Jiri Fryda | Czech University of Life Sciences Prague (original) (raw)

Papers by Jiri Fryda

Palaeobiodiversity and Palaeoenvironments, Apr 20, 2017

Conodonts, foraminifers and inorganic carbon isotopes (d13Ccarb) from the Lower/Middle Tournaisia... more Conodonts, foraminifers and inorganic carbon isotopes (d13Ccarb) from the Lower/Middle Tournaisian were studied in the high-resolution manner in the Lesni lom and Anaklety sections and preliminary results are presented herein.

Stabilni izotopy uhliku byly studovany v hranicnim intervalu devon-karbon v jizni casti Moravskeh... more Stabilni izotopy uhliku byly studovany v hranicnim intervalu devon-karbon v jizni casti Moravskeho krasu. Zvysene hodnoty d13C z profilu v Lesnim lomu jsou korelovany s podobne vysokymi hodnotami na jinych svetovych profilech a mohou byt spojene s anoxickou fazi hangenberskeho eventu.

The current state of the Devonian-Carboniferous (D-C) boundary definition is a subject of wide cr... more The current state of the Devonian-Carboniferous (D-C) boundary definition is a subject of wide criticzm. Based on the gamma-ray spectrometry, magnetic susceptibility, stable carbon isotope and element (EDXRF) geochemistry were carried out correlations between the most important D-C boundary sections in the Europe. Positive shift of the carbon isotopes, decrease of the Th/U (paleo-redox proxy for lowering of the oxygenation) and consequent increase of the gamma-ray and magnetic susceptibility signal just bellow the D-C boundary are the most distinct correlatable patterns between the majority of the studied sections. Using of the quantitative multi-instrumental methods bring objective correlation and upgrade the former biostratigraphic correlations.

The Devonian–Carboniferous system boundary (DCB), as defined by the GSSP at La Serre, southern Fr... more The Devonian–Carboniferous system boundary (DCB), as defined by the GSSP at La Serre, southern France, has been critically revised in recent years. Currently, there is ongoing debate on the choice of better criteria for the DCB redefinition. As neither conodonts nor foraminifers can provide a satisfactory candidate, a cyclo- and event stratigraphic approach, based on petrophysical and geochemical proxies, can provide an auxiliary solution. The geochemical record in the deep-and shallow-water sections with otherwise indistinct facies shifts suggests that the latest Famennian sea-level fall affected all these marine environments ranging from shallow water into the pelagic.

The GSSP of the Devonian-Carboniferous (D-C) boundary is currently subject of extensive criticism... more The GSSP of the Devonian-Carboniferous (D-C) boundary is currently subject of extensive criticism due to the problems with the first appearance datum of the conodont Siphonodella sulcata. The multiphase Hangenberg Event (HBE), a sedimentary record of environmental perturbations at the end of the Famennian was proposed as an alternative solution (Walliser, 1986). However, multi-proxy approach is necessary for understanding which of the event phases is really of global importance and hence useful for correlations and new definition. Carbon and oxygen isotope chemostratigraphic studies have been carried out in the European and North American sections recently (e.g. Kaiser et al. 2008). At present, the positive shift of carbon isotopes at the base or within the HBE interval is the most distinct correlative feature. This contribution presents new results of high-resolution element (EDXRF) and bulk stable carbon isotope geochemistry survey of the D-C boundary sections from the Moravian Ka...

This contribution is focused on a high-resolution multidisciplinary research of three Devonian-Ca... more This contribution is focused on a high-resolution multidisciplinary research of three Devonian-Carboniferous boundary sections (Gendron-Celles, Rivage, Les Ardennes) in shallow-water carbonate rocks (outer to inner ramp depositional settings) from the Namur-Dinant Basin (Belgium and northern France). The aim of the research was to provide a clearer correlation supported by objective, independent and quantitative proxies used also herein for paleoenvironmnetal reconstructions.

Secondary shell deposits are described in a new plectonotid genus, Blodgettinotus, from the Bouco... more Secondary shell deposits are described in a new plectonotid genus, Blodgettinotus, from the Boucotonotus-Palaeozygopleura Community of the Prague Basin (Bohemia). The new taxon was found in the uppermost part of the T ̄ebotov Limestone (Daleje-T ̄ebotov Formation; late Emsian, late Early Devonian). The genera Boucotonotus and Blodgettinotus share some shell characters and are placed in a new tribe Boucotonotini of the subfamily Plectonotinae. The occurrence of secondary shell deposits in bellerophontiform molluscs is discussed. It is suggested that they were developed independently in several groups of these molluscs; thus, this feature has limited significance for their suprageneric classification.

Life, 2021

The most ancient macroscopic plants fossils are Early Silurian cooksonioid sporophytes from the v... more The most ancient macroscopic plants fossils are Early Silurian cooksonioid sporophytes from the volcanic islands of the peri-Gondwanan palaeoregion (the Barrandian area, Prague Basin, Czech Republic). However, available palynological, phylogenetic and geological evidence indicates that the history of plant terrestrialization is much longer and it is recently accepted that land floras, producing different types of spores, already were established in the Ordovician Period. Here we attempt to correlate Silurian floral development with environmental dynamics based on our data from the Prague Basin, but also to compile known data on a global scale. Spore-assemblage analysis clearly indicates a significant and almost exponential expansion of trilete-spore producing plants starting during the Wenlock Epoch, while cryptospore-producers, which dominated until the Telychian Age, were evolutionarily stagnate. Interestingly cryptospore vs. trilete-spore producers seem to react differentially to...

Palaeobiodiversity and Palaeoenvironments, 2020

Fossil Imprint, 2019

The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily re... more The lower Silurian strata of the Prague Basin, as well as in many other regions, are primarily represented by black shales, with limited to no record of benthic life. In this paper, we describe an exceptional late Aeronian volcanic-carbonate succession from the Hýskov locality near Beroun, which contains a diverse and well-preserved fossil assemblage and specific microfacies features. The studied section is mostly represented by well-washed, poorly sorted skeletal grainstones, rudstones and floatstones along with volcaniclastic material. The environment is interpreted as agitated, above storm wave base, and with rapid sedimentation and burial. The collection of acid-resistant microfossils includes abundant scolecodonts, conodonts and chitinozoans, of which only the chitinozoans have previously been studied. The scolecodonts recovered represent at least 14 polychaete genera and 20 species. The fauna bears a great similarity to the early Silurian assemblages previously reported from B...