sediments and sedimentary rocks
DESCRIPTION
Sediments and Sedimentary Rocks. Sediments and Sedimentary Rocks. And. Pressure. Cementation. Erosion. Sedimentary Rocks. Sediment. Erosion. Heat. Erosion. Pressure. Heat and Pressure. Igneous Rocks. Metamorphic Rocks. Cooling. Heat. Magma. Sediments ( soft ) - PowerPoint PPT PresentationTRANSCRIPT
Sedimentsand
Sedimentary Rocks
Sediments and Sedimentary Rocks
SedimentaryRocks
IgneousRocks
MetamorphicRocks
Magma
Sediment
Pressure And Cementation
Erosion
Erosion
Heat and Pressure
CoolingHeat
Heat
Pressure 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-nonclastic
Types of Sediments
Clastic
Nonclastic
1. Biogenic
2. Chemical
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
•Sphericity
•Sorting
Clastic Sediment Size
Clastic Texture
Roundness – the shape of sediment grains.
Related to the distance a sediment has been transported.
Sphericity - how close to a spherical shape a grain is or will be.
Roundness / Sphericity of Sediments
Size
Rounding
Sphericity
Sorting
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.
Sorting of Sediments
Sorting - a function of transported
1. Water
2. Wind
3. Glaciers
Texture and Transport Distance
In general, as transport distance increases, rounding and sorting increase.
Examples: Breccia – cemented close to sourceConglomerate – transported thencemented
Sorting by Water
Graded Beds
Fining up
Graded Beds
Sorting by Wind
Cross Bedding – water or wind
Sorting by Glaciers
Clast Size / Rock Name Relationship
Large Clasts Small Clasts
Breccia - Formed at the source
Conglomerate – Formed near the source
Sandstone – Down stream to just off shore
Stream Deposit
Tidal Flat Deposit
Off-Shore Environments
StrataStratumStratigraphyStratigraphic
- relating to layered sedimentary rocks
Bedding – Layering or stratification in sedimentary rock
2. Biogenic – composed of remains of plants or animals.
Types of Sediments
Biogenic Sediments
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
Coral (carbonate)
Foramanifera
Diatoms
3. Chemical – formed by minerals precipitating from solution.
Inorganic process, no biological activity involved.
Types of Sediments
Bonneville Salt Flats
Chemical Sediments
1. Terestrial - Evaporites: Gypsum - CaSO4 . H2O Anhydrite - CaSO4 Halite - NaCl
2. Marine - Carbonates - CaCO3 (Whitings)
Clastic Rock – composed of fragments of preexisting rocks.
Nonclastic Rock – composed of chemical precipitates or biogenic matter.
Sedimentary Rocks
Ripple Marks
Mud Cracks
Burrows
Depositional Environments
Where sedimentary rock live!