The Barents Shelf provides a unique arena to investigate long-term landscape evolution as it has undergone significant glacial modification during the Quaternary and has an extensive stratigraphic data repository motivated by decades of hydrocarbon seismic and well exploration. Here, we assimilate new geological datasets with ice sheet erosion modelling to incrementally reconstruct the geomorphic evolution of the Eurasian Arctic domain over each of the 47 glaciations since the intensification of Northern Hemisphere glaciation ∼2.74 Ma. We utilise this time-transgressive framework to review hypotheses regarding the heterogenous development of the Barents Shelf and the timing of key topographic reconfiguration episodes. Our results demonstrate that up to 2.6 km of bedrock was glacially removed to the shelf margins, and though the mean rate of erosion declines over the Quaternary, the efficacy of glacial erosion has a more complex timeline. Initially, erosion was highly effective as large expanses of the Eurasian Arctic switched from subaerial exposure to marine conditions around 2 Ma. Thereafter, erosional efficacy decreased as the landscape desensitised to successive glaciations but, after 1 Ma, it increased as a dynamic, marine-based ice sheet drained by ice streams expanded, selectively eroding large outlet troughs to the shelf edge. Critically for Arctic climate, at ∼0.69 Ma this episode of enhanced preferential erosion opened up the Barents Seaway establishing a new circulation pathway between the Atlantic and Arctic Oceans. Our 4D landscape reconstruction provides key boundary conditions for paleoclimate models and establishes a new framework for assessing the profound impact of late-Cenozoic glaciation on the Eurasian Arctic landscape.sic reservoir directly into the water column has been documented at the Sentralbanken high in the northern Norwegian Barents Sea. However, it remains unclear whether the hydrocarbon leakage occurs only from the middle-upper Triassic reservoir units in geological settings exceptionally conducive to hydrocarbon leakage, or if other reservoir formations contributed to the release of hydrocarbons into the water column. It is also not clear whether complete erosion of the caprock is a prerequisite for widespread liberation of natural gas and oil from glacially eroded reservoirs across Arctic continental shelves. Here we analyze multibeam echosounder data covering ∼5,000 km² and a suite of high-resolution P-cable seismic lines from a range of geological structures across the northern Norwegian Barents Sea. Our analyses reveal that ∼21,700 natural gas seeps originate from exhumed, faulted and variably eroded structural highs bearing a range of Mesozoic reservoir formations. All investigated structural highs fuel seabed methane release hotspots with no exception. Evident from observations of seismic anomalies, fluid accumulations are pervasive in the subsurface and likely to continue fuelling seabed gas seepage into the future. We also document that gas seepage through faults piercing overburden, caprocks and reaching potential reservoir levels is pervasive at all investigated structural highs. On the Storbanken high and the Kong Karl platform, such fault-controlled seepage is more prevalent than seepage from reservoir formations subcropping below the seafloor. Using a simple parametrization approach, we estimate that seeps identified within our multibeam data coverage produce a seabed methane flux of 61 x 10⁷ mol/yr (9,803 ton/yr), which is one to two orders of magnitude higher than other globally known submarine methane seepage provinces. Fluxes of methane from sea water to the air above the thermogenic gas seep provinces in the northern Norwegian Barents Sea remain to be determined.

Widespread natural gas and oil leakage from the glacially eroded middle-upper Triassic reservoir directly into the water column has been documented at the Sentralbanken high in the northern Norwegian Barents Sea. However, it remains unclear whether the hydrocarbon leakage occurs only from the middle-upper Triassic reservoir units in geological settings exceptionally conducive to hydrocarbon leakage, or if other reservoir formations contributed to the release of hydrocarbons into the water column. It is also not clear whether complete erosion of the caprock is a prerequisite for widespread liberation of natural gas and oil from glacially eroded reservoirs across Arctic continental shelves. Here we analyze multibeam echosounder data covering ∼5,000 km² and a suite of high-resolution P-cable seismic lines from a range of geological structures across the northern Norwegian Barents Sea. Our analyses reveal that ∼21,700 natural gas seeps originate from exhumed, faulted and variably eroded structural highs bearing a range of Mesozoic reservoir formations. All investigated structural highs fuel seabed methane release hotspots with no exception. Evident from observations of seismic anomalies, fluid accumulations are pervasive in the subsurface and likely to continue fuelling seabed gas seepage into the future. We also document that gas seepage through faults piercing overburden, caprocks and reaching potential reservoir levels is pervasive at all investigated structural highs. On the Storbanken high and the Kong Karl platform, such fault-controlled seepage is more prevalent than seepage from reservoir formations subcropping below the seafloor. Using a simple parametrization approach, we estimate that seeps identified within our multibeam data coverage produce a seabed methane flux of 61 x 10⁷ mol/yr (9,803 ton/yr), which is one to two orders of magnitude higher than other globally known submarine methane seepage provinces. Fluxes of methane from sea water to the air above the thermogenic gas seep provinces in the northern Norwegian Barents Sea remain to be determined.

Our results demonstrate extreme spatial and temporal heterogeneity in subglacial erosion, with rates ranging from 0 to 5 mm a−1 and a net volume equating to ~130,000 km3 of bedrock excavated to depths of ~190 m. A hierarchy of environmental controls ostensibly underpins this complex signature: lithology, topography and climate, though it is basal thermodynamics that ultimately regulates erosion, which can be variously protective, pervasive, or, highly selective. Our analysis highlights the remarkable yet fickle nature of glacial erosion — critically modulated by transient ice-sheet dynamics — with its capacity to impart a profound but piecemeal geological legacy across mid and high latitudes.