A Horizontal Ice Core From Taylor Glacier, Its Implications for Antarctic Climate History, and an Improved Taylor Dome Ice Core Time Scale

Abstract

Ice core records from Antarctica show mostly synchronous temperature variations during the last deglacial transition, an indication that the climate of the entire continent reacted as one unit to the global changes. However, a record from the Taylor Dome ice core in the Ross Sea sector of East Antarctica has been suggested to show a rapid warming, similar in style and synchronous with the Oldest Dryas—Bølling warming in Greenland. Since publication of the Taylor Dome record, a number of lines of evidence have suggested that this interpretation is incorrect and reflects errors in the underlying time scale. The issues raised regarding the dating of Taylor Dome currently linger unresolved, and the original time scale remains the de facto chronology. We present new water isotope and chemistry data from nearby Taylor Glacier to resolve the confusion surrounding the Taylor Dome time scale. We find that the Taylor Glacier record is incompatible with the original interpretation of the Taylor Dome ice core, showing that the warming in the area was gradual and started at ∼18 ka BP (before 1950) as seen in other East Antarctic ice cores. We build a consistent, up‐to‐date Taylor Dome chronology from 0 to 60 ka BP by combining new and old age markers based on synchronization to other ice core records. The most notable feature of the new TD2015 time scale is a gas age—ice age difference of up to 12,000 years during the Last Glacial Maximum, by far the largest ever observed.

Spatial pattern of accumulation at Taylor Dome during Marine Isotope Stage 4: stratigraphic constraints from Taylor Glacier

“…If indeed the Antarctic ice sheet extended far enough into the Ross Sea to alter the atmospheric circulation during the Last Glacial Maximum, the implication of our new data is that a similar situation did not exist during MIS 4. This hypothesis seems at odds with independent evidence that the Southern Hemisphere experienced full glacial conditions during MIS 4 (Schaefer et al, 2015;Barker and Diz, 2014). A possible explanation is that the sea level minimum at MIS 4 was 25 m higher than during the Last Glacial Maximum due to the lack of extensive Northern Hemisphere ice sheets (Shakun et al, 2015;Siddall et al, 2003;Cutler et al, 2003), which limited how far grounded ice from the West Antarctic Ice Sheet could extend into the Ross Embayment.…”

Enhanced Moisture Delivery into Victoria Land, East Antarctica During the Early Last Interglacial: Implications for West Antarctic Ice Sheet Stability

“…Here, we present a record of the accumulation rate of Site 27 derived from independently constrained ice and gas chronologies. This approach has previously been applied to Taylor Glacier blue ice samples to estimate accumulation rates (Baggenstos et al, 2018;Menking et al, 2019). We take advantage of the fact that the age of the ice is older than the age of the trapped gases at the same depth.…”

Mapping the age of ice of Gauligletscher combining surface radionuclide contamination and ice flow modeling

“…Recently, Gäggeler et al (2020) used 210 Pb activity concentration decays of surface ice samples collected in the ablation zone of Aletschgletscher to determine relative ages between samples and deduce ice flow rates. Nevertheless, knowing the absolute age of glacier surface ice would be highly useful for conducting "horizontal ice cores", i.e., collecting and analyzing old ice (the proxies that have not been altered by ice thermo-mechanical changes) without having to perform expensive and logistically complex deep ice-core drilling (Reeh et al, 2002;Baggenstos et al, 2018). The main challenge when doing so is to find undisturbed isochrones, and to sample across them.…”