Geochemical and Molecular Biomarkers Dataset - BIC 3A
Description
This dataset supports a study of PAH source attribution in the Norian BIC 3A drill core, a charcoal-rich fluvio-lacustrine succession from eastern Tasmania. It contains stratigraphically resolved data for 53 sediment samples and five isolated-charcoal samples, including commonly applied PAH diagnostic ratios, LMW/(LMW+HMW), APDI values and component calculations, retene and cadalene concentrations, total organic carbon, and bulk organic carbon isotope data. The dataset also includes compound identities and molecular ions, together with modern gymnosperm smoke and combustion-residue data from Karp et al. (2020) used for comparison. These data can be reused to evaluate the reliability and transferability of PAH source-discrimination thresholds, compare char- and smoke-derived PAH signatures, and support meta-analyses of wildfire, combustion products, and organic-matter source attribution in ancient sedimentary archives.
Files
Steps to reproduce
The dataset was generated from the 60–160 m interval of the BIC 3A drill core, eastern Tasmania. Fifty-three sediment samples were selected at approximately every fifth available core sample. Sampling resolution was 0.60–1.20 m between 60 and 80 m, where lithology and sample availability were more variable, and 1.5–3.0 m between 80 and 160 m. Five charcoal samples (94.1, 102.5, 124.4, 139.4 and 157.5 m) were hand-picked from charcoal-rich sandstone and muddy sandstone using clean stainless-steel tools. For charcoal characterization, fragments were mounted on carbon tape, coated with gold using a JEOL JEC-3000FC coater, and examined with a QUANTA FEG-250 field-emission scanning electron microscope. Preserved anatomy, pit morphology, cell-wall homogenization and abrasion were documented. For total organic carbon (TOC) and bulk organic-carbon isotope analysis, sediments were sonicated three times for 5 min in ultrapure water, dried at 30 °C and powdered in an agate mortar. Carbonates were removed with 40 mL of 3 M HCl at 50 °C for 4 h, followed by fresh acid overnight, rinsing to neutrality and drying at 50–55 °C. Aliquots of 0.04–8 mg were analysed by nano-EA/IRMS at JAMSTEC using a modified Flash EA1112, ConFlo III interface and Delta Plus XP IRMS. δ¹³C values were calibrated to VPDB using BG-T, BG-A, BG-P, CERKU-01 and CERKU-02 standards. For PAH analysis, glassware was annealed at 550 °C and solvent-rinsed. Samples were sonicated three times in 9:1 dichloromethane:methanol, dried, crushed and extracted in 30 mL of the same solvent mixture for 7 days. Extracts were centrifuged, decanted, rinsed with dichloromethane and concentrated under N₂. Bitumen was separated on activated silica into saturate (4 mL n-hexane), aromatic (4 mL 1:1 dichloromethane:n-hexane) and polar (4 mL 9:1 dichloromethane:methanol) fractions. Saturate and aromatic fractions were analysed by GC–MS (Agilent 7890A; VF-5ms, 30 m × 250 µm × 0.1 µm; He, 1 mL min⁻¹). The oven program was 40 °C for 2 min, 30 °C min⁻¹ to 120 °C, then 6 °C min⁻¹ to 320 °C with a 20-min hold. Compounds were quantified using AccuStandard Z-014G, identified from molecular ions, and confirmed against authentic standard retention times and published literature. Procedural blanks were run between standard and sample batches. To reproduce the reported outputs, calculate the listed PAH diagnostic ratios and APDI from the corresponding compound abundances, then plot them against sample depth or the published source-classification thresholds. The workbook provides sediment ratios, charcoal data, the Karp et al. (2020) comparison dataset, APDI intermediate terms, TOC/δ¹³C data and compound m/z information.
Institutions
- Khalifa University of Science and TechnologyAbu Dhabi, Abu Dhabi
- Japan Agency for Marine-Earth Science and TechnologyKanagawa, Yokosuka