sedimentary rock phe

8/9/2019 Sedimentary Rock Phe

1/19

Middle Triassic marginal marine sequence of siltstones

(below) and limestones (above), Virgin Formation,

southwestern Utah, USA

Sedimentary rocks on Mars, investigated by NASA's

Curiosity Mars rover

Sedimentary rock From Wikipedia, the free encyclopedia

Sedimentary rocks are types of rock that are

formed by the deposition of mater ial at the

Earth's surface and within bodies of water.

Sedimentation is the collective name for

processes that cause mineral and/or organic

particles (detritus) to settle and accumulate or

minerals to precipitate from a solution. Par ticles

that form a sedimentary rock by accumulating

are called sediment. Before being deposited,

sediment was formed by weathering and erosion

in a source area, and then transported to the

place of deposition by water, wind, ice, mass

movement or glaciers which are called agents of

denudation.

The sedimentary rock cover of the continents of

the Earth's crust is extensive, but the total

contribution of sedimentary rocks is estimated

to be only 8% of the total volume of the crust.[1]

Sedimentary rocks are only a thin veneer over a

crust consisting mainly of igneous and

metamorphic rocks. Sedimentary rocks are

deposited in layers as strata, forming a structure

called bedding. The study of sedimentary rocks

and rock strata provides information about the

subsurface that is usef ul for civil engineering,

for example in the construction of roads,

houses, tunnels, canals or other structures.

Sedimentary rocks are also important sources of

natural resources like coal, fossil fuels, drinking

water or ores.

The study of the sequence of sedimentary rock strata is the main source for scientific knowledge about the

Earth's history, including palaeogeography, paleoclimatology and the history of life. The scientificdisci pline that studies the properties and origin of sedimentary rocks is called sedimentology.

Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in

the Earth sciences, such as pedology, geomorphology, geochemistry and structural geology.

Contents

1 Genetic classification

http://en.wikipedia.org/wiki/Earth_sciencehttp://en.wikipedia.org/wiki/Pedology_(soil_study)http://en.wikipedia.org/wiki/Geomorphologyhttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Physical_geographyhttp://en.wikipedia.org/wiki/List_of_academic_disciplineshttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Househttp://en.wikipedia.org/wiki/Tunnelhttp://en.wikipedia.org/wiki/Canalhttp://en.wikipedia.org/wiki/Roadhttp://en.wikipedia.org/wiki/Civil_engineeringhttp://en.wikipedia.org/wiki/Bed_(geology)http://en.wikipedia.org/wiki/Stratumhttp://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Crust_(geology)http://en.wikipedia.org/wiki/Denudationhttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Solutionhttp://en.wikipedia.org/wiki/Detritushttp://en.wikipedia.org/wiki/Sedimentationhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Deposition_(sediment)http://en.wikipedia.org/wiki/Wikipedia:Protection_policy#semihttp://en.wikipedia.org/wiki/File:PIA17603-MarsCuriosityRover-SheepbedMudstone-20130214.jpghttp://en.wikipedia.org/wiki/Earth_sciencehttp://en.wikipedia.org/wiki/Physical_geographyhttp://en.wikipedia.org/wiki/Geomorphologyhttp://en.wikipedia.org/wiki/Evolutionary_history_of_lifehttp://en.wikipedia.org/wiki/Civil_engineeringhttp://en.wikipedia.org/wiki/Geochemistryhttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/List_of_academic_disciplineshttp://en.wikipedia.org/wiki/Triassichttp://en.wikipedia.org/wiki/Sedimentationhttp://en.wikipedia.org/wiki/Wikipedia:Protection_policy#semihttp://en.wikipedia.org/wiki/Sedimentologyhttp://en.wikipedia.org/wiki/Palaeogeographyhttp://en.wikipedia.org/wiki/Natural_resourcehttp://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Tunnelhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Geologyhttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/Solutionhttp://en.wikipedia.org/wiki/Bed_(geology)http://en.wikipedia.org/wiki/Curiosity_(rover)http://en.wikipedia.org/wiki/Deposition_(sediment)http://en.wikipedia.org/wiki/Igneous_rockhttp://en.wikipedia.org/wiki/Drinking_waterhttp://en.wikipedia.org/wiki/Canalhttp://en.wikipedia.org/wiki/Detritushttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Erosionhttp://en.wikipedia.org/wiki/Paleoclimatologyhttp://en.wikipedia.org/wiki/Structural_geologyhttp://en.wikipedia.org/wiki/Stratumhttp://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Pedology_(soil_study)http://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/File:Triassic_Utah.JPGhttp://en.wikipedia.org/wiki/Organic_matterhttp://en.wikipedia.org/wiki/Denudationhttp://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Crust_(geology)http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Glacierhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Househttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Roadhttp://en.wikipedia.org/wiki/Windhttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/History_of_the_Earth


2/19

1.1 Clastic sedimentary rocks

1.1.1 Conglomerates and breccias

1.1.2 Sandstones

1.1.3 Mudrocks

1.2 Biochemical sedimentary rocks

1.3 Chemical sedimentary rocks

1.4 "Other" sedimentary rocks

2 Compositional classification schemes

3 Deposition and diagenesis

3.1 Sediment transport and deposition

3.2 Diagenesis

4 Properties

4.1 Color

4.2 Texture

4.3 Mineralogy

4.4 Fossils

4.5 Primary sedimentary structures

4.6 Secondary sedimentary structures

5 Sedimentary environments

5.1 Sedimentary facies

6 Sedimentary basins

6.1 Influence of astronomical cycles

7 Sedimentation rates

8 Stratigraphy

9 See also

10 References

10.1 Bibliography

11 External links

Genetic classification

Based on the processes responsible for their formation, sedimentary rocks can be subdivided into four

groups: clastic sedimentary rocks, biochemical (or biogenic) sedimentary rocks, chemical sedimentary

rocks and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor

processes.

Clastic sedimentary rocks

http://en.wikipedia.org/wiki/Volcanism


3/19

Claystone deposited in Glacial Lake

Missoula, Montana, United States.

Note the very fine and flat bedding,

common for distal lacustrine

deposition.

Clastic sedimentary rocks are composed of silicate minerals and

rock fragments that were transported by moving fluids (as bed load,

suspended load, or by sediment gravity flows) and were deposited

when these fluids came to rest. Clastic rocks are composed largely

of quartz, feldspar, rock (lithic) fragments, clay minerals, and mica;

numerous other minerals may be present as accessories and may be

important locally.

Clastic sediment, and thus clastic sedimentary rocks, are subdividedaccording to the dominant particle size (diameter). Most geologists

use the Udden-Wentworth grain size scale and divide

unconsolidated sediment into three fractions: gravel (>2 mm

diameter), sand (1/16 to 2 mm diameter), and mud (clay is

90% quartz grains

Feldspathic sandstones have


4/19

Lower Antelope Canyon was carved

out of the surrounding sandstone by

both mechanical weathering and

chemical weathering. Wind, sand, an

water from flash flooding are the

primary weathering agents.

Abundance of muddy matrix between sand grains

When sand-sized particles are deposited, the space between the sand grains either remains ope

or is filled with mud (silt and/or clay sized particle).

"Clean" sandstones with open pore space (that may later be filled with cement) are calle

arenites

Muddy sandstones with abundant (>10%) muddy matrix are called wackes.

Six sandstone names are possible using descriptors for grain composition (quartz-, feldspathic-, and lithic-

and amount of matrix (wacke or arenite). For example, a quartz arenite would be composed of mostly

(>90%) quartz grains and have little/no clayey matrix between the grains, a lithic wacke would have

abundant lithic grains (


5/19

Outcrop of Ordovician oil shale

(kukersite), northern Estonia

Deposits of chert formed from the accumulation of siliceous skeletons from microscopic organisms

such as radiolaria and diatoms.

Chemical sedimentary rocks

Chemical sedimentary rock forms when mineral constituents in solution become supersaturated and

inorganically precipitate. Common chemical sedimentary rocks include oolitic limestone and rocks

composed of evaporite minerals such as halite (rock salt), sylvite, barite and gypsum.

