1 / 50

Clasificación general de los ambientes de depósito.

AMBIENTE SEDIMENTARIO: conjunto de procesos físicos, químicos y biológicos que afectan la sedimentación (Fraser, 1989).  Se reconocen tres sitios primarios para el depósito de sedimentos: (1) Continental, (2) Marino-marginal o transicional, y (3) Marino.

janna-warner
Download Presentation

Clasificación general de los ambientes de depósito.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. AMBIENTE SEDIMENTARIO: conjunto de procesos físicos, químicos y biológicos que afectan la sedimentación (Fraser, 1989).  Se reconocen tres sitios primarios para el depósito de sedimentos: (1) Continental, (2) Marino-marginal o transicional, y (3) Marino. Cada uno de éstos se encuentra dividido en diferentes sistemas de depósito, así como en una serie de ambientes y sub-ambientes asociados. Clasificación general de los ambientes de depósito. http://www.geocities.com/SiliconValley/Bridge/3339/index50.html http://www.geologia.uson.mx/academicos/grijalva/ambientesfluviales/introduccion.htm

  2. Factores físicos, químicos y biológicos que afectan la sedimentación Factores físicos: incluyen aspectos dinámicos como la velocidad. dirección y variaciones en el movimiento del fluido que condicionan el medio; corrientes de agua. oleaje, mareas. vientos. etc.. asi como los parámetros geográficos y climáticos del mismo, como tipo de meteorización, clima, temperatura, humedad, frecuencia de las heladas, precipitación. etc. Factores químicos: condiciones de pH y eH del medio, la geoquímica de la roca madre y la interacción química entre el sedimento y el ambiente; principalmente en los subacuáticos. Factores biológicos: tipo de flora y fauna y su influencia en los procesos sedimentarios, formación de suelos, erosión, etc., así como las correspondientes interacciones con el ambiente que puede motivar la individualización de algún medio sedimentario.

  3. Boggs, 1995

  4. 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. 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: the total textural, compositional and structural characteristics of a sedimentary deposit resulting from accumulation and modification in a particular environment. • grain size, sorting, rounding • lithology • sedimentary structures • bedding type

  5. Ley Facies de Walter Johannes Walther, states that the vertical succession of facies reflects lateral changes in environment. Conversely, it states that when a depositional environment "migrates" laterally, sediments of one depositional environment come to lie on top of another. http://higheredbcs.wiley.com/legacy/college/levin/0471697435/chap_tut/chaps/chapter05-11.html

  6. http://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htmhttp://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htm CHARACTERISTICS OF NON-MARINE ENVIRONMENTS USEFUL IN IDENTIFICATION OF DEPOSITIONAL ENVIRONMENT Alluvial fan lots of coarse particles, usually sandstone and conglomerate, poor sorting, deposited by high energy floods or mudflows Fluvial (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 halite Glacial extremely 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 well rounded and frosted, rocks may be polished and faceted (windblown)

  7. Transitional Environments Beach sizes range from cobbles to fine sand, well sorted and well-rounded, may be plane bedded or cross-bedded dunes Estuary and Tidal Flats water 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 Lagoon mud and silt common occasional sandy layers deposited by storms highly bioturbated oyster hash common http://dept.kent.edu/geology/ehlab/sed_environ/sed_environment.htm

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

  9. CONTINENTAL SEDIMENTARY ENVIRONMENTS http://facstaff.gpc.edu/~pgore/geology/historical_lab/environmentchart.htm

  10. TRANSITIONAL SEDIMENTARY ENVIRONMENTS http://facstaff.gpc.edu/~pgore/geology/historical_lab/environmentchart.htm

  11. MARINE SEDIMENTARY ENVIRONMENTS http://facstaff.gpc.edu/~pgore/geology/historical_lab/environmentchart.htm

  12. Boggs, 1995

  13. SISTEMA FLUVIAL      Los depósitos fluviales están constituidos por sedimentos que se acumulan a partir de la actividad de los ríos y los procesos de deslizamiento por gravedad asociados. Aunque estos depósitos se están generando actualmente bajo una diversidad de condiciones climáticas, desde desérticas hasta glaciales, se reconocen cuatro sistemas fluviales bien definidos: (1) sistema de abanicos aluviales (alluvial fans), (2) sistema de ríos trenzados (braidded), (3) sistema de ríos meándricos (meandering), y (4) sistema de ríos anastomosados (anastomosing). Diferentes tipos de canales dentro de los sistemas fluviales http://www.geologia.uson.mx/academicos/grijalva/ambientesfluviales/introduccion.htm

  14. ALLUVIAL FAN DEPOSITS Boggs, 1995

  15. Boggs, 1995

  16. Walker, 1984

  17. Boggs, 1995

  18. Meandering stream Walker, 1984

  19. Walker, 1984

  20. Desert Environment (eolian) Boggs, 1995

  21. Lakes Boggs, 1995

  22. Boggs, 1995

  23. Glacial

  24. Boggs, 1995

  25. Delta Walker, 1984

  26. Walker, 1984

  27. Lewis and McConchie, 1994

  28. Boggs, 1995

  29. Beach/ barrier bar Walker, 1984

  30. Playa Boggs, 1995

  31. Estuario Boggs, 1995

  32. Reineck and Singh, 1980 Boggs, 1995

  33. Lagoon Boggs, 1995

  34. Tidal Flat Boggs, 1995

  35. Marine Environment Lewis and McConchie, 1994

  36. Shallow marine environments • Shallow seas can be subdivided into clastic and carbonate-dominated systems, depending mainly on sediment supply and climatic setting • Idealized models predict a general decrease of grain size with water depth (i.e., away from the shoreline); however, this simple picture is complicated by a large number of factors (e.g., shelf bathymetry) http://www.uic.edu/classes/geol/eaes350/

  37. Walker, 1984

  38. 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 carbonate production (temperature, salinity, light conditions) are favorable • Isolated platforms (atolls) are found in shallow seas surrounded by deep water, like extinct volcanoes http://www.uic.edu/classes/geol/eaes350/

  39. Lewis and McConchie, 1994

  40. Boggs, 1995

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

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

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

  44. Arrecifal Walker, 1984 Boggs, 1995

  45. Walker, 1984

  46. Boggs, 1995

  47. Talud Walker, 1984

  48. Deep marine environments • The continental slope is a major source of sediment for the deep sea, and is 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 be triggered by external forcing (e.g., an earthquake) or by the slope reaching 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 bottom waters http://www.uic.edu/classes/geol/eaes350/

  49. Abanico Submarino Reineck and Singh, 1980

  50. Turbiditas Reineck and Singh, 1980

More Related