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Diagenesis
Diagenesis
Published: 2008/11/29
Channel: atasse
Sedimentary Petrology: Siliciclastic Diagenesis
Sedimentary Petrology: Siliciclastic Diagenesis
Published: 2014/07/07
Channel: worldethq
Sedimentary Rocks - Compaction and Cementation
Sedimentary Rocks - Compaction and Cementation
Published: 2014/03/07
Channel: 12Cschaffer
Conceptos básicos de los procesos sedimentarios.
Conceptos básicos de los procesos sedimentarios.
Published: 2009/12/02
Channel: juanitorocklicker
Diagenesis Meaning
Diagenesis Meaning
Published: 2015/04/13
Channel: SDictionary
"Diagenesis" by: Joshua Gagliardi
"Diagenesis" by: Joshua Gagliardi
Published: 2012/10/22
Channel: Joshua Gagliardi
Physical Geology: Sedimentary, Lithification
Physical Geology: Sedimentary, Lithification
Published: 2014/08/12
Channel: DCC - Geology Online
What does diagenesis mean?
What does diagenesis mean?
Published: 2015/03/14
Channel: What Does That Mean?
Formación de rocas sedimentarias
Formación de rocas sedimentarias
Published: 2013/03/13
Channel: Dani Bio Geo
Meteoric and burial diagenesis
Meteoric and burial diagenesis
Published: 2017/09/19
Channel: Vidya-mitra
Burial Diagenesis (Diagenesis and Porosity Evolution)
Burial Diagenesis (Diagenesis and Porosity Evolution)
Published: 2017/08/20
Channel: Franco S. A.
Subaerial Diagenesis   Overview - Diagenesis and Porosity Evolution
Subaerial Diagenesis Overview - Diagenesis and Porosity Evolution
Published: 2017/07/02
Channel: Franco S. A.
Marine Diagenesis - Diagenesis and Porosity Evolution
Marine Diagenesis - Diagenesis and Porosity Evolution
Published: 2017/07/02
Channel: Franco S. A.
Tidal Flat Dolomitization Model (Diagenesis and Porosity Evolution)
Tidal Flat Dolomitization Model (Diagenesis and Porosity Evolution)
Published: 2017/08/20
Channel: Franco S. A.
Sea floor diagenesis
Sea floor diagenesis
Published: 2017/09/19
Channel: Vidya-mitra
Diagenesis
Diagenesis
Published: 2017/07/28
Channel: Civil Engineering Academy
Diagenesis
Diagenesis
Published: 2008/05/14
Channel: Thaddeus Thacker
Dolomitization Models   Overview (Diagenesis and Porosity Evolution)
Dolomitization Models Overview (Diagenesis and Porosity Evolution)
Published: 2017/08/20
Channel: Franco S. A.
Burial Compaction Dolomitization Model (Diagenesis and Porosity Evolution)
Burial Compaction Dolomitization Model (Diagenesis and Porosity Evolution)
Published: 2017/08/24
Channel: Franco S. A.
Diagenesis Mug2 by Magisto
Diagenesis Mug2 by Magisto
Published: 2013/03/26
Channel: Andy Klein
Subaerial Diagenesis in older Carbonate Rocks - Diagenesis and Porosity Evolution
Subaerial Diagenesis in older Carbonate Rocks - Diagenesis and Porosity Evolution
Published: 2017/07/02
Channel: Franco S. A.
Diagenesis (Evaporites and their Role in Petroleum Exploration)
Diagenesis (Evaporites and their Role in Petroleum Exploration)
Published: 2017/08/26
Channel: Franco S. A.
diagenesis
diagenesis
Published: 2013/12/15
Channel: glasstraps
General Considerations - Diagenesis and Porosity Evolution
General Considerations - Diagenesis and Porosity Evolution
Published: 2017/07/02
Channel: Franco S. A.
Deposition Diagenesis and Weathering of Organic Matter Rich Sediments Lecture Notes in Earth Science
Deposition Diagenesis and Weathering of Organic Matter Rich Sediments Lecture Notes in Earth Science
Published: 2016/12/05
Channel: Sharon M
22 - Carbonate processes
22 - Carbonate processes
Published: 2015/05/24
Channel: Matthew E. Clapham
Dolomitization   General Considerations (Diagenesis and Porosity Evolution)
Dolomitization General Considerations (Diagenesis and Porosity Evolution)
