Unraveling the Deep‐Sea Sedimentary Record of Ice Sheet History

Abstract

AbstractIce rafted debris (IRD) is a proxy used to interpret the deep‐sea sedimentary record of ice sheet history. McKay et al. (2022, https://doi.org/10.1029/2021PA004404) focused on methods used to reconstruct past iceberg presence around Antarctica using IRD from deep‐sea sediment cores and address the efficacy of the following three common methodologies of IRD quantification: counting clasts >2 mm in x‐radiographs; the sieved weight percent of the medium‐to‐coarse sand fraction (250 μm–2 mm); and volumetric estimates of the >125 μm sand fraction using laser particle size analysis. A high correlation occurred between IRD percentage determined by sieve analysis and visual clast counts using radiograph analysis. Although each method has pros and cons that are considered by the authors, the separation of coarse sand (>250 μm–2 mm) from fine‐grained sediment by sieving provided the cleanest signal. In addition, IRD grains can be used for paleoenvironment or provenance analyses providing more complete marine ice sheet paleorecords. This thorough analysis highlights a topic that has been previously overlooked and has become increasingly important in understanding the response of marine ice sheets to a warming atmosphere and ocean.