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    AMBIENTE SEDIMENTARIO: conjunto de procesos fsicos, qumicos y biolgicosque afectan la sedimentacin (Fraser, 1989).

    Se reconocen tres sitios primarios para el depsito de sedimentos:(1) Continental, (2) Marino-marginal o transicional, y (3) Marino.

    Cada uno de stos se encuentra dividido en diferentes sistemas de depsito, ascomo en una serie de ambientes y sub-ambientes asociados.

    SITIO PRIMARIODE DEPSITO

    SISTEMASPRINCIPALES

    CONTINENTAL

    FLUVIALDESRTICOLACUSTREGLACIALVOLCANICLSTICO

    MARINO-MARGINAL

    DELTAICOLAGUNARESTUARIO

    PLAYABARRAS DE ARENAPLANICIE DE MAREAS

    MARINO

    PLATAFORMACARBONATADAPLATAFORMASILICICLSTICAABANICO SUBMARINOPLANICIES ABISALES

    Clasificacin general de los ambientes de depsito.

    http://www.geologia.uson.mx/academicos/grijalva/ambientesfluviales/introduccion.htm

    http://www.geocities.com/SiliconValley/Bridge/3339/index50.html

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    Factores fsicos: incluyen aspectos dinmicos como la velocidad. direccin yvariaciones en el movimiento del fluido que condicionan el medio; corrientes

    de agua. oleaje, mareas. vientos. etc.. asi como los parmetros geogrficos y

    climticos del mismo, como tipo de meteorizacin, clima, temperatura,

    humedad, frecuencia de las heladas, precipitacin. etc.

    Factores qumicos: condiciones de pH y eH del medio, la geoqumica de laroca madre y la interaccin qumica entre el sedimento y el ambiente;

    principalmente en los subacuticos.

    Factores biolgicos: tipo de flora y fauna y su influencia en los procesos

    sedimentarios, formacin de suelos, erosin, etc., as como lascorrespondientes interacciones con el ambiente que puede motivar la

    individualizacin de algn medio sedimentario.

    Factores fsicos, qumicos y biolgicos que afectan la sedimentacin

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    Boggs, 1995

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    The concept of facies goes back to Armand Gressly (1830), who used the term to

    designate rocks of different aspect within a particular stratigraphic unit. The idea of

    facies sequences was emphasized by Johannes Walther (1896), and since about

    1965, facies sequences of various types have been a standard part of

    sedimentological interpretation.

    facies are a body of rock with specified characteristics. [Reading (1996)]Ideally, a facies is a distinctive rock unit that forms under certain conditions of

    sedimentation, reflecting a particular process or environment.

    facies: the total textural, compositional and structuralcharacteristics of a sedimentary deposit resulting from

    accumulation and modification in a particularenvironment. grain size, sorting, rounding

    lithology

    sedimentary structures

    bedding type

    http://en.wikipedia.org/wiki/Rock_unithttp://en.wikipedia.org/wiki/Rock_unit
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    CHARACTERISTICS OF NON-MARINE ENVIRONMENTS USEFUL INIDENTIFICATION OF DEPOSITIONAL ENVIRONMENT

    Alluvial fanlots of coarse particles, usually sandstone and conglomerate, poor sorting, deposited by

    high energy floods or mudflowsFluvial (stream channel)sandstone and conglomerate, ripple marks and cross-beds, graded bedding

    Fluvial (floodplain)usually plane bedding, fine-grained sand, silt, and clay,

    Paludal (swamps)dominantly fine-grained, coal common

    Lacustrine (lakes)beaches along edge; coarse-grained, well-sorted sandstone, sediments in lake are finer

    grained, can find evaporites such as gypsum and haliteGlacialextremely poorly sorted, usually coarse material in moraines, better sorting in outwash

    deposits, large cobbles may be striated

    Aeolian (desert)

    sand usually fine-grained, very large scale cross-bedding, well sorted, usually wellrounded and frosted, rocks may be polished and faceted (windblown)

    http://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htm

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    Transitional Environments