Published: 2017/08/20
Channel: Franco S. A.
Leaving no stone unturned: the feedback between biotic diversity and early diagenesis
Leaving no stone unturned: the feedback between biotic diversity and early diagenesis
Published: 2016/02/21
Channel: Palaeo cast
PETROLEO, ORIGEN, DIAGENESIS DE LA ROCA
PETROLEO, ORIGEN, DIAGENESIS DE LA ROCA
Published: 2016/12/17
Channel: David Tole
Early Diagenesis
Early Diagenesis
Published: 2016/11/10
Channel: Făgărășanu
Subaerial Diagenesis in Young Carbonate sediments
Subaerial Diagenesis in Young Carbonate sediments
Published: 2017/08/20
Channel: Franco S. A.
Diagenesis Earle Brown Concert
Diagenesis Earle Brown Concert
Published: 2016/10/10
Channel: Jennifer Bewerse
Fracturing (Diagenesis and Porosity Evolution)
Fracturing (Diagenesis and Porosity Evolution)
Published: 2017/08/24
Channel: Franco S. A.
ROCAS SEDIMENTARIAS
ROCAS SEDIMENTARIAS
Published: 2013/07/09
Channel: TESLA WEGENER
Dolomite Porosity and Permeability (Diagenesis and Porosity Evolution)
Dolomite Porosity and Permeability (Diagenesis and Porosity Evolution)
Published: 2017/08/20
Channel: Franco S. A.
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Published: 2017/02/20
Channel: A. Bilerdo
Download Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Strat
Download Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Strat
Published: 2017/03/11
Channel: Jevera M.
Chemical Diagenesis in the Tamar Estuary Contributions to Sedimentology
Chemical Diagenesis in the Tamar Estuary Contributions to Sedimentology
Published: 2017/02/08
Channel: Patricia Weissinger
sabulous ammophilous naupathia diagenesis
sabulous ammophilous naupathia diagenesis
Published: 2010/10/17
Channel: Frank May
Diagenesis A Quantitative Perspective Implications for Basin Modelling and Rock Property Prediction
Diagenesis A Quantitative Perspective Implications for Basin Modelling and Rock Property Prediction
Published: 2016/12/07
Channel: Toledo
NGEMC 2016  Diagenesis Event Week
NGEMC 2016 Diagenesis Event Week
Published: 2016/03/07
Channel: upgems1975
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Published: 2017/03/22
Channel: olisa
Diagenesis II Developments in Sedimentology v  2
Diagenesis II Developments in Sedimentology v 2
Published: 2016/12/07
Channel: Toledo
The Persian Gulf Holocene Carbonate Sedimentation and Diagenesis in a Shallow Epicontinental Sea
The Persian Gulf Holocene Carbonate Sedimentation and Diagenesis in a Shallow Epicontinental Sea
Published: 2016/12/06
Channel: Levent
Download Sediments, Diagenesis, and Sedimentary Rocks Treatise on Geochemistry, Second Edition, Volu
Download Sediments, Diagenesis, and Sedimentary Rocks Treatise on Geochemistry, Second Edition, Volu
Published: 2017/02/13
Channel: E. Venedictos
Rock Classes 3. Chemical Sediments
Rock Classes 3. Chemical Sediments
Published: 2008/09/16
Channel: rednasrotsen
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Published: 2017/02/24
Channel: Ciprian
Carbonate Reservoirs Porosity, Evolution and Diagenesis in a Sequence Stratigraphic Framework, Volum
Carbonate Reservoirs Porosity, Evolution and Diagenesis in a Sequence Stratigraphic Framework, Volum
Published: 2017/06/12
Channel: Madison C
Diagenesis: The Story of Diabetes and Its Treatment
Diagenesis: The Story of Diabetes and Its Treatment
Published: 2013/11/13
Channel: BiochemJM
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Carbonate Reservoirs, Volume 67, Second Edition Porosity and Diagenesis in a Sequence Stratigraphic
Published: 2017/03/02
Channel: Bénce Pcz.
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WIKIPEDIA ARTICLE