"Other" sedimentary rocks

This fourth miscellaneous category includes rocks formed by

Pyroclastic flows, impact breccias, volcanic breccias, and other

relatively uncommon processes.

Compositional classification schemes

Alternatively, sedimentary rocks can be subdivided into

compositional groups based on their mineralogy:

Siliciclastic sedimentary rocks, as described above, are

dominantly composed of silicate minerals. The sediment that makes up these rocks was transported

bed load, suspended load, or by sediment gravity flows. Siliciclastic sedimentary rocks are

subdivided into conglomerates and breccias, sandstone, and mudrocks.

Carbonate sedimentary rocks are composed of calcite (rhombohedral CaCO3), aragonite

(orthorhombic CaCO3), dolomite (CaMg(CO3)2), and other carbonate minerals based on the CO2−3

ion. Common examples include limestone and dolostone.

Evaporite sedimentary rocks are composed of minerals formed from the evaporation of water. The

most common evaporite minerals are carbonates (calcite and others based on CO2−

3 ), chlorides (halit

and others built on Cl−

), and sulfates (gypsum and others built on SO2−

4 ). Evaporite rocks commonly

include abundant halite (rock salt), gypsum, and anhydrite.

Organic-rich sedimentary rocks have significant amounts of organic material, generally in excess

of 3% total organic carbon. Common examples include coal, oil shale as well as source rocks for oil

and natural gas .

Siliceous sedimentary rocks are almost entirely composed of silica (SiO2), typically as chert, opal,

chalcedony or other microcrystalline forms.

Iron-rich sedimentary rocks are composed of >15% iron; the most common forms are banded iron

formations and ironstones[4]

Phosphatic sedimentary rocks are composed of phosphate minerals and contain more than 6.5%

http://en.wikipedia.org/wiki/Sylvitehttp://en.wikipedia.org/wiki/Chalcedonyhttp://en.wikipedia.org/wiki/Brecciahttp://en.wikipedia.org/wiki/Baritehttp://en.wikipedia.org/wiki/Banded_iron_formationhttp://en.wikipedia.org/wiki/Oolitehttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Oil_shalehttp://en.wikipedia.org/wiki/Ironstonehttp://en.wikipedia.org/wiki/Carbonate_mineralshttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Kukersitehttp://en.wikipedia.org/wiki/Sediment_transport#Suspended_loadhttp://en.wikipedia.org/wiki/Precipitatehttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Cherthttp://en.wikipedia.org/w/index.php?title=Source_rocks&action=edit&redlink=1http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Dolostonehttp://en.wikipedia.org/wiki/Solutionhttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Phosphoritehttp://en.wikipedia.org/wiki/Mudrockhttp://en.wikipedia.org/wiki/Chlorine#Occurrencehttp://en.wikipedia.org/wiki/Ordovicianhttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Carbonate_rockhttp://en.wikipedia.org/wiki/Opalhttp://en.wikipedia.org/wiki/Conglomerate_(geology)http://en.wikipedia.org/wiki/Siliceous_rockhttp://en.wikipedia.org/wiki/Gypsumhttp://en.wikipedia.org/wiki/Organic-rich_sedimentary_rockshttp://en.wikipedia.org/wiki/Radiolarianhttp://en.wikipedia.org/wiki/Sediment_gravity_flowshttp://en.wikipedia.org/wiki/Supersaturationhttp://en.wikipedia.org/wiki/Sediment_transport#Bed_Loadhttp://en.wikipedia.org/wiki/Breccia#Impacthttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Breccia#Volcanichttp://en.wikipedia.org/wiki/Clastic_rockhttp://en.wikipedia.org/wiki/Sandstonehttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Anhydritehttp://en.wikipedia.org/wiki/Sulfate_mineralhttp://en.wikipedia.org/wiki/Diatomhttp://en.wikipedia.org/wiki/File:OilShaleEstonia.jpghttp://en.wikipedia.org/wiki/Iron-rich_sedimentary_rockshttp://en.wikipedia.org/wiki/Cherthttp://en.wikipedia.org/wiki/Pyroclastic_flow


6/19

Cross-bedding and scour in a fine

sandstone; the Logan Formation

(Mississippian) of Jackson County,

Ohio

Pressure solution at work in a clastic

rock. While material dissolves at

places where grains are in contact,

material crystallizes from the solution

(as cement) in open pore spaces. This

means there is a net flow of material

from areas under high stress to those

under low stress. As a result, the rock

becomes more compact and harder.

Loose sand can become sandstone in

this way.

phosphorus; examples include deposits of phosphate nodules, bone beds, and phosphatic mudrocks[5

eposition and diagenesis

Sediment transport and deposition

Sedimentary rocks are formed when sediment is deposited out of air,

ice, wind, gravity, or water flows carrying the particles in

suspension. This sediment is often formed when weathering and

erosion break down a rock into loose material in a source area. The

material is then transported from the source area to the deposition

area. The type of sediment transported depends on the geology of

the hinterland (the source area of the sediment). However, some

sedimentary rocks, like evaporites, are composed of material that

formed at the place of deposition. The nature of a sedimentary rock,

therefore, not only depends on sediment supply, but also on the

sedimentary depositional environment in which it formed.

Diagenesis

The term diagenesis is used to describe all the chemical, physical,

and biological changes, including cementation, undergone by a

sediment after its initial deposition, exclusive of surface weathering.

Some of these processes cause the sediment to consolidate: a

compact, solid substance forms out of loose material. Young

sedimentary rocks, especially those of Quaternary age (the most

recent period of the geologic time scale) are often still

unconsolidated. As sediment deposition builds up, the overburden

(or lithostatic) pressure rises, and a process known as lithification

takes place.

Sedimentary rocks are often saturated with seawater or groundwater,

in which minerals can dissolve or from which minerals can

precipitate. Precipitating minerals reduce the pore space in a rock, a

process called cementation. Due to the decrease in pore space, the

original connate fluids are expelled. The precipitated minerals form

a cement and make the rock more compact and competent. In this

way, loose clasts in a sedimentary rock can become "glued"

together.

When sedimentation continues, an older rock layer becomes buried

deeper as a result. The lithostatic pressure in the rock increases due to the weight of the overlying sedimen

This causes compaction, a process in which grains mechanically reorganize. Compaction is, for example, a

important diagenetic process in clay, which can initially consist of 60% water. During compaction, this

interstitial water is pressed out of pore spaces. Compaction can also be the result of dissolution of grains by

http://en.wikipedia.org/wiki/Groundwaterhttp://en.wikipedia.org/wiki/Cementation_(geology)http://en.wikipedia.org/wiki/Diagenesishttp://en.wikipedia.org/wiki/Evaporitehttp://en.wikipedia.org/wiki/Ohiohttp://en.wikipedia.org/wiki/Cementation_(geology)http://en.wikipedia.org/wiki/Deposition_(geology)http://en.wikipedia.org/wiki/File:Logan_Formation_Cross_Bedding_Scour.jpghttp://en.wikipedia.org/wiki/Logan_Formationhttp://en.wikipedia.org/wiki/Erosionhttp://en.wikipedia.org/wiki/Competence_(geology)http://en.wikipedia.org/wiki/Pressure_solutionhttp://en.wikipedia.org/wiki/Suspension_(chemistry)http://en.wikipedia.org/wiki/Geologic_time_scalehttp://en.wikipedia.org/wiki/Overburden_pressurehttp://en.wikipedia.org/wiki/Quaternaryhttp://en.wikipedia.org/wiki/Porosityhttp://en.wikipedia.org/wiki/Mississippian_agehttp://en.wikipedia.org/wiki/Connate_fluidshttp://en.wikipedia.org/wiki/Consolidation_(soil)http://en.wikipedia.org/wiki/Lithificationhttp://en.wikipedia.org/wiki/Hinterlandhttp://en.wikipedia.org/wiki/Sandstonehttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/File:Pressure_solution_sandstone.svghttp://en.wikipedia.org/wiki/Sedimentary_depositional_environmenthttp://en.wikipedia.org/wiki/Weatheringhttp://en.wikipedia.org/wiki/Sediment_transporthttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Phosphate_nodulehttp://en.wikipedia.org/wiki/Sedimenthttp://en.wikipedia.org/wiki/Clastic_rock


7/19


8/19

Diagram showing well-sorted (left)

and poorly sorted (right) grains

Diagram showing the rounding and

sphericity of grains

to determine the velocity and direction of current in the sedimentary

environment where the rock was formed; fine, calcareous mud only

settles in quiet water while gravel and larger clasts are only

deposited by rapidly moving water.[10][11] The grain size of a rock is

usually expressed with the Wentworth scale, though alternative

scales are sometimes used. The grain size can be expressed as a

diameter or a volume, and is always an average value – a rock is

composed of clasts with different sizes. The statistical distributionof grain sizes is different for different rock types and is described in

a property called the sorting of the rock. When all clasts are more or

less of the same size, the rock is called 'well-sorted', and when there is a large spread in grain size, the rock

is called 'poorly sorted'.[12][13]

The form of clasts can reflect the origin of the rock.

