Changes

Jump to navigation Jump to search
no edit summary
Line 72: Line 72:     
==Dunham Classification==  
 
==Dunham Classification==  
Dunham’s Criteria
+
===Dunham’s Criteria===
 
Dunham classification system is based on three depositional textural features:
 
Dunham classification system is based on three depositional textural features:
 
• The presence or absence of lime mud.
 
• The presence or absence of lime mud.
 
• The abundance of grains.[j]  
 
• The abundance of grains.[j]  
 
• the presence of in situ organic binding   
 
• the presence of in situ organic binding   
Dunham (1962) Classification
+
 
 +
===Dunham (1962) Classification===
 
The original Dunham classification system composes of six classes summarized in Figure 12:  
 
The original Dunham classification system composes of six classes summarized in Figure 12:  
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure12.png|thumbnail|Fig. 12 Dunham classification system for carbonate rock (1962) [12]]] 
Fig. 12 Dunham classification system for carbonate rock (1962) [12]
+
 
 
• Mudstone: a mud-supported rock with < 10% grains, and original components are not organically bounded together during deposition (Figure 13).   
 
• Mudstone: a mud-supported rock with < 10% grains, and original components are not organically bounded together during deposition (Figure 13).   
 
• Wackestone: a mud-supported rock with > 10% grains, and original components are not organically bounded together during deposition (Figure 14).   
 
• Wackestone: a mud-supported rock with > 10% grains, and original components are not organically bounded together during deposition (Figure 14).   
Line 87: Line 88:  
• Boundstone: a rock with the presence of organic components bounded together during deposition.  
 
• Boundstone: a rock with the presence of organic components bounded together during deposition.  
 
• Crystalline: a rock with unrecognizable depositional texture (Figure 17).   
 
• Crystalline: a rock with unrecognizable depositional texture (Figure 17).   
Extended Dunham Classification (1971)
+
 
 +
===Extended Dunham Classification (1971)===
 
Embry and Klovan expanded the original Dunham classification due to the lack of:
 
Embry and Klovan expanded the original Dunham classification due to the lack of:
 
• Classifying coarse-grained (>2mm) rocks.  
 
• Classifying coarse-grained (>2mm) rocks.  
 
• Subdividing organically-bound rocks (boundstones).  
 
• Subdividing organically-bound rocks (boundstones).  
 
The extended Dunham Classification is shown in Figure 18.  
 
The extended Dunham Classification is shown in Figure 18.  
   
+
  [[File:GeoWikiWriteOff2021-Abdulwahab-Figure18.png|thumbnail|Fig. 18 Extended Dunham classification (1971) [18]]] 
Fig. 18 Extended Dunham classification (1971) [18]
+
 
Coarse-Grained Rocks Classification
+
====Coarse-Grained Rocks Classification====
 
• Floatstone: a matrix-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition (Figure 19).   
 
• Floatstone: a matrix-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition (Figure 19).   
 
• Rudstone: a grain-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition (Figure 20).
 
• Rudstone: a grain-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition (Figure 20).
Organically-Bound Rocks Subdivision
+
====Organically-Bound Rocks Subdivision====
 
• Bafflestone: in situ organically-bound rock in which organisms act as baffles (Figure 21).
 
• Bafflestone: in situ organically-bound rock in which organisms act as baffles (Figure 21).
 
• Bindstone: in situ organically-bound rock in which organisms encrust and bind (Figure 22).
 
• Bindstone: in situ organically-bound rock in which organisms encrust and bind (Figure 22).
 
• Framestone: in situ organically-bound rock in which organisms build a rigid framework (Figure 23).[k]
 
• Framestone: in situ organically-bound rock in which organisms build a rigid framework (Figure 23).[k]
Depositional Energy Setting and Reservoir Quality Indications
+
 
 +
===Depositional Energy Setting and Reservoir Quality Indications===
 
Generally, mud-supported rocks: mudstones and wackestones are formed in low-energy settings and show poor reservoir quality.
 
Generally, mud-supported rocks: mudstones and wackestones are formed in low-energy settings and show poor reservoir quality.
 
