View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Open Research Exeter This is the author-formatted version of Ullmann et al, 2017, in Chemical Geology, http://doi.org/10.1016/j.chemgeo.2017.03.034. Element/Ca, C and O isotope ratios in modern brachiopods: species-specific signals of biomineralization C.V. ULLMANN1,*, R. FREI2, C. KORTE2, C. LÜTER3 1University of Exeter, Camborne School of Mines & Environment and Sustainability Institute, Penryn Campus, Penryn, TR10 9FE, United Kingdom 2University of Copenhagen, Department of Geoscience and Natural Resource Management, Øster Voldgade 10, 1350 Copenhagen, Denmark 3Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, 10115 Berlin, Germany *Correspondence:
[email protected]; Tel: 0044 1326 259165 Abstract: Fossil brachiopods are of major importance for the reconstruction of palaeoenvironmental conditions, particularly of the Palaeozoic. In order to better understand signals of ancient shell materials, modern analogue studies have to be conducted. Here we present C and O isotope data in conjunction with Mg/Ca, Sr/Ca, Mn/Ca and Fe/Ca data for nine modern rhynchonellid and terebratulid brachiopod species from tropical to intermediate latitudes and shallow to very deep marine settings. C and O isotope signals of most species suggest formation of secondary shell layers near or in isotopic equilibrium with ambient seawater. Some species – especially in the suborder Terebratellidina – show partly distinct disequilibrium signals, suggesting some degree of phylogenetic control on the expression of vital effects. Mn/Ca and Fe/Ca ratios measured in the modern species form a baseline to assess fossil preservation, but also yield environmental information Mg/Ca and Sr/Ca ratios follow previously observed patterns, with all studied brachiopod species comprising low-Mg calcite.