Rifting and pre‐rift lithosphere variability in the Orphan Basin, Newfoundland margin, Eastern Canada

• Published in: Basin Research
• Main Authors: Gouiza, M., Hall, J., Bertotti, G.
• Other Authors: Nalcor Energy, Husky Energy and the Natural Sciences and Engineering Council of Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Canada; Newfoundland
• Online Access: http://dx.doi.org/10.1111/bre.12078; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbre.12078; https://onlinelibrary.wiley.com/doi/pdf/10.1111/bre.12078

Abstract The O rphan B asin, lying along the N ewfoundland rifted continental margin, formed in M esozoic time during the opening of the N orth A tlantic O cean and the breakup of I beria/ E urasia from N orth A merica. To investigate the evolution of the O rphan B asin and the factors that governed its formation, we (i) analysed the stratigraphic and crustal architecture documented by seismic data (courtesy of TGS ), (ii) quantified the tectonic and thermal subsidence along a constructed geological transect, and (iii) used forward numerical modelling to understand the state of the pre‐rift lithosphere and the distribution of deformation during rifting. Our study shows that the pre‐rift lithosphere was 200‐km thick and rheologically strong (150‐km‐thick elastic plate) prior to rifting. It also indicates that extension in the O rphan B asin occurred in three distinct phases during the J urassic, the E arly C retaceous and the L ate C retaceous. Each rifting phase is characterized by a specific crustal and subcrustal thinning configuration. Crustal deformation initiated in the eastern part of the basin during the J urassic and migrated to the west during the C retaceous. It was coupled with a subcrustal thinning which was reduced underneath the eastern domain and very intense in the western domains of the basin. The spatial and temporal distribution of thinning and the evolution of the lithosphere rheology through time controlled the tectonic, stratigraphic and crustal architecture that we observe today in the O rphan B asin.