Authigenesis (original) (raw)
Authigenesis is the process whereby a mineral or sedimentary rock deposit is generated where it is found or observed. Such deposits are described as authigenic. Authigenic sedimentary minerals form during sedimentation by precipitation or recrystallization instead of being transported from elsewhere (allogenic) by water or wind. Authigenic sediments are the main constituents of deep sea sedimentation. Authigenic clays tend to reduce the porosity of sediments, thus reducing permeability.
| Property | Value |
|---|---|
| dbo:abstract | Authigenesis is the process whereby a mineral or sedimentary rock deposit is generated where it is found or observed. Such deposits are described as authigenic. Authigenic sedimentary minerals form during sedimentation by precipitation or recrystallization instead of being transported from elsewhere (allogenic) by water or wind. Authigenic sediments are the main constituents of deep sea sedimentation. Authigenic clays tend to reduce the porosity of sediments, thus reducing permeability. In metamorphic petrology an authigenic mineral is one formed in situ during metamorphism, again by precipitation from fluids or recrystallization. For any mineral to be precipitated, the water must be supersaturated with respect to that mineral. For calcite, this means that the area of deposition must be above the carbonate compensation depth, or that the pore waters are sufficiently saturated due to dissolution of other grains that precipitation can begin. The alkalinity can also be reduced by microbial sulphate reduction. (en) Als authigen werden in der Petrographie Komponenten eines Gesteins, in der Regel Mineralkörner oder -aggregate bzw. das entsprechende Mineral, bezeichnet, die „an Ort und Stelle“ entstanden sind. Das Gegenteil von authigen ist allothigen. Beide Bezeichnungen wurden im Jahre 1880 vom deutschen Geologen Ernst Kalkowsky in die Fachliteratur eingeführt. Bei Sedimentgesteinen werden damit Gesteinsbestandteile bezeichnet, die sich erst nach Ablagerung des Sedimentes gebildet haben, z. B. Glaukonit oder Pyrit (siehe auch → Diagenese). Bisweilen wird die Bezeichnung auch für das gesamte Gestein verwendet, etwa bei Kalksteinen, die überwiegend aus Material bestehen, das direkt aus der Wassersäule passiv ausgefällt wurde oder von Organismen im Ablagerungsraum abgeschieden wurde. In diesem Zusammenhang spricht man auch von autochthonen oder in situ gebildeten Sedimenten bzw. Sedimentgesteinen. Ein Gestein, bei dem die Bezeichnung authigen im eigentlichen Sinne zutrifft ist Phosphorit, da die Phosphatabscheidung tatsächlich frühdiagenetisch abläuft. Bei magmatischen Gesteinen bedeutet authigen, dass die entsprechenden Komponenten durch Kristallisation aus ein und demselben Magma bzw. ein und derselben Lava hervorgegangen sind. Bei metamorphen Gesteinen sind all jene Minerale authigen, die während der Metamorphose entstanden sind. (de) Per autigenesi (dal greco aythi, nello stesso luogo) si intende il processo di formazione dei nuovi minerali, che avviene durante la diagenesi delle rocce sedimentarie. Questo processo avviene nel sottosuolo a bassa profondità, solitamente entro rocce sedimentarie, spesso non consolidate, in condizioni di temperatura non elevata e bassa pressione, e questo lo differenzia dalla formazione dei minerali nelle rocce ignee o dalle trasformazioni mineralogiche per metamorfismo. Spesso l'autigenesi provoca la deposizione di cemento calcareo (sotto forma di aragonite o, meno frequentemente, calcite) o più raramente siliceo. Alcune miche e minerali argillosi possono essere generati durante questo processo, riducendo la porosità e la permeabilità della roccia. (it) |
