Abstract
The Inner Moray Firth Basin (IMFB) forms the western arm of the North Sea trilete rift system that initiated mainly during the Late Jurassic–Early Cretaceous with the widespread development of major NE–SW-trending dip-slip growth faults. The IMFB is superimposed over the southern part of the older Devonian Orcadian Basin. The potential influence of older rift-related faults on the kinematics of later Mesozoic basin opening has received little attention, partly owing to the poor resolution of offshore seismic reflection data at depth. New field observations augmented by drone photography and photogrammetry, coupled with U–Pb geochronology, have been used to explore the kinematic history of faulting in onshore exposures along the southern IMFB margin. Dip-slip north–south- to NNE–SSW-striking Devonian growth faults are recognized that have undergone later dextral reactivation during NNW–SSE extension. The U–Pb calcite dating of a sample from the synkinematic calcite veins associated with this later episode shows that the age of fault reactivation is 130.99 ± 4.60 Ma (Hauterivian). The recognition of dextral-oblique Early Cretaceous reactivation of faults related to the underlying and older Orcadian Basin highlights the importance of structural inheritance in controlling basin- to sub-basin-scale architectures and how this influences the kinematics of IMFB rifting. Supplementary material: Analytical protocols and analysed sample details are available at https://doi.org/10.6084/m9.figshare.c.5635432
Highlights
PT Key words: Inner Moray Firth Basin, Orcadian Basin, structural inheritance, I reactivation, U-Pb calcite geochronology SCR Many sedimentary basins worldwide are superimposed partially or completely over U the sites of older, pre-existing basins, e.g. Colorado Basin (Lovecchio et al 2018); AN East African Rift (Macgregor 2015; Ragon et al 2018); the Gulf of Aden (Fournier et M al. 2004); the Northeast Atlantic margin (Hansen et al 2012; Henstra et al 2019); East Greenland rift system (Rotevatn et al 2018), the North Sea Rift
NU This paper focuses on the nature, age and regional significance of faulting A and fracturing present in the onshore Devonian succession of the southern Inner Moray Firth Basin (IMFB) M and Orcadian Basin (Fig. 1a-c)
New detailed field observations in the Turriff Subbasin (Fig. 1c) coupled with U-Pb dating of syn-kinematic calcite mineralisation are ED used to document and characterise the kinematic history of faulting. The latter is T utilised to explore the role that inherited Devonian structures played in basin P development during subsequent (Mesozoic and Cenozoic) deformation
Summary
The Inner Moray Firth Basin (IMFB) forms the western arm of the North Sea trilete. D rift system that initiated mainly during the Late Jurassic-Early Cretaceous with the E widespread development of major NE-SW-trending dip-slip growth faults. Dichiarante et al (2016) used Re-Os geochronology to date base metal sulphides in syn-tectonic normal to transtensional fault infills and veins in Devonian rocks of the Dounreay area These yielded a mid-Permian (267.5 ± 3.4 [3.5] Ma) age of faulting, which Dichiarante et al (2016, 2020) argued was related to the development of the offshore West Orkney Basin located just the northwest. P were considered by Ashcroft and Wilson (1976) to have initiated during PermoE Carboniferous times, based on the observation that a dyke swarm interpreted by CC Buchan (1932) to be of that age has a similar trend across NE Scotland
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
