Here we present a biomarker dataset from marine sediment core MD99-2304, which was retrieved from the eastern Fram Strait (77°37'15.6N, 9°56'54E) with piston corer at 1348 m water depth during cruise Marion Dufresne IMAGES 5 1999 leg MD114. This dataset contains sea ice history in the eastern Fram Strait between 40 and 36.5 ka b2k during MIS 3, with a temporal resolution of 20–40 yrs/sample, for the mechanical understanding of abrupt climate change during the Dansgaard-Oeschger events. Total Organic Carbon (TOC), Highly Branched Isoprenoids (HBIs) IP25, HBI diene, HBI-III (Z-isomer), and HBI III (E-isomer), and the sterols brassicasterol, dinosterol, campesterol, and sitosterol were measured in the organic geochemistry lab at the Alfred Wegener Institute (AWI), Germany in 2022 and 2023. Biomarker values are presented as biomarker μg/TOC. The age model of MD99-2304 is established by tuning is low field magnetic susceptibility to the magnetic susceptibility of Core MD95-2010 from the Norwegian Sea (Kissel et al., 1999 (doi:10.1016/S0012-821X(99)00162-4); updated in Sadatzki et al. (2020, doi:10.1073/pnas.2005849117)), and the age model of MD95-2010 was tied to the chronology of MD99-2284 (Berben et al., 2020, doi:10.1016/j.quascirev.2020.106277).
The biomarkers were measured on an Agilent 7890B GC (30m DB-1MS column, 0.25 mm i.d., 0.25 µm film thickness) coupled to an Agilent 5977A mass selective detector (MSD, 70 eV constant ionization potential, Scan 50–550 m/z, 1 scan/s, ion source temperature 230°C, Performance Turbo Pump), with selected ion monitoring mode (SIM) for HBIs and full scan mode (50-550 m/Z) for sterols. For biomarker concentration normalization, total organic carbon (TOC) was measured using a Carbon-Sulfur Analyzer (CS-125, Leco).
