Gravity anomalies and subsurface geology in the Westerwald volcanic area, Germany

The area of the present study constitutes an alkaline volcanic province in the eastern sector of the Rhenish massif. A series of gravity measurements were carried out on the volcanic fields of the Westerwald. Three-dimensiona l modelling and wavelength filtering processing techniques were used to ana lyze the gravity data. The filtered Bouguer anomaly maps show two major reg ional gravity features: (a) Increasing Bouguer values towards the northeast ern part of the study area could be caused by lateral lithological variatio ns within the upper crust. (2) Local negative Bouguer values in the southwe st correlate with magmatic materials of intermediate type. The modelling re sults indicate that the volcanics of the Westerwald are underlain by two di fferent magmatic complexes at a depth in the range 3.3-10 km with density v alues of 2680 and 2750 kg/m(3). The densities assigned to the local igneous intrusions are in the range of 2314-2948 kg/m(3) and at depths between 0.4 and 1.3 km. In the NE a diabase bed was modelled to a maximum depth of app roximately 1.6 km using the assigned density of 2800 kg/m(3).