ROLE OF THE CRUSTAL DETACHEMENTS DURING RIFTING, INSIGHTS FROM LABRADOR SEA

• Main Authors: DEDIU, M. -C., MUNTEANU, I., DINU, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Zenodo 2020
• Subjects: Labrador Sea; detachment; rifting; S shape reflectors; hyperextended; Newfoundland; Baffin Bay; Canada; Greenland; Nares; Labrador Shelf; Lister; Davis Strait; Nares strait
• Online Access: https://dx.doi.org/10.5281/zenodo.4686426; https://zenodo.org/record/4686426

The Labrador Sea is part of the Atlantic rift system which opens during Early Cretaceous times in the intracontinental domain. The rifting stage continues and generates an expansion center, with the establishments of an oceanic ridge during Late Cretaceous-Paleocene times. The rifting was asymmetric with a gradual propagation northward. The Cretaceous stretching and thinning of the continental crust led to the development of the transitional domain, with a controversial origin either thinned continental or oceanic. With this study, we bring new evidences for the presence of exhumed upper mantle in the transition domain based on geometry of the detachment faults, typical “S” shape, and we emphasize the role of the detachments in the rifting of continental crust and its ultimate break-up. We observed the lateral change, from South to North, of the continental to oceanic crust transition, from a step-up to a step-down. Based on, we suggest that it might reflect the changes in the upper versus lower plate position of the Labrador Sea, a change accommodated across the Snorri Fracture Zone. : {"references": ["Chian, D., Keen, C., Reid, I., Louden, K.E. (1995). Evolution of nonvolcanic rifted margins: New results from the conjugate margins of the Labrador Sea. Geology, 23: 589-592.", "Balkwill, H.R., McMillan, N.J., MacLean, B., Williams, G.L., Srivastava, S.P., Keen, M.J., Williams, G.L. (1990). Geology of the Labrador Shelf, Baffin Bay, and Davis Strait, Geology of the Continental Margin of Eastern Canada. Geological Society of America, 863 p.", "Dickie, K., Keen, C.E., Williams, G.L., Dehler S.A. (2010). New insights into the Tectonostratigraphic Evolution of the Labrador Sea. Offshore Technology Conference Houston Texas, USA, 1-15.", "Dickie, K., Keen, C.E., Williams, G.L., Dehler, S.A. (2011). Tectonostratigraphic evolution of the Labrador margin, Atlantic Canada. Marine and Petroleum Geology, 28: 1663-1675.", "Gouiza, M., Paton, D.A. (2019). The Role of Inherited Lithospheric Heterogeneities in Defining the Crustal Architecture of Rifted Margins and the Magmatic Budget During Continental Breakup. Geochemistry, Geophysics, Geosystems, 20: 1836-1853.", "Keen, C.E., Dickie, K., Dafoe, L.T. (2018). Structural characteristics of the ocean-continent transition along the rifted continental margin, offshore central Labrador. Marine and Petroleum Geology, 89: 443-463.", "Keen, C.E., Dickie, K., Dehler, S.A. (2012). The volcanic margins of the northern Labrador Sea: insights to the rifting process. Tectonics, 31: TC1011. http://dx.doi.org/10.1029/2011TC002985.", "Lister, C.R.B., Davis, G.A. (1989). The origin of metamorphic core complexes and detachment faults formed during Tertiary continental extension in the northern Colorado River region, U.S.A. Journal of Structural Geology, 11: 65-89.", "Oakey, G.N., Chalmars, J.A. (2012). A new model for the Paleogene motion of Greenland relative to North America: Plate reconstructions of the Davis Strait and Nares Strait regions between Canada and Greenland, J. Geographys. Res., 117, B10401, doi:10.1029/2011JB008942.", "P\u00e9ron-Pinvidic, G., Manatschal, G. (2008). The final rifting evolution at deep magma-poor passive margins from Iberia-Newfoundland: a new point of view. International Journal of Earth Sciences, 98: 1581-1597.", "P\u00e9ron-Pinvidic, G., Manatschal, G., Masini, E., Sutra, E., Flament, J.M., Haupert, I., Unternehr, P. (2017). Unravelling the along-strike variability of the Angola\u2013Gabon rifted margin: a mapping approach. Geological Society London, Special Publications, 438: 49-76.", "Roest, W.R., Srivastava, S.P. (1989). Sea-floor spreading in the Labrador Sea: A new reconstruction. Geology, 17: 1000-1003.", "Srivastava, S.P., Roest, W.R. (1999). Extent of oceanic crust in the Labrador Sea. Marine and Petroleum Geology,16: 65-84.", "Wernicke, B. (1985). Uniform-sense normal simple shear of the continental lithosphere. Canadian Journal of Earth Sciences, 22: 108-125."]}