DOI: 10.1594/pangaea.925552
title: NEEM ice core High Resolution (0.05m) Water Isotope Ratios (18O/16O, 2H/1H) covering 8-129 ky b2k

description: We present here a high resolution water isotope (18O/16O, 2H/1H) record from the NEEM ice core covering the period 8 - 129 ky b2k. The depth resolution of the record is 0.05 m. The analysis has been performed using Cavity Ring Down Spectroscopy with an average precision for the whole record equal to 0.05 and 0.3 ‰ for δ18O and δD respectively. Measurements are calibrated and reported on the SMOW/SLAP scale using a 2-fixed-point calibration. Results are also reported on the GICC05 and AICC2012 timescale.
description: NEEM ice core stable water isotope record in the interval 1210.5 m (8000 years b2k) - 2536.5 m. The record is measured on discrete samples with a depth resolution of 0.05 m using Cavity Ring Down Spectroscopy. Measurements are reported in permile on the SMOW-SLAP scale using a two-fixed-point calibration. The standard deviation columns (1-sigma_of_run_d18 and 1-sigma_of_run_dD) contain the precision of each individual analysis run the data-point belongs to. The offset columns (accuracy_check_offset_d18 and accuracy_check_offset_dD) contain the accuracy check metrics of each analysis run. **All depth, age and isotope values refer to the bottom of each interval**----------------------------------------The GICC05, GICC05_modelext and AICC2012 timescales for the NEEM ice core in 5cm resolution1) The GICC05 time scale has been transferred to NEEM depths in the following ways:1a) NEEM depths have been transferred to NGRIP1 by linear interpolation between match points and tephras, and from these, GICC05 ages were obtained using the NGRIP1 (depth, age) relationship for the section from 19.85m to 1335.85m NEEM depths (see Rasmussen et al. 2013 for matching details).1b) NEEM depths have been transferred to NGRIP2 by linear interpolation between match points and tephras, and from these, GICC05 ages were obtained using the NGRIP2 (depth, age) relationship for the section from 1335.90m to 1955.90m NEEM depths (see Rasmussen et al. 2013 for matching details).Note that for GICC05 the value "MCE" is the Maximum Counting Error of the time scale. See Rasmussen et al. 2006 for a full description. In a standard deviation context, the maximum counting error should be regarded as 2 sigma as discussed in Andersen et al., 2006.2) The GICC05_modelext time scale has been transferred to NEEM depths in the following ways:2a) NEEM depths have been transferred to NGRIP2 by linear interpolation between match points and tephras, and from these, GICC05 ages were obtained using the NGRIP2 (depth, age) relationship for the section from 1955.95m to 2203.55m NEEM depths (see Rasmussen et al. 2013 for matching details).2b) For the section below 2203.55m NEEM depths the ice in the NEEM core contains time reversals due to foldings. A detailed discussion of the matching and GICC05modelext timescale transfer between NEEM and NGRIP in this folded part of the core can be found in Dahl-Jensen et al. 2013. The depth-age relationship for this section is interpolated to 5cm resolution from the relation-ship given in the Dahl-Jensen et al. 2013 supplementary data file.3) The AICC2012 time scale has been transferred to NEEM depths in the following ways:3a) NEEM depths have been transferred to NGRIP2 by linear interpolation between match points and tephras, and from these, AICC2012 ages were obtained using the NGRIP2 (depth, age) relationship for the section from 1955.95m to 2196.95m NEEM depths (see Rasmussen et al. 2013 for matching details, and Veres et al. 2013 for the NGRIP AICC2012 timescale). 3b) For the section below 2196.95m NEEM depths the ice in the NEEM core contains time reversals due to foldings. The depth-age relationship for this section is dereived from a matching of the NEEM and EDML cores (Dahl-Jensen et al. 2013). The NEEM-EDML1 timescale given in the Dahl-Jensen et al. 2013 supplementary data has been interpolated to 5cm resolution, and EDML1 ages have subsequently been converted to AICC2012 ages using the relationship between EDML1 and AICC2012 (see Ruth et al. 2007, Veres et al., 2013 and Govin et al. 2015).Note, that transferring AICC2012 to NEEM from NGRIP and from EDML do not yield the exact same ages for all NEEM depths. Between 2196.95m and 2197.00m the two transfers of AICC2012 do, however, yield intersecting ages. Hence, to ensure continuity the change between methodology 3a and 3b takes place between these depths.