A 3D regional crustal model of the NE Atlantic based on seismic and gravity data

Abstract

We present a 3D regional crustal model for the North Atlantic, which is based on the integration of seismic constraints and gravity data. The model addresses the crustal thickness geometry, and includes information on sedimentary thickness, the presence of high-velocity zones in the lower crust, and information on the crustal density distribution in the continental and oceanic domains. Using an iterative forward- and inverse-modelling approach, we adhere to the seismic constraints within their uncertainty, but manage to enhance the crustal geometry in areas where seismic data are sparse or absent. A number of basins are resolved with more detail. Recently released seismic reflection data beneath the NE Greenland Shelf allowed for a major improvement of the crustal thickness estimates. Estimated Moho depths beneath the basins there vary between 15 and 25 km, which is compatible with the conjugate Norwegian margin. A major lower-crustal seismic velocity anomaly in the vicinity of the Greenland–Iceland–Faroe Ridge complex is supported by density modelling. We discuss the validity and uncertainties of our model assumptions and discuss the correlation with the main structural elements of the North Atlantic.

Break-up and seafloor spreading domains in the NE Atlantic

“…Plate reconstructions of gridded data (presentday magnetic anomaly, isostatic gravity and crustal thickness) at 54 Ma, the time of early seafloor spreading in the NE Atlantic, are shown in Figure 5b, c. Present-day crustal thickness estimated from gravity inversion (Haase et al 2016) gives a firstorder approximation of the crustal architecture and amount of margin extension due to rifting. A reconstruction at 54 Ma (the time of early seafloor spreading in the NE Atlantic) shows regions of thin and thick crust (Fig.…”

The NE Atlantic region: a reappraisal of crustal structure, tectonostratigraphy and magmatic evolution – an introduction to the NAG-TEC project

“…The paper by Haase et al (2016) describes a 3D regional crustal model for the NE Atlantic, based on the integration of seismic constraints and gravity data. For the NAG-TEC Atlas, the 'DTU10' gravity dataset provided by Andersen (2010) had a homogeneous coverage and sufficient good resolution for the purpose of the project.…”

“…Haase & Ebbing (2014) used it as their main input to compute Bouguer, free air, isostatic and tilt derivative versions of the grid to the Atlas and GIS database. Based on this first-order compilation, and on additional information from the seismic refraction compilation (see Funck et al 2014), the model presented by Haase et al (2016) offers a 3D perspective of the basement and Moho geometries in the NE Atlantic that permits an improved resolution of some areas, such as basins along the NE Greenland margin, as well as the GIFRC. The maps generated are particularly useful in areas with poor seismic data coverage, in particular where the Moho and basement maps obtained from the seismic refraction database are very coarse and lack detailed structure (Funck et al 2016a).…”

“…Along the Mid-Norwegian margin, they use the density model built for the Haase et al (2016) gravity inversion to forward-calculate bathymetry. They propose that the misfits with the observed bathymetry point to poorly understood regions that require further investigations.…”

Regional distribution of volcanism within the North Atlantic Igneous Province

“…compared to NE Greenland Haase et al 2016). Nevertheless, the possibility that the magmatically rich half of the conjugate pairs seems to be the one closest to the stable cratons and thick lithosphere is intriguing and suggests preexisting lithospheric structure may play a role in asymmetric volcanic margin development.…”