The gravitational effect of the sedimentary cover located in the Republic of Niger

Abstract

Introduction: The article considers the approaches and results of creating a conceptual geological model of the sedimentary cover in the Republic of Niger and its framing to be used to calculate the gravitational effect of the sedimentary cover in the studied area. The anomalous field of the cover is necessary to reduce the observed gravitational field due to density heterogeneities in the sedimentary cover. The structure of the sedimentary cover in the region: The study considered the main features of the structure of the sedimentary cover located in the Republic of Niger. It also described the lithological composition and thicknesses of major structural levels of the cover for syneclises, basins, and grabens in the West African Rift System. The provided data were used to create a model of the sedimentary cover in the Republic of Niger and the neighbouring countries. Density model of the sedimentary cover: The overall density model of the cover includes regional data on the density of sedimentary rocks contained in the LITHO1 model and detailed data generated by using 2D CDP seismic data and the data of petrodensity research in the deep wells of the region. Density characteristic of sedimentary rock layers was provided in the overall model of the cover. The gravitational effect of the sedimentary cover: The anomalous gravitational effect of the overall digital model of the sedimentary cover was calculated and a generalised morphological characteristic of the field anomalies was provided. The features of the field anomalies in the area of graben development in the West African Rift System were determined. Conclusions: The main results of the study were formulated and the tasks regarding the calculation of the anomalous gravitational field generated by sources in the crystalline crust were outlined.