Stable carbon isotope composition of macroalgal, invertebrate and vertebrate fossils: implications from the Kalana Lagerstätte.

Stable carbon isotope composition of sediments has long been used as a tool in stratigraphic correlations as well as a proxy for palaeoenvironmental changes in the carbon cycle. Several studies have demonstrated that various rock components, such as carbonate fossils or organic matter of different taxonomic groups, show carbon isotope compositions which differ from that of the surrounding sedimentary rock. Here we present results of carbon isotope analyses from completely or partially organically-preserved invertebrate fossils such as crinoids, sponges and worms, but also hemichordate and vertebrate fossils from the Kalana Lagerstätte, Estonia of Aeronian (Llandovery, Silurian) age. In the present study we sampled thalli of red and green (dasycladalean) algae, crinoids, periderms of graptoloid and dendroid graptolites, and an agnathan fish. The d13Corg analyses of individual fossils were supplemented with whole-rock d13Ccarb and dispersed organic material d13Corg analyses from the same rock slabs. The acquired data were compared with the published values from previous studies from different Lagerstätten.