Post on 16-Dec-2015
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Sediments and Sedimentary Rocks
SedimentaryRocks
IgneousRocks
MetamorphicRocks
Magma
Sediment
Pressure And Cementation
Weathering/Erosion
Weathering/Erosion
Heat and Pressure
CoolingHeat
Heat
Pressure W
eath
erin
g E
rosi
on
Sediments (soft)Material (such as gravel, sand, mud, and lime) that is transported by wind, water, ice, or gravity;Material that is precipitated from solution; Deposits of organic origin (such as coal and coral reefs).
Sedimentary Rock (hard)Rock formed by the accumulation and consolidation of sediment.
Sediments - unconsolidated particles created by
1. The weathering of rock
2. The secretions of organisms or decomposition of organic matter
3. Chemical precipitation
Sedimentary Rocks
Composed of lithified sediments- by compaction- by cementation
Two (Textures) clastic (detrital) non-clastic
1. Clastic
2. Non-clastic
* Biochemical
* Chemical
1. Phaneritic
2 .Aphanitic
* Glassy
* Vesicular
Igneous Rocks Sedimentary Rocks
1. Clastic – broken fragments of rock produced by weathering.
Range in size from largest boulder to smallest clay particle.
Classified according to size.
Found everywhere on the Earth.
Types of Sediments
Clastic TextureTexture - Size, shape, and distribution of particles that collectively make up a rock
•Size
•Rounding
•Sorting
Clastic Texture
Roundness – the shape of sediment grains.
Related to the distance a sediment has been transported.
Clastic Sediments Sorting
Sorting – separation of sediments by grain size and density.
Poorly sorted – sediment with a wide range of grain sizes.
Well sorted – sediment with a small range of grain sizes.
Texture and Transport Distance
In general, as transport distance increases, rounding and sorting increase.
Examples: Breccia – cemented close to sourceConglomerate – transported thencemented
Source Downstream Beach OffshoreBasinBr
eccia
Cong
lom
erat
eAr
kose
Sand
ston
e
Swamp
Lithi
c San
dsto
ne
Quartz
Sand
ston
e
Reef
Silts
tone
Shal
e
Halite, Gypsum, Chert(Evaporites)
(Playa Lake)
Coal
Limestone
Clastic Sedimentary RocksSmaller….Rounder…..Better Sorted
Nonclastic Sedimentary Rocks
Coquina
Depositional Environments of Sedimentary Rocks
Transport by WaterSaltation – particles move downstream in
short jumps.
Bed load – material transported by saltation
Suspended load – material carried in water for long distances
Biochemical Sediments (non-clastic)
Corals - Large components of reefs.
Bivalves, Gastropods, Foraminifers - Whole or partial skeletons form sand and gravels.
Aglae, Crinoids, Echinoderms, Bryozoans - disintergrate to form some sand particles and lime mud.
Diatoms, Radiolaria – Bedded chert SiO2
Terestrial Sediments - mainly plant matter
Marine Sediments - mainly carbonates
3. Chemical (non-clastic)
– formed by minerals precipitating from solution.
- Inorganic process, no biological activity involved.
Types of Sediments
Chemical Sediments (non-clastic)
1. Terestrial - Evaporites: Gypsum - CaSO4 . H2O Anhydrite - CaSO4 Halite - NaCl
2. Marine - Carbonates - CaCO3 (Whitings)
Clastic Rock – composed of fragments of preexisting rocks.
Non-clastic Rock – composed of chemical precipitates or biogenic matter.
Sedimentary Rocks