1. Lithification/ Diagenesis
From pile of sand to solid rock
Loose sediment, like that shown in (A) may someday become a rock like the one in (B) if compacted and cement fills the spaces between clasts

2. Diagenesis: How Sediment Becomes Rock
Diagenesis: collective term for all the chemical, physical, and biological changes that affect sediment as it goes from deposition through lithification
Sand or other
sediment, grains
separate
After compaction,
grains crushed
together and
interlocked
A term often applied to sedimentary rocks is Diagenesis, which is the collective term for all the chemical, physical, and biological changes that affect sediment as it goes from deposition through lithification.
And I will talk about each of these changes more.
After cementation,
mineral crystals
cemented grains
together

3. Diagenesis: Processes Involved
1. Compaction - packing together of sediment grains
When sediment has been deposited we start with a pile of fragments that enclose a great deal of pore space
As sediment continues to accumulate the sediment undergoes compaction: the geometric arrangement of grains changes so that pore space is reduced
Diagenesis/Lithification is the conversion of sediment into rock, and as I said this processes results from a number of processes:
Compaction involves packing together of sediment grains through burial, leading to a reduction in sediment volume by up to 40%. Reduction of volume generally results from the pressure or weight of overlying sediments.
In principle, compacted sediment can sit there forever
without becoming a rock - normally this doesn't happen

4. Diagenesis: Processes Involved
2. Desiccation – loss of water from sediment pore spaces
2. Desiccation involves the loss of water from sediment pore spaces, typically resulting from compaction but also from evaporation in air.
Desiccation cracks

5. ie. Desiccation and Compaction of Shale

6. Diagenesis: Processes Involved
3. Cementation – ions precipitate out in the pore spaces to form a cement that binds clasts together
                                                            
3. Cementation As groundwater moves through the pore space, it brings with it ions in solution. Often, these ions precipitate out in the pore space to form a cement that binds the clasts together. This cement provides mechanical cohesiveness and gives us our rock.
- Model sandstone formation begins with sedimentation (left), as grains of different sizes settle under the action of gravity
- Adding the pressure of overburden causes compaction (center)
- Cementation (right) is one of the final processes that turns sediment into rock

7. ie. Compaction and Cementation of Sand

8. Clastic Sedimentary Rocks
Breccia
Conglomerate
The four basic classes of clastic sedimentary rocks are:
- Breccia/Conglomerate, a lithified gravel.
- Sandstone, consisting mainly of sand grains.
- Siltstone, composed mainly of silt-size mineral fragments, commonly quartz and feldspar.
- Mudstone, still-finer grain size.
Shale
Sandstone

9. Breccia Angular fragments Breccia
Coarse-grained sedimentary rock.  Cemented angular gravel in a matrix of fine-grained material.

10. Conglomerate Conglomerate
Coarse-grained sedimentary rock.  Cemented rounded gravel in a matrix of fine-grained material.
Uses: conglomerate is used in the construction industry
Rounded particles & dissimilar lithologies

11. Quartz Sandstone - > 90% qtz
Sandstone – there are different types of sandstone. They are all a medium-grained sedimentary rock with cemented sand-sized material. One example is quartz sandstone that has greater than 90% quartz grains. It is almost pure quartz.
Uses: Sandstone is used for flagstone to line your walkway or patio. It is also an important building stone.
Quartz Sandstone - > 90% qtz

12. Mudstone Shale – fissile (layered)
Mudstone: Fine-grained sedimentary rock.  Cemented clay- (2/3) and silt- (1/3) sized material.
Mudrocks comprise about 40% of all detrital sedimentary rocks, and are deposited in low-energy environments. They are subdivided into: Mudstones, which may be blocky or massive in appearance, are composed of a mixture of silt- and clay-sized particles (< mm) of including clay, quartz, feldspar, calcite, and dolomite. Claystones are massive and composed mostly of clay (smooth), or Shales, the most abundant detrital rock, they are similar to a mudstones or claystones except that the rock breaks into layers parallel to the bedding (fissile).
Claystone –
not fissile (not layered)

13. Non-Clastic Sedimentary Rock
Organic sediments
Sediment precipitates from solution in water originating from chemical and organic processes
These chemical precipitants settle to the bottom of a body of water. When first deposited, these sediments are loose and non-structured. In time, they are slowly hardened by compaction, cementation, and re-crystallization

