Crustal structure of the Northeast Greenland shelf from regional 3D gravity modeling on the basis of sparse seismic data

Deep imaging data for crustal and sub-crustal studies on the Northeast Greenland shelf are sparse and the interpretation of the crust-mantle interface (Moho) is widely based on inter- and extrapolations. However, this interface also constitutes a prominent density contrasts in the subsurface and gravity data are a valuable additional tool for estimating Moho depth. Satellite-derived gravity data do not face the same acquisition restrictions as seismic data and is uniformly available across the Northeast Greenland shelf. We present an excerpt from a regional study, where satellite-derived gravity data have been used in a forward and inverse modeling approach for the compilation of a 3D crustal model of the entire Northeast Atlantic. The model includes a seismic-derived Moho, sediment thickness information, a differentiated crust, and the lithospheric mantle to model the long-wavelength signals. Our approach respects seismic constraints on the Moho interface within their uncertainties but at the same time enhances our understanding of the crustal geometry in areas where seismic data are sparse or absent. For the Northeast Greenland shelf in particular, crustal thickness estimations were greatly improved by this regional modeling, even though a number of simplifications were made. The estimated Moho depth underneath the basins varies between 15 and 25 km and is consistent with the one on the conjugate Norwegian margin. In order to refine the large-scale, coarse model, published results from more local studies are included in a next step. The crustal structure could be modeled in more detail and gravity residuals across the shelf were reduced significantly by adding further constraints and details, such as e.g. the distribution of volcanics and high-density lower crust.