An assessment of latest Cretaceous <i>Pycnodonte vesicularis</i> (Lamarck, 1806) shells as records for palaeoseasonality: A multi-proxy investigation

Abstract

18In order to assess the potential of the honeycomb oyster Pycnodonte vesicularis for the 19 reconstruction of palaeoseasonality, several specimens recovered from the late Maastrichtian 20Neuquén Basin (Argentina) were subject to a multi-proxy investigation, involving scanning 21 techniques, trace element and isotopic analysis. Combined CT scanning and light microscopy reveals 22 two major calcite micromorphologies in P. vesicularis shells (vesicular and foliated calcite O of about 1‰, which is 35 ascribed to a combination of varying salinity due to fresh water input in the winter and spring season 36 and a moderate temperature seasonality. Attempts to independently verify the seasonality in sea 37 water temperature by Mg/Ca ratios of shell calcite are hampered by significant uncertainty due to 38 the lack of proper transfer functions for pycnodontein oysters. The multi-proxy approach employed 39 here enables us to differentiate between well-preserved and diagenetically altered portions of the 40 shells and provides an improved methodology for reconstructing palaeoenvironmental conditions in 41 deep time. While establishing a chronology for these shells was severely complicated by growth 42

Clumped isotopes in modern marine bivalves

“…Moreover, despite promising potential for paleoclimate reconstructions, the use of clumped isotopes for reconstructing past seasonal contrasts has received little attention so far, even if some works showed the high potential for seasonal reconstruction with D 47 at highresolution (Hren et al, 2013;Ghosh et al, 2018;Van Plantinga and Grossman, 2018;Zhang et al, 2018;Briard et al, 2020;Caldarescu et al, 2021;de Winter et al, 2021). Among technical limitations, D 47 generally requires an amount of carbonate powder unsuitable for seasonal analyses (de Winter et al, 2018). But to date, we still lack this type of approach on specimens from the field.…”

Temperature Dependence of Clumped Isotopes (∆47) in Aragonite

“…islandica data set ( N = 278; see Figure 3) to resolve. However, in paleoclimate reconstructions (e.g., Agterhuis et al., 2022; de Winter, Müller et al., 2021; de Winter et al., 2017; Meckler et al., 2022; Petersen et al., 2016; Vickers, Fernandez, et al., 2020), this temperature offset may have significant consequences. A ∼1.5°C cold bias in temperature reconstructions may lead to a significant underestimation of climate sensitivity to CO 2 forcing, biasing the physical science basis for informing policymakers about future climate change (e.g., Dennis et al., 2013; IPCC, 2021; Modestou et al., 2020; Tierney et al., 2020; Westerhold et al., 2020).…”