Grain-supported rocks: packstones and grainstones are formed in high-energy settings and show good reservoir quality. Grainstones is considered to be the best reservoir quality rock, especially if it is partially cemented. It is usually characterized by good porosity & permeability, and good sorting.  
 
Grain-supported rocks: packstones and grainstones are formed in high-energy settings and show good reservoir quality. Grainstones is considered to be the best reservoir quality rock, especially if it is partially cemented. It is usually characterized by good porosity & permeability, and good sorting.  
Line 107: Line 110:  
Rudstones and framestones are usually formed in high-energy settings (above wave base).  
 
Rudstones and framestones are usually formed in high-energy settings (above wave base).  
 
Organically-bound rocks show good reservoir quality if the skeletal growth is interconnected.  
 
Organically-bound rocks show good reservoir quality if the skeletal growth is interconnected.  
Gallery
     −
+
==Gallery==
Fig. 3 Intrasparite [3]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure3.png|thumbnail|Fig. 3 Intrasparite [3]]]  
   
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure4.png|thumbnail|Fig. 4 Oosparite [4]]]  
Fig. 4 Oosparite [4]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure5.png|thumbnail|Fig. 5 Biosparite [5]]]  
   
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure6.png|thumbnail|Fig. 6 Pelsparite [6]]]  
Fig. 5 Biosparite [5]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure7.png|thumbnail|Fig. 7 Intramicrite [7]]]  
   
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure8.png|thumbnail|Fig. 8 Oomicrite [8]]] 
Fig. 6 Pelsparite [6]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure9.png|thumbnail|Fig. 9 Biomicrite [9]]] 
   
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure10.png|thumbnail|Fig. 10 Pelmicrite [10]]] 
Fig. 7 Intramicrite [7]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure13.png|thumbnailFig. 13 Mudstone [13]]] 
   
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure14.png|thumbnail|Fig. 14 Wackestone [14]]]
Fig. 8 Oomicrite [8]
+
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure15.png|thumbnail|Fig. 15 [15]]]
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure16.png|thumbnail|Fig. 16 [16]]] 
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure17.png|thumbnail|Fig. 17 Crystalline rock [17] ]] 
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure19.png|thumbnail|Fig. 19 Floatstone [19]]] 
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure20.png|thumbnail|Fig. 20 Rudstone [20]]]
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure21.png|thumbnail|Fig. 21 Bafflestone [21]]]
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure22.png|thumbnail|Fig. 22 Bindstone [22]]]
 +
[[File:GeoWikiWriteOff2021-Abdulwahab-Figure23.png|thumbnail|Fig. 23 Framestone [23]]]  
   −
+
==Notes==
Fig. 9 Biomicrite [9]
+
1. ^[a] Early carbonate classification is grain-size based system: Calcilutite (grains < 63 μm), calcarenite (63 μm < grains < 2mm), calcirudite (grains > 2mm).  
  −
Fig. 10 Pelmicrite [10]
  −
  −
Fig. 13 Mudstone [13]
  −
  −
Fig. 14 Wackestone [14]
  −
  −
Fig. 15 [15]
  −
  −
Fig. 16 [16]
      +
2. ^[b] This family has restricted limits because cement by itself cannot form a rock and the supported framework component (allochems) has limited packing.
    +
3. ^[c] If the microcrystalline limestone had been disturbed either by bioturbation or soft-sediment deformation, the term “disturbed microcrystalline limestone” or “dismicrite” could be assigned. 
   −
+
4. ^[d] Examples of biolithites are: algal biolithite and coral biolithite.  
Fig. 17 Crystalline rock [17]  
  −
  −
Fig. 19 Floatstone [19]
  −
  −
Fig. 20 Rudstone [20]
  −
  −
Fig. 21 Bafflestone [21]
     −
+
5. ^[e] Naming of a subdivision is a composite of two parts. The first part refers to the name of the allochem. The second part refers to the family type. For Example, intrasparite: intra- refers to intraclasts, and –sparite refers to family I.     
Fig. 22 Bindstone [22]
  −
  −
Fig. 23 Framestone [23]
  −
   
