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Breakwater Quarry, BrixhamDesignations: CGS/RIGS Middle Devonian limestones from the quarry were used to build Brixham Breakwater GCR block / key theme: Permian-Triassic Associated SSSI: Not applicable Geological / geomorphological features: "Middle Devonian limestone, mainly massive and micritic but bioclastic in part. Bedding is obscure, the dip is steep to the SE. Cleavage seen in places dips about 20° NW. The limestone has an irregular palaeokarst surface and is penetrated by deep narrow fissures filled with brown Permian sandstone which contains angular limestone fragments in places, some of large size. Pleistocene/Holocene solution fissures in the limestone are associated with coatings of flowstone. Engineering geological applications include the use of rock bolts for the large scale stabilisation of rock faces in association with steel mesh to prevent falls of smaller rock fragments." Reasons for registration as a RIGS sites: "The quarry provides an excellent demonstration of pre-Permian solution fissures in the Devonian limestone (palaeokarst) with later, Permian, sandstone and limestone fragment infilling. The vertical extent of the fissure is particularly notable. Other useful aspects included structural features and solution fissures with flowstone in the limestone; also engineering application of rock bolts to stabilise faces and the use of mesh to prevent falls of smaller material." |