Tilting and Flexural Stresses in Basins Due to Glaciations—An Example from the Barents Sea

Abstract

Many of the Earth’s sedimentary basins are affected by glaciations. Repeated glaciations over millions of years may have had a significant effect on the physical conditions in sedimentary basins and on basin structuring. This paper presents some of the major effects that ice sheets might have on sedimentary basins, and includes examples of quantifications of their significance. Among the most important effects are movements of the solid Earth caused by glacial loading and unloading, and the related flexural stresses. The driving factor of these movements is isostasy. Most of the production licenses on the Norwegian Continental Shelf are located inside the margin of the former Last Glacial Maximum (LGM) ice sheet. Isostatic modeling shows that sedimentary basins near the former ice margin can be tilted as much as 3 m/km which might significantly alter pathways of hydrocarbon migration. In an example from the SW Barents Sea we show that flexural stresses related to the isostatic uplift after LGM deglaciation can produce stress changes large enough to result in increased fracture-related permeability in the sedimentary basin, and lead to potential spillage of hydrocarbons out of potential reservoirs. The results demonstrate that future basin modeling should consider including the loading effect of glaciations when dealing with petroleum potential in former glaciated areas.

Hydrogeologic and Thermal Effects of Glaciations on the Intracontinental Basins in Central and Northern Europe

“…This intraplate region has been repeatedly affected by glaciations and periglacial processes during the whole Pleistocene, which have affected its morphology and subsurface hydrogeology. Previous studies have been successful in correlating the induced viscoelastic rebound to the Holocene sea level change (Lambeck et al, 1998;Steffen and Wu, 2011) and/or its relation to paleo-fault activity (Wahlström, 1993;Klemann and Wolf, 1998;Lund et al, 2009a;e.g., Bungum et al, 2010;Steffen et al, 2014;Løtveit et al, 2019). However, quantifying the impact of periglacial and glacial climate conditions on the resulting groundwater flow and heat transport dynamics has been limited to local studies nearby proposed repository sites, thereby preventing a unifying description of the regional thermo-hydraulic response of the system to the ice dynamics.…”

A regional CO2 containment assessment of the northern Utsira Formation seal and overburden, northern North Sea

“…If their margins are faulted (Løseth et al., 2013; Rundberg & Eidvin, 2016), they could present migration routes into the Seal Interval. Small‐scale faults (below seismic resolution) have been hypothesised to be the cause of intra‐formation seal breach (metre‐scale mudstones) at Sleipner, as a result of post‐depositional ice‐sheet loading and unloading (Cavanagh & Haszeldine, 2014; Løtveit et al., 2019). Similar small‐scale faulting could be present in the study area, but here a minimum seal thickness of 50 m is required and thus they are unlikely to present a major risk to CO 2 containment.…”

On the Processes that Produce Hydrocarbon and Mineral Resources in Sedimentary Basins

“…The North Sea presents many examples of this kind of lateral migration and trapping, and the process is well described in [10]. Even a slight change in the tilt of the North Sea carrier sands can be important, and Løtviet et al [11] show how tilting by glacial isostatic adjustment can redistribute oil in the North Sea.…”