Compound-specific 14C isotope composition in marine and terrestrial sedimentary archives from sub-Antarctic South Georgia

• Main Authors: Berg, Sonja, Kusch, Stephanie, Jivcov, Sandra
• Format: Dataset
• Language: English
• Published: PANGAEA 2024
• Subjects: Age; 14C AMS; comment; dated; dated material; dated standard deviation; ANT-XXIX/4; Area/locality; Co1305; Co1306; Co1308; compound-specific radiocarbon analysis; Core; Cruise/expedition; DATE/TIME; Depth; bathymetric; bottom/max; sediment/rock; top/min; ELEVATION; Event label; fjord; Fraction modern carbon; error; GC; Gravity corer; lake; LATITUDE; LONGITUDE; MICADAS Accelerator Mass Spectrometer; PCUWI; peat; Piston corer; UWITEC; Polarstern; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; PS81; PS81/283-1; Reference/source; Reference of data; Russian peat corer and gravity corer; Arctic; Antarctic; Fid; in Berg; Antarc*; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.967398; https://doi.org/10.1594/PANGAEA.967398

The dataset comprises radiocarbon (14C) data that was obtained on sediment samples from sub-Antarctic South Georgia. The sediments were collected from a range of different sites, including lakes, peat deposits, a marine inlet and a fjord during RV Polarstern expedition PS81 in 2013. Prior to the geochemical analyses reported here, the sediments were freeze-dried and ground. More details on the study sites, sampling and data evaluation can be found in Berg et al. (submitted manuscript). Sediment and plant samples for Radiocarbon (14C) analysis were pre-treated and analyzed as described by Rethemeyer et al. (2019). For the analysis of 14C in bulk organic carbon (bulk OC) and plant fossils were washed with 1% HCl (1 hr, 60°C followed by ca. 10 hr at room temperature) to remove carbonates. The acid insoluble fraction was then graphitized and analyzed for 14C at the CologneAMS facility (Cologne, Germany). For compound-specific 14C analysis individual alkanoic acids, alkanes and alkanols were isolated by preparative capillary GC using a gas chromatograph (7680 Agilent Technologies, USA) equipped with a CIS 4 injection system (Gerstel, Germany), coupled with a preparative fraction collector (PFC; Gerstel, Germany). The purity and quantity of individual compounds was monitored by GC-FID (Agilent 7890B equipped with an on-column injector, Agilent Technologies, USA). Samples with a purity of >98% were processed further. For samples from core Co1305 compound-specific 14C analysis was performed on a MICADAS AMS system equipped with a gas ionization source (ETH Zurich, Switzerland, Wacker et al., 2010) on purified CO2 produced by combustion in vacuum-sealed quartz tubes. Compound ages were corrected for processing blanks and carbon added during derivatization using mass balance (Berg et al., 2020). For core Co1308 compound-specific 14C analysis was conducted on the original isolated compounds with a High Voltage 6 MV Tandetron coupled to an EA-GIS periphery at the CologneAMS facility (Stolz et al., 2019). ...