Coquina, a rock composed of clasts of broken shells, can only form

in energetic water. The form of a clast can be described by using

four parameters:

[14][15]

Surface texture describes the amount of small-scale relief of

the surface of a grain that is too small to influence the general

shape.

rounding describes the general smoothness of the shape of a grain.

'Sphericity' describes the degree to which the grain approaches a sphere.

'Grain form' describes the three dimensional shape of the grain.

Chemical sedimentary rocks have a non-clastic texture, consisting entirely of crystals. To describe such atexture, only the average size of the crystals and the fabric are necessary.

Mineralogy

Most sedimentary rocks contain either quartz (especially siliciclastic rocks) or calcite (especially carbonate

rocks). In contrast to igneous and metamorphic rocks, a sedimentary rock usually contains very few

different major minerals. However, the origin of the minerals in a sedimentary rock is often more complex

than in an igneous rock. Minerals in a sedimentary rock can have formed by precipitation during

sedimentation or by diagenesis. In the second case, the mineral precipitate can have grown over an older

generation of cement.[16] A complex diagenetic history can be studied by optical mineralogy, using a

petrographic microscope.

Carbonate rocks dominantly consist of carbonate minerals like calcite, aragonite or dolomite. Both cement

and clasts (including fossils and ooids) of a carbonate rock can consist of carbonate minerals. The

mineralogy of a clastic rock is determined by the supplied material from the source area, the manner of

transport to the place of deposition and the stability of a particular mineral. The stability of the major rock

forming minerals (their resistance to weathering) is expressed by Bowen's reaction series. In this series,

quartz is the most stable, followed by feldspar, micas, and other less stable minerals that are only present

http://en.wikipedia.org/wiki/Sphericityhttp://en.wikipedia.org/wiki/Wentworth_scalehttp://en.wikipedia.org/wiki/File:Rounding_%26_sphericity_EN.svghttp://en.wikipedia.org/wiki/Optical_mineralogyhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Bowen%27s_reaction_serieshttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Sorting_(sediment)http://en.wikipedia.org/wiki/Rounding_(sediment)http://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Carbonate_rockhttp://en.wikipedia.org/wiki/Sphericityhttp://en.wikipedia.org/wiki/Rounding_(sediment)http://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Coquinahttp://en.wikipedia.org/wiki/Current_(stream)http://en.wikipedia.org/wiki/Ooidhttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/File:Sorting_in_sediment.svghttp://en.wikipedia.org/wiki/Sorting_(sediment)http://en.wikipedia.org/wiki/Aragonitehttp://en.wikipedia.org/wiki/Petrographic_microscopehttp://en.wikipedia.org/w/index.php?title=Calcareous_mud&action=edit&redlink=1http://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/w/index.php?title=Grain_form&action=edit&redlink=1http://en.wikipedia.org/wiki/Distribution_(mathematics)http://en.wikipedia.org/wiki/Siliciclastic


9/19

Fossil-rich layers in a sedimentary

rock, Año Nuevo State Reserve,

California

Burrows in a turbidite, made by

crustaceans, San Vincente Formation

(early Eocene) of the Ainsa Basin,

southern foreland of the Pyrenees

when little weathering has occurred.[17] The amount of weathering depends mainly on the distance to the

source area, the local climate and the time it took for the sediment to be transported there. In most

sedimentary rocks, mica, feldspar and less stable minerals have reacted to clay minerals like kaolinite, illit

or smectite.

Fossils

Among the three major types of rock, fossils are most commonlyfound in sedimentary rock. Unlike most igneous and metamorphic

rocks, sedimentary rocks form at temperatures and pressures that do

not destroy fossil remnants. Often these fossils may only be visible

when studied under a microscope (microfossils) or with a loupe.

Dead organisms in nature are usually quickly removed by

scavengers, bacteria, rotting and erosion, but sedimentation can

contribute to exceptional circumstances where these natural

processes are unable to work, causing fossilisation. The chance of

fossilisation is higher when the sedimentation rate is high (so that a

carcass is quickly buried), in anoxic environments (where little

bacterial activity occurs) or when the organism had a particularly

hard skeleton. Larger, well-preserved fossils are relatively rare.

Fossils can be both the direct remains or imprints of organisms and

their skeletons. Most commonly preserved are the harder parts of

organisms such as bones, shells, and the woody tissue of plants. Soft

tissue has a much smaller chance of being preserved and fossilized,

and soft tissue of animals older than 40 million years is very rare.[18]

Imprints of organisms made while still alive are called trace fossils.

Examples are burrows, footprints, etc.

Being part of a sedimentary or metamorphic rock, fossils undergo

the same diagenetic processes as rock. A shell consisting of calcite

can, for example, dissolve while a cement of silica then fills the

cavity. In the same way, precipitating minerals can fill cavities

formerly occupied by blood vessels, vascular tissue or other soft

tissues. This preserves the form of the organism but changes the

chemical composition, a process called permineralization.[19][20] The most common minerals in

permineralization cements are carbonates (especially calcite), forms of amorphous silica (chalcedony, flint

chert) and pyrite. In the case of silica cements, the process is called lithification.

At high pressure and temperature, the organic material of a dead organism undergoes chemical reactions in

which volatiles like water and carbon dioxide are expulsed. The fossil, in the end, consists of a thin layer o

pure carbon or its mineralized form, graphite. This form of fossilisation is called carbonisation. It is

particularly important for plant fossils.[21] The same process is responsible for the formation of fossil fuels

like lignite or coal.

Primary sedimentary structures

http://en.wikipedia.org/wiki/Foreland_basinhttp://en.wikipedia.org/wiki/Organic_materialhttp://en.wikipedia.org/wiki/File:Graafgang.jpghttp://en.wikipedia.org/wiki/Blood_vesselhttp://en.wikipedia.org/wiki/Permineralizationhttp://en.wikipedia.org/wiki/Hypoxia_(environmental)http://en.wikipedia.org/wiki/Lithificationhttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Tissue_(biology)http://en.wikipedia.org/w/index.php?title=Ainsa_Basin&action=edit&redlink=1http://en.wikipedia.org/wiki/Californiahttp://en.wikipedia.org/wiki/Burrowhttp://en.wikipedia.org/wiki/Decompositionhttp://en.wikipedia.org/wiki/Eocenehttp://en.wikipedia.org/wiki/Amorphous_silicahttp://en.wikipedia.org/wiki/Chalcedonyhttp://en.wikipedia.org/wiki/Vascular_tissuehttp://en.wikipedia.org/wiki/Crustaceanhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/w/index.php?title=San_Vincente_Formation&action=edit&redlink=1http://en.wikipedia.org/wiki/Fossil_fuelhttp://en.wikipedia.org/wiki/Flinthttp://en.wikipedia.org/wiki/Scavengerhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Illitehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbonisationhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Loupehttp://en.wikipedia.org/wiki/Diagenesishttp://en.wikipedia.org/wiki/Microfossilhttp://en.wikipedia.org/wiki/Lignitehttp://en.wikipedia.org/wiki/Cherthttp://en.wikipedia.org/wiki/Volatileshttp://en.wikipedia.org/wiki/Burrowhttp://en.wikipedia.org/wiki/File:Fossils_in_a_beach_wall.JPGhttp://en.wikipedia.org/wiki/Smectitehttp://en.wikipedia.org/wiki/Turbiditehttp://en.wikipedia.org/wiki/Footprinthttp://en.wikipedia.org/wiki/Clay_mineralshttp://en.wikipedia.org/wiki/Pyritehttp://en.wikipedia.org/wiki/Pyreneeshttp://en.wikipedia.org/wiki/Trace_fossilhttp://en.wikipedia.org/wiki/A%C3%B1o_Nuevo_State_Reservehttp://en.wikipedia.org/wiki/Kaolinite


