Seismic, structural and stratigraphic evolution of the cretaceous sequences of the orphan basin, offshore Newfoundland and Labrador

• Main Author: Hardy, Victoria E.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2008
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/1655/; https://research.library.mun.ca/1655/1/Hardy_VictoriaER.pdf; https://research.library.mun.ca/1655/3/Hardy_VictoriaER.pdf

The continental margin of Newfoundland is made up of a series of interconnected, deep, Mesozoic sedimentary basins. Between the Cumberland Belt Transform Zone and the Charlie Gibbs Transform Zone the Avalon terrane is dissected into a 450 km wide track of extensional ridges and grabens collectively known as the Orphan Basin. From both a tectonic and a petroleum potential point of view the basin can be divided into an older (Late Triassic - Early Jurassic) sub-basin known as the East Orphan Basin and a younger (Cretaceous) sub-basin known as the West Orphan Basin. The Orphan Basin is an underexplored area and few studies have been completed on the structural, tectonic and stratigraphic framework of the area. -- Seismic stratigraphic analysis of the basin identified six major sequence boundaries ranging in age from pre-Mesozoic (Seismic Basement) to present (Water Bottom) and four Cretaceous sequences were identified, mapped and described. Four fault families were defined within the study area on the basis of their regionality, timing and duration of movement and depths of detachment: the Basin Bounding Fault Family, the Basement Involved Fault Family, the Sedimentary Fault Family and the Transfer Fault Family. -- Based on the mapping of the Cretaceous sequences and the orientations of major faults seen in the study area, the Orphan Basin can be divided into three distinct tectonostratigraphic regions. From west to east they are Areas A, B, and C. Areas B and C were affected by the Late Triassic - Early Jurassic Tethys Rift and the Late Jurassic - Early Cretaceous Atlantic Rift. Area B was reactivated for a third time with the Aptian - Albian Labrador rift that caused uplift and inversion of large structures in this area. Area A was predominantly affected by the Aptian - Albian Labrador rift and has Early and Late Cretaceous basin fill. The orientation of the major basement involved and basin bounding faults in the basin show a counterclockwise rotation from east to west as the rift propagated landward. The oldest ...