Investigating the tectonic evolution of the NE Newfoundland-Porcupine Atlantic conjugate margins using new seismic reflection data and deformable plate modelling

• Main Author: Yang, Pei
• Format: Text
• Language: English
• Published: Memorial University of Newfoundland 2021
• Subjects: Porcupine Bank; Newfoundland; North Atlantic
• Online Access: https://dx.doi.org/10.48336/3vm8-jb78; https://research.library.mun.ca/15248/

In recent years, there has been an improved understanding of the multi-episodic extensional processes that were active along the NE Newfoundland-Porcupine Atlantic conjugate margins during the Mesozoic. However, there are still unresolved key issues about this rift system, including unclear structural styles and crustal architecture due to lacking seismic data constraints, uncertainties about the effects of structural inheritance and rift segmentation on margin development, skepticism about the role of extension obliquity, and increased scrutiny about the conjugate relationship between the Flemish Cap and Goban Spur. In this thesis, an integrated geophysical study, based on newly acquired seismic reflection data, seismic refraction data, borehole data, and potential field data along the rift system, is undertaken to define the crustal architecture. The faults, sedimentary layers, and basement features display distinct 3D characteristics and the crustal architecture is highly variable along the margin. Along-strike variability is associated with changes in extension rates, rift obliquity, and the effect of reactivation of inherited Caledonian and Variscan basement fabrics, indicative of segmentation of the rift system. In conjunction with constraints from newly acquired seismic data, this study improves upon published deformable plate models in GPlates by introducing segmentation of the Porcupine Bank and transfer faults on the continental crust of the Goban Spur, generating a better fit compared with previous plate reconstruction models. The updated deformable plate model allows us to visualize the crustal thickness evolution through time and further quantify the amount, orientation, and timing of extension events between the NE Newfoundland, Iberia, and Irish Atlantic margins. This model shows that the NE Newfoundland-Porcupine Atlantic margin pair is highly segmented and obliquely hyperextended. The model also demonstrates the significant role played by continental ribbons/microplates in controlling crustal thickness within the deformable region. The thesis results reshape our understanding of the complex kinematic evolution of the NE Newfoundland-Porcupine Atlantic rift system and of rift compartmentalization across the southern North Atlantic. The conjugate relationships between the Goban Spur, Porcupine Bank, and Flemish Cap are also renewed, which is beneficial to derisk petroleum exploration in the underexplored conjugate margin basins. Finally, these results can potentially offer insights into the evolution of other rifted margins (e.g., the Red Sea) on the Earth.