@article{2535e05f13064443a957d8064504da31,
title = "Pre-breakup Extension in the Northern North Sea Defined by Complex Strain Partitioning and Heterogeneous Extension Rates",
abstract = "The early stages of continental rifting are accommodated by the growth of upper crustal normal fault systems that are distributed relatively evenly across the rift width. Numerous fault systems define fault arrays, the kinematics of which are poorly understood due to a lack of regional studies drawing on high-quality subsurface data. Here we investigate the long-term (~150 Myr) growth of a rift-related fault array in the East Shetland Basin, northern North Sea, using a regionally extensive subsurface data set comprising 2-D and 3-D seismic reflection surveys and 107 boreholes. We show that rift-related strain during the pre-Triassic to Middle Triassic was originally distributed across several subbasins. The Middle to Late Triassic saw a decrease in extension rate (~14 m/Myr) as strain localized in the western part of the basin. Early Jurassic strain initially migrated eastward, before becoming more diffuse during the main, Middle-to-Late Jurassic rift phase. The highest extension rates (~89 m/Myr) corresponded with the main rift event in the East Shetland Basin, before focusing of strain within the rift axis and ultimate abandonment of the East Shetland Basin in the Early Cretaceous. We also demonstrate marked spatial variations in timing and magnitude of slip along strike of major fault systems during this protracted rift event. Our results imply that strain migration patterns and extension rates during the initial, prebreakup phase of continental rifting may be more complex than previously thought; this reflects temporal and spatial changes in both thermal and mechanical properties of the lithosphere, in addition to varying extension rates.",
keywords = "continental rift, East Shetland Basin, extension rate, normal fault array, North Sea, strain behavior",
author = "Claringbould, {Johan S.} and Bell, {Rebecca E.} and Jackson, {Christopher A.L.} and Gawthorpe, {Robert L.} and Tore Odinsen",
note = "Funding Information: We acknowledge funding from the Equinor Departmental Scholarship at Imperial College London and the MultiRift Project, which is funded by the Research Council of Norway (PETROMAKS Project 215591) and Equinor (data provider/supporter) to the University of Bergen, and partners Imperial College London, University of Manchester, and University of Oslo. We thank Editor Laurent Jolivet, Douglas Paton, Emmanuel Masini, and an anonymous reviewer for their constructive reviews. Al Fraser and Jon Bull are thanked for their comments on the initial version of this work. For their involvement in providing the data and permission to publish, we are grateful Thomas Weight, Tom Dreyer, Mark Lawson, Claire Thomas, and Bart Hendriks at Equinor, Richard Lamb and Emma Taylor at PGS, and Bent Kj?lhamar at TGS. Schlumberger is thanked for providing Petrel to Imperial College London and the Earthquake Research Institute of The University of Tokyo. We also thank the members of the Basins Research Group at Imperial College London and the MultiRift Project, in particular Thilo Wrona, for fruitful discussions. Funding Information: We acknowledge funding from the Equinor Departmental Scholarship at Imperial College London and the MultiRift Project, which is funded by the Research Council of Norway (PETROMAKS Project 215591) and Equinor (data provider/supporter) to the University of Bergen, and partners Imperial College London, University of Manchester, and University of Oslo. We thank Editor Laurent Jolivet, Douglas Paton, Emmanuel Masini, and an anonymous reviewer for their constructive reviews. Al Fraser and Jon Bull are thanked for their comments on the initial version of this work. For their involvement in providing the data and permission to publish, we are grateful Thomas Weight, Tom Dreyer, Mark Lawson, Claire Thomas, and Bart Hendriks at Equinor, Richard Lamb and Emma Taylor at PGS, and Bent Kj{\o}lhamar at TGS. Schlumberger is thanked for providing Petrel to Imperial College London and the Earthquake Research Institute of The University of Tokyo. We also thank the members of the Basins Research Group at Imperial College London and the MultiRift Project, in particular Thilo Wrona, for fruitful discussions. Publisher Copyright: {\textcopyright}2020. The Authors.",
year = "2020",
month = aug,
day = "1",
doi = "10.1029/2019TC005924",
language = "English",
volume = "39",
journal = "Tectonics",
issn = "0278-7407",
publisher = "John Wiley & Sons Ltd",
number = "8",
}