Reef knoll

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]

  1. ^ Cope, F. Wolverson (1976) Geology Explained in the Peak District, David & Charles
  2. ^ "Definition of BIOHERM".
  3. ^ "Definition of BIOSTROME".
  4. ^ 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.{{cite book}}: CS1 maint: multiple names: authors list (link)