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!