10/19

Cross-bedding in a fluviatile

sandstone, Middle Old Red Sandston

(Devonian) on Bressay, Shetland

Islands

A flute cast, a type of sole marking,

from the Book Cliffs of Utah

Ripple marks formed by a current in

a sandstone that was later tilted

(Haßberge, Bavaria)

Structures in sedimentary rocks can be divided into 'primary'

structures (formed during deposition) and 'secondary' structures

(formed after deposition). Unlike textures, structures are always

large-scale features that can easily be studied in the field.

Sedimentary structures can indicate something about the

sedimentary environment or can serve to tell which side originally

faced up where tectonics have tilted or overturned sedimentary

layers.

Sedimentary rocks are laid down in layers called beds or strata. A

bed is defined as a layer of rock that has a uniform lithology and

texture. Beds form by the deposition of layers of sediment on top of

each other. The sequence of beds that characterizes sedimentary

rocks is called bedding.[22][23] Single beds can be a couple of

centimetres to several meters thick. Finer, less pronounced layers

are called laminae, and the structure it forms in a rock is called

lamination. Laminae are usually less than a few centimetres

thick.

[24]

Though bedding and lamination are often originallyhorizontal in nature, this is not always the case. In some

environments, beds are deposited at a (usually small) angle.

Sometimes multiple sets of layers with different orientations exist in

the same rock, a structure called cross-bedding.[25] Cross-bedding

forms when small-scale erosion occurs during deposition, cutting off

part of the beds. Newer beds then form at an angle to older ones.

The opposite of cross-bedding is parallel lamination, where all

sedimentary layering is parallel.[26] With laminations, differences

are generally caused by cyclic changes in the sediment supply,caused, for example, by seasonal changes in rainfall, temperature or

biochemical activity. Laminae that represent seasonal changes

(similar to tree rings) are called varves. Any sedimentary rock

composed of millimeter or finer scale layers can be named with the

general term laminite. Some rocks have no lamination at all; their

structural character is called massive bedding.

Graded bedding is a structure where beds with a smaller grain size

occur on top of beds with larger grains. This structure forms when

fast flowing water stops flowing. Larger, heavier clasts insuspension settle first, then smaller clasts. Though graded bedding

can form in many different environments, it is characteristic for

turbidity currents.[27]

The bedform (the surface of a particular bed) can be indicative for a

particular sedimentary environment, too. Examples of bed forms

include dunes and ripple marks. Sole markings, such as tool marks

and flute casts, are groves dug into a sedimentary layer that are preserved. These are often elongated

structures and can be used to establish the direction of the flow during deposition.[28][29]

http://en.wikipedia.org/wiki/Bedformhttp://en.wikipedia.org/wiki/Ripple_markshttp://en.wikipedia.org/wiki/Lamination_(geology)http://en.wikipedia.org/wiki/Bavariahttp://en.wikipedia.org/wiki/Dunehttp://en.wikipedia.org/wiki/Shetland_Islandshttp://en.wikipedia.org/wiki/Ripple_markshttp://en.wikipedia.org/wiki/Sandstonehttp://en.wikipedia.org/wiki/Tree_ringhttp://en.wikipedia.org/wiki/Graded_beddinghttp://en.wikipedia.org/wiki/Varvehttp://en.wikipedia.org/wiki/Bed_(geology)http://en.wikipedia.org/wiki/Fluviatilehttp://en.wikipedia.org/wiki/File:Rippelmarken_Hassberge_ReiKi.jpghttp://en.wikipedia.org/wiki/Way_up_structurehttp://en.wikipedia.org/wiki/File:FluteCast.JPGhttp://en.wikipedia.org/wiki/Flute_casthttp://en.wikipedia.org/wiki/Cross-beddinghttp://en.wikipedia.org/wiki/Lithologyhttp://en.wikipedia.org/wiki/Bressayhttp://en.wikipedia.org/wiki/Devonianhttp://en.wikipedia.org/wiki/Stratumhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Sedimentary_structureshttp://en.wikipedia.org/wiki/Book_Cliffshttp://en.wikipedia.org/wiki/Cross-beddinghttp://en.wikipedia.org/wiki/File:Crossbeddingbressay.jpghttp://en.wikipedia.org/wiki/Old_Red_Sandstonehttp://en.wikipedia.org/wiki/Turbidity_currenthttp://en.wikipedia.org/wiki/Sole_markinghttp://en.wikipedia.org/wiki/Bed_(geology)http://en.wikipedia.org/wiki/Ha%C3%9Fberge_(district)


11/19

Halite crystal mold in dolomite,

Paadla Formation (Silurian),

Saaremaa, Estonia

Chert concretions in chalk, Middle

Lefkara Formation (upper Paleocene

to middle Eocene), Cyprus

Ripple marks also form in flowing water. There are two types: asymmetric wave ripples and symmetric

current ripples. Environments where the current is in one direction, such as rivers, produce asymmetric

ripples. The longer flank of such ripples is oriented opposite to the direction of the current.[30][31][32] Wave

ripples occur in environments where currents occur in all directions, such as tidal flats.

Mudcracks are a bed form caused by the dehydration of sediment that occasionally comes above the water

surface. Such structures are commonly found at tidal flats or point bars along rivers.

Secondary sedimentary structures

Secondary sedimentary structures are structures in sedimentary

rocks which formed after deposition. Such structures form by

chemical, physical and biological processes inside the sediment.

They can be indicators for circumstances after deposition. Some can

be used as way up criteria.

Organic presence in a sediment can leave more traces than just

fossils. Preserved tracks and burrows are examples of trace fossils

(also called ichnofossils).[33] Some trace fossils such as paw prints

of dinosaurs or early humans can capture human imagination, but

such traces are relatively rare. Most trace fossils are burrows of

molluscs or arthropods. This burrowing is called bioturbation by

sedimentologists. It can be a valuable indicator of the biological and

ecological environment after the sediment was deposited. On the

other hand, the burrowing activity of organisms can destroy other (primary) structures in the sediment,

making a reconstruction more difficult.

Secondary structures can also have been formed by diagenesis or the

formation of a soil (pedogenesis) when a sediment is exposed above

the water level. An example of a diagenetic structure common in

carbonate rocks is a stylolite.[34] Stylolites are irregular planes

where material was dissolved into the pore fluids in the rock. The

result of precipitation of a certain chemical species can be colouring

and staining of the rock, or the formation of concretions.

Concretions are roughly concentric bodies with a different

composition from the host rock. Their formation can be the result of

localized precipitation due to small differences in composition or

porosity of the host rock, such as around fossils, inside burrows or

around plant roots.[35] In carbonate rocks such as limestone or chalk,

chert or flint concretions are common, while terrestrial sandstones

can have iron concretions. Calcite concretions in clay are called septarian concretions.

