Upper Wenlock δ13C chemostratigraphy, conodont biostratigraphy and palaeoecological dynamics in the Ledai-179 drill core (Eastern Lithuania); pp. 293–299

Abstract

Based on the integrated chemostratigraphic and lithostratigraphic studies, as well as biostratigraphic and palaeo- ecological analyses of conodonts in the Ledai-179 core, we present a combined model of change in the upper Wenlock and lowermost Ludlow strata of the inner shelf settings in the eastern part of the Baltic Basin. The comparison of the δ 13 C trend, and conodont and lithological successions confirms previous suggestions that the Birstonas and Nevėžis formations correspond to the Homerian. This is quite unexpected, however, that the chronostratigraphic position of the Sirvinta Formation changed from the Gorstian to the upper part of the Homerian. The numerical biostratigraphic changepoint analyses of local conodont richness, per capita immigration and also per capita extirpation rates revealed several episodes of permanent change. These episodes of dynamic states either preceded or postdated the Mulde extinction interval at the beginning of the late Homerian δ 13 C excursion,