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The spore record of early land plants from upper Silurian strata in Klinta 1 well, Skåne, Sweden

Mehlqvist, Kristina (2009) In Dissertations in Geology at Lund University
Department of Geology
Abstract (Swedish)
Prover från Öved-Ramsåsagruppen i Skåne från övre Silur har undersökts palynologiskt, främst med avseende på sporer från landväxter. Sedimenten består av karbonater med silisiklastiskt innehåll och paleomiljön har tolkats till ett strandnära marint ekosystem. Detta har graderat från öppen marin, grund-subtidal till lagun eller intertidal miljö, vilket erbjuder en god möjlighet till palynologiska analyser av strandnära marina facies. 28 prover processades palynologiskt från borrkärnan Klinta borrhål 1. Sedimenten är marina, men material från landmiljö är representerat av sporer från tidiga landväxter. Denna studie visar en välbevarad palynologisk association dominerad av sporer från landväxter. Totalt 14 arter tillhörande 11 släkten av... (More)
Prover från Öved-Ramsåsagruppen i Skåne från övre Silur har undersökts palynologiskt, främst med avseende på sporer från landväxter. Sedimenten består av karbonater med silisiklastiskt innehåll och paleomiljön har tolkats till ett strandnära marint ekosystem. Detta har graderat från öppen marin, grund-subtidal till lagun eller intertidal miljö, vilket erbjuder en god möjlighet till palynologiska analyser av strandnära marina facies. 28 prover processades palynologiskt från borrkärnan Klinta borrhål 1. Sedimenten är marina, men material från landmiljö är representerat av sporer från tidiga landväxter. Denna studie visar en välbevarad palynologisk association dominerad av sporer från landväxter. Totalt 14 arter tillhörande 11 släkten av sporer identifierades, samt tre taxa som endast bestämdes till släktnivå. Den relativa förekomsten av sporer varierar i kärnan från 100 % ner till 0 % i vissa prover. Där sporförekomsten sjunker ökar generellt förekomsten av marina mikrofossil så som akritarker, skolecodonter och chitinozoer. Nivå 85 m i kärnan karakteriseras av total avsaknad av sporer och en hög andel ved, vilket tolkas bero på dåliga bevaringsförhållanden. Den höga andelen av sporer på vissa nivåer indikerar en strandnära, intertidal miljö. Förutom sporer från landväxter förekommer också vedrester och marina palynomorfer så som akritarker, chitinozoer och skolecodonter i proverna. Sedimenten har daterats med hjälp av sporerna till sen Silur (sen Ludlow; Ludfordian, ca. 420 miljoner år) med hjälp av följande nyckelarter; Emphanisporites negelctus, Hispanediscus verrucatus, Synorisporites cf. libycus och Apiculiretusispora? burgsvikensis. Dateringen baserad på sporer har korrelerats med nuvarande biostratigrafisk zonering, i sin tur baserad på conodonter, graptoliter och tentaculiter. Sporer ändrar färg med ökande begravningsdjup och detta har visat sig vara en bra metod för att tolka paleotemperatur och mognad i moderbergarter för kolväten. Denna studie påvisar ett ”Thermal alteration index” (TAI) på –3 och ett ”spore Color index” (SCI) på 7, vilket indikerar att det finns en möjlighet för kolväten att existera eftersom (TAI) är inom ”oljefönstret”. (Less)
Abstract
Samples from the upper Silurian Öved-Ramsåsa Group, Skåne, Sweden have been investigated palynologically. The sediments are dominated by siliciclastic deposits with minor carbonate units and the palaeoenvironmental setting has been interpreted as a near shore marine ecosystem which grade from open marine shallow subtidal to lagoonal intertidal conditions, offering a prime target for palynological analysis of near shore marine facies. A total of 28 samples were processed palynologically from the drill-core Klinta BH 1 and the terrestrial record is, in this marine setting, represented by spores of early land plants. The study has revealed a well preserved palynological assemblage dominated by spores from land plants. A total of 14 spore... (More)
Samples from the upper Silurian Öved-Ramsåsa Group, Skåne, Sweden have been investigated palynologically. The sediments are dominated by siliciclastic deposits with minor carbonate units and the palaeoenvironmental setting has been interpreted as a near shore marine ecosystem which grade from open marine shallow subtidal to lagoonal intertidal conditions, offering a prime target for palynological analysis of near shore marine facies. A total of 28 samples were processed palynologically from the drill-core Klinta BH 1 and the terrestrial record is, in this marine setting, represented by spores of early land plants. The study has revealed a well preserved palynological assemblage dominated by spores from land plants. A total of 14 spore species belonging to 11 genera were identified and