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Linda Hinnov, Johns Hopkins University (United States)
Frank Niessen, Alfred Wegener Institute for Polar and Marine Research (Germany)
Diana Magens, Alfred Wegener Institute for Polar and Marine Research (Germany)
Lawrence Krissek, Ohio State University (United States)
Gary Wilson, University of Otago (New Zealand)
Ross Powell, Northern Illinois University (United States)
Timothy Naish, Victoria University of Wellington (New Zealand)
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During the drilling phase of the ANDRILL McMurdo Ice Shelf (MIS) Project, on-site measurements of whole-core physical properties were taken at an unprecedented high resolution ranging between 1 to 4 cm (avg. 1.8 cm) through the entire 1285 m (13 million-year) long AND-1B Core. Only sporadic, mostly very limited gaps in data coverage occur along the core. The wet bulk density, magnetic susceptibility and P-wave velocity logs contain extended intervals of persistent meter-decameter scale cyclicity, which are constrained to the Milankovitch band by argon radio-isotope dating. We examined this cyclicity using time-frequency analysis to seek hallmark quasi-periodic behavior of the astronomical parameters, and to screen the sediments for down-core accumulation rate changes and hiatuses. Distinctive variations occur at orbital eccentricity scales; higher frequency variations at obliquity and precession scales are also present. We compared these variations to the astronomical forcing parameters indicated by the La2004 Solar System model to explore the feasibility of an astronomically calibrated timescale for the AND-1B Core, and to begin the task of comparing recovered Milankovitch signals with the global paleoclimate archive.
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