Calcium concentration in sediment cores from the Arctic Ocean

Cores analyzed in this dataset were retrieved from three Swedish expeditions: Arctic Ocean Expedition 1996 (AO96), Lomonosov Ridge off Greenland (LOMROG) 2007 and 2012. The four cores include AO96-B7 (85°32.6'N, 156°35.6'E, water depth: 2385 m), AO96-13-1PC (87°09.2'N, 145°10.1'E, water depth: 978 m), LOMROG12-TC03 (87°43.3'N, 54°25.3'W, water depth: 1607 m), and LOMROG07-PC08 (85°19.1'N, 14°51.3'W, water depth: 1038 m). Stable carbon isotopes and trace element analysis were conducted on Neogloboquadrina pachyderma in the size fraction of 212-250 μm. The stable carbon isotopes analyses were performed on a Micromass IsoPrime isotopes ratio mass spectrometer equipped with a Gilson autosampler device at the Department of Earth Sciences, National Taiwan Normal University, and a Thermo Fisher Scientific MAT 253plus mass spectrometer coupled to a Kiel IV carbonate preparation line at the Institute of Earth Sciences, Heidelberg University. The cleaning steps for trace element analysis are shown as follows: (1) crush foraminifera, (2) remove clay minerals, (3) remove organic matter, (4) remove iron compounds, (5) remove Mn-Fe-oxides, and (6) acid leach surface contamination (Shen et al., 2001, Barker et al., 2003). The cleaned foraminiferal samples were dissolved in 5% ultra-pure JT Baker nitric acid and analyzed on a Thermo Electron Element II Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) at the High-precision Mass Spectrometry and Environment Change (HISPEC) Laboratory, Department of Geosciences, National Taiwan University. The radiocarbon dating results were both from Chiu et al. (2017) and measured in the NTUAMS lab, Department of Geosciences, National Taiwan University, following the analytical method of Chiu et al. (2017). The XRF data and XRF analytical method are both from Chiu et al. (2017).