| Titre | Crustal structure of Baffin Bay from constrained three-dimensional gravity inversion and deformable plate tectonic models |
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| Auteur | Welford, J K ;
Peace, A L; Geng, M X; Dehler, S A; Dickie, K |
| Source | Geophysical Journal International vol. 214, 2, 2018 p. 1281-1300, https://doi.org/10.1093/gji/ggy193 |
| Image |  |
| Année | 2018 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200215 |
| Éditeur | Oxford Univ Press |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1093/gji/ggy193 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Nunavut |
| Région | Baie de Baffin |
| Lat/Long OENS | -90.0000 -40.0000 78.0000 64.0000 |
| Sujets | anomalies gravimétriques; tectonique de plaques; mouvements des plaques; marges continentales; structure de la croûte; géologie générale; Nature et environnement; Sciences et technologie; géologie
structurale; tectonique; Mésozoïque; Cénozoïque |
| Illustrations | cartes de localisation; profiles gravimétriques; profils bathymétriques; graphiques; diagrammes 3D |
| Diffusé | 2018 05 18 |
| Résumé | (disponible en anglais seulement)
Mesozoic to Cenozoic continental rifting, breakup and spreading between North America and Greenland led to the opening, from south to north, of the Labrador Sea
and eventually Baffin Bay between Baffin Island, northeast Canada and northwest Greenland. Baffin Bay lies at the northern limit of this extinct rift, transform and spreading system and remains largely underexplored. With the sparsity of existing
crustal-scale geophysical investigations of Baffin Bay, regional potential field methods and quantitative deformation assessments based on plate reconstructions provide two means of examining Baffin Bay at the regional scale and drawing conclusions
about its crustal structure, its rifting history and the role of pre-existing structures in its evolution. Despite the identification of extinct spreading axes and fracture zones based on gravity data, insights into the nature and structure of the
underlying crust have only been gleaned from limited deep seismic experiments, mostly concentrated in the north and east where the continental shelf is shallower and wider. Baffin Bay is partially underlain by oceanic crust with zones of variable
width of extended continental crust along its margins. 3-D gravity inversions, constrained by bathymetric and depth to basement constraints, have generated a range of 3-D crustal density models that collectively reveal an asymmetric distribution of
extended continental crust, approximately 25-30 km thick, along the margins of Baffin Bay, with a wider zone on the Greenland margin. A zone of 5-13 km thick crust lies at the centre of Baffin Bay, with the thinnest crust (5 km thick) clearly
aligning with Eocene spreading centres. The resolved crustal thicknesses are generally in agreement with available seismic constraints, with discrepancies mostly corresponding to zones of higher density lower crust along the Greenland margin and
Nares Strait. Deformation modelling from independent plate reconstructions using GPlates of the rifted margins of Baffin Bay was performed to gauge the influence of original crustal thickness and the width of the deformation zone on the crustal
thicknesses obtained from the gravity inversions. These results show the best match with the results from the gravity inversions for an original unstretched crustal thickness of 34-36 km, consistent with present-day crustal thicknesses derived from
teleseismic studies beyond the likely continentward limits of rifting around the margins of Baffin Bay. The width of the deformation zone has only a minimal influence on the modelled crustal thicknesses if the zone is of sufficient width that edge
effects do not interfere with the main modelled domain. |
| GEOSCAN ID | 326627 |
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