1. Sedimentary rocks - lithification
Sedimentary rocks are formed through lithification. Shown in (A) are unconsolidated particles. When subjected to lithification, they become sedimentary rock shown in (B).

2. Detrital Sedimentary rocks Chemical
Classification of sedimentary rocks
Sedimentary rocks
Detrital
Chemical
Sedimentary rocks are primarily grouped into two main types according to how they were formed. Detrital sedimentary rocks were formed through physical means (pressure) while chemical sedimentary rocks were chemically formed.

3. Detrital sedimentary rocks – fissility
Fissility refers to the property of detrital sedimentary rocks that enables them to be split into thin sheets.
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4. Detrital sedimentary rocks – sorting
The particles that make up detrital sedimentary rocks undergo sorting. Rocks upstream tend to be angular and poorly sorted while rocks downstream are rounded and well sorted.
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5. Very fine (less than 1/256 mm)
Classification of sedimentary rocks
Sedimentary rocks
Detrital
Coarse (>2mm)
Medium (1/16 to 2mm)
Fine (1/16 to 1/256mm)
Very fine (less than 1/256 mm)
Chemical
Detrital rocks are classified according to the size of their particles.
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6. Classification of sedimentary rocks
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Coarse (>2mm)
Gravel
Conglomerate (Rounded particles)
Breccia (Angular particles)
Medium (1/16 to 2mm)
Sand
Quartz sandstone (little feldspar)
Arkose (abundant feldspar)
Fine (1/16 to 1/256mm)
Mud
Siltstone
Very fine (less than 1/256 mm)
Shale

7. Classification of sedimentary rocks
Detrital
Chemical
Calcite, CaCO3
Quartz,
SiO2
Gypsum, CaSO4
Halite, NaCl
Plant fragments
Chemical sedimentary rocks are classified according to their predominant component.
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8. Classification of sedimentary rocks
Calcite, CaCO3
Inorganic limestone
Nonclastic: fine to coarse crystalline
Crystalline limestone
Travertine
Biochemical limestone
Clastic: visible shell fragments loosely cemented
Coquina
Clastic: various size coral fragments cemented with calcite
Fossiliferous limestone
Clastic: Microscopic shells and clay
Chalk
Calcite rocks are grouped according to how they were formed (inorganic or via biochemical processes). Inorganic limestones are described as nonclastic which means that they are not made of particles. Biochemical limestones on the other hand, are made of particles and so are clastic.
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9. Classification of sedimentary rocks
Quartz, SiO2
Nonclastic: very fine crystalline
Chert
(light colored)
Flint
(dark colored)
Gypsum, CaSO4
Nonclastic: fine to coarse crystalline
Rock gypsum
Halite, NaCl
Nonclastic: Fine to coarse crystalline
Rock Salt
Plant fragments
Nonclastic: Fine-grained organic matter
Bituminous coal
Sedimentary rocks, environments and structures

10. Conglomerate (detrital, gravel, rounded particles)
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11. Breccia (detrital, gravel, angular particles)
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12. Quartz sandstone (detrital, sand, mostly quartz)
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13. Arkose (detrital, sand, abundant felspar)
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14. Siltstone (detrital, fine-sized particles, mud)
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15. Shale (detrital, very fine particles, mud, may contain fossils)
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16. Crystalline limestone (chemical, nonclastic, fine to coarse crystalline)
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17. Travertine (chemical, nonclastic, fine to coarse, cavewaters)
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18. Coquina (chemical, clastic, shell fragments, loosely cemented)
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19. Fossiliferous limestone (chemical, clastic, coral fragments, calcite cement)
Fossiliferous limestone are made of coral reef fragments cemented strongly by calcite.
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20. Chalk (chemical, clastic, microscopic shells and clay)
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21. Chert (chemical, nonclastic, quartz, light colored)
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22. Flint (chemical, nonclastic, quartz, dark colored)
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23. Rock gypsum (chemical, nonclastic, CaSO4)
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24. Rock salt (chemical, nonclastic, NaCl, evaporite)
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25. Rock salt (chemical, nonclastic, NaCl, evaporite)
Halites are known as evaporites because they are formed through the evaporation of water from chemically-concentrated solutions.
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26. Coal (chemical, nonclastic, plant remains)
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Coal exists in many forms. The first form is peat which is still impure and damp (and hence contains a low amount of stored energy). Peat that has undergone burial and pressure becomes lignite or bituminous coal (which is now more concentrated and hence has more energy). Anthracite is the metamorphic form of coal which is formed after intense pressure and heat.

27. Peat
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28. Lignite or bituminous coal
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29. Bituminous coal can be metamorphosed into anthracite
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