences on lithologies

Black shales, cherts, and associated lithologies in the Early Cambrian of the Yangtze Platform yielded abundant phytoplankton, the earliest well preserved skeletons of zooplankton (radiolarians) and abundant phosphatic ovoid bodies, probably representing fecal pellets, produced by Mesozooplankton grazing on phytoplankton. The oceanic food chain in surface waters is therefore considered to be more complete than known up to now with respect to primary and secondary consumers in the Early Cambrian plankton ecosystem. On the basis of primary sedimentary compositions preserved in phosphorite concretions and chert layers it is shown that biosiliceous sedimentation mixed with organic substance played a significant role within the black shale sequence of the Hetang and Niutitang formations. The resulting lithology corresponds closely in character to the bituminous Alum shale and Lydite sequences of Lower Silurian (Llandoverian) age along northern Gondwana (e.g. Thuringia, Bohemia).