Palaeocommunities, diversity and sea-level change from middle Eocene shell beds of the Paris Basin

Author(s)
Stefano Dominici, Martin Zuschin
Abstract

The middle Eocene interval at some Paris Basin localities was studied through high-resolution stratigraphy. Abundance data (499 species, 37 719 individuals) on the distribution of molluscs, collected at 12 shell beds of the middle Lutetian and lower Bartonian, formed the basis for a palaeoecological study. The middle Lutetian succession is subdivided into several elementary depositional sequences (EDS) interpreted as the product of relative sea-level change. Species-abundance distributions are better correlated with EDS than with geographical locality, suggesting that sea level played an important role in the distribution of palaeocommunities. Diversities were compared with analogous data from modern subtropical and warm-temperate intertidal and subtidal communities. We found that sea-level variation is responsible for a major change in the upper part of the middle Lutetian succession, leading from high-to low-diversity palaeocommunities. From base to top sampled palaeocommunities indicate a transition from high-energy and mesotrophic (EDS 2) to oligotrophic low-energy conditions of a sandy lower shoreface (EDS 4) to an upper shoreface (EDS 5 and lower Bartonian), the last with mangroves and a seagrass cover. Notwithstanding the Lutetian cooling, we found that subtropical conditions reached as far north as the Paris Basin. Our study suggests that climatic fluctuations might be obscured by facies control.

Organisation(s)
Department of Palaeontology
External organisation(s)
University of Florence
Journal
Journal of the Geological Society
Volume
173
Pages
889-900
No. of pages
12
ISSN
0016-7649
DOI
https://doi.org/10.1144/jgs2015-150
Publication date
11-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
105118 Palaeontology
Keywords
ASJC Scopus subject areas
Geology
Portal url
https://ucrisportal.univie.ac.at/en/publications/0c208940-fef8-46a9-b5bc-3f635c3cfee6