Laminated sediments in the magnificent Edisto Inlet (Victoria Land): What processes control their deposition and preservation?

Laminated diatom ooze deposits have been documented in different regions of the Antarctic margin, including the Antarctic Peninsula and the Ross Sea. Few fundamental modern oceanographic factors favor varve preservation. In general, very high sedimentation rates can overwhelm limited bioturbation and thus additionally foster the preservation of varves, for example in some glacimarine settings. Laminated sediments were collected in Edisto Inlet during the Holoferne project (PNRA2013) with well-defined dark and light laminae on mm- to cm-scale. Dark laminae contained relatively high concentrations of a biomarker of land-fast ice IPSO₂₅, whereas, low IPSO₂₅ concentrations characterized light laminae and the diatom Corethron pennatum became the dominant species. Based on these assumptions, fast ice dynamics were reconstructed over the last 2.6 ka for the western part of the Ross Sea. Nevertheless, the absence of rigorous varve validation leaves uncertain the paleoclimatic and paleoceanographic interpretation of these marine laminated sediments. Here, we propose a multidisciplinary study integrating fast-ice, water column and surface sediment characteristics, supported by biological data collected in situ and time-series of satellite images of sea-ice, to gain information on factors influencing the laminated sediment formation and preservation in Edisto Inlet. The LASAGNE project will give new insight into the sub-seasonal formation of laminated sediments providing a backbone for the interpretation of paleoclimate sediment archives.