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- Title
ArcCRUST: Arctic Crustal Thickness From 3‐D Gravity Inversion.
- Authors
Lebedeva‐Ivanova, Nina; Gaina, Carmen; Minakov, Alexander; Kashubin, Sergey
- Abstract
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. Plain Language Summary: An excess or deficit of mass is reflected in the gravity anomaly data. Gravity anomalies measured by satellite and airborne and shipborne instruments show variations in topography and bathymetry, sedimentary thickness, basement rock density contrast, crustal thickness, and even mantle convection. Using new geophysical data and an improved 3‐D gravity inversion method, we calculate the crustal thickness of oceanic domains in the High Arctic and northern North Atlantic. This model helps to better understand the tectonic structure of poorly surveyed and difficult to access Arctic regions. ArcCRUST can be used to better constrain the deeper Arctic region structure. Key Points: We construct a new Arctic crustal model using forward and inverse gravity modelingMicrocontinents in the deep Arctic Ocean have thin crust and less dense and/or thin mantle lithosphereAn ~3‐km misfit between gravity‐derived and seismically modeled crustal thickness in the Greenland Sea indicates a hotter upper mantle
- Subjects
GEOCHEMISTRY; GEOPHYSICS; TOPOGRAPHY; PLATE tectonics; ROCK density
- Publication
Geochemistry, Geophysics, Geosystems: G3, 2019, Vol 20, Issue 7, p3225
- ISSN
1525-2027
- Publication type
Article
- DOI
10.1029/2018GC008098