Biominerals and Biomaterial

Calcium isotopes in deep time: Potential and limitations

“…It was originally debated whether this fractionation is constant or dependent on temperature, and consequently, if variations in the δ 44/40 Ca record reflect changes in the Ca budget or paleo-temperatures (e.g., Skulan et al, 1997). Although it is now established that Ca isotopes have little sensitivity to temperature (generally <0.03‰/°C, e.g., compilation in Gussone and Heuser, 2016), this initial debate initiated a series of detailed calibration studies. These studies identified parameters that influence Ca isotope fractionation in inorganic mineral phases and in biogenic minerals, including species-specific Ca isotope fractionation (e.g., Böhm et al, 2006;Gussone et al, 2003;Lemarchand et al, 2004;Marriott et al, 2004;Sime et al, 2005).…”

“…Calcium isotope fractionation as a function of different environmental parameters have been studied for various taxa. This includes the main contributors to the present-day global Ca export production, namely corals (e.g., Böhm et al, 2006;Chen et al, 2016;Gothmann et al, 2016;Inoue et al, 2015), coccolithophores (e.g., Langer et al, 2007;Meija et al 2018) and foraminifers (e.g., Griffith et al, 2008b;Gussone and Heuser, 2016;Kasemann et al, 2008;Sime et al, 2005). In addition, taxa were studied that were considered as archives for the reconstruction of δ 44/40 Caseawater records, such as brachiopods (e.g., Farkaš et al, 2007a;von Allmen et al, 2010), mussels (e.g., Hippler et al, 2013;Ullmann et al, 2013), ostracods (Gussone and Greifelt, 2019), sponges (Gussone et al, 2005) and dinoflagellates .…”

“…While Ca isotope fractionation during inorganic mineral formation is highly dependent on precipitation rates, Ca:CO3 stoichiometry, supersaturation, carbonate chemistry and salinity, these parameters have overall a relatively small impact on Ca isotope fractionation in corals, coccolithophores and foraminifers (e.g., Inoue et al, 2015;Kısakürek et al, 2011;Langer et al, 2007;Roberts et al, 2018). However, Ca isotope fractionation appears to be substantially reduced at low calcite saturation states in cultured coccolithophores (Gussone et al, 2007;Meija et al, 2018), a process that may also be responsible for anomalously small Ca isotope fractionation found in planktic and benthic foraminifers and ostracods collected from water masses with low temperatures and calcite saturation (Gussone et al 2009;Gussone and Filipsson, 2010;Gussone et al, 2016;Gussone and Greifelt, 2019).…”

“…Indeed, a significant positive correlation is observed for a carbonate-poor PETM deep-sea core (Griffith et al, 2015), which may indicate that a unique diagenetic regime characterizes predominantly siliciclastic d 44/40 Ca records. Data from the Late Silurian exhibit a linear inverse relationship between d 44/40 Ca and Sr/Ca, potentially reflecting variable precipitation rates and not diagenesis (Farkaš et al, 2016 (Lau et al, 2017), the Late Silurian (Farkaš et al, 2016), the end-Ordovician glaciation (Holmden et al, 1998;Kimmig and Holmden, 2017;Jones et al, 2020), the Ediacaran Shuram excursion (Husson et al, 2015), and the Marinoan cap carbonate sequence (Ahm et al, 2019 (Fantle, 2015;Fantle and DePaolo, 2007;Gussone and Heuser, 2016;Kısakürek et al, 2011), coccoliths (Gussone et al, 2007;Langer et al, 2007), and dinoflagellates , (5) Modern biogenic skeletal aragonite corals (Chen et al, 2016;Gothmann et al, 2016;Inoue et al, 2015), ( 6) authigenic aragonite clathrites (Teichert et al, 2005), ( 7) highmagnesium calcite from Site 1131 and high-magnesium foraminifers (Gussone et al, 2016), ( 8) inorganic calcite from laboratory experiments with varying precipitation rates (AlKhatib and Eisenhauer, 2017a;Tang et al, 2008b;Lemarchand et al, 2004), ( 9) authigenic carbonates from the Miocene Monterey Formation and the northern South China Sea (Blättler et al, 2015;Wang et al, 2012;, ( 10) Synthetic and natural ikarite (Gussone et al, 2011), (11) platform dolomites from the Great and Little Bahamas Bank Holocene, but timing and magnitude of the variation differ. Because of the larger isotope fractionation, the barite records…”

Calcium isotopic variability of cervid bioapatite and implications for mammalian physiology and diet

“…Alternatively, the consumption of milk during nursing can also generate TLE discrepancies by changing the diet Ca isotope composition of non-weaned individuals compared to weaned individuals (Chu et al, 2006;Li et al, 2016Li et al, , 2020Tacail et al, 2017Tacail et al, , 2019. Finally, Ca enriched mineral supplementation such as with mineral licks and osteophagia, as well as the Ca isotopic variability inherent to plants (Holmden and Bélanger, 2010;Gussone and Heuser, 2016;Schmitt, 2016;Moynier and Fujii, 2017;Martin et al, 2018;Griffith et al, 2020), are also able to blur the trophic clustering of Ca isotope compositions. The aim of this study is thus to investigate how these seven factors can affect bone and enamel Ca isotope compositions in modern animals, then to use this background to unravel a case study of TLE discrepancy previously documented.…”