Influence of the residual anomaly features on the detail of 2D density models

Abstract

The study of the calculation features of two-dimensional density models with different ratios of the curves of the gravity anomalies and the calculated gravitating effect is carried out on the example of the South Ukrainian monocline within the Black Sea. Studies have shown that a decrease in the magnitude of the residual anomaly (Δgr) taking into account the accuracy of its determination can result in both a refinement of the structure of the Earth’s crust and its almost complete restructuring. In this case, the nature of changes in the structure of the Earth’s crust depends on the type of residual anomaly that needs to be reduced. The smoothing of curves Δgr of the same sign only leads to a more precise section, while those of different signs forming the Helmert anomalies lead to a significant restructuring of the model due to the need to mutually correlate the influence of closely spaced contrasting changes in gravitating masses (compaction and decompaction), which can give a qualitative leap in the study of the structure of the lithosphere. In particular, a decrease in the residual anomaly to ±2.0 mGal when modeling the structure of the Earth’s crust within the Biostromnaya zone made it possible to identify apromising area for the search for hydrocarbons. Therefore, at the stage of prospecting, it is necessary to recalculate in greater detail the sections of the profile in the zones of lateral changes in the field, if in the density simulations the curves of Δgr have the form of Helmert anomalies.