We present the new reference chronology (AICC2023) providing an age vs depth relationship covering the last 800 kyr (thousands of years) for five ice cores (EDC, EDML, NGRIP, TALDICE and Vostok). To construct the new AICC2023 chronology, we used new highly resolved measurements for EDC ice core as well as novel absolute 81Kr ages, stratigraphic links between the five ice cores and accurate firn modeling estimates. The new chronological and glaciological information were combined in the Bayesian dating tool Paleochrono to obtain the AICC2023 timescale.
This database is a compilation of studies published and unpublished quantifying calcareous nannofossils absolute abundances using Geisen et al. (1999) random-settling calibration. The data are ranging from Sinemurian (Lower Jurassic) to Quaternary. They were made on DSDP-ODP-IODP deep sea drilling, land sediment cores or, in most cases, land outcrop sections samples. Calcareous nannofossil accumulation rates (NAR) were calculated or updated by estimating sedimentation rates following sub-stages and biozones durations provided by Gradstein et al. (2012) or astrochronology when possible. In most sites, there were no indication of the dry bulk density (DBD), hence a type value was selected. This parameter is not critical for NAR calculated from land outcrop section samples (see Suchéras-Marx et al., 2014 Marine Micropaleontology). The results of the compilation is published in Suchéras-Marx et al., 2019 Biogeosciences.