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Evidence of epibenthic microbial mats in Early Jurassic (Sinemurian) tidal deposits, Kulla Gunnarstorp, southern Sweden

Peterffy, Olof LU (2013) In Dissertations in Geology at Lund University GEOL01 20131
Department of Geology
Abstract
Wrinkle structures, a type of microbially induced sedimentary structures (MISS) were found in Jurassic tidally deposited heterolites of Kulla Gunnarstorp, southern Sweden. Wrinkle structures are characterizeded by minute, commonly elongate crinkles on the upper bedding planes of fine grained arenites. These structures, as well as MISS in general, form in siliciclastic sediments due to bacterial secretion of extracellular polymeric substance (EPS), which is strongly cohesive. The wrinkle structures of the present study originated as thick epibenthic microbial mats, and are of the non-transparent type, meaning that underlying bedforms are completely concealed by the bacterial remains. Where the mat grew, EPS hindered erosion of the... (More)
Wrinkle structures, a type of microbially induced sedimentary structures (MISS) were found in Jurassic tidally deposited heterolites of Kulla Gunnarstorp, southern Sweden. Wrinkle structures are characterizeded by minute, commonly elongate crinkles on the upper bedding planes of fine grained arenites. These structures, as well as MISS in general, form in siliciclastic sediments due to bacterial secretion of extracellular polymeric substance (EPS), which is strongly cohesive. The wrinkle structures of the present study originated as thick epibenthic microbial mats, and are of the non-transparent type, meaning that underlying bedforms are completely concealed by the bacterial remains. Where the mat grew, EPS hindered erosion of the substrate, thus changing the premises of the physical distribution of sediments.
The wrinkle structures were exclusively found on the upper bedding planes of wavy bedded micaceous arenites whose bioturbation indices range from 2–4. Microbial mat formation and preservation was facilitated since bioturbation and grazing was restricted by the fluctuating conditions (for instance regarding salinity) in the tidal depositional environment. (Less)
Abstract (Swedish)
Skrynkelstrukturer, en typ av mikrobiellt inducerade sedimentstrukturer (MISS) har återfunnits i jurassiska tidalt avsatta heteroliter i skånska Kulla Gunnarstorp. Skrynkelstrukturer kännetecknas av små, ofta avlånga veck på överytan av finkorniga sandstenar. Dessa strukturer, liksom MISS i allmänhet, bildas i siliciklastiska sediment under inverkan av bakteriellt utsöndrad extracellulär polymerisk substans (EPS), vilket är starkt kohesivt.
Skrynkelstrukturerna i den aktuella avhandlingen härrör från tjocka, epibentiska bakteriemattor, och är av den icke-transparenta typen, vilket innebär att underliggande bäddformer helt täcks av de bakteriella lämningarna. Där mattan växte hindrades erosionen av EPS och på detta vis ändrades premisserna... (More)
Skrynkelstrukturer, en typ av mikrobiellt inducerade sedimentstrukturer (MISS) har återfunnits i jurassiska tidalt avsatta heteroliter i skånska Kulla Gunnarstorp. Skrynkelstrukturer kännetecknas av små, ofta avlånga veck på överytan av finkorniga sandstenar. Dessa strukturer, liksom MISS i allmänhet, bildas i siliciklastiska sediment under inverkan av bakteriellt utsöndrad extracellulär polymerisk substans (EPS), vilket är starkt kohesivt.
Skrynkelstrukturerna i den aktuella avhandlingen härrör från tjocka, epibentiska bakteriemattor, och är av den icke-transparenta typen, vilket innebär att underliggande bäddformer helt täcks av de bakteriella lämningarna. Där mattan växte hindrades erosionen av EPS och på detta vis ändrades premisserna för den rent fysiska distributionen av sediment.
Skrynkelstrukturerna återfanns uteslutande på det övre bäddplanet glimmerrika areniter, vilkas bioturbationsindex varierar mellan 2–4. Bildning och bevaring av bakteriemattan möjliggjordes då bioturbation och betning hölls nere av de fluktuerande förhållandena (avseende bl. a. salthalt) som rådde i den tidala bildningsmiljön. (Less)
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author
Peterffy, Olof LU
supervisor
organization
alternative title
Bevis på epibentiska mikrobiella mattor i tidala avlagringar från äldre jura (Sinemurian), Kulla Gunnarstorp i Skåne
course
GEOL01 20131
year
type
M2 - Bachelor Degree
subject
keywords
Sweden, Kulla Gunnarstorp, jurassic, wrinkle structures, microbially induced sedimentary structures, skrynklestrukturer, mikrobiellt inducerade sedimentstrukturer, jura, Sverige
publication/series
Dissertations in Geology at Lund University
report number
345
language
English
id
3809529
date added to LUP
2013-06-11 12:25:03
date last changed
2013-06-11 12:25:03
@misc{3809529,
  abstract     = {Wrinkle structures, a type of microbially induced sedimentary structures (MISS) were found in Jurassic tidally deposited heterolites of Kulla Gunnarstorp, southern Sweden. Wrinkle structures are characterizeded by minute, commonly elongate crinkles on the upper bedding planes of fine grained arenites. These structures, as well as MISS in general, form in siliciclastic sediments due to bacterial secretion of extracellular polymeric substance (EPS), which is strongly cohesive. The wrinkle structures of the present study originated as thick epibenthic microbial mats, and are of the non-transparent type, meaning that underlying bedforms are completely concealed by the bacterial remains. Where the mat grew, EPS hindered erosion of the substrate, thus changing the premises of the physical distribution of sediments.
	The wrinkle structures were exclusively found on the upper bedding planes of wavy bedded micaceous arenites whose bioturbation indices range from 2–4. Microbial mat formation and preservation was facilitated since bioturbation and grazing was restricted by the fluctuating conditions (for instance regarding salinity) in the tidal depositional environment.},
  author       = {Peterffy, Olof},
  keyword      = {Sweden,Kulla Gunnarstorp,jurassic,wrinkle structures,microbially induced sedimentary structures,skrynklestrukturer,mikrobiellt inducerade sedimentstrukturer,jura,Sverige},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Evidence of epibenthic microbial mats in Early Jurassic (Sinemurian) tidal deposits, Kulla Gunnarstorp, southern Sweden},
  year         = {2013},
}