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European Geosciences Union, Cryosphere Discussions, p. 1-21

DOI: 10.5194/tc-2016-244

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

This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

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Data provided by SHERPA/RoMEO

Abstract

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 (~ 250 years; 2691.50–2688.65 m depth) across the transitions of GI-21.2, a short-lived interstadial prior to interstadial GI-21.1 (GI-21.2: 84.87–85.09 ka b2k). 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 "major" 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 tenfold) 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.