Data report: geochemical and microbial biomarker investigations of sedimentary successions from the Belgica carbonate mound province in the Porcupine Basin, offshore Ireland: Expedition 307

Abstract

This report contains a compilation of geochemical (long-chain n-alkanes) and microbial biomarkers (hopanoids and phospholipids), elemental parameters (total organic carbon [TOC] content and bulk carbon isotope data), gas composition data (methane, ethane, propane, n-butane, and iso-butane), and methane carbon and hydrogen isotope data from sediment samples of Sites U1316, U1317, and U1318 drilled during Integrated Ocean Drilling Program Expedition 307 in the Belgica carbonate mound province (Porcupine Basin, offshore Ireland). At the mound site (U1317), we detected the highest concentrations of microbial biomarkers in the sediments below the mound base. At the upslope site (U1318), microbial biomarkers show high abundances in lithostratigraphic Subunits 1B and 1C, which are also characterized by high TOC contents. Methane, ethane, and propane concentrations are low in the sediments of the mound section (Site U1317) but increase with increasing depth below the mound base. Methane carbon isotope data range between –63.9‰ and –64.5‰ and hydrogen isotope data range between –148‰ and –163‰. Gas wetness data plot in the mixed gas zone between thermogenic and biogenic gas.