    Beachsizes range from cobbles to fine sand,

    well sorted and well-rounded,may be plane bedded or cross-bedded dunes

    Estuary and Tidal Flatswater level rises and falls depending on tides,

    ripples will stack on top of each other in opposite directions

    mud drapes common, often find a mix of marine and non-marine animals,

    tidal flats may have mud cracks

    Lagoonmud and silt common

    occasional sandy layers deposited by stormshighly bioturbated

    oyster hash common

    http://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htm

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    Shallow marine (less than 200 meters)reef structures

    limestone, dolomite, and gray shale common

    sediments rich in glauconite and phosphate

    Deep marine (greater than 200 meters)graded gray sandstone

    interbedded with gray shale

    bedded chert

    Marine Environment

    http://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htm

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    CONTINENTAL SEDIMENTARY ENVIRONMENTS

    ALLUVIAL FAN FLUVIALPALUDAL

    Rock Type Breccia,conglomerate,

    arkose

    Conglomerate,

    sandstone, siltstone,

    shale

    Peat, coal, black

    shale, siltstone

    Composition Terrigenous Terrigenous Terrigenous

    Color Brown or red Brown or red Black, gray, orbrown

    Grain Size Clay to gravel Clay to gravel (Finingupward)

    Clay to silt

    Grain Shape Angular Rounded to angular ---

    Sorting Poor Variable Variable

    Inorganic Sedimentary Structures Cross-bedding andgraded bedding

    Asymmetrical ripples,

    cross-bedding, graded

    bedding, tool marks

    Laminated to

    massive

    Organic or Biogenic SedimentaryStructures

    --- Tracks, trails,burrows Root marks,

    burrows

    Fossils --- Rare freshwater shells,bones, plant fragments

    Plant fossils, rare

    freshwater shells,

    bones, fish

    http://facstaff.gpc.edu/~pgore/geology/historical_lab/environmentchart.htm

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    TRANSITIONAL SEDIMENTARY ENVIRONMENTS

    DELTA BARRIER BEACH LAGOON TIDAL FLAT

    Rock Type Sandstone,siltstone, shale, coal

    Quartz arenite,

    coquina

    Siltstone, shale,

    limestone, oolitic

    limestone or gypsum

    Siltstone, shale,

    calcilutite, dolostone

    or gypsum

    Composition Terrigenous Terrigenous orcarbonate

    Terrigenous,

    carbonate, or

    evaporite

    Terrigenous,

    carbonate, or

    evaporite

    Color Brown, black, gray,

    green, red

    White to tan Dark gray to black Gray, brown, tan

    Grain Size Clay to sand(Coarsening upward

    Sand Clay to silt Clay to silt

    Grain Shape --- Rounded to angular --- ---

    Sorting Poor Good Poor Variable

    InorganicSedimentaryStructures

    Cross-bedding,

    graded bedding

    Cross-bedding,

    symmetrical ripples

    Lamination, ripples,

    cross-bedding

    Lamination,

    mudcracks, ripples,

    cross-bedding

    Organic orBiogenicSedimentaryStructures

    Trails, burrows Tracks, trails,

    burrows

    Trails, burrows Stromatolites, trails,

    tracks, burrows

    Fossils Plant fragments,shells

    Marine shells Marine shells Marine shells

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    MARINE SEDIMENTARY ENVIRONMENTS

    REEFCONTINENTAL

    SHELFCONTINENTAL

    SLOPE AND RISEABYSSAL PLAIN

    Rock Type Fossiliferouslimestone

    Sandstone, shale,

    siltstone, fossiliferous

    limestone, oolitic

    limestone

    Litharenite,

    siltstone, and shale

    (or limestone)

    Shale, chert, micrite,

    chalk, diatomite

    Composition Carbonate Terrigenous orcarbonate

    Terrigenous or

    carbonate

    Terrigenous or

    carbonate

    Color Gray to white Gray to brown Gray, green, brown Black, white red

    Grain Size Variable,frameworks, few

    to no grains

    Clay to sand Clay to sand Clay

    Grain Shape --- --- --- ---

    Sorting --- Poor to good Poor Good

    InorganicSedimentaryStructures

    --- Lamination, cross-

    bedding

    Graded bedding,

    cross-bedding,

    lamination, flute

    marks, tool marks

    (turbidites)

    Lamination

    Organic or BiogenicSedimentaryStructures

    --- Trails, burrows Trails, burrows Trails, burrows

    Fossils Corals, marine

    shells

    Marine shells Marine shells, rare

    plant fragments

    Marine shells

    (mostly microscopic)

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    SISTEMA FLUVIAL

    Los depsitos fluviales estn constituidos por sedimentos que se acumulan apartir de la actividad de los ros y los procesos de deslizamiento por gravedadasociados. Aunque estos depsitos se estn generando actualmente bajo una

    diversidad de condiciones climticas, desde desrticas hasta glaciales, sereconocen cuatro sistemas fluviales bien definidos: (1) sistema de abanicosaluviales (al luvial fans), (2) sistema de ros trenzados (braidded), (3) sistema deros mendricos (meander ing), y (4) sistema de ros anastomosados(anastomosing).

