DOI: 10.1594/pangaea.957182
title: Biomarker indices and concentrations and biomarker-based temperature estimates from the Iberian Margin core MD95-2042

description: This dataset provides the following information for core MD95-2042: depth, age, summed OH-GDGT, iGDGT, and di-unsaturated and tri-unsaturated C37 alkenone concentrations, OH-GDGT-based, iGDGT-based, and alkenone-based paleothermometric indices, GDGT-2/GDGT-3 ratio, and biomarker-based sea surface temperature (SST) and 0‐ to 200‐m sea temperature (subT; gamma function probability distribution for target temperatures with a = 4.5 and b = 15) estimates. Sediment samples were taken every 5 cm from core MD95-2042 and homogenized before lipid extraction. The lipid extracts were splitted into two fractions: one for alkenone analysis by gas chromatography coupled to a flame ionization detector, and the other for GDGT analysis by high-performance liquid chromatography coupled to mass spectrometry. All GDGT analyses were done in duplicate. The 1σ analytical uncertainties from 37 replicate analyses of the core catcher sample from core MD95-2042 are 0.007 (0.4 °C) for RI-OH, 0.008 (0.2 °C) for RI-OH′, 0.003 (0.2 °C) for TEX86, 0.238 for GDGT-2/GDGT-3, and 0.010 (0.26 °C) for UK′37. RI-OH′-SST estimates are from the following global calibration: SST = (RI-OH′ + 0.029)/0.0422 (Fietz et al., 2020). RI-OH-SST estimates are from the following global calibration: SST = (RI-OH − 1.11)/0.018 (Lü et al., 2015). TEX86H-SST estimates are from the following regional paleocalibration: SST = 68.4 × TEX86H + 33.0 (Darfeuil et al., 2016). UK′37-SST estimates are from the following global calibration: SST = 29.876 × UK′37 − 1.334 (Conte et al., 2006). Bayesian calibrations were also used for TEX86-SST and TEX86-subT estimates (BAYSPAR; Tierney & Tingley, 2014, 2015) and for UK′37-SST estimates (BAYSPLINE; Tierney & Tingley, 2018). Alkenone data covering the 160–70 and 70–0 ka BP periods are from Davtian et al. (2021) and Darfeuil et al. (2016), respectively. GDGT data covering the 160–45 ka BP period are from Davtian et al. (2021). The age model of core MD95-2042 for the 160–43 and 43–0 ka BP periods was obtained by tuning to Chinese speleothems (Cheng et al., 2016) and by recalibrating existing 14C ages with the Marine20 calibration curve (Heaton et al., 2020), respectively. MIS, Marine Isotope Stage; GDGT, glycerol dialkyl glycerol tetraether; and N/A, not available.
description: The age model has been defined by 14C dating (14C ages calibrated using Marine20 calibration curve, Heaton et al., 2020 Radiocarbon, https://doi.org/10.1017/RDC.2020.68) and two additional tie points for the 0–43 ka BP period and by synchronization to the Chinese speleothem record by Cheng et al. (2016) Nature (https://doi.org/10.1038/nature18591) for the 43–160 ka BP periodRI-OH′ stands for 'Ring Index of hydroxylated tetraethers with OH-GDGT-0' (Lü et al., 2015 OG; https://doi.org/10.1016/j.orggeochem.2015.10.004)Annual SSTs were calculated from RI-OH′ following Fietz et al. (2020) Oceanography (https://doi.org/10.5670/oceanog.2020.207)RI-OH stands for 'Ring Index of hydroxylated tetraethers without OH-GDGT-0' (Lü et al., 2015 OG; https://doi.org/10.1016/j.orggeochem.2015.10.004)Annual SSTs were calculated from RI-OH following Lü et al. (2015) OG (https://doi.org/10.1016/j.orggeochem.2015.10.004)TEX86 stands for 'TetraEther indeX of tetraethers consisting of 86 carbon atoms' (Schouten et al., 2002 EPSL; https://doi.org/10.1016/S0012-821X(02)00979-2)Annual SSTs were calculated from TEX86 following Darfeuil et al. (2016) Paleoceanography (https://doi.org/10.1002/2015PA002831)Annual SSTs were calculated from TEX86 following Tierney and Tingley (2014) GCA (https://doi.org/10.1016/j.gca.2013.11.026) and Tierney and Tingley (2015) Scientific Data (https://doi.org/10.1038/sdata.2015.29)Annual subTs were calculated from TEX86 following Tierney and Tingley (2014) GCA (https://doi.org/10.1016/j.gca.2013.11.026) and Tierney and Tingley (2015) Scientific Data (https://doi.org/10.1038/sdata.2015.29)GDGT-2/GDGT-3 ratio introduced by Taylor et al. (2013) GPC (https://doi.org/10.1016/j.gloplacha.2013.06.011)UK′37 stands for 'C37 ketone unsaturation ratio' (Prahl and Wakeham, 1987 Nature; https://doi.org/10.1038/330367a0)Annual SSTs were calculated from UK′37 following the linear calibration by Conte et al. (2006) Geochemistry, Geophysics, Geosystems (https://doi.org/10.1029/2005GC001054)Annual SSTs were calculated from UK′37 following Tierney and Tingley (2018) Paleoceanography and Paleoclimatology (https://doi.org/10.1002/2017PA003201)