Physical properties, gas compositon, and δ¹³C DIC measured on sediment cores from an active pockmark on Vestnesa Ridge, Arctic Ocean

We report on the geochemistry of hydrocarbons and pore waters down to 62.5 mbsf, collected by drilling with the MARUM‐MeBo70 and by gravity coring at the Lunde pockmark in the Vestnesa Ridge. Our data document the origin and transformations of volatiles feeding gas emissions previously documented in this region. Gas hydrates are present where a fracture network beneath the pockmark focusses migration of thermogenic hydrocarbons characterized by their C1/C2+ and stable isotopic compositions (δ2H‐CH4, δ13C‐CH4). Measured geothermal gradients (~80°C km‐1) and known formation temperatures (>70°C) suggest that those hydrocarbons are formed at depths >800 mbsf. […]

本研究报告了使用MARUM‐MeBo70钻探和重力取心法在维斯涅萨脊的伦德凹坑中采集至62.5米深处的烃类和孔隙水地球化学特征。所获得的数据记录了该区域已记录的烃类挥发物向气体排放的起源和转化过程。在凹坑下方的裂缝网络中，热成因烃类的迁移聚焦于此，其特征为C1/C2+和稳定的同位素组成（δ2H-CH4，δ13C-CH4）。测量的地热梯度（约80°C km-1）和已知的成岩温度（>70°C）表明，这些烃类在深度超过800米处形成。