    Diferentes tipos de canales dentro de los sistemas fluvialeshttp://www.geologia.uson.mx/academicos/grijalva/ambientesfluviales/introduccion.htm

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    ALLUVIAL FAN DEPOSITS

    Boggs, 1995

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    M d i t

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    Meandering stream

    Walker, 1984

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    D t E i t ( li )

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    Boggs, 1995

    Desert Environment (eolian)

    Lakes

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    Lakes

    Boggs, 1995

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    Boggs, 1995

    Gl i l

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    Glacial

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    Boggs, 1995

    D lt

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    Delta

    Walker, 1984

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    Walker, 1984

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    Lewis and McConchie, 1994

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    Boggs, 1995

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    Beach/ barrier bar

    Walker, 1984

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    Boggs, 1995

    Playa

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    Estuario

    Boggs, 1995

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    Reineck and Singh, 1980 Boggs, 1995

    Lagoon

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    Lagoon

    Boggs, 1995

    Tidal Flat

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    Tidal Flat

    Boggs, 1995

    Marine Environment

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    Marine Environment

    Lewis and McConchie, 1994

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    Shallow seas can be subdivided into clastic and carbonate-

    dominated systems, depending mainly on sediment supply andclimatic setting

    Idealized models predict a general decrease of grain size withwater depth (i.e., away from the shoreline); however, thissimple picture is complicated by a large number of factors (e.g.,

    shelf bathymetry)

    http://www.uic.edu/classes/geol/eaes350/

    Shallow marine environments

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    Walker, 1984

    Shallow Carbonate marine environments

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    Shallow Carbonate marine environments Shallow seas within the photic zone are the premier carbonate

    factories

    Carbonate platforms can cover continental shelves or

    epicontinental seas, when the conditions for carbonateproduction (temperature, salinity, light conditions) are favorable

    Isolated platforms (atolls) are found in shallow seas surroundedby deep water, like extinct volcanoes

    http://www.uic.edu/classes/geol/eaes350/

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    Lewis and McConchie, 1994

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    Boggs, 1995

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    http://www.uic.edu/classes/geol/eaes350/

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    http://www.uic.edu/classes/geol/eaes350/

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    Boggs, 1995http://www.uic.edu/classes/geol/eaes350/

    Arrecifal

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    Boggs, 1995

    Walker, 1984

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    Boggs, 1995

    Talud

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    Walker, 1984

    Deep marine environments

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    p

    The continental slope is a major source of sediment for the deep sea, andis a setting where slumps can occur

    Debris flows and turbidity currents are the main mechanisms of transport

    from the continental slope into the deep sea; these processes can betriggered by external forcing (e.g., an earthquake) or by the slopereaching a critical state as a result of ongoing deposition

    Debris-flow deposits and turbidites are often genetically related

    Turbidites can be both clastic (commonly leading to the formation of

    wackes) or calcareous

    Pelagic sediments primarily have a biogenic origin Calcareous ooze (e.g., foraminifera) forms above the calcite compensation depth

    (CCD) at ~4000 m depth

    Siliceous ooze (e.g., radiolarians, diatoms) forms between the CCD and ~6000 m

    depth where silica dissolves; it lithifies into cherts Hemipelagic sediments consist of fine-grained (muddy) terrigenous

    material that is deposited from suspension Eolian dust is an important component (~50%) of hemipelagic (and pelagic)

    facies

    Black shales have a 1-15% organic-matter content and form in anoxic bottomwaters http://www.uic.edu/classes/geol/eaes350/

    Abanico Submarino

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    Reineck and Singh, 1980

    Abanico Submarino

    Turbiditas

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    Turbiditas