      +
6. ^[f] Oosparites are more common than Oomicrites because the need of strong current to form these rocks.
   −
Notes
  −
1. ^[a] Early carbonate classification is grain-size based system: Calcilutite (grains < 63 μm), calcarenite (63 μm < grains < 2mm), calcirudite (grains > 2mm). 
  −
2. ^[b] This family has restricted limits because cement by itself cannot form a rock and the supported framework component (allochems) has limited packing.
  −
3. ^[c] If the microcrystalline limestone had been disturbed either by bioturbation or soft-sediment deformation, the term “disturbed microcrystalline limestone” or “dismicrite” could be assigned. 
  −
4. ^[d] Examples of biolithites are: algal biolithite and coral biolithite.
  −
5. ^[e] Naming of a subdivision is a composite of two parts. The first part refers to the name of the allochem. The second part refers to the family type. For Example, intrasparite: intra- refers to intraclasts, and –sparite refers to family I.     
  −
6. ^[f] Oosparites are more common than Oomicrites because the need of strong current to form these rocks.
   
7. ^[g] Intrasparites are more common than intramicrites because the need of strong current to transfer course rock fragments.  
 
7. ^[g] Intrasparites are more common than intramicrites because the need of strong current to transfer course rock fragments.  
 +
 
8. ^[h] Both biosparites and biomicrites are common. However, biosparites are usually more rounded and abraded because of the strong current.  
 
8. ^[h] Both biosparites and biomicrites are common. However, biosparites are usually more rounded and abraded because of the strong current.  
 +
 
9. ^[i] The subdivisions could be applied considering other types of allochems: intraclasts, oolites, and pellets.  
 
9. ^[i] The subdivisions could be applied considering other types of allochems: intraclasts, oolites, and pellets.  
 +
 
10. ^[j] The abundance of grains defines the nature of the framework. In other words, whether it is mud-supported or grain-supported.  
 
10. ^[j] The abundance of grains defines the nature of the framework. In other words, whether it is mud-supported or grain-supported.  
 +
 
11. ^[k] The term “boundstone” is retained if the organic bounding type is not recognized.   
 
11. ^[k] The term “boundstone” is retained if the organic bounding type is not recognized.   
References  
+
 
 +
==References==
 
19. ^ [1] [2] [11] Folk, R. L., 1959, Practical petrographic classification of limestones: AAPG Bulletin, v. 43, p. 1–38.
 
19. ^ [1] [2] [11] Folk, R. L., 1959, Practical petrographic classification of limestones: AAPG Bulletin, v. 43, p. 1–38.
 +
 
20. ^ [3] [4] [5] [9] Folk Classification. Wikipedia. https://en.wikipedia.org/wiki/Folk_classification#cite_ref-2
 
20. ^ [3] [4] [5] [9] Folk Classification. Wikipedia. https://en.wikipedia.org/wiki/Folk_classification#cite_ref-2
 +
 
21. ^ [6] Gregg, Jay. (December 18). Limestone Petrology. Missouri S&T. https://web.mst.edu/~greggjay/carbonate_page/lsgallery/pages/c-ACS190_10.htm
 
21. ^ [6] Gregg, Jay. (December 18). Limestone Petrology. Missouri S&T. https://web.mst.edu/~greggjay/carbonate_page/lsgallery/pages/c-ACS190_10.htm
 +
 
22. ^ [7] (2021, March 29). Microscopic Gallery. SEPM Strata. http://sepmstrata.org/microscopic_gallery_details.aspx?gid=165&pg=1&gcid=9
 
22. ^ [7] (2021, March 29). Microscopic Gallery. SEPM Strata. http://sepmstrata.org/microscopic_gallery_details.aspx?gid=165&pg=1&gcid=9
 +
 
23. ^ [8] (2021, March 29). Microscopic Gallery. SEPM Strata. http://www.sepmstrata.org/microscopic_gallery_details.aspx?gid=207&pg=3&gcid=11
 
23. ^ [8] (2021, March 29). Microscopic Gallery. SEPM Strata. http://www.sepmstrata.org/microscopic_gallery_details.aspx?gid=207&pg=3&gcid=11
 +
 