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Diagenesis ( /ˌdəˈɛnɪsɪs/) is the change of sediments or existing sedimentary rocks into a different sedimentary rock during and after rock formation (lithification), at temperatures and pressures less than that required for the formation of metamorphic rocks.[1] It does not include changes from weathering.[1] It is any chemical, physical, or biological change undergone by a sediment after its initial deposition, after its lithification. This process excludes surface alteration (weathering) and metamorphism. These changes happen at relatively low temperatures and pressures and result in changes to the rock's original mineralogy and texture. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, porosity, permeability, solubility, and time are all influential factors.

After deposition, sediments are compacted as they are buried beneath successive layers of sediment and cemented by minerals that precipitate from solution. Grains of sediment, rock fragments and fossils can be replaced by other minerals during diagenesis. Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization.

The study of diagenesis in rocks is used to understand the geologic history they have undergone and the nature and type of fluids that have circulated through them. From a commercial standpoint, such studies aid in assessing the likelihood of finding various economically viable mineral and hydrocarbon deposits.

The process of diagenesis is also important in the decomposition of bone tissue.[2]

Role of diagenesis in anthropology and paleontology[edit]

Originally calcitic crinoid stem (in cross-section) diagenetically replaced by marcasite in a siderite concretion; Lower Carboniferous.

The term diagenesis, literally meaning "across generation",[3] is extensively used in geology. However, this term has filtered into the field of anthropology, archaeology and paleontology to describe the changes and alterations that take place on skeletal (biological) material. Specifically, diagenesis "is the cumulative physical, chemical and biological environment; these processes will modify an organic object's original chemical and/or structural properties and will govern its ultimate fate, in terms of preservation or destruction".[4][5] In order to assess the potential impact of diagenesis on archaeological or fossil bones, many factors need to be assessed, beginning with elemental and mineralogical composition of bone and enveloping soil, as well as the local burial environment (geology, climatology, groundwater).[5]

The composite nature of bone, comprising one-third organic (mainly protein collagen) and two thirds mineral (calcium phosphate mostly in the form of hydroxyapatite) renders its diagenesis more complex.[6] Alteration occurs at all scales from molecular loss and substitution, through crystallite reorganization, porosity and microstructural changes, and in many cases, to disintegration of the complete unit.[7] Three general pathways of the diagenesis of bone have been identified:

  1. chemical deterioration of the organic phase.
  2. chemical deterioration of the mineral phase.
  3. (micro) biological attack of the composite.[8]

They are as follows:

  1. The dissolution of collagen depends on time, temperature and environmental pH.[8] At high temperatures, the rate of collagen loss will be accelerated and extreme pH can cause collagen swelling and accelerated hydrolysis.[8] Due to the increase in porosity of bones through collagen loss, the bone becomes susceptible to hydrolytic infiltration where the hydroxyapatite, with its affinity for amino acids, permits charged species of endogenous and exogenous origin to take up residence.[2]
  2. The hydrolytic activity plays a key role in the mineral phase transformations that exposes the collagen to accelerated chemical- and bio-degradation.[8] Chemical changes affect crystallinity.[2] Mechanisms of chemical change, such as the uptake of F or CO3 may cause recrystallization where hydroxyapatite is dissolved and re-precipitated allowing for the incorporation of substitution of exogenous material.[2]
  3. Once an individual has been interred, microbial attack, the most common mechanism of bone deterioration, occurs rapidly.[8] During this phase, most bone collagen is lost and porosity is increased.[2] The dissolution of the mineral phase caused by low pH permits access to the collagen by extracellular microbial enzymes thus microbial attack.[8]

Role of diagenesis in hydrocarbon generation[edit]

When animal or plant matter is buried during sedimentation, the constituent organic molecules (lipids, proteins, carbohydrates and lignin-humic compounds) break down due to the increase in temperature and pressure. This transformation occurs in the first few hundred meters of burial and results in the creation of two primary products: kerogens and bitumens.

It is generally accepted that hydrocarbons are formed by the thermal alteration of these kerogens (the biogenic theory). In this way, given certain conditions (which are largely temperature-dependent) kerogens will break down to form hydrocarbons through a chemical process known as cracking, or catagenesis.

