Oxygen isotopes and MgCO3 in brachiopod calcite and a new paleotemperature equation

The Mg/Ca–temperature relationship in brachiopod shells: Calibrating a potential palaeoseasonality proxy

“…Unlike Brand et al (2013), we chose not to include a correction for the effect of Mg on δ 18 O, as this is derived from a study of synthetic magnesian calcite, where it is required for Mg/Ca values above 100 mmol/mol (Jiménez-López et al, 2004). Our δ 18 O-based temperatures range from~8.5 to 13°C.…”

“…This equation is based upon the thorough delineation of the relationship between δ 18 O and seawater temperature in modern brachiopod calcite recently provided by Brand et al (2013); it is a second-order polynomial fit to data from their supplementary data Table S2. Unlike Brand et al (2013), we chose not to include a correction for the effect of Mg on δ 18 O, as this is derived from a study of synthetic magnesian calcite, where it is required for Mg/Ca values above 100 mmol/mol (Jiménez-López et al, 2004).…”

“…Although the Mg/Ca-temperature relationship in biogenic carbonates likely represents a combination of thermodynamic and physiological effects (Rosenthal et al, 1997), initial studies by Lee et al (2004), Perez-Huerta et al (2008) and Brand et al (2013) suggest that a consistent Mg/Catemperature dependence may also be found in brachiopod calcite.…”

“…Previous work has suggested that the incorporation of Mg into brachiopod calcite may be controlled by temperature (Brand et al, 2013). Here we build upon this work by using laser ablation sampling to define the intra-shell variations in two modern brachiopod species, Terebratulina retusa (Linnaeus, 1758) and Liothyrella neozelanica (Thomson, 1918).…”

Mapping of recent brachiopod microstructure: A tool for environmental studies

“…Brachiopod shells in particular are high resolution biomineral archives used to reconstruct global marine environments in the recent and deep past, because: 1) they record the physical and chemical composition of the seawater in which they live with no or limited vital effects (e.g., Parkinson et al, 2005;Brand et al, 2013Brand et al, , 2015; 2) they precipitate a low-Mg calcite shell, which is generally resistant to diagenetic alteration (Lowenstam, 1961;Brand and Veizer, 1980;Popp et al, 1986;Brand et al, 2011); 3) they are common in the Phanerozoic, especially during the Palaeozoic when they dominated benthic communities (Curry and Brunton, 2007); and, 4) they are low metabolic and physiologically unbuffered organisms sensitive to change in the physicochemical composition of the ambient seawater (Peck et al, 1997;Peck, 2007).…”