| Title | Crustal structure of Baffin Bay from constrained three-dimensional gravity inversion and deformable plate tectonic models |
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| Author | 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 |  |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20200215 |
| Publisher | Oxford Univ Press |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Nunavut |
| Area | Baffin Bay; Greenland |
| Lat/Long WENS | -90.0000 -40.0000 78.0000 64.0000 |
| Subjects | general geology; Nature and Environment; Science and Technology; structural geology; tectonics; gravity anomalies; plate tectonics; plate motions; continental margins; crustal structure; Mesozoic;
Cenozoic |
| Illustrations | location maps; gravity profiles; bathymetric profiles; plots; 3-D diagrams |
| Released | 2018 05 18 |
| Abstract | 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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