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==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]
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* Wentworth (1922) [a]
Bramkamp & Powers (1958)
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* Bramkamp & Powers (1958)
Folk (1959,1962)
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* Folk (1959,1962)
Dunham (1962)
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* Dunham (1962)
Leignton & Pendexter (1962)
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* Leignton & Pendexter (1962)
Todd (1966)
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* Todd (1966)
Embry & Klovan (1971)
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* Embry & Klovan (1971)
Wright (1992)
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* Wright (1992)
Hallsworth & Knox (1999)
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* 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.  
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===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.  
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* 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.  
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* Microcrystalline lime mud: matrix component of the rock < 4 μm in size.  
Sparry calcite cement (sparite): pore-filling component precipitated during deposition.  
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* 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]
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* 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.  
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* 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]  
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* Family III: microcrystalline limestone (micrite) that consists of 0-10% allochems within mud. In other words, composes almost entirely of mud.[c]  
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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]]]

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