Changes

==History==

==History==

Various classification systems had been proposed for both academia and industry purposes:

Various classification systems had been proposed for both academia and industry purposes:

• Wentworth (1922) [a]

* Wentworth (1922) [a]

• Bramkamp & Powers (1958)

* Bramkamp & Powers (1958)

• Folk (1959,1962)

* Folk (1959,1962)

• Dunham (1962)

* Dunham (1962)

• Leignton & Pendexter (1962)

* Leignton & Pendexter (1962)

• Todd (1966)

* Todd (1966)

• Embry & Klovan (1971)

* Embry & Klovan (1971)

• Wright (1992)

* Wright (1992)

• Hallsworth & Knox (1999)

* Hallsworth & Knox (1999)

Among all of the attempts, Folk (1959, 1962) and Dunham (1962) extended by Embry & Klovan (1971) classifications were widely accepted.  

Among all of the attempts, Folk (1959, 1962) and Dunham (1962) extended by Embry & Klovan (1971) classifications were widely accepted.  

===Folk’s Criteria===

===Folk’s Criteria===

Folk classification system is based on three basic components of limestone:  

Folk classification system is based on three basic components of limestone:  

• Allochems (sediment grains): framework component of the rock. There are four major types of allochems in Folk system: intraclasts, oolites, fossils, and pellets.  

* Allochems (sediment grains): framework component of the rock. There are four major types of allochems in Folk system: intraclasts, oolites, fossils, and pellets.  

• Microcrystalline lime mud: matrix component of the rock < 4 μm in size.  

* Microcrystalline lime mud: matrix component of the rock < 4 μm in size.  

• Sparry calcite cement (sparite): pore-filling component precipitated during deposition.  

* Sparry calcite cement (sparite): pore-filling component precipitated during deposition.  

===Major Families Classification===

===Major Families Classification===

Based on the relative proportions of matrix and pore-filling components surrounding the framework component, Folk defined three major families plotted on a triangular diagram (Figure 1).   

Based on the relative proportions of matrix and pore-filling components surrounding the framework component, Folk defined three major families plotted on a triangular diagram (Figure 1).   

• Family I: sparry allochemical limestone that consists of allochems cemented by sparry calcite cement.[b]

* Family I: sparry allochemical limestone that consists of allochems cemented by sparry calcite cement.[b]

• Family II: microcrystalline allochemical limestone that consists of > 10% allochems within lime mud.  

* Family II: microcrystalline allochemical limestone that consists of > 10% allochems within lime mud.  

• Family III: microcrystalline limestone (micrite) that consists of 0-10% allochems within mud. In other words, composes almost entirely of mud.[c]  

* Family III: microcrystalline limestone (micrite) that consists of 0-10% allochems within mud. In other words, composes almost entirely of mud.[c]  

 

Folk defined a fourth family based on in situ organic growth deposits: biolithite.[d]

Folk defined a fourth family based on in situ organic growth deposits: biolithite.[d]

[[File:GeoWikiWriteOff2021-Abdulwahab-Figure1.png|thumbnail|Folk classification system for carbonate rock (1959) [1]]]

[[File:GeoWikiWriteOff2021-Abdulwahab-Figure1.png|thumbnail|Folk classification system for carbonate rock (1959) [1]]]