Glacial ice-sheet dynamics and retreat deduced from southeastern Weddell Sea sediment (LAMINAE)

As part of research bundle RIDDLE (Reconstructing ice-sheet dynamics on different scales), the key goal of project LAMINAE is to provide detailed insight into glacial ice sheet dynamics in the southeastern Weddell Sea section of Antarctica. Ten existing sediment sites that preserved at least five millennia of varved sequences during the last glacial maximum (LGM) will be studied with a multi-proxy approach.

First, the final retreat of the Antarctic Ice Sheet at the end of the LGM will be dated with ¹⁴C. The results will help to confine the timing of the initial sea-level rise for both the West and East Antarctic Ice Sheets, including potential asynchronies. Second, we will establish floating chronologies from new methods for laminae recognition and varve counting. Thereby, it will be possible to study glacial ice sheet dynamics at unprecedented resolution, including the role of decadal-centennial scale solar cycles in climate change, and the detection of Antarctic Isotopic Maxima in sites penetrating Marine Isotopic Stage 3. Third, with the combination of absolute and floating chronologies, we will define marker horizons in core sections that are rich in bioturbation, ice-rafted debris, or ash layers, for correlation between the sites and to the EDML ice core. This will put our results into a larger-scale perspective and allow for synchronization of the atmospheric and oceanic response to climate change.



Fig. 1: Input mask of the BMPix tool. RGB and gray scale data are generated at pixel resolution along a green profile line between predefined start (yellow box) and end (blue box) points for any given BMP image. Here 2940 data points (pixels 429–3369) were measured over a 25 cm long X–radiograph image (387–412 cm); that is, resolution is 12 measurements/mm or 85 μm. White numbers in list at bottom right contain reference data from previous profile line in section 362–387 cm. Upon completion, gray scale data will be extracted from all profile lines added to list, see also figure 2 in Weber et al. (2010).

Scientists

Dr. Michael E. Weber
Institute for Geology and Mineralogy
University of Cologne

Dr. Gerhard Kuhn
Alfred-Wegener-Institute Bremerhaven

Daniela Sprenk
Institute for Geology and Mineralogy
University of Cologne

Research areas

Southeastern Weddell Sea

Publications

Weber ME, et al., 2010. BMPix and PEAK tools: New methods for automated laminae recognition and counting—Application to glacial varves from Antarctic marine sediment. Geochemistry Geophysics Geosystems, 11.

Weber ME, Bonami G, Fütterer KD, 1994. Sedimentation processes within channel-ridge systems, southeastern Wedell Sea, Antarctica. Paleoceanography, 9(6): 1027-1048.

Kuhn G, Weber ME, 1993. Acoustical characterization of sediments by Parasound and 3.5 kHz systems: Related sedimentary processes on the southeastern Weddell Sea continental slope, Antarctica. Mar. Geol.(113): 201-217.

Homepage

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Research funding organisation

German Research Foundation

Project number: WE 2039-8/1, KU 683/12-1
Funding period: 2010 – 2013