Methane fluxes into the oceans are largely dependent on the methane phase as it migrates upward through the sediments. Here we document decoupled methane transport by gaseous and aqueous phases in Storfjordrenna (offshore Svalbard) and propose a three‐stage evolution model for active seepage in the region where gas hydrates are present in the shallow subsurface. In a preactive seepage stage, solute ...

Formation of deep water in the high‐latitude North Atlantic is important for the global meridional ocean circulation, and its variability in the past may have played an important role in regional and global climate change. Here we study ocean circulation associated with the last (de)glacial period, using water‐column radiocarbon age reconstructions in the Faroe‐Shetland Channel, southeastern Norwegian ...

Localized tephra deposition in marine sequences is the product of many complex primary and secondary depositional processes. These can significantl y influence the potential applicability of tephra depos- its as isochronous marker horizons and current techniques, used in isolation, may be insufficient to fully unravel these processes. Here we demonstrate the innovative application of X-ray ...

Large amounts of the greenhouse gas methane are released from the seabed to the water column, where it may be consumed by aerobic methanotrophic bacteria. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column, are thought to be mainly controlled by nutrient and redox dynamics. Here, we report repeated measurements of methanotrophic ...

Natural quartz single crystals were experimentally deformed in two orientations: (1) ⊥ to one prism plane and (2) in O+ orientation at 900 and 1000°C, 1.0 and 1.5 GPa, and strain rates of ~1 × 10−6 s−1. In addition, hydrostatic and annealing experiments were performed. The starting material was milky quartz, which consisted of dry quartz with a large number of fluid inclusions of variable size up ...

Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this light, understanding the distribution and contribution of potential geological methane sources is important. Here we present empirical observations of hitherto undocumented, widespread and extensive methane ...

The distribution and concentration of subseafloor natural gas hydrate across margins is not well understood, because these systems are challenging to image and quantify remotely. Furthermore, it is unknown if shallow hydrate systems are linked to deeper oil and gas reservoirs. Herein, we analyze petroleum industry well logs with data in the gas hydrate stability zone and find that low concentrations ...

During the mid-Pliocene (Zanclean, ca. ~ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–228C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative ...

To date the final stage in deglaciation of the Greenland shelf, when a contiguous ice sheet margin on the inner shelf transitioned to outlet glaciers in troughs with intervening ice-free areas, we generated cosmogenic ¹⁰Be dates from bedrock knobs on six outlying islands along a stretch of 300 km of the southwestern Greenland coast. Despite ¹⁰Be inheritance influencing some ...