Advanced

Lateral variability in the quantification of calcareous nannofossils in the Upper Triassic, Austria

Fägersten, Andreas LU (2018) In Dissertations in Geology at Lund University GEOL01 20181
Department of Geology
Abstract
Calcareous nannofossils are microscopic remains of organisms that diversified considerably in and after the Late Triassic, and which may have influenced seawater chemistry and carbonate production. Coccoliths, nannoliths, and calcareous dinoflagellate cysts are important parts of many calcareous nannofossil assemblages in the Upper Triassic. This is a quantification study of an Upper Triassic limestone bed, in order to examine lateral variability in calcareous nannofossil abundance at Steinbergkogel in the Northern Calcareous Alps, Austria. Steinbergkogel was at the time of deposition a deep shelf setting in the Tethys Ocean, a hemipelagic environment as a result of salt diapirism. A scanning electron microscope was used to quantify the... (More)
Calcareous nannofossils are microscopic remains of organisms that diversified considerably in and after the Late Triassic, and which may have influenced seawater chemistry and carbonate production. Coccoliths, nannoliths, and calcareous dinoflagellate cysts are important parts of many calcareous nannofossil assemblages in the Upper Triassic. This is a quantification study of an Upper Triassic limestone bed, in order to examine lateral variability in calcareous nannofossil abundance at Steinbergkogel in the Northern Calcareous Alps, Austria. Steinbergkogel was at the time of deposition a deep shelf setting in the Tethys Ocean, a hemipelagic environment as a result of salt diapirism. A scanning electron microscope was used to quantify the absolute number of calcareous nannofossils in six limestone rock samples with a 2.5 m width span between the first and last sample. Each individual specimen was counted along transects in each sample. The nannolith Prinsiosphaera triassica was the most abundant species in the nannofossil assemblage, whereas coccoliths and calcareous dinoflagellate cysts were very rare. The average quantity of calcareous nannofossils in the bed was slightly lower compared to previous studies on other nearby beds at Steinbergkogel. The lateral variations in calcareous nannofossil abundance was higher than anticipated, with a quantity difference of about 10x between two of the rock samples. (Less)
Abstract (Swedish)
Kalkskaliga nannofossil är spår av mikroskopiska organismer som utvecklades signifikativt under och efter slutet av trias, vilket kan ha påverkat havskemin samt kalkbildning i haven. Coccoliter, nannoliter och kalkskaliga dinoflagellater är vanligen förekommande kalkskaliga nannofossil som påträffas i övre trias. Denna studie syftar till att kvantifiera och undersöka laterala variationer hos kalkskaliga nannofossil i ett sedimentärt lager från övre trias, vid Steinbergkogel i Nördliche Kalkalpen i Österrike. Bildningsmiljön var i en hemipelagisk miljö på ett stort djup i Tetyshavet, som en konsekvens av underliggande saltdiapirer. Ett svepelektronmikroskop användes för att kvantifiera antalet kalkskaliga nannofossil längs ett tvärsnitt i... (More)
Kalkskaliga nannofossil är spår av mikroskopiska organismer som utvecklades signifikativt under och efter slutet av trias, vilket kan ha påverkat havskemin samt kalkbildning i haven. Coccoliter, nannoliter och kalkskaliga dinoflagellater är vanligen förekommande kalkskaliga nannofossil som påträffas i övre trias. Denna studie syftar till att kvantifiera och undersöka laterala variationer hos kalkskaliga nannofossil i ett sedimentärt lager från övre trias, vid Steinbergkogel i Nördliche Kalkalpen i Österrike. Bildningsmiljön var i en hemipelagisk miljö på ett stort djup i Tetyshavet, som en konsekvens av underliggande saltdiapirer. Ett svepelektronmikroskop användes för att kvantifiera antalet kalkskaliga nannofossil längs ett tvärsnitt i sex stycken kalkstensprov, med 2,5 meters lateralt mellanrum från första till sista provet. Nannoliten Prinsiosphaera triassica var den mest vanligt förekommande arten bland fossilen. Coccoliter och kalkskaliga dinoflagellater var normalt sett mycket sällsynta i samtliga kalkstenprov. Medelvärdet av kalkskaliga fossil beräknades vara strax under vad som beräknats i tidigare studier från nära underliggande sedimentära lager vid Steinbergkogel. Den laterala variationen hos kalkskaliga nannofossil bedömdes vara högre än väntat – omkring tio gånger fler fossil i provet med flest exemplar, jämfört med det kalkstensprov som hade lägst antal påträffade kalkskaliga nannofossil. (Less)
Please use this url to cite or link to this publication:
author
Fägersten, Andreas LU
supervisor
organization
course
GEOL01 20181
year
type
M2 - Bachelor Degree
subject
keywords
Calcareous nannofossils, Upper Triassic, Steinbergkogel, lateral variability, limestone
publication/series
Dissertations in Geology at Lund University
report number
536
language
English
id
8947958
date added to LUP
2018-06-11 14:20:11
date last changed
2018-06-11 14:20:11
@misc{8947958,
  abstract     = {Calcareous nannofossils are microscopic remains of organisms that diversified considerably in and after the Late Triassic, and which may have influenced seawater chemistry and carbonate production. Coccoliths, nannoliths, and calcareous dinoflagellate cysts are important parts of many calcareous nannofossil assemblages in the Upper Triassic. This is a quantification study of an Upper Triassic limestone bed, in order to examine lateral variability in calcareous nannofossil abundance at Steinbergkogel in the Northern Calcareous Alps, Austria. Steinbergkogel was at the time of deposition a deep shelf setting in the Tethys Ocean, a hemipelagic environment as a result of salt diapirism. A scanning electron microscope was used to quantify the absolute number of calcareous nannofossils in six limestone rock samples with a 2.5 m width span between the first and last sample. Each individual specimen was counted along transects in each sample. The nannolith Prinsiosphaera triassica was the most abundant species in the nannofossil assemblage, whereas coccoliths and calcareous dinoflagellate cysts were very rare. The average quantity of calcareous nannofossils in the bed was slightly lower compared to previous studies on other nearby beds at Steinbergkogel. The lateral variations in calcareous nannofossil abundance was higher than anticipated, with a quantity difference of about 10x between two of the rock samples.},
  author       = {Fägersten, Andreas},
  keyword      = {Calcareous nannofossils,Upper Triassic,Steinbergkogel,lateral variability,limestone},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Lateral variability in the quantification of calcareous nannofossils in the Upper Triassic, Austria},
  year         = {2018},
}