Adventdalen is a medium-sized (513 km2) catchment in continuous permafrost zone of central Spitsbergen. It has 11.7 % glacier cover, a large flat valley floor comprised of uplifted, glaciomarine sediments, covered in the lower part by a veneer of aeolian sediments up to 4 m thick. The geology of the catchment is dominated by sandstones, shales and carbonates. Freshwater samples were collected typically every second day throughout the principal runoff season (late May until early September) during 2015 and 2016 from a downstream site located at the head of the delta. Analysis of major ions (by ion chromatography) and minor constituents (trace metals by icpms and silica by colorimetric analysis). Funding was provided by the NERC grant NE/M019829/1.

These data are (1) porewater extractions of cores of the permafrost and active layer of Adventdalen, Svalbard, (2) solid-phase extractions of the same cores, and (3) in-situ porewater sampling from the end of the summer, 2017. The aqueous parameters are: major ions (Ca2+, Mg2+, Na+, K+, Cl-, NO3-, SO42-), Fe(aq), Mn(aq), aqueous CH4 and CO2 concentrations, delta 13C- CH4, acetate, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid, isocaproic acid, caproic acid, heptanoic acid, pH, oxidation-reduction potential, dissolved oxygen and alkalinity. The solid parameters are: organic carbon, nitrogen, acid volatile sulphur (AVS), chromium-reducible sulphur (CRS), amorphous and nanoparticulate iron (oxyhydr)oxides, crystalline iron (oxyhydr)oxides, iron bound in carbonates, and magnetite. Funding was provided by the NERC grant NE/M019829/1.