The separation of North America and Greenland: tectonic and palaeobathymetric reconstruction of southern Baffin Bay and Davis Strait

• Main Authors: Suckro, Sonja, Gohl, Karsten, Funck, Thomas, Heyde, Ingo, Damm, Volkmar, Altenbernd, Tabea, Jokat, Wilfried, Schreckenberger, Bernd, Ehrhardt, Axel, Gerlings, Joanna
• Format: Conference Object
• Language: unknown
• Published: 2013
• Subjects: Baffin Bay; Canada; Greenland; Hudson; Arctic; Baffin; Davis Strait; Labrador Sea
• Online Access: https://epic.awi.de/id/eprint/32277/; https://hdl.handle.net/10013/epic.40888

The crustal nature and tectonic development of the Baffin Bay and Davis Strait were enigmatic for a long time due to the lack of unequivocal data. Although it was proposed in earlier studies that oceanic crust underlies the Baffin Bay, no clear magnetic spreading anomalies were detected. Stretched continental crust underlying the basin could be another possibility. The nature of the Davis Strait crust has been discussed as being of continental or oceanic origin. In 2008 and 2010, we collected new geophysical data in the Davis Strait and Baffin Bay as part of a German-Danish-Canadian cooperation project. The aim of this study is to reveal the tectonic reconstruction of the Canada-Greenland separation in the southern Baffin Bay and to provide new insight into the role of the Davis Strait as a polar ocean gateway. We present a 710-km-long crustal model in southern Baffin Bay and a 315-km-long model in the central Davis Strait. We developed P-wave velocity models from ocean-bottom seismograph data and corresponding density models from free-air gravity data. Additional seismic reflection and magnetic anomaly data were evaluated. We find oceanic crust in southern Baffin Bay with an average thickness of 7.5 km. The margins exhibit large volcanic affinity. The Davis Strait crust consists mainly of continental blocks that are divided by a 45-km-long section of highly intruded or new igneous crust. This section coincides with the location of the Ungava Fault Complex. With these new data we developed a new tectonic model and conclude that the Ungava Fault Complex acted as a plate boundary in pre-Eocene times. With a direction change of plate motion during the opening, the Hudson Fracture Zone developed with major strike-slip motion and acted as subsequent boundary. We further compiled published and new seismic stratigraphy data with drill site information and calculated palaeobathymetric grids for the ocean gateway between southern Baffin Bay and northern Labrador Sea. The grids reveal that a water transport between the Labrador Sea and Baffin Bay was not possible in pre-Eocene times. A cyclonic current similar to today probably existed in the early Labrador Sea since the Paleocene. Our palaeobathymetric reconstruction can be used in global palaeocean and palaeoclimate models.