A 120,000-year long climate record from a NW-Greenland deep ice core at ultra-high resolution

Abstract

We report high resolution measurements of the stable isotope ratios of ancient ice (δ¹⁸O, δD) from the North Greenland Eemian deep ice core (NEEM, 77.45° N, 51.06° E). The record covers the period 8-130 ky b2k (y before 2000) with a temporal resolution of ≈0.5 and 7 y at the top and the bottom of the core respectively and contains important climate events such as the 8.2 ky event, the last glacial termination and a series of glacial stadials and interstadials. At its bottom part the record contains ice from the Eemian interglacial. Isotope ratios are calibrated on the SMOW/SLAP scale and reported on the GICC05 (Greenland Ice Core Chronology 2005) and AICC2012 (Antarctic Ice Core Chronology 2012) time scales interpolated accordingly. We also provide estimates for measurement precision and accuracy for both δ¹⁸O and δD.

Fig. 1

Sampling scheme for the NEEM ice core. CFA refers to the section sampled for Continuous Flow Analysis and Iso refers to the section sampled for water isotope analysis.

Fig. 2

Vaporiser pulse example and run tray configuration. (a) A sequence of four vaporiser pulses focused at the transition from the “−40” to the “NEEM” standard water. (b) Vial tray configuration and raw δD data of a full measurement run as a function of time.

Fig. 3

The compiled NEEM record from the depth of 1210.5 (corresponding to 8000 y b2k) and below.

Fig. 4

δ¹⁸O record and the coverage obtained for every instrument type.

Fig. 5

Quality-control metrics based on the measurement of the “check” standard. The top row presents the precision level of every measurement run while at the bottom row we present the offset of the “check” standard measurement from its assigned value- a measure of accuracy for every measurement run.

Fig. 6

Histograms of the quality-control metrics of Fig. 5.