A reef knoll is a landform that comprises an immense pile of calcareous material that had previously accumulated on an ancient sea floor.[1] Reef knolls are geological remnants of reefs and other organic concentrations of calcareous organisms. Reef knolls are often fossil-rich, with prehistoric corals, sponges, calcareousalgae, and other reef-builders contributing to a large portion of the structure's volume. This density of skeletal material allows the structure to withstand sea currents and stand freely.
Reef knolls can be divided into bioherms and biostromes. A bioherm is a landform of organic sedimentary rock enclosed or surrounded by rock of different origin.[2] A biostrome is a distinctly bedded or broadly lenticular sedimentary rock landform.[3]Krumbein additionally used these terms to distinguish different shapes of stromatolites: "Distinctly bedded, widely extensive, blanketlike build-ups are biostromes. Nodular, biscuit-like, dome-shaped or columnar stromatolites are also referred to as bioherms".[4]
These structures are often most clearly seen where the surrounding rocks are much softer and so can be preferentially eroded. All the Derbyshire examples quoted lie at the edge of the limestone areas; Chrome and Parkhouse lie at the divide between limestone and the much softer shale.
Examples in the Yorkshire Dales[5] lie on the downthrow side (north) of the Mid Craven Fault. There is one set located around Thorpe (Skelterton, Butter Haw, Stebden, Elbolton, Thorpe Kail, Myra Bank and Hartlington Kail); one set located around Malham (Burns Hill, Cawden, and Wedber); and a set around Settle (High Hill and Scaleber).
It was once proposed that in Lancashire, reef knolls could be seen between the villages of Worston and Downham near Clitheroe.[6][7][8]
Thorpe Kail, Stebden and Elbolton hills, against Thorpe Fell, from north east, near Hebden
^Krumbein, W.E., Brehm, U., Gerdes, G., Gorbushina, A.A., Levit, G. and Palinska, K.A. (2003). "Biofilm, Biodictyon, Biomat Microbialites, Oolites, Stromatolites, Geophysiology, Global Mechanism, Parahistology". In Krumbein, W.E.; Paterson, D.M.; Zavarzin, G.A. (eds.). (PDF). Kluwer Academic. pp. 1–28. ISBN978-1-4020-1597-7. Archived from the original (PDF) on January 6, 2007. Retrieved 2008-07-09.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Ramsbottom, W.H.C.; R.F.Goosens; E.G. Smith; M.A. Calver (1974). D.H. Rayner and J.E. Hemingway (ed.). The Geology and Mineral Resources of Yorkshire. Yorkshire Geological Society. pp. 61–64.
^. Archived from the original on 2 July 2007. Retrieved 13 September 2015.
^Miller, J.; Grayson, R.F. (1972). "Origin and structure of Lower Viséan "reef"limestones near Clitheroe, Lancashire". Proceedings of the Yorkshire Geological Society. 38 (4): 607–638. doi:10.1144/pygs.38.4.607.
British Geological Survey website, on Chrome, Parkhouse and Derbyshire atolls
August 18, 2023
reef, knoll, reef, knoll, landform, that, comprises, immense, pile, calcareous, material, that, previously, accumulated, ancient, floor, geological, remnants, reefs, other, organic, concentrations, calcareous, organisms, often, fossil, rich, with, prehistoric,. A reef knoll is a landform that comprises an immense pile of calcareous material that had previously accumulated on an ancient sea floor 1 Reef knolls are geological remnants of reefs and other organic concentrations of calcareous organisms Reef knolls are often fossil rich with prehistoric corals sponges calcareous algae and other reef builders contributing to a large portion of the structure s volume This density of skeletal material allows the structure to withstand sea currents and stand freely Reef knolls can be divided into bioherms and biostromes A bioherm is a landform of organic sedimentary rock enclosed or surrounded by rock of different origin 2 A biostrome is a distinctly bedded or broadly lenticular sedimentary rock landform 3 Krumbein additionally used these terms to distinguish different shapes of stromatolites Distinctly bedded widely extensive blanketlike build ups are biostromes Nodular biscuit like dome shaped or columnar stromatolites are also referred to as bioherms 4 Contents 1 England 2 See also 3 References 4 External linksEngland EditExamples on the Derbyshire Staffordshire border include Thorpe Cloud and Bunster Hill in southern Dovedale and also Chrome Hill and Parkhouse Hill at the northern end These structures are often most clearly seen where the surrounding rocks are much softer and so can be preferentially eroded All the Derbyshire examples quoted lie at the edge of the limestone areas Chrome and Parkhouse lie at the divide between limestone and the much softer shale Examples in the Yorkshire Dales 5 lie on the downthrow side north of the Mid Craven Fault There is one set located around Thorpe Skelterton Butter Haw Stebden Elbolton Thorpe Kail Myra Bank and Hartlington Kail one set located around Malham Burns Hill Cawden and Wedber and a set around Settle High Hill and Scaleber It was once proposed that in Lancashire reef knolls could be seen between the villages of Worston and Downham near Clitheroe 6 7 8 Thorpe Kail Stebden and Elbolton hills against Thorpe Fell from north east near HebdenSee also EditWaulsortian mudmoundReferences Edit Cope F Wolverson 1976 Geology Explained in the Peak District David amp Charles Definition of BIOHERM Definition of BIOSTROME Krumbein W E Brehm U Gerdes G Gorbushina A A Levit G and Palinska K A 2003 Biofilm Biodictyon Biomat Microbialites Oolites Stromatolites Geophysiology Global Mechanism Parahistology In Krumbein W E Paterson D M Zavarzin G A eds Fossil and Recent Biofilms A Natural History of Life on Earth PDF Kluwer Academic pp 1 28 ISBN 978 1 4020 1597 7 Archived from the original PDF on January 6 2007 Retrieved 2008 07 09 a href Template Cite book html title Template Cite book cite book a CS1 maint multiple names authors list link Ramsbottom W H C R F Goosens E G Smith M A Calver 1974 D H Rayner and J E Hemingway ed The Geology and Mineral Resources of Yorkshire Yorkshire Geological Society pp 61 64 English Nature Lancashire Geology Archived from the original on 2 July 2007 Retrieved 13 September 2015 Miller J Grayson R F 1972 Origin and structure of Lower Visean reef limestones near Clitheroe Lancashire Proceedings of the Yorkshire Geological Society 38 4 607 638 doi 10 1144 pygs 38 4 607 Kabrna Paul Clitheroe Reef Belt Craven Basin Waulsortian Mudmounds Craven amp Pendle Geological Society Retrieved 8 October 2015 External links EditBritish Geological Survey website on Chrome Parkhouse and Derbyshire atolls Retrieved from https en wikipedia org w index php title Reef knoll amp oldid 1169375049, wikipedia, wiki, book, books, library,