14. Non-Clastic Sedimentary Rock
Classified based on composition:
Siliceous Rocks
Carbonates
Evaporites

15. Non-Clastic Sediments: Siliceous rocks
Siliceous rocks - The siliceous rocks are those which are dominated by silica (SiO2)
Siliceous rocks - The siliceous rocks are those which are dominated by silica (SiO2), therefore, very fine grained. They commonly form from silica-secreting organisms such as diatoms, radiolarians, or some types of sponges. A couple of examples include diatomite - looks like chalk, but does not fizz in acid. Made of microscopic planktonic organisms called diatoms. May also resemble kaolinite, but is much lower in density and more porous. Another example is chert, which is usually massive and hard, microcrystalline quartz. Varies in color. Does not fizz in acid.
Chert - Palaeoindian projectile points
Chert from Washademoak Lake, NB

16. Non-Clastic Sediments: Carbonates
Carbonates - The carbonate sedimentary rocks are formed through both chemical and biochemical processes
Example: Limestone
Carbonates - The carbonate sedimentary rocks are formed through both chemical and biochemical processes. They include the limestones (many types) and dolostones. Some carbonate rock names: Micrite (microcrystalline limestone) - very fine-grained; may be light gray or tan to nearly black in colour. Made of lime mud. Oolitic limestone (look for the sand-sized oolites). Fossiliferous limestone (look for various types of fossils in a limestone matrix). Coquina (fossil hash cemented together; may resemble granola), and Chalk (made of microscopic planktonic organisms; fizzes readily in acid).
Chalk cliffs - Dover, England

17. Non-Clastic Sediments: Evaporites
Evaporites form from the evaporation of water (usually sea water or lake water)
Example: Rock salt (halite)
Evaporites - The evaporites form from the evaporation of water (usually seawater). The most important salts that precipitate from seawater are halite (rock salt) and gypsum. Much of the common table salt we use daily and the gypsum used for plaster and construction materials are recovered from marine evaporate deposits.
Rock salt forms as a result of
changing physical conditions
(increasing temperature), where
minerals dissolved in seawater are
precipitated when the water
evaporates
Bonneville Salt Flats of the Great Salt Lake, Utah.

18. Non-Clastic Sedimentary Rocks
Oolitic Limestone
Fossiliferous Limestone
There are a number of basic non-clastic (chemical) sedimentary rocks.
Dolostone
Chalk

19. Non-Clastic Sedimentary Rocks Fossil Fuels Deposits
Found in areas of sedimentary rock formation
Basically, plant and animal remains were deposited in swamp and mud areas.
Result: Poor oxygen quality, hence they did not decay.
Overtime, they accumulated and then sands, silts and clay buried them
As lithification of the sediments took place, the organic remains beneath turned to valuable fossil fuels

20. Fossil Fuel Deposits: Example
Coal – made of organic matter which is the end product of large amounts of plant material buried for millions of years
Coal: is made of organic matter which is the end product of large amounts of plant material, buried for millions of years. Close examination of coal reveals plant structures such as leaves, bark, and wood that have been chemically altered but are sometimes still identifiable. Coal is a major energy resource. Its role as a fuel and some of the problems associated with burning coal are still under study.
Coal bed, Trinidad

21. Fossil Fuel Deposits: Example
Natural Gas and Oil Deposits
Drops of oil were scattered throughout source rocks
As source rock was squeezed, this oil becomes trapped in reservoirs / traps
These reservoirs make this an economic goldmine
Common characteristics for reservoir / trap
Source rock can be squeezed
Reservoir rock is porous and permeable
Cap rock is impermeable
Groundwater pushes the lighter gas and oil to the top
When a trap is tapped, an extreme amount of pressure is released
Think oil well

22. Fossil Fuel Deposits: Common Trap Types
Structural traps hold oil and gas because the earth has been bent and deformed in some way.  The trap may be a simple dome (or big bump), just a "crease" in the rocks, or it may be a more complex.
Types: Anticline trap, Fault trap, Salt dome
Stratigraphic traps are depositional in nature.  This means they are formed in place, usually by a sandstone ending up enclosed in shale.  The shale keeps the oil and gas from escaping the trap.
Types: Stratigraphic (pinch out) trap

23. Types of Traps

24. Sedimentary Rock: Non- Metallic Industrial Mineral Deposits
Products of deposition, minerals in these rocks are non-metallic
Example:
Thick salt beds are the result of the movement of ocean water into basins. As the water evaporates due to desert-like conditions, the salt is left behind
These are Evaporites