Calibrated cryo-cell UV-LA-ICPMS elemental concentrations from the NGRIP ice core reveal abrupt, sub-annual variability in dust across the GI-21.2 interstadial period

• Published in: The Cryosphere
• Main Authors: Lunga, Damiano, Müller, Wolfgang, Rasmussen, Sune Olander, Svensson, Anders, Vallelonga, Paul
• Format: Text
• Language: English
• Published: 2018
• Subjects: Greenland; Dansgaard-Oeschger events; Greenland ice cores; ice core; NGRIP
• Online Access: https://doi.org/10.5194/tc-11-1297-2017; https://tc.copernicus.org/articles/11/1297/2017/

Several abrupt shifts from periods of extreme cold (Greenland stadials, GS) to relatively warmer conditions (Greenland interstadials, GI) called Dansgaard–Oeschger events are recorded in the Greenland ice cores. Using cryo-cell UV-laser-ablation inductively coupled-plasma mass spectrometry (UV-LA-ICPMS), we analysed a 2.85 m NGRIP ice core section (2691.50–2688.65 m depth, age interval 84.86–85.09 ka b2k, thus covering ∼ 230 years) across the transitions of GI-21.2, a short-lived interstadial prior to interstadial GI-21.1. GI-21.2 is a ∼ 100-year long period with δ 18 O values 3–4 ‰ higher than the following ∼ 200 years of stadial conditions (GS-21.2), which precede the major GI-21.1 warming. We report concentrations of <q>major</q> elements indicative of dust and/or sea salt (Na, Fe, Al, Ca, Mg) at a spatial resolution of ∼ 200 µm, while maintaining detection limits in the low-ppb range, thereby achieving sub-annual time resolution even in deep NGRIP ice. We present an improved external calibration and quantification procedure using a set of five ice standards made from aqueous (international) standard solutions. Our results show that element concentrations decrease drastically (more than 10-fold) at the warming onset of GI-21.2 at the scale of a single year, followed by relatively low concentrations characterizing the interstadial part before gradually reaching again typical stadial values.