Geophysical evidence for the extent of crustal types and the type of margin along a profile in the northeastern Baffin Bay

Abstract

Investigating the crust of northern Baffin Bay provides valuable indications for the still debated evolution of this area. The crust of the southern Melville Bay is examined based on wide‐angle seismic and gravity data. The resulting P wave velocity, density, and geological models give insights into the crustal structure. A stretched and rifted continental crust underneath southern Melville Bay is up to 30 km thick, with crustal velocities ranging between 5.5 and 6.9 km/s. The deep Melville Bay Graben contains a 9 km thick infill with velocities of 4 to 5.2 km/s in its lowermost part. West of the Melville Bay Ridge, a ~80 km wide and partly only 5 km thick Continent‐Ocean Transition (COT) is present. West of the COT, up to 5 km thick sedimentary layers cover a 4.3 to 7 km thick, two‐layered oceanic crust. The upper oceanic layer 2 has velocities of 5.2 to 6.0 km/s; the oceanic layer 3 has been modeled with rather low velocities of 6.3 to 6.9 km/s. Low velocities of 7.8 km/s characterize the probably serpentinized upper mantle underneath the thin crust. The serpentinized upper mantle and low thickness of the oceanic crust are another indication for slow or ultraslow spreading during the formation of the oceanic part of the Baffin Bay. By comparing our results on the crustal structure with other wide‐angle seismic profiles recently published, differences in the geometry and structure of the crust and the overlying sedimentary cover are revealed. Moreover, the type of margin and the extent of crustal types in the Melville Bay area are discussed.

High Arctic geopotential stress field and implications for geodynamic evolution

“…2, top left) with depths of 10 km and more in the southern Canada Basin/Beaufort-MacKenzie Sea (Stephenson et al, 1994b;Sippel et al, 2013), Chukchi Basin (Drachev, 2011) and in the eastern Barents Sea (Drachev et al, 2010;Minakov et al, 2012;Klitzke et al, 2015). Other areas with locally substantial sedimentary thickness >5 km are observed in Baffin Bay (Funck et al, 2012;Suckro et al, 2012;Altenbernd et al, 2015), the Sverdrup Basin (Embry, 1991;Embry & Beauchamp, 2008;Oakey & Stephenson, 2008;, the Lincoln Sea (Jackson et al, 2010;Funck et al, 2011), the western Barents Sea (Ritzmann et al, 2007;Klitzke et al, 2015), the Kara Sea (Drachev et al, 2010) and the Russian Arctic shelf (Drachev & Shkarubo, this volume;Drachev, 2011).…”

Evolution of Labrador Sea–Baffin Bay: Plate or Plume Processes?

“…A mantle plume (Morgan 1971) has been proposed as the causal mechanism for continental breakup and magmatism between Greenland and Canada (e.g. Storey et al 1998;Courtillot et al 1999;Nielsen et al 2002;Funck et al 2007;Gerlings et al 2009;Altenbernd et al 2015). It is postulated that initial rifting was relatively amagmatic (Nielsen et al 2002;Altenbernd et al 2015) and that the arrival of a mantle plume at ca.…”

Breakup volcanism and plate tectonics in the NW Atlantic

“…1). However, modern wide-angle seismic datasets reveal that the southern Baffin Bay is underlain by 6 to 9 km thick oceanic crust (Funck et al, 2012;Suckro et al, 2012), and the northwestern Baffin Bay is underlain by 3.5 to 6 km oceanic crust (Altenbernd et al, 2014(Altenbernd et al, , 2015. Regional crustal structure derived from 3D gravity inversion modeling shows a good correlation with the seismic reflection data and supports the occurrence of oceanic crust in the center of Baffin Bay (Welford and Dehler, 2016).…”