Mg∕Ca, Sr∕Ca and stable isotopes from the planktonic foraminifera <i>T. sacculifer</i>: testing a multi-proxy approach for inferring paleotemperature and paleosalinity

Abstract. Over the last decades, sea surface temperature (SST) reconstructions based on Mg∕Ca of foraminiferal calcite have frequently been used in combination with δ18O signal from same material to provide estimates water (δ18Ow), a proxy for global ice volume and salinity (SSS). However, because error propagation one step next, better calibrations are required increase accuracy robustness existing isotope element relationships. Towards that goal, we determined Mg∕Ca, Sr∕Ca oxygen isotopic composition Trilobatus sacculifer (previously referenced as Globigerinoides sacculifer) collected waters (0–10 m) along north–south transect eastern basin tropical subtropical Atlantic Ocean. We established new paleotemperature calibration Sr∕Ca. Subsequently, sensitivity analysis was performed which one, two or three different equations were considered. Results indicate allows an accurate reconstruction temperature. Combining equations, δ18Ow can be reconstructed precision about ± 0.5 ‰. best possible locally calibrated only allowed uncertainty 2.49. This confirmed by Monte Carlo simulation, applied test successive “ideal case” explanatory variables known. simulation shows purely statistical point view, involving δ18Oc preclude than 1.69 hardly 2.65 due propagation. Nevertheless, direct linear fit reconstruct measured (Mg∕Ca δ18Oc) established. led much estimation (± 0.26) reconstructions.