The Gravity Potential Derivatives as a Means to Classify the Barents Sea Basin in the Context of Cratonic Basins

Abstract

Summary Detailed study of the gravity field and the isostatic state of the Barents Sea Region shows that the Eastern Barents Sea basins are not typical rift basins. They exhibit distinctive features such as large wavelengths, high lithospheric mantle density, thick sequences of sediments, a flat Moho and high elastic thickness. These attributes are normally associated with cratonic or intracratonic basins. To understand the geological history of the Eastern Barents Sea basins, we make a comparison with other well studied cratonic basins: the West Siberian basin, the Michigan basin in North America, the Solimoes, Amazon, Parnaiba and Parana basins in South America, the Tarim basin in Central Asia and the Congo basin in Africa. For these basins, the structure, subsidence history and temperature evolution is relatively well known. Our analysis includes the characterization in terms of gravity, geoid undulations, isostatic state, age and igneous activity. An important constraint in sedimentary basin evolution is the presence of the volcanism and the relative age of the volcanic strata with respect to the sedimentary package. In all the considered basins, except the Congo basin, volcanic masses are present at some time-stage and at some depth at the basin. Each of the basins exhibits some deviation from the classic isostatic equilibrium model that predicts the crustal thickness (thinning in this case) from the topographic and sedimentary load. Instead of crustal thinning, high density masses in the crust and mantle appear to be a typical feature. The basins may be divided into two groups, one in which the given basin correlates with the geoid, the second in which the geoid is independent. This discrimination points towards different density characteristics in the integrated crustal column.