additionally three taxa were identified to genus level. The high percentage of spores at some levels signifies a near-shore, intertidal environment. Apart from spores, wood remains and marine palynomorphs, such as acritarchs, are present in the palynological assemblages. The relative abundance of spores varies throughout the core, from abundances as high as 100% down to 0% in some samples. A decrease of relative spore abundance is generally met by an increase in marine microfossils such as acritarchs, scolecodonts and chitinozoans. The sediments at the level 85 m in the core, are characterized by a lack of spores and instead a high abundance of wood, which possibly indicates poor conditions of preservation. Palynostratigraphy based on the identified spores indicate that the studied sediments are of a late Ludlowian (Ludfordian) age (420 Ma) based on the presence of the following key-species; Emphanisporites negelctus, Hispanediscus verrucatus, Synorisporites cf. libycus and Apiculiretusispora? burgsvikensis. The spore zonation has subsequently been correlated with the existing biostratigraphical scheme based on conodonts, graptolites and tentaculitids. Spores change in colour with increasing depth of burial and this has shown to be a widely applicable method for thermal maturity determination in hydrocarbon source rocks. This study shows a maturity index of -3 (TAI) and 7 (SCI). Indicating that hydrocarbon presence is potentially possible as the Thermal Alteration Index (TAI) is within the “oil window”. (Less)
Please use this url to cite or link to this publication:
author
Mehlqvist, Kristina
supervisor
organization
alternative title
Sporer från tidiga landväxter från över siluriska strata i Klinta borrhål 1, Skåne, Sverige
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Silurian, spores, flora, palynology, Klinta 1 drillcore, silur, sporer, palynologi, Klinta borrkärna 1
publication/series
Dissertations in Geology at Lund University
report number
239
language
English
id
2303057
date added to LUP
2012-01-27 14:41:32
date last changed
2012-01-30 11:41:08
@misc{2303057,
  abstract     = {Samples from the upper Silurian Öved-Ramsåsa Group, Skåne, Sweden have been investigated palynologically. The sediments are dominated by siliciclastic deposits with minor carbonate units and the palaeoenvironmental setting has been interpreted as a near shore marine ecosystem which grade from open marine shallow subtidal to lagoonal intertidal conditions, offering a prime target for palynological analysis of near shore marine facies. A total of 28 samples were processed palynologically from the drill-core Klinta BH 1 and the terrestrial record is, in this marine setting, represented by spores of early land plants. The study has revealed a well preserved palynological assemblage dominated by spores from land plants. A total of 14 spore species belonging to 11 genera were identified and additionally three taxa were identified to genus level. The high percentage of spores at some levels signifies a near-shore, intertidal environment. Apart from spores, wood remains and marine palynomorphs, such as acritarchs, are present in the palynological assemblages. The relative abundance of spores varies throughout the core, from abundances as high as 100% down to 0% in some samples. A decrease of relative spore abundance is generally met by an increase in marine microfossils such as acritarchs, scolecodonts and chitinozoans. The sediments at the level 85 m in the core, are characterized by a lack of spores and instead a high abundance of wood, which possibly indicates poor conditions of preservation. Palynostratigraphy based on the identified spores indicate that the studied sediments are of a late Ludlowian (Ludfordian) age (420 Ma) based on the presence of the following key-species; Emphanisporites negelctus, Hispanediscus verrucatus, Synorisporites cf. libycus and Apiculiretusispora? burgsvikensis. The spore zonation has subsequently been correlated with the existing biostratigraphical scheme based on conodonts, graptolites and tentaculitids. Spores change in colour with increasing depth of burial and this has shown to be a widely applicable method for thermal maturity determination in hydrocarbon source rocks. This study shows a maturity index of -3 (TAI) and 7 (SCI). Indicating that hydrocarbon presence is potentially possible as the Thermal Alteration Index (TAI) is within the “oil window”.},
  author       = {Mehlqvist, Kristina},
  keyword      = {Silurian,spores,flora,palynology,Klinta 1 drillcore,silur,sporer,palynologi,Klinta borrkärna 1},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {The spore record of early land plants from upper Silurian strata in Klinta 1 well, Skåne, Sweden},
  year         = {2009},
}