Localities Explained 22. South Devon, UK

Where can you teach the fundamental principles of geology in three short field days? In this feature article, I introduce South Devon as a classic area of geology, useful for introducing basic concepts relevant to school and first-year degree curricula. That this region remains a catalyst for developing young geologists is especially fitting given that it was here that Henry de la Beche embarked on the first mapping project of what would later become the British Geological Survey. In South Devon, a novice geologist can learn about plate tectonics, the unifying theory of our subject, through a visit to two quarries. At Chipley Quarry, near Newton Abbott, sea-floor spreading is well illustrated by Devonian pillow-lavas extruded within the back-arc margins of the Rheic Ocean. At Burrator Quarry, near Yelverton, the aftermath of continental collision is represented by the north-verging Variscan fold belt, intruded and thermally metamorphosed by the Dartmoor granite. A trip along the coast to Paignton provides an informative lesson about the distinctive stratigraphic imprint that is created by this plate tectonic cycle. Here, tightly folded Devonian slates are unconformably overlain by near-horizontal Permian breccia-conglomerates at Waterside Cove. The ‘abyss of time’ at their junction represents the tens of millions of years involved in the uplift and denudation of Rheic Ocean sediments in the course of the Variscan Orogen. The Devonian and Permian successions of South Devon additionally serve as an excellent training ground for interpreting ancient environments with both marine and terrestrial facies spectacularly represented. Fossils abound in these strata, too, including the stromatoporoid life assemblage at Triangle Point, Torquay, where students have the opportunity to do a virtual scuba-dive over a Devonian reef. Finally, given current discussions about employability in UK universities, there is even room in an excursion to instill the practical importance of geology: for example, a trip to the scenic Burrator Reservoir on Dartmoor reveals what can go wrong for geotechnical engineers when a major dam is sited on a granite weakened by chemical weathering. In summary, South Devon has it all—a brilliant natural laboratory for training and inspiring the next generation of geologists.