After deposition, physical processes can deform the sediment, forming a third class of secondary structures

Density contrasts between different sedimentary layers, such as between sand and clay, can result in flame

structures or load casts, formed by inverted diapirism.[36] The diapirism causes the denser upper layer to

sink into the other layer. Sometimes, density contrast can result or grow when one of the lithologies

dehydrates. Clay can be easily compressed as a result of dehydration, while sand retains the same volume

http://en.wikipedia.org/wiki/Eocenehttp://en.wikipedia.org/wiki/Burrowhttp://en.wikipedia.org/wiki/Trace_fossilhttp://en.wikipedia.org/wiki/Halitehttp://en.wikipedia.org/wiki/Saaremaahttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Chalkhttp://en.wikipedia.org/wiki/Cherthttp://en.wikipedia.org/wiki/Pedogenesishttp://en.wikipedia.org/wiki/Point_barhttp://en.wikipedia.org/wiki/Paleocenehttp://en.wikipedia.org/wiki/Chalkhttp://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Load_casthttp://en.wikipedia.org/wiki/Stylolitehttp://en.wikipedia.org/wiki/Diagenesishttp://en.wikipedia.org/wiki/Arthropodhttp://en.wikipedia.org/wiki/Septarian_nodulehttp://en.wikipedia.org/w/index.php?title=Middle_Lefkara_Formation&action=edit&redlink=1http://en.wikipedia.org/wiki/Flame_structurehttp://en.wikipedia.org/wiki/File:HaliteCrystalMold.jpghttp://en.wikipedia.org/wiki/Silurianhttp://en.wikipedia.org/wiki/Molluscshttp://en.wikipedia.org/wiki/Concretionhttp://en.wikipedia.org/wiki/Way_up_structurehttp://en.wikipedia.org/wiki/Deformation_(science)http://en.wikipedia.org/wiki/Flinthttp://en.wikipedia.org/wiki/Bioturbationhttp://en.wikipedia.org/wiki/Cyprushttp://en.wikipedia.org/wiki/File:Vuursteenknollen_in_krijtgesteente.jpghttp://en.wikipedia.org/wiki/Diapirismhttp://en.wikipedia.org/wiki/Cherthttp://en.wikipedia.org/wiki/Mudcrack


12/19

and becomes relatively less dense. On the other hand, when the pore fluid pressure in a sand layer surpasse

a critical point, the sand can flow through overlying clay layers, forming discordant bodies of sedimentary

rock called sedimentary dykes (the same process can form mud volcanoes on the surface).

A sedimentary dyke can also be formed in a cold climate where the soil is permanently frozen during a

large part of the year. Frost weathering can form cracks in the soil that fill with rubble from above. Such

structures can be used as climate indicators as well as way up structures.[37]

Density contrasts can also cause small-scale faulting, even while sedimentation goes on (syn-sedimentary

faulting).[38] Such faulting can also occur when large masses of non-lithified sediment are deposited on a

slope, such as at the front side of a delta or the continental slope. Instabilities in such sediments can result

slumping. The resulting structures in the rock are syn-sedimentary folds and faults, which can be difficult t

distinguish from folds and faults formed by tectonic forces in lithified rocks.

Sedimentary environments

The setting in which a sedimentary rock forms is called the sedimentary environment. Every environment

has a characteristic combination of geologic processes and circumstances. The type of sediment that isdeposited is not only dependent on the sediment that is transported to a place, but also on the environment

itself.[39]

A marine environment means the rock was formed in a sea or ocean. Often, a distinction is made between

deep and shallow marine environments. Deep marine usually refers to environments more than 200 m

below the water surface. Shallow marine environments exist adjacent to coastlines and can extend out to th

boundaries of the continental shelf. The water in such environments has a generally higher energy than tha

in deep environments, because of wave activity. This means coarser sediment particles can be transported

and the deposited sediment can be coarser than in deep environments. When the available sediment is

transported from the continent, an alternation of sand, clay and silt is deposited. When the continent is far away, the amount of such sediment brought in may be small, and biochemical processes dominate the type

of rock that forms. Especially in warm climates, shallow marine environments far offshore mainly see

deposition of carbonate rocks. The shallow, warm water is an ideal habitat for many small organisms that

build carbonate skeletons. When these organisms die their skeletons sink to the bottom, forming a thick

layer of calcareous mud that may lithify into limestone. Warm shallow marine environments also are ideal

environments for coral reefs, where the sediment consists mainly of the calcareous skeletons of larger

organisms.[40]

In deep marine environments, the water current over the sea bottom is small. Only fine particles can be

transported to such places. Typically sediments depositing on the ocean floor are fine clay or smallskeletons of micro-organisms. At 4 km depth, the solubility of carbonates increases dramatically (the depth

zone where this happens is called the lysocline). Calcareous sediment that sinks below the lysocline

dissolve, so no limestone can be formed below this depth. Skeletons of micro-organisms formed of silica

(such as radiolarians) still deposit though. An example of a rock formed out of silica skeletons is radiolarit

When the bottom of the sea has a small inclination, for example at the continental slopes, the sedimentary

cover can become unstable, causing turbidity currents. Turbidity currents are sudden disturbances of the

normally quite deep marine environment and can cause the geologically speaking instantaneous deposition

of large amounts of sediment, such as sand and silt. The rock sequence formed by a turbidity current is

called a turbidite.[41]

http://en.wikipedia.org/wiki/Pore_fluid_pressurehttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Wind_wavehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Fault_(geology)http://en.wikipedia.org/wiki/River_deltahttp://en.wikipedia.org/wiki/Slump_(geology)http://en.wikipedia.org/wiki/Continental_slopehttp://en.wikipedia.org/wiki/Continental_slopehttp://en.wikipedia.org/wiki/Seahttp://en.wikipedia.org/wiki/Clastic_dikehttp://en.wikipedia.org/wiki/Oceanhttp://en.wikipedia.org/wiki/Fold_(geology)http://en.wikipedia.org/wiki/Radiolaritehttp://en.wikipedia.org/wiki/Turbiditehttp://en.wikipedia.org/wiki/Continental_shelfhttp://en.wikipedia.org/wiki/Sandhttp://en.wikipedia.org/wiki/Silicahttp://en.wikipedia.org/wiki/Silthttp://en.wikipedia.org/wiki/Mud_volcanohttp://en.wikipedia.org/wiki/Radiolarianhttp://en.wikipedia.org/wiki/Oceanhttp://en.wikipedia.org/wiki/Lysoclinehttp://en.wikipedia.org/wiki/Coral_reefhttp://en.wikipedia.org/wiki/Tectonicshttp://en.wikipedia.org/wiki/Turbidity_currenthttp://en.wikipedia.org/wiki/Discordant


13/19

The coast is an environment dominated by wave action. At the beach, dominantly coarse sediment like san

or gravel is deposited, often mingled with shell fragments. Tidal flats and shoals are places that sometimes

dry out because of the tide. They are often cross-cut by gullies, where the current is strong and the grain

size of the deposited sediment is larger. Where along a coast (either the coast of a sea or a lake) rivers ente

the body of water, deltas can form. These are large accumulations of sediment transported from the

continent to places in front of the mouth of the river. Deltas are dominantly composed of clastic sediment.

A sedimentary rock formed on the land has a continental sedimentary environment. Examples of

continental environments are lagoons, lakes, swamps, floodplains and alluvial fans. In the quiet water of swamps, lakes and lagoons, fine sediment is deposited, mingled with organic material from dead plants an

animals. In rivers, the energy of the water is much higher and the transported material consists of clastic

sediment. Besides transport by water, sediment can in continental environments also be transported by win

or glaciers. Sediment transported by wind is called aeolian and is always very well sorted, while sediment

transported by a glacier is called glacial till and is characterized by very poor sorting.[42]

Aeolian deposits can be quite striking. The depositional environment of the Touchet Formation, located in

the Northwestern United States, had intervening periods of aridity which resulted in a series of rhythmite

layers. Erosional cracks were later infilled with layers of soil material, especially from aeolian processes.