| dbo:thumbnail | wiki-commons:Special:FilePath/Authigenic-mineral2_hg.jpg?width=300 |
| dbo:wikiPageExternalLink | https://web.archive.org/web/20170403012727/http:/geology.uprm.edu/Morelock/dpseaauth.htm |
| dbo:wikiPageID | 9004520 (xsd:integer) |
| dbo:wikiPageLength | 3613 (xsd:nonNegativeInteger) |
| dbo:wikiPageRevisionID | 1112933968 (xsd:integer) |
| dbo:wikiPageWikiLink | dbr:Calcite dbr:Calcium_carbonate dbr:Carbonate_compensation_depth dbr:Precipitation_(chemistry) dbr:Pyrite dbr:Alkalinity dbr:Apatite dbr:Petrology dbr:Sedimentary_rock dbr:Clay_mineral dbr:Clays dbr:Glauconite dbr:Limonite dbr:Siderite dbr:Silica dbr:Permeability_(earth_sciences) dbr:Recrystallization_(geology) dbr:Hematite dbc:Sedimentology dbc:Mineralogy dbr:Chamosite dbr:Sulphate dbr:Supersaturated dbr:Metamorphism dbr:Mineral dbr:Minerals dbr:Neomorphism dbr:In_situ dbr:Porosity dbr:Microbial dbr:Sedimentation dbr:File:Authigenic-mineral2_hg.jpg dbr:File:GreensandSample.jpg |
| dbp:wikiPageUsesTemplate | dbt:Geology-stub dbt:Authority_control dbt:Reflist |
| dct:subject | dbc:Sedimentology dbc:Mineralogy |
| rdf:type | owl:Thing |
| rdfs:comment | Authigenesis is the process whereby a mineral or sedimentary rock deposit is generated where it is found or observed. Such deposits are described as authigenic. Authigenic sedimentary minerals form during sedimentation by precipitation or recrystallization instead of being transported from elsewhere (allogenic) by water or wind. Authigenic sediments are the main constituents of deep sea sedimentation. Authigenic clays tend to reduce the porosity of sediments, thus reducing permeability. (en) Als authigen werden in der Petrographie Komponenten eines Gesteins, in der Regel Mineralkörner oder -aggregate bzw. das entsprechende Mineral, bezeichnet, die „an Ort und Stelle“ entstanden sind. Das Gegenteil von authigen ist allothigen. Beide Bezeichnungen wurden im Jahre 1880 vom deutschen Geologen Ernst Kalkowsky in die Fachliteratur eingeführt. Bei magmatischen Gesteinen bedeutet authigen, dass die entsprechenden Komponenten durch Kristallisation aus ein und demselben Magma bzw. ein und derselben Lava hervorgegangen sind. (de) Per autigenesi (dal greco aythi, nello stesso luogo) si intende il processo di formazione dei nuovi minerali, che avviene durante la diagenesi delle rocce sedimentarie. Questo processo avviene nel sottosuolo a bassa profondità, solitamente entro rocce sedimentarie, spesso non consolidate, in condizioni di temperatura non elevata e bassa pressione, e questo lo differenzia dalla formazione dei minerali nelle rocce ignee o dalle trasformazioni mineralogiche per metamorfismo. (it) |
| rdfs:label | Authigene Bildung (de) Authigenesis (en) Autigenesi (it) |
| owl:sameAs | wikidata:Authigenesis dbpedia-de:Authigenesis dbpedia-fa:Authigenesis dbpedia-it:Authigenesis https://global.dbpedia.org/id/4wfrG |
| prov:wasDerivedFrom | wikipedia-en:Authigenesis?oldid=1112933968&ns=0 |
| foaf:depiction | wiki-commons:Special:FilePath/GreensandSample.jpg wiki-commons:Special:FilePath/Authigenic-mineral2_hg.jpg |
| foaf:isPrimaryTopicOf | wikipedia-en:Authigenesis |
| is dbo:wikiPageRedirects of | dbr:Authigenic dbr:Authigenic_mineral dbr:Authigenic_minerals dbr:Authigenic_sediment dbr:Authigenous |
| is dbo:wikiPageWikiLink of | dbr:Anaerobic_oxidation_of_methane dbr:Glauconite dbr:Faujasite dbr:Fluorine_cycle dbr:Fossil dbr:Cold_seep dbr:Authigenic dbr:NOAAS_Okeanos_Explorer_Gulf_of_Mexico_2017_Expedition dbr:Seatearth dbr:Southern_Hydrate_Ridge dbr:Authigenic_mineral dbr:Authigenic_minerals dbr:Authigenic_sediment dbr:Authigenous |
| is foaf:primaryTopic of | wikipedia-en:Authigenesis |
