HR: 1330h
AN: T12A-0449    [PDF]
TI: The structure and evolution of Baffin Bay and its implication on the development of the continental margins of northwest Greenland, the Nares Strait, and Baffin Island, Canada
AU: Oakey, G
EM: GOakey@nrcan.gc.ca
AF: Geological Survey of Canada - Atlantic, PO BOX 1006, Dartmouth, NS B2Y 4A2 Canada
AU: * Roest, W R
EM: walter.roest@ifremer.fr
AF: Departement des Geosciences Marines, IFREMER, Centre de Brest BP 70, Plouzane, 29280 France
AU: Lundin, E
EM: Erik.Lundin@ngu.no
AF: Norges Geologiske Undersokelse, Leiv Erikssons vei 39, Trondheim, N-7491 Norway
AU: Damaske, D
EM: D.Damaske@bgr.de
AF: Bundesanstalt fur Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, Hannover, D-30655 Germany
AB: Baffin Bay, located between northern Greenland and North America, is an ocean basin with a poorly understood seafloor spreading history. Magnetic anomalies identified in the North Atlantic, Norwegian-Greenland Sea and Labrador Sea have defined the independent motion of the Greenland Plate during the Cretaceous and Tertiary. However, defining the age and geometry of the crustal rocks of Baffin Bay remains key to understanding the plate tectonic history of the North Atlantic and Arctic Ocean. Satellite derived gravity data over Baffin Bay have revealed an axial low with large offsets that has been interpreted as an extinct spreading ridge and transform fault system, and this geometry has been used to improve the rotation pole for Greenland relative to North America. Based on the timing of a change in the direction of plate motions in the Labrador Sea, the latest phase of the spreading system in Baffin Bay is assumed to have been active between chron 24R (55Ma) and 13N (35Ma). Since no recent magnetic data exist in the Baffin Bay area, and older surveys suffer from the extremely large diurnal effects, observed in the auroral zone, the independent dating of the rift system remains enigmatic. However, Jackson et al. (Can. J. Earth Sci., 1979) report a magnetic survey corrected with independent diurnal observations from a moored magnetometer. A re-evaluation of this data, in context with the identified spreading system, reveals the existence of linear magnetic anomalies consistent with patterns of seafloor spreading, proving an oceanic character of the basin. The identified anomalies are tentatively interpreted as magnetic chrons 25N and 26N, and provide the first definitive ages of the plate geometry within Baffin Bay. Modern aeromagnetic data collected in the Nares Strait region in 2001 and 2003, in collaboration between the German Federal Institute of for Geosciences and Natural Resources (BGR) and the Geological Survey of Canada (GSC) have revealed new insights into the geometry of the plate boundaries between Canada and Greenland, implying that a simple linear Wegener fault along Nares Strait is likely not valid. Questions that remain unsolved, and for which a variety of hypotheses have been proposed include: Did Greenland behave as one plate during the Cenozoic or was it acting as at least two distinct plates; How much displacement took place along Nares Strait; How is the opening of Baffin Bay related to the development of the Sverdrup Basin? We present reconstructions of compiled magnetic, gravity, and bathymetric data between Canada and Greenland (Oakey et. al, 2001) to show how the evolution of Baffin Bay relates to the opening of the North Atlantic as a whole, and speculate on how the early opening history affected the evolution of the conjugate continental margins of northwest Greenland, Nares Strait, and Baffin Island, Canada.
DE: 3005 Geomagnetism (1550)
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 9315 Arctic region
DE: 9325 Atlantic Ocean
SC: Tectonophysics [T]
MN: 2003 Fall Meeting