The infilled sections formed vertical inclusions in the horizontally deposited layers of the TouchetFormation, and thus provided evidence of the events that intervened in time among the forty-one layers tha

were deposited.[43]

Sedimentary facies

Sedimentary environments usually exist alongside each other in certain natural successions. A beach, wher

sand and gravel is deposited, is usually bounded by a deeper marine environment a little offshore, where

finer sediments are deposited at the same time. Behind the beach, there can be dunes (where the dominant

deposition is well sorted sand) or a lagoon (where fine clay and organic material is deposited). Every

sedimentary environment has its own characteristic deposits. The typical rock formed in a certain

environment is called its sedimentary facies. When sedimentary strata accumulate through time, the

environment can shift, forming a change in facies in the subsurface at one location. On the other hand,

when a rock layer with a certain age is followed laterally, the lithology (the type of rock) and facies

eventually change.[44]

Facies can be distinguished in a number of ways: the most common ways are by the lithology (for example

limestone, siltstone or sandstone) or by fossil content. Coral for example only lives in warm and shallow

marine environments and fossils of coral are thus typical for shallow marine facies. Facies determined by

lithology are called lithofacies; facies determined by fossils are biofacies.[45]

Sedimentary environments can shift their geographical positions through time. Coastlines can shift in the

direction of the sea when the sea level drops, when the surface rises due to tectonic forces in the Earth's

crust or when a river forms a large delta. In the subsurface, such geographic shifts of sedimentary

environments of the past are recorded in shifts in sedimentary facies. This means that sedimentary facies

can change either parallel or perpendicular to an imaginary layer of rock with a fixed age, a phenomenon

described by Walther's Law.[46]

http://en.wikipedia.org/wiki/Walther%27s_Lawhttp://en.wikipedia.org/wiki/Beachhttp://en.wikipedia.org/wiki/Sea_levelhttp://en.wikipedia.org/wiki/Gullyhttp://en.wikipedia.org/wiki/Dunehttp://en.wikipedia.org/wiki/Shoalhttp://en.wikipedia.org/wiki/Alluvial_fanhttp://en.wikipedia.org/wiki/Gravelhttp://en.wikipedia.org/wiki/Fossilhttp://en.wikipedia.org/wiki/Lagoonhttp://en.wikipedia.org/wiki/Northwestern_United_Stateshttp://en.wikipedia.org/wiki/Aeolian_processeshttp://en.wikipedia.org/wiki/Sorting_(sediment)http://en.wikipedia.org/wiki/Floodplainhttp://en.wikipedia.org/wiki/River_deltahttp://en.wikipedia.org/wiki/Sedimentary_facieshttp://en.wikipedia.org/wiki/Lagoonhttp://en.wikipedia.org/wiki/Biofacieshttp://en.wikipedia.org/wiki/Lithologyhttp://en.wikipedia.org/wiki/Aeolian_processeshttp://en.wikipedia.org/wiki/Tidal_flathttp://en.wikipedia.org/wiki/Coralhttp://en.wikipedia.org/wiki/Touchet_Formationhttp://en.wikipedia.org/wiki/Facieshttp://en.wikipedia.org/wiki/Glacial_tillhttp://en.wikipedia.org/wiki/Rhythmitehttp://en.wikipedia.org/wiki/Tidehttp://en.wikipedia.org/wiki/Swamp


14/19

Shifting sedimentary facies in the case of

transgression (above) and regression of the sea

(below)

The situation in which coastlines move in the direction of

the continent is called transgression. In the case of

transgression, deeper marine facies are deposited over

shallower facies, a succession called onlap. Regression is

the situation in which a coastline moves in the direction

of the sea. With regression, shallower facies are

deposited on top of deeper facies, a situation called

offlap.

[47]

The facies of all rocks of a certain age can be plotted on a

map to give an overview of the palaeogeography. A

sequence of maps for different ages can give an insight in

the development of the regional geography.

Sedimentary basins

Places where large-scale sedimentation takes place are called sedimentary basins. The amount of sediment

that can be deposited in a basin depends on the depth of the basin, the so-called accommodation space.Depth, shape and size of a basin depend on tectonics, movements within the Earth's lithosphere. Where the

lithosphere moves upward (tectonic uplift), land eventually rises above sea level, so that and erosion

removes material, and the area becomes a source for new sediment. Where the lithosphere moves

downward (tectonic subsidence), a basin forms and sedimentation can take place. When the lithosphere

keeps subsiding, new accommodation space keeps being created.

A type of basin formed by the moving apart of two pieces of a continent is called a rift basin. Rift basins ar

elongated, narrow and deep basins. Due to divergent movement, the lithosphere is stretched and thinned, s

that the hot asthenosphere rises and heats the overlying rift basin. Apart from continental sediments, rift

basins normally also have part of their infill consisting of volcanic deposits. When the basin grows due tocontinued stretching of the lithosphere, the rift grows and the sea can enter, forming marine deposits.

When a piece of lithosphere that was heated and stretched cools again, its density rises, causing isostatic

subsidence. If this subsidence continues long enough the basin is called a sag basin. Examples of sag basin

are the regions along passive continental margins, but sag basins can also be found in the interior of

continents. In sag basins, the extra weight of the newly deposited sediments is enough to keep the

subsidence going in a vicious circle. The total thickness of the sedimentary infill in a sag basins can thus

exceed 10 km.

A third type of basin exists along convergent plate boundaries - places where one tectonic plate moves

under another into the asthenosphere. The subducting plate bends and forms a fore-arc basin in front of the

overriding plate—an elongated, deep asymmetric basin. Fore-arc basins are filled with deep marine deposi

and thick sequences of turbidites. Such infill is called flysch. When the convergent movement of the two

plates results in continental collision, the basin becomes shallower and develops into a foreland basin. At

the same time, tectonic uplift forms a mountain belt in the overriding plate, from which large amounts of

material are eroded and transported to the basin. Such erosional material of a growing mountain chain is

called molasse and has either a shallow marine or a continental facies.

http://en.wikipedia.org/wiki/Passive_marginhttp://en.wikipedia.org/wiki/Transgression_(geology)http://en.wikipedia.org/wiki/Erosionhttp://en.wikipedia.org/wiki/Deformation_(mechanics)http://en.wikipedia.org/wiki/Tectonic_platehttp://en.wikipedia.org/w/index.php?title=Sag_basin&action=edit&redlink=1http://en.wikipedia.org/wiki/Sedimentary_basinhttp://en.wikipedia.org/wiki/Transgression_(geology)http://en.wikipedia.org/wiki/Rift_basinhttp://en.wikipedia.org/wiki/Foreland_basinhttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/w/index.php?title=Offlap&action=edit&redlink=1http://en.wikipedia.org/wiki/Flyschhttp://en.wikipedia.org/wiki/Volcanic_rockhttp://en.wikipedia.org/wiki/File:Offlap_%26_onlap_EN.svghttp://en.wikipedia.org/wiki/Fore-arc_basinhttp://en.wikipedia.org/wiki/Tectonic_uplifthttp://en.wikipedia.org/wiki/Molassehttp://en.wikipedia.org/wiki/Rifthttp://en.wikipedia.org/w/index.php?title=Accommodation_space&action=edit&redlink=1http://en.wikipedia.org/wiki/Convergent_boundaryhttp://en.wikipedia.org/wiki/Isostasyhttp://en.wikipedia.org/wiki/Lithospherehttp://en.wikipedia.org/wiki/Palaeogeographyhttp://en.wikipedia.org/wiki/Marine_regressionhttp://en.wikipedia.org/wiki/Tectonic_subsidencehttp://en.wikipedia.org/wiki/Marine_regressionhttp://en.wikipedia.org/wiki/Virtuous_circle_and_vicious_circlehttp://en.wikipedia.org/wiki/Asthenospherehttp://en.wikipedia.org/wiki/Continental_collisionhttp://en.wikipedia.org/wiki/Tectonicshttp://en.wikipedia.org/wiki/Subductionhttp://en.wikipedia.org/wiki/Continental_marginhttp://en.wikipedia.org/wiki/Mountain_belthttp://en.wikipedia.org/w/index.php?title=Onlap_(geology)&action=edit&redlink=1


15/19

Cyclic alternation of competent and

less competent beds in the Blue Lias

at Lyme Regis, southern England

At the same time, the growing weight of the mountain belt can cause isostatic subsidence in the area of the

overriding plate on the other side to the mountain belt. The basin type resulting from this subsidence is

called a back-arc basin and is usually filled by shallow marine deposits and molasse.[48]

Influence of astronomical cycles

In many cases facies changes and other lithological features in

sequences of sedimentary rock have a cyclic nature. This cyclicnature was caused by cyclic changes in sediment supply and the

sedimentary environment. Most of these cyclic changes are caused

by astronomic cycles. Short astronomic cycles can be the difference

between the tides or the spring tide every two weeks. On a larger

time-scale, cyclic changes in climate and sea level are caused by

Milankovitch cycles: cyclic changes in the orientation and/or

position of the Earth's rotational axis and orbit around the Sun.