24. ^ [10] Sahraeyan, Mohammad. (2013, June). Sedimentary Basin Analysis of Sachun Formation in Southwestern Iran: Implication for Sedimentary Environments and Tectonic Setting. ResearchGate. https://www.researchgate.net/figure/Photomicrographs-showing-micrite-and-pelmicrite-in-the-argillaceous-limestone-facies-of_fig8_262337097
 
24. ^ [10] Sahraeyan, Mohammad. (2013, June). Sedimentary Basin Analysis of Sachun Formation in Southwestern Iran: Implication for Sedimentary Environments and Tectonic Setting. ResearchGate. https://www.researchgate.net/figure/Photomicrographs-showing-micrite-and-pelmicrite-in-the-argillaceous-limestone-facies-of_fig8_262337097
 +
 
25. ^ [12] [18] K. Bjørlykke (ed). Petroleum Geoscience: From Sedimentary Environments to Rock Physics, DOI 10.1007/978-3-642-34132-8_5, Ⓒ Springer-Verlag Berlin Heidelberg 2015.
 
25. ^ [12] [18] K. Bjørlykke (ed). Petroleum Geoscience: From Sedimentary Environments to Rock Physics, DOI 10.1007/978-3-642-34132-8_5, Ⓒ Springer-Verlag Berlin Heidelberg 2015.
 +
 
26. ^ [13] Mudstone. Wikipedia. https://en.wikipedia.org/wiki/Mudstone
 
26. ^ [13] Mudstone. Wikipedia. https://en.wikipedia.org/wiki/Mudstone
 +
 
27. ^ [14] Carbonate Rock Classification. Carbonateworld. https://carbonateworld.com/carbonate-atlas/carbonate-rock-classification/images/wackstone/
 
27. ^ [14] Carbonate Rock Classification. Carbonateworld. https://carbonateworld.com/carbonate-atlas/carbonate-rock-classification/images/wackstone/
 +
 
28. ^ [15] [16] F. Jerry Lucia. Estimating Permeability in Carbonates Using the Rock-Fabric Method. Bureau of Economic Geology. https://www.beg.utexas.edu/lmod/_IOL-CM07/cm07-step02a.htm
 
28. ^ [15] [16] F. Jerry Lucia. Estimating Permeability in Carbonates Using the Rock-Fabric Method. Bureau of Economic Geology. https://www.beg.utexas.edu/lmod/_IOL-CM07/cm07-step02a.htm
 +
 
29. ^ [17] Ardakani, Omid H. (2013, June). Diagenetic evolution and associated mineralization of Middle Devonian carbonates, southwestern Ontario, Canada. ResearchGate. https://www.researchgate.net/figure/Thin-section-photomicrographs-of-Middle-Devonian-rocks-A-Syntaxial-and-equant-calcite_fig3_235413575
 
29. ^ [17] Ardakani, Omid H. (2013, June). Diagenetic evolution and associated mineralization of Middle Devonian carbonates, southwestern Ontario, Canada. ResearchGate. https://www.researchgate.net/figure/Thin-section-photomicrographs-of-Middle-Devonian-rocks-A-Syntaxial-and-equant-calcite_fig3_235413575
 +
 
30. ^ [19] [20] Al-Awwad, Saad F. & pomar, Luis. (2015, May 21). Origin of the rudstone–floatstone beds in the Upper Jurassic Arab-D reservoir, Khurais Complex, Saudi Arabia. ScienceDirect. https://www.sciencedirect.com/science/article/pii/S0264817215001634
 
30. ^ [19] [20] Al-Awwad, Saad F. & pomar, Luis. (2015, May 21). Origin of the rudstone–floatstone beds in the Upper Jurassic Arab-D reservoir, Khurais Complex, Saudi Arabia. ScienceDirect. https://www.sciencedirect.com/science/article/pii/S0264817215001634
31. ^ [21] Khanaqa, Polla. (2018, December). Stratigraphy and Facies Analysis of the Govanda Formation from Western Zagros, Kurdistan Region, Northeastern Iraq. ResearchGate. https://www.researchgate.net/figure/a-Photo-of-the-Coral-Bafflestone-of-Barda-Balaka-Outcrop-Between-the-stems-Fine_fig12_330094098
+
 
