Antarctic Ice-Sheet discharge over the last glacial cycle (AIS-DIS)

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With climate warming in recent decades, the Antarctic Ice Sheet (AIS) is currently loosing ice at an accelerated pace. This is socially relevant because global sea levels could rise substantially in the near future. A number of scientific disciplines try to better understand the current state of the AIS to provide more sustained projections for the future. In project AIS-DIS we would like to better understand the dynamics of the AIS for key periods of the past, so that models can be calibrated and future projections improved. We would like to focus our studies on the last glacial cycles and specifically on glacial terminations 1–5 because the AIS mass loss was greatest during these natural periods of climate warming. Our investigations shall concentrate on the center of Iceberg Alley, a unique gateway to lower latitudes where most icebergs breaking off the Antarctic continent, route through before they melt down above our core sites. Hence this is the only area where a representative and integrative signal of AIS mass loss can be obtained through time. Here, IODP Expedition 382 retrieved the longest and highest resolution climate and ice-sheet archive ever obtained near Antarctica. We wish to study Sites U1537 and U1538 from Dove Basin and Pirie Basin, respectively. Our goal is to decipher the timing, pace, and magnitude of AIS mass loss. This will mainly be achieved analyzing iceberg-rafted debris (IBRD) – coarse-grained sedimentary particles that are encapsulated in icebergs, released upon melting, and deposited and in the sediments of the deep ocean. First, we shall test if variations of magnetic susceptibility, Ca and Fe (measured through XRF-scanning) can be correlated to dust proxy records of Antarctic ice cores to establish high-resolution age models for our sites and to decipher dust-climate couplings, which is important for the carbon cycle. Indicators for IBRD shall be obtained from the x-ray image logger and through grain-size analysis. To put our findings into a wider paleoclimatic context, Fourier Transform Infrared Spectroscopy and color reflectance data (L*a*b*) shall also be utilized. Collaboration with IODP 382 scientists shall provide independent age control through ash layers and relative paleointensity, and potential sources of IBRD shall be deciphered through geochemical fingerprinting. Results of project AIS-DIS shall be implemented into ice-ocean-climate models and published as common efforts in highly-ranked journals.