There are a number of Milankovitch cycles known, lasting between

10,000 and 200,000 years.[49]

Relatively small changes in the orientation of the Earth's axis or length of the seasons can be a major

influence on the Earth's climate. An example are the ice ages of the past 2.6 million years (the Quaternary

period), which are assumed to have been caused by astronomic cycles.[50][51] Climate change can influenc

the global sea level (and thus the amount of accommodation space in sedimentary basins) and sediment

supply from a certain region. Eventually, small changes in astronomic parameters can cause large changes

in sedimentary environment and sedimentation.

Sedimentation rates

The rate at which sediment is deposited differs depending on the location. A channel in a tidal flat can see

the deposition of a few metres of sediment in one day, while on the deep ocean floor each year only a few

millimetres of sediment accumulate. A distinction can be made between normal sedimentation and

sedimentation caused by catastrophic processes. The latter category includes all kinds of sudden

exceptional processes like mass movements, rock slides or flooding. Catastrophic processes can see the

sudden deposition of a large amount of sediment at once. In some sedimentary environments, most of the

total column of sedimentary rock was formed by catastrophic processes, even though the environment is

usually a quiet place. Other sedimentary environments are dominated by normal, ongoing sedimentation. [5

In many cases, sedimentation occurs slowly. In a desert, for example, the wind deposits siliciclastic materi

(sand or silt) in some spots, or catastrophic flooding of a wadi may cause sudden deposits of large quantiti

of detrital material, but in most places eolian erosion dominates. The amount of sedimentary rock that

forms is not only dependent on the amount of supplied material, but also on how well the material

consolidates. Erosion removes most deposited sediment shortly after deposition.[52]

Stratigraphy

http://en.wikipedia.org/wiki/Quaternary_glaciationhttp://en.wikipedia.org/wiki/Spring_tidehttp://en.wikipedia.org/wiki/Mass_wastinghttp://en.wikipedia.org/wiki/File:Blue_lias_cliffs_at_Lyme_Regis.jpghttp://en.wikipedia.org/wiki/Geologic_time_scalehttp://en.wikipedia.org/wiki/Rock_slidehttp://en.wikipedia.org/wiki/Quaternaryhttp://en.wikipedia.org/wiki/Wadihttp://en.wikipedia.org/wiki/Blue_Liashttp://en.wikipedia.org/wiki/Floodhttp://en.wikipedia.org/wiki/Back-arc_basinhttp://en.wikipedia.org/wiki/Astronomyhttp://en.wikipedia.org/wiki/Tidehttp://en.wikipedia.org/wiki/Competence_(geology)http://en.wikipedia.org/wiki/Deserthttp://en.wikipedia.org/wiki/Milankovitch_cycleshttp://en.wikipedia.org/wiki/Lyme_Regis


16/19

The Permian through Jurassic stratigraphy of the

Colorado Plateau area of southeastern Utah that

makes up much of the famous prominent rock

formations in protected areas such as Capitol Reef

National Park and Canyonlands National Park.

From top to bottom: Rounded tan domes of the

Navajo Sandstone, layered red KayentaFormation, cliff-forming, vertically jointed, red

Wingate Sandstone, slope-forming, purplish

Chinle Formation, layered, lighter-red Moenkopi

Formation, and white, layered Cutler Formation

sandstone. Picture from Glen Canyon National

Recreation Area, Utah.

That new rock layers are above older rock layers is stated in the principle of superposition. There are

usually some gaps in the sequence called unconformities.

These represent periods where no new sediments were

laid down, or when earlier sedimentary layers raised

above sea level and eroded away.

Sedimentary rocks contain important information about

the history of the Earth. They contain fossils, the

preserved remains of ancient plants and animals. Coal isconsidered a type of sedimentary rock. The composition

of sediments provides us with clues as to the original

rock. Differences between successive layers indicate

changes to the environment over time. Sedimentary rocks

can contain fossils because, unlike most igneous and

metamorphic rocks, they form at temperatures and

pressures that do not destroy fossil remains.

See alsoBack-stripping

Deposition (geology)

Dunham classification

Erosion

Growth fault

List of minerals

List of rock typesSediment transport

References

1. Buchner & Grapes (2011), p. 24

2. Dott (1964)

3. Blatt et al. (1980), p. 782

4. Prothero & Schwab (2004)

5. Boggs (2006)

6. Stow (2005)

7. Levin (1987), p. 57

8. Tarbuck & Lutgens (1999), pp. 145–146

9. Boggs (1987), p. 105


11. Levin (1987), p. 58

12. Boggs (1987), pp. 112–115

13. Blatt et al. (1980), . 55–58

http://en.wikipedia.org/wiki/File:SEUtahStrat.JPGhttp://en.wikipedia.org/wiki/Unconformityhttp://en.wikipedia.org/wiki/Kayenta_Formationhttp://en.wikipedia.org/wiki/Colorado_Plateauhttp://en.wikipedia.org/wiki/Glen_Canyon_National_Recreation_Areahttp://en.wikipedia.org/wiki/Back-strippinghttp://en.wikipedia.org/wiki/Law_of_superpositionhttp://en.wikipedia.org/wiki/Dunham_classificationhttp://en.wikipedia.org/wiki/Chinle_Formationhttp://en.wikipedia.org/wiki/Moenkopi_Formationhttp://en.wikipedia.org/wiki/Planthttp://en.wikipedia.org/wiki/Sediment_transporthttp://en.wikipedia.org/wiki/Erosionhttp://en.wikipedia.org/wiki/Permianhttp://en.wikipedia.org/wiki/Navajo_Sandstonehttp://en.wikipedia.org/wiki/List_of_mineralshttp://en.wikipedia.org/wiki/Capitol_Reef_National_Parkhttp://en.wikipedia.org/wiki/Wingate_Sandstonehttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Growth_faulthttp://en.wikipedia.org/wiki/History_of_the_Earthhttp://en.wikipedia.org/wiki/Deposition_(geology)http://en.wikipedia.org/wiki/Cutler_Formationhttp://en.wikipedia.org/wiki/List_of_rock_typeshttp://en.wikipedia.org/wiki/Canyonlands_National_Parkhttp://en.wikipedia.org/wiki/Fossilhttp://en.wikipedia.org/wiki/Jurassichttp://en.wikipedia.org/wiki/Animal


17/19

14. Levin (1987), p. 60

15. Blatt et al. (1980), pp. 75–80

16. Folk (1965), p. 62

17. For an overview of major minerals in siliciclastic rocks and their relative stabilities, see Folk (1965), pp. 62–64

18. Stanley (1999), pp. 60–61

19. Levin (1987), p. 92

20. Stanley (1999), p. 6121. Levin (1987), pp. 92–93


23. Press et al. (2003), p. 171

24. Boggs (1987), p. 138

25. For descriptions of cross-bedding, see Blatt et al. (1980), p. 128, pp. 135–136; Press et al. (2003), pp. 171–172

26. Blatt et al. (1980), pp. 133–135

27. For an explanation about graded bedding, see Boggs (1987), pp. 143–144; Tarbuck & Lutgens (1999), p. 161;

Press et al. (2003), p. 172.

28. Collinson et al. (2006), pp. 46–52

29. Blatt et al. (1980), pp. 155–157

30. Tarbuck & Lutgens (1999), p. 162

31. Levin (1987), p. 62

32. Blatt et al. (1980), pp. 136–154

33. For a short description of trace fossils, see Stanley (1999), p. 62; Levin (1987), pp. 93–95; and Collinson et al.

(2006), pp. 216–232.