 +
31. ^ [21] Khanaqa, Polla. (2018, December). Stratigraphy and Facies Analysis of the Govanda Formation from Western Zagros, Kurdistan Region, Northeastern Iraq. ResearchGate. https://www.researchgate.net/figure/a-Photo-of-the-Coral-
 +
Bafflestone-of-Barda-Balaka-Outcrop-Between-the-stems-Fine_fig12_330094098
 +
 
 
32. ^ [22] Bindstone. Bureau of Economic Geology. https://www.beg.utexas.edu/lmod/_IOL-CM02/st21-ancbindstone.htm
 
32. ^ [22] Bindstone. Bureau of Economic Geology. https://www.beg.utexas.edu/lmod/_IOL-CM02/st21-ancbindstone.htm
 +
 
33. ^ [23] Camuera, Jon. (2014, July). Origin and palaeo-environmental significance of the Berrazales carbonate spring deposit, North of Gran Canaria Island, Spain. ResearchGate. https://www.researchgate.net/figure/A-Framestone-facies-composed-of-parallel-plant-moulds-coated-with-calcite-B-Plant_fig4_283498781
 
33. ^ [23] Camuera, Jon. (2014, July). Origin and palaeo-environmental significance of the Berrazales carbonate spring deposit, North of Gran Canaria Island, Spain. ResearchGate. https://www.researchgate.net/figure/A-Framestone-facies-composed-of-parallel-plant-moulds-coated-with-calcite-B-Plant_fig4_283498781
 
    
 
    
 +
==Sources==
 +
1. Lokier, Stephen W.; Al Junaibi, Mariam (2016). "The petrographic description of carbonate facies: are we all speaking the same language?". Sedimentology. 63 (7): 1843–1885. doi:10.1111/sed.12293
   −
Sources
  −
1. Lokier, Stephen W.; Al Junaibi, Mariam (2016). "The petrographic description of carbonate facies: are we all speaking the same language?". Sedimentology. 63 (7): 1843–1885. doi:10.1111/sed.12293
   
2. Folk, R. L., 1959, Practical petrographic classification of limestones: AAPG Bulletin, v. 43, p. 1–38.
 
2. Folk, R. L., 1959, Practical petrographic classification of limestones: AAPG Bulletin, v. 43, p. 1–38.
 +
 
3. Folk, R.L., 1962, Spectral subdivision of limestone types, in Ham, W.E., ed., Classification of carbonate Rocks-A Symposium: American Association of Petroleum Geologists Memoir 1, p. 62-84.
 
3. Folk, R.L., 1962, Spectral subdivision of limestone types, in Ham, W.E., ed., Classification of carbonate Rocks-A Symposium: American Association of Petroleum Geologists Memoir 1, p. 62-84.
 +
 
4. Dunham, R. J., 1962, Classification of carbonate rocks according to depositional texture, in Ham, W. E., ed., Classification of Carbonate Rocks: AAPG Memoir 1, p. 108–121.
 
4. Dunham, R. J., 1962, Classification of carbonate rocks according to depositional texture, in Ham, W. E., ed., Classification of Carbonate Rocks: AAPG Memoir 1, p. 108–121.
 +
 
5. Embry, Ashton F.; Klovan, J. Edward (1971-12-01). "A late Devonian reef tract on northeastern Banks Island, N.W.T". Bulletin of Canadian Petroleum Geology. 19 (4): 730–781.
 
5. Embry, Ashton F.; Klovan, J. Edward (1971-12-01). "A late Devonian reef tract on northeastern Banks Island, N.W.T". Bulletin of Canadian Petroleum Geology. 19 (4): 730–781.
 +
 
6. K. Bjørlykke (ed). Petroleum Geoscience: From Sedimentary Environments to Rock Physics, DOI 10.1007/978-3-642-34132-8_5, Ⓒ Springer-Verlag Berlin Heidelberg 2015.
 
6. K. Bjørlykke (ed). Petroleum Geoscience: From Sedimentary Environments to Rock Physics, DOI 10.1007/978-3-642-34132-8_5, Ⓒ Springer-Verlag Berlin Heidelberg 2015.

Navigation menu