Dunham classification
（重定向自Packstone）
![Grainstone in the Dunham Classification (Brassfield Formation near Fairborn, Ohio). Grains are crinoid fragments.](/Images/godic/202502/01/BrassfieldEncrinite0421124820.jpg")
![Grainstone rich in peloids and shell fragments; calcite cement; Upper Carboniferous of Nevada.](/Images/godic/202502/01/PeloidsCarboniferousNV4820.jpg")
![](/Images/godic/202502/01/Micrite4820.jpg")
![](/Images/godic/202502/01/Oomicrite4820.jpg")
The Dunham classification system for carbonate sedimentary rocks was devised by Robert J. Dunham in 1962, and refined by Embry and Klovan in 1971 to include sediments that were organically bound during deposition.