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Abstract

Models of sedimentary basins mostly regard the lithospheric mantle as a homogeneously dense body.Tomographic and seismological studies, in contrast, indicate lateral heterogeneities in the mantle. Several studiesaddressed these heterogeneities by inverting seismic wave velocity from tomographic models to tem-perature and density. Whilst these studies have shown that sensitivity of seismic velocity to variations in temperature is larger than to variations in density (e.g. Sobolev et al., 1996), the differentiation of thermal from compositional anomalies remains difficult. We aim to solve this problem by quantifying the impact of varying mantle compositions on inverted density dis-tributions and the calculated gravity field of the mantle above 300km depth. Therefore, we use forward calculation of s- and p-wave velocities to invert tomographic models for temperature and density, considering laboratory mineral properties and different mantle compositions (Goes et al., 2000). Thereby, we consider tomographic models on global and regional scale. Our results indicate a significant impact on the inferred gravity field and thus on interpretations of lithospheric-scale models. Furthermore, we find that the integration of inverted density distributions may decrease uncertainties in the interpretation of gravity-constrained basin models. Additionally, for models with well constrained upper lithospheric structure, i.e. from reflection and refraction seismics, the integration of inverted density distributions in the upper mantle may help to identify compositional or thermal anomalies in the mantle.