A kinetic model based on experimental data can capture most of the essential transformation in diagenesis,[9] and a mathematical model in a compacting porous medium to model the dissolution-precipitation mechanism.[10] These models have been intensively studied and applied in real geological applications.

Diagenesis has been divided, based on hydrocarbon and coal genesis into: eodiagenesis (early), mesodiagenesis (middle) and telodiagenesis (late). During the early or eodiagenesis stage shales lose pore water, little to no hydrocarbons are formed and coal varies between lignite and sub-bituminous. During mesodiagenesis, dehydration of clay minerals occurs, the main development of oil genesis occurs and high to low volatile bituminous coals are formed. During telodiagenesis organic matter undergoes cracking and dry gas is produced; semi-anthracite coals develop.[11]

Early diagenesis in newly formed aquatic sediments is mediated by microorganisms using different electron acceptors as part of their metabolism. Organic matter is mineralized, liberating gaseous carbon dioxide (CO2) in the porewater, which, depending on the conditions, can diffuse into the water column. The various processes of mineralization in this phase are nitrification and denitrification, manganese oxide reduction, iron hydroxide reduction, sulfate reduction, and fermentation.[12]

Role of diagenesis in bone decomposition[edit]

Diagenesis alters the proportions of organic collagen and inorganic components (hydroxyapatite, calcium, magnesium) of bone exposed to environmental conditions, especially moisture. This is accomplished by the exchange of natural bone constituents, deposition in voids or defects, adsorption onto the bone surface and leaching from the bone.[2][13]

See also[edit]

References[edit]

  1. ^ a b Marshak, Stephen, 2009, Essentials of Geology, W. W. Norton & Company, 3rd ed. ISBN 978-0393196566
  2. ^ a b c d e f Hedges, R. E. M. (2002). "Bone Diagenesis: An Overview of Processes". Archaeometry. 44 (3): 319–328. doi:10.1111/1475-4754.00064. 
  3. ^ Oxford English Dictionary.
  4. ^ Wilson, L. and M. Pollard, "Here today, gone tomorrow? Integrated experimentation and geochemical modeling in studies of archaeological diagenetic change". Accounts of Chemical Research, 2002. 35(8): p. 644–651.
  5. ^ a b Zapata, J.; et al. (2006). "Diagenesis, not biogenesis: Two late Roman skeletal examples". Science of Total Environment. 369: 357–368. 
  6. ^ Nicholson, R. A. (1996). "Bone Degradation, Burial Medium and Species Representation: Debunking the Myths, and Experiment-based Approach". Journal of Archaeological Science. 23: 513–533. 
  7. ^ Nielsen-Marsh, C. M. (2000). "Patterns of Diagenesis in Bone I: The Effects of Site Environments". Journal of Archaeological Science. 27: 1139–1150. doi:10.1006/jasc.1999.0537. 
  8. ^ a b c d e f Collins, M. J.; et al. (2002). "The Survival of Organic Matter in Bone: A Review". Archaeometry. 44 (3): 383–394. 
  9. ^ Abercrombie, H. J.; Hutcheon, I. E.; Bloch, J. D.; Caritat, P. (1994). "Silica activity and the smectite-illite reaction". Geology. 22: 539–542. doi:10.1130/0091-7613(1994)022<0539:saatsi>2.3.co;2. 
  10. ^ Fowler, A. C.; Yang, X. S. (2003). "Dissolution/precipitation mechanisms for diagenesis in sedimentary basins". J. Geophys. Res. 108 (B10): 2269. Bibcode:2003JGRB..108.2509F. doi:10.1029/2002jb002269. 
  11. ^ Foscolos, A. E.; Powell, T. G.; Gunther, P. R. (1976). "The use of clay minerals and inorganic and organic geochemical indicators for evaluating the degree of diagenesis and oil generating potential of shales". Geochimica et Cosmochimica Acta. 40 (8): 953–966. doi:10.1016/0016-7037(76)90144-7. 
  12. ^ Lovley, D. R. (1991). "Dissimilatory Fe(II) and Mn(IV) reduction". Microbiological Reviews. 55 (2): 259–287. 
  13. ^ "Beyond the grave: understanding human decomposition" A. A. Vass Microbiology Today 2001 [1]

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