A novel approach to process brittle ice for continuous flow analysis of stable water isotopes

• Published in: Journal of Glaciology
• Main Authors: REBECCA L. PYNE, ELIZABETH D. KELLER, SILVIA CANESSA, NANCY A. N. BERTLER, ALEX R. PYNE, DARCY MANDENO, PAUL VALLELONGA, STEFANIE SEMPER, HELLE A. KJÆR, ED HUTCHINSON, W. TROY BAISDEN
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2018
• Subjects: glaciological instruments and methods; ice core; paleoclimate; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Roosevelt Island; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2018.19; https://doaj.org/article/e6b3a24a889148e68c44943f629fb138

Brittle ice, which occurs in all intermediate-depth and deep ice cores retrieved from high-latitude regions, presents a challenge for high-resolution measurements of water isotopes, gases, ions and other quantities conducted with continuous flow analysis (CFA). We present a novel method of preserving brittle ice for CFA stable water isotope measurements using data from a new ice core recovered by the Roosevelt Island Climate Evolution (RICE) project. Modest modification of the drilling technique and the accommodation of non-horizontal fractures (‘slanted breaks’) in processing led to a substantial improvement in the percentage of brittle ice analyzed with CFA (87.8%). Whereas traditional processing methods remove entire fragmented pieces of ice, our method allowed the incorporation of a total of 3 m of ice (1% of the 261 m of brittle ice and ~1300 years of climate history) that otherwise would not have been available for CFA. Using the RICE stable water isotope CFA dataset, we demonstrate the effect of slanted breaks and analyze the resulting smoothing of the data with real and simulated examples. Our results suggest that retaining slanted breaks are a promising technique for preserving brittle ice material for CFA stable water isotope measurements.