34. Collinson et al. (2006), p. 215

35. For concretions, see Collinson et al. (2006), pp. 206–215.




39. For an overview of different sedimentary environments, see Press et al. (2003) or Einsele (2000), part II.

40. For a definition of shallow marine environments, see Levin (2003), p. 63.


42. For an overview over continental environments, see Levin (2003), pp. 67–68.

43. Baker, Victor R. and Nummedal, Dag, ed. (1978). The Channeled Scabland: A Guide to the Geomorphology of

the Columbia Basin, Washington (http://fax.libs.uga.edu/J84xNASx1x18xCx36/1f/). Washington, D.C.:Planetary Geology Program, Office of Space Science, National Aeoronautics and Space Administration. pp. 173–

177. ISBN 0-88192-590-X.


45. Reading (1996), pp. 19–20

46. Reading (1996), pp. 20–21

47. For an overview over facies shifts and the relations in the sedimentary rock record by which they can be

recognized, see Reading (1996), pp. 22–33.

48. For an overview of sedimentary basin types, see Press et al. (2003), pp. 187–189; Einsele (2000), pp. 3–9.

http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/0-88192-590-Xhttp://fax.libs.uga.edu/J84xNASx1x18xCx36/1f/


18/19

Wikimedia Commons has

media related to

Sedimentary rock .

Bibliography

Andersen, B. G. & H. W. Borns, Jr. (1994). The Ice Age World . Scandinavian University Press. ISBN 82-00-

37683-4.

Blatt, H., G. Middleton & R. Murray (1980). Origin of Sedimentary Rocks. Prentice-Hall. ISBN 0-13-642710-3

Boggs, S., Jr. (1987). Principles of Sedimentology and Stratigraphy (1st ed.). Merrill. ISBN 0-675-20487-9.

Boggs, S., Jr. (2006). Principles of Sedimentology and Stratigraphy (4th ed.). Upper Saddle River, NJ: Pearson

Prentice Hall. ISBN 978-0-13-154728-5.

Buchner, K & R. Grapes (2011). "Metamorphic rocks". Petrogenesis of Metamorphic Rocks

(http://books.google.co.uk/books?id=FFcHarai9GEC&pg=PA21). Springer. pp. 21–56. doi:10.1007/978-3-540-

74169-5_2 (https://dx.doi.org/10.1007%2F978-3-540-74169-5_2). ISBN 978-3-540-74168-8.

Collinson, J., N. Mountney & D. Thompson (2006). Sedimentary Structures (3rd ed.). Terra Publishing.

ISBN 1-903544-19-X.

Dott, R. H. (1964). "Wacke, graywacke and matrix - what approach to immature sandstone classification".

Journal of Sedimentary Petrology 34 (3): 625–632. doi:10.1306/74D71109-2B21-11D7-8648000102C1865D

(https://dx.doi.org/10.1306%2F74D71109-2B21-11D7-8648000102C1865D).

Einsele, G. (2000). Sedimentary Basins, Evolution, Facies, and Sediment Budget (2nd ed.). Springer. ISBN 3-

540-66193-X.

Folk, R. L. (1965). Petrology of Sedimentary Rocks (http://www.lib.utexas.edu/geo/folkready/). Hemphill.

Levin, H. L. (1987). The Earth through time (3rd ed.). Saunders College Publishing. ISBN 0-03-008912-3.

Press, F., R. Siever, J. Grotzinger & T. H. Jordan (2003). Understanding Earth (4th ed.). W. H. Freeman and

Company. ISBN 0-7167-9617-1.

Prothero, D. R. & F. Schwab (2004). Sedimentary Geology (2nd ed.). W. H. Freeman and Company.

Reading, H. G. (1996). Sedimentary Environments: Processes, Facies and Stratigraphy (3rd ed.). Blackwell

Science. ISBN 0-632-03627-3.

Stanley, S. M. (1999). Earth System History. W. H. Freeman and Company. ISBN 0-7167-2882-6.

Stow, D. A. V. (2005). Sedimentary Rocks in the Field . Burlington, MA: Academic Press. ISBN 978-1-874545

69-9.Tarbuck, E. J. & F. K. Lutgens (1999). Earth, an introduction to Physical Geology (6th ed.). Prentice Hall.

ISBN 0-13-011201-1.

External links

Basic Sedimentary Rock Classification

(http://csmres.jmu.edu/geollab/fichter/SedRx/sedclass.html)

. , , . – ,

14–15.

50. Stanley (1999), p. 536

51. Andersen & Borns (1994), pp. 29–32

52. Reading (1996), p. 17

http://en.wikipedia.org/wiki/W._H._Freeman_and_Companyhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Pearson_Prentice_Hallhttp://en.wikipedia.org/wiki/Special:BookSources/0-7167-2882-6http://en.wikipedia.org/wiki/Prentice-Hallhttp://en.wikipedia.org/wiki/Special:BookSources/978-1-874545-69-9http://en.wikipedia.org/wiki/Special:BookSources/82-00-37683-4http://en.wikipedia.org/wiki/Digital_object_identifierhttp://en.wikipedia.org/wiki/Special:BookSources/0-13-642710-3http://en.wikipedia.org/wiki/Special:BookSources/1-903544-19-Xhttp://dx.doi.org/10.1007%2F978-3-540-74169-5_2http://books.google.co.uk/books?id=FFcHarai9GEC&pg=PA21http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/978-3-540-74168-8http://en.wikipedia.org/wiki/W._H._Freeman_and_Companyhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Blackwell_Sciencehttp://en.wikipedia.org/wiki/Digital_object_identifierhttp://en.wikipedia.org/wiki/Special:BookSources/0-13-011201-1http://en.wikipedia.org/wiki/Springer_Science%2BBusiness_Mediahttp://en.wikipedia.org/wiki/Springer_Science%2BBusiness_Mediahttp://dx.doi.org/10.1306%2F74D71109-2B21-11D7-8648000102C1865Dhttp://en.wikipedia.org/wiki/Special:BookSources/0-675-20487-9http://en.wikipedia.org/wiki/Academic_Presshttp://en.wikipedia.org/wiki/Special:BookSources/978-0-13-154728-5http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://commons.wikimedia.org/wiki/Sedimentary_rockhttp://en.wikipedia.org/wiki/Special:BookSources/0-7167-9617-1http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/w/index.php?title=Hemphill_(publisher)&action=edit&redlink=1http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/0-03-008912-3http://en.wikipedia.org/wiki/Special:BookSources/3-540-66193-Xhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Prentice_Hallhttp://en.wikipedia.org/wiki/W._H._Freeman_and_Companyhttp://en.wikipedia.org/wiki/Special:BookSources/0-632-03627-3http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://csmres.jmu.edu/geollab/fichter/SedRx/sedclass.htmlhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://www.lib.utexas.edu/geo/folkready/http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/International_Standard_Book_Number


19/19

Sedimentary Rocks Tour, introduction to sedimentary rocks

(http://geology.cnsm.ad.csulb.edu/people/bperry/Sedimentary%20Rocks%20Tour/sedimentary_rock

_tour_homepage.htm)

Retrieved from "http://en.wikipedia.org/w/index.php?title=Sedimentary_rock&oldid=654214661"

Categories: Sedimentary rocks Petrology

This page was last modified on 30 March 2015, at 18:01.Text is available under the Creative Commons Attribution-ShareAlike License; additional terms mayapply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is aregistered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
http://wikimediafoundation.org/wiki/Terms_of_Usehttp://en.wikipedia.org/wiki/Help:Categoryhttp://en.wikipedia.org/wiki/Category:Petrologyhttp://geology.cnsm.ad.csulb.edu/people/bperry/Sedimentary%20Rocks%20Tour/sedimentary_rocks_tour_homepage.htmhttp://www.wikimediafoundation.org/http://en.wikipedia.org/wiki/Category:Sedimentary_rockshttp://en.wikipedia.org/w/index.php?title=Sedimentary_rock&oldid=654214661http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_Licensehttp://wikimediafoundation.org/wiki/Privacy_policy

sedimentary rock phe

Documents