ArcCRUST: Arctic Crustal Thickness From 3-D Gravity Inversion

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Lebedeva-Ivanova, Nina, Gaina, Carmen, Minakov, Alexander, Kashubin, Sergey
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley-Blackwell 2019
• Subjects: Arctic; crustal model; gravity inversion; Moho depth; Arctic Ocean; Greenland; Greenland Sea; North Atlantic
• Online Access: https://eprints.qut.edu.au/231415/

The ArcCRUST model consists of crustal thickness and estimated crustal thinning factors grids for the High Arctic and Circum-Arctic regions (north of 67°N). This model is derived by using 3-D forward and inverse gravity modeling. Updated sedimentary thickness grid, an oceanic lithosphere age model together with inferred microcontinent rifting ages, variable crystalline crust and sediment densities, and dynamic topography models constrain this inversion. We use published high-quality 2-D seismic crustal-scale models to create a database of Depths to Seismic Moho (DSM) profiles. To check the quality of the ArcCRUST model, we have performed a statistical analysis of misfits between the ArcCRUST Moho depths and DSM values. Systematic analysis of the misfits within the Arctic sedimentary basins provides information about tectonic processes unaccounted by the assumed model of pure-shear lithospheric extension. In particular, our model implies a less dense and/or thin mantle lithosphere underneath microcontinents in the deep Arctic Ocean where the ArcCRUST depth to Moho values exceed the DSM. A systematically larger gravity-derived crustal thickness (~3 km) under the western and northern Greenland Sea points to a hotter upper mantle implied by the seismic tomography models in the North Atlantic.