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 phyto-plankton, the earliest well preserved skeletons of zooptankton (ractiolarians) 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 rote wit bin the black shale sequence of the Hetang and Niutitang formations. The resulting lithology corresponds closely in character to the bituminous alum-shale and Lyclite-sequences of lower Silurian (Llandoverian) age along northern Gondwana (e.g. Thuringia, Bohemia).