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The Congo basin is one of the largest intracratonic basins in the World, locating within a cold lithospheric plate. The structure of the thick sedimentary layer is investigated by seismic studies only in limited places. Here, we present a map of sedimentary thickness for the whole Congo basin, based on the inversion of the decompensative gravity anomalies. Contrary to the conventional Bouguer or isostatic gravity anomalies, the effect of the isostatic compensation of sediments is reduced in the decompensative anomalies, which provides a possibility to recover the full effect of low-density sediments. The calculated decompensative correction reaches ±70 mGal and exceeds the amplitude of the isostatic anomalies, especially in the long wavelengths. The final decompensative anomalies are negative over the whole basin and their patterns well correspond to its tectonic fragmentation. By inverting these anomalies with the predefined density-depth relationship we have obtained the sedimentary thickness map for the whole Congo basin. The maximum basement depth exceeding 10 km is found in the Lokoro basin and basins in the South. In the Lomami basin, thickness of sediments reaches about 6.5 km. It is important to note, that these deep depressions, are not covered by seismic studies. Furthermore, we found a new deep basin adjacent to the Lokonia High (on the SW side) that we propose to name as the Salonga basin.

The Arabian Plate shows a strong asymmetry between its Shield and Platform, in terms of topography, seismic velocity and density structure of the upper mantle. This asymmetry also results in significant rheological differences between these blocks, as revealed by the effective elastic thickness (EET) estimates, obtained using a spectral gravity method. However, these estimates may be biased due to various factors: therefore, other approaches based on a direct rheological modeling of the lithospheric structure should be employed to verify these results. In this study, we use a recent model of the lithosphere, based on an integrative interpretation of the gravity field and seismic tomography, to correct an initial thermal model obtained from the inversion of seismic velocity, assuming a uniform composition. The results are used together with the most recent crustal model of the Arabian Plate to construct two alternative models of strength and EET of the lithosphere. The first model (Model I) assumes a constant value of 10− 15 s− 1 for the strain rates. In the second model (Model II), we used the strain rates obtained from a global mantle flow model. Model I confirms the asymmetry in the rigidity of the Shield and Platform. In contrast, Model II shows that the influence of the variable strain rates causes a significant increase in the strength and EET of the central and eastern part of the Shield and in contrast to previous studies, reveals that most of the Arabian Plate is a long-term stable tectonic feature, predominantly characterized by large EET values (≥ 70 km). Do you want to read the rest of this article?Request full-text Strength and elastic thickness variations in the Arabian Plate: A combination of temperature, composition and strain rates of the lithosphere. Available from: https://www.researchgate.net/publication/314832634_Strength_and_elastic_thickness_variations_in_the_Arabian_Plate_A_combination_of_temperature_composition_and_strain_rates_of_the_lithosphere [accessed Apr 18, 2017].