Quantitative allochem compositional analysis of Lochkovian-Pragian boundary sections in the Prague Basin (Czech Republic)

0476461 - GLÚ 2018 RIV NL eng J - Journal Article
Weinerová, Hedvika - Hron, K. - Bábek, O. - Šimíček, D. - Hladil, Jindřich
Quantitative allochem compositional analysis of Lochkovian-Pragian boundary sections in the Prague Basin (Czech Republic).
Sedimentary geology. Roč. 354, JUN 1 (2017), s. 43-59. ISSN 0037-0738. E-ISSN 1879-0968
R&D Projects: GA ČR GA14-18183S
Institutional support: RVO:67985831
Keywords : compositional analysis * carbonate petrography * multivariate statistics * log-ratio coordinates * Prague Basin * Lower Devonian
OECD category: Geology
Impact factor: 2.575, year: 2017

Quantitative allochem compositional trends across the Lochkovian-Pragian boundary Event were examined at three sections recording the proximal to more distal carbonate ramp environment of the Prague Basin. Multivariate statistical methods (principal component analysis, correspondence analysis, cluster analysis) of point-counted thin section data were used to reconstruct facies stacking patterns and sea-level history. Both the closed-nature allochem percentages and their centred log-ratio (clr) coordinates were used. Both these approaches allow for distinguishing of lowstand, transgressive and highstand system tracts within the Praha Formation, which show gradual transition from crinoid-dominated fades deposited above the storm wave base to dacryoconarid-dominated facies of deep-water environment below the storm wave base. Quantitative compositional data also indicate progradative-retrogradative trends in the macrolithologically monotonous shallow-water succession and enable its stratigraphic correlation with successions from deeper-water environments. Generally, the stratigraphic trends of the clr data are more sensitive to subtle changes in allochem composition in comparison to the results based on raw data. A heterozoan-dominated allochem association in shallow-water environments of the Praha Formation supports the carbonate ramp environment assumed by previous authors.
Permanent Link: http://hdl.handle.net/11104/0272951