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The Great Glen Fault (GGF) trends NNE-SSW across northern Scotland. According to previous studies, the GGF developed as a left-lateral strike slip fault during the Caledonian Orogeny (Ordovician to Early Devonian). However, it then reactivated right-laterally in the Tertiary. We discuss additional e...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.400.311 http://hal.inria.fr/docs/00/83/60/55/PDF/LeBreton-etal_13_JGSaccepted.pdf |
| Summary: | The Great Glen Fault (GGF) trends NNE-SSW across northern Scotland. According to previous studies, the GGF developed as a left-lateral strike slip fault during the Caledonian Orogeny (Ordovician to Early Devonian). However, it then reactivated right-laterally in the Tertiary. We discuss additional evidence for this later phase. At Eathie and Shandwick, minor folds and faults in fossiliferous Jurassic marine strata indicate post-depositional right-lateral slip. In Jurassic shale, we have found bedding-parallel calcite veins (‘beef ’ and ‘cone-incone’) that may provide evidence for overpressure development and maturation of organic matter at significant depth. Thus, the Jurassic strata at Eathie and Shandwick accumulated deeper offshore in the Moray Firth and were subject to Cenozoic exhumation during rightlateral displacement along the GGF, as suggested by previous authors. Differential sea-floor spreading along the North East Atlantic ridge system generated left-lateral transpressional displacements along the Faroe Fracture Zone (FFZ) from the Early Eocene to the Late Oligocene (c. 47–26 Ma), a period of uplift and exhumation in Scotland. We suggest that such 1 27 28 differential spreading was responsible for reactivation of the GGF. Indeed, left-lateral slip along the FFZ is compatible with right-lateral reactivation of the GGF. 29 |
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