457 research outputs found
The ichnocoenosis of the bottom nepheloid layer (BNL) deposits : a case study from the Scaglia Toscana Formation (Paleogene, central Italy)
No full textSome fine-grained sediments from the Eocene in age Scaglia Toscana Formation in the Northern Apennines (Trasimeno area), previously interpreted as mud-silt turbidites, have been reinterpreted herein as bottom nepheloid layers (BNL). They contain a rich ichnocoenosis dominated by endichnial forms, that formed progressively in line with the slow accumulation rate of mud transported by the oceanic thermohaline bottom currents. In a BNL idealized sequence, a slight upward increasing density of trace fossils, suggests some differences with typical muddy turbidites. Together with sedimentary structures, trace fossils form an ichno-sedimentary sequence through the bed, which is explained by a step by step colonization that accompanies deposition of the bottom nepheloid layer by continuous currents. It is possible that these ichnological features are recurrent and helpful in recognition of similar deposits within other geological contexts
sj-xlsx-1-hol-10.1177_09596836221126130 – Supplemental material for Mammal tracks record anthropogenic environmental influence in late-Holocene inland dunes of the European Sand Belt, Poland
No full textSupplemental material, sj-xlsx-1-hol-10.1177_09596836221126130 for Mammal tracks record anthropogenic environmental influence in late-Holocene inland dunes of the European Sand Belt, Poland by Shannon Hsieh, Krzysztof Ninard, Alfred Uchman, Weronika Łaska and Piotr Łapcik in The Holocene</p
Taphonomy and ichnofabric of the trace fossil Avetoichnus luisae Uchman & Rattazzi, 2011 in Paleogene deep-sea fine-grained turbidites : examples from Italy, Poland and Spain
No full textThe poorly known, helical spiral trace fossil Avetoichnus luisae Uchman & Rattazzi, 2011 has been investigated in fine-grained Paleogene turbidites in Italy, Poland and Spain. It shows a typical stratinomic preservation as endichnia and was developed in turbiditic mud and bioclastic deposits occupying the upper intervals (typically E3-F) of turbidite sequences. Other ichnotaxa occur in deeper levels (e.g., Alcyonidiopsis and Zoophycos in the Trasimeno area), while tree-like forms (e.g., Chondrites intricatus, C. targionii and Cladichnus in the same area), string-like forms (e.g., Planolites or Palaeophycus) and other undetermined burrows are usually found in shallower levels. The distribution of the ichnotaxa indicates an upwards increasing ichnodensity towards the higher intervals in many mud-bioclastic turbidite sequences. Detailed taphonomic analysis of 104 specimens of frequently branched Avetoichnus luisae has shown that a high degree of variation can be observed in their length, general shape, maximum diameter, maximum width of dots, shape of dots, dot distribution, spiral arrangement, central part (axis) and raised edges. These variations suggest that an unknown organism adjusted its activity (agrichnial or fodinichnial) using different strategies in accordance with changes in the turbiditic environment
Probable root structures and associated trace fossils from the Lower Pleistocene calcarenites of Favignana Island, southern Italy : dilemmas of interpretation
No full textTwo types of large, branched structures from the Lower Pleistocene (Calabrian) high-energy calcarenites of Favignana Island are described: Faviradixus robustus gen. et sp. nov. and Egadiradixus rectibrachiatus gen. et sp. nov. They may be interpreted as root structures of large plants, trees and trees or shrubs, respectively. The former taxon co-occurs with the marine animal trace fossils Ophiomorpha nodosa, Ophiomorpha isp., Thalassinoides isp. and Beaconites isp. The interpretation as root structures although tentative is probable and can be related to short emergence episodes for the formation of E. rectibrachiatus or to longer emergence, responsible for the discontinuity at the base of the overlying Tyrrhenian deposits, for F. robustus. Calcified root mats of smaller plants associated with the Tyrrhenian or younger emergence surfaces are common
Konjugáty klastrů bóru jako stavební bloky pro přípravu polymerních nanostruktur
No full textCharles University in Prague Faculty of Science Department of Physical and Macromolecular Chemistry Author: Bc. Filip Steiner Supervisor: prof. RNDr. Pavel Matějíček, Ph.D. Advisor: Ing. Mariusz Uchman, Ph.D. Title: Boron Cluster Conjugates as Building Blocks for the Preparation of Polymeric Nanostructures Abstract This diploma thesis investigates the synthesis and supramolecular behaviour of amphiphilic conjugates of closo-dodecaborate dianion, [B12H12]2- , with polycationic diblock copolymer poly(ethylene oxide)-block-poly(2-(N, N, N', N'-tetramethyl guanidium ethyl acrylate), PEOn-b-PGEAm. The boron cluster dumbbells were synthesised by the exoskeletal, electrophile-induced nucleophilic substitution (EINS) and by subsequently ring-opening reaction with various aliphatic diols, resulting in a hybrid dumbbell molecule. These molecules were used for preparation of nanoparticles by co- assembly with polycationic diblock copolymer in water. Resulted nanostructures were characterised by static and dynamic light scattering and NMR spectroscopy. Keywords: boron cluster compounds, polymeric nanoparticles, co-assembly, NMR, light scatteringUniverzita Karlova v Praze Přírodovědecká fakulta Katedra fyzikální a makromolekulární chemie Autor: Bc. Filip Steiner Vedoucí práce: prof. RNDr. Pavel Matějíček, Ph.D. Konzultant: Ing. Mariusz Uchman, Ph.D. Název diplomové práce: Konjugáty klastrů bóru jako stavební bloky pro přípravu polymerních nanostruktur Abstrakt Tato diplomová práce se zabývá syntézou a supramolekulárním chováním amfifilních konjugátů closo-dodekaborátového dianiontu, [B12H12]2- , s polykationtovým diblokovým kopolymerem poly(ethylen oxid)-b-poly(2-(N, N, N', N'-tetramethylguanidium ethylakrylát), PEOn-b-PGEAm. Konjugáty klastrů bóru byly syntetizovány pomocí exoskeletální, elektrofilem indukované nukleofilní substituce (EINS) a následnou reakcí s různými alifatickými dioly, což vedlo ke vzniku amfifilních molekul činkovitého tvaru. Ty byly následně využity k přípravě nanočástic spoluskládáním s polykationtovými blokovými kopolymery ve vodě. Výsledné nanostruktury byly charakterizovány pomocí statického a dynamického rozptylu světla a spektroskopie NMR. Klíčová slova: klastrové sloučeniny bóru, polymerní nanočástice, spoluskládání, NMR, rozptyl světlaKatedra fyzikální a makromol. chemieDepartment of Physical and Macromolecular ChemistryFaculty of SciencePřírodovědecká fakult
Evolutionary trend of Zoophycos morphotypes from Upper Cretaceous–Lower Miocene in the type pelagic sections of Gubbio, central Italy
No full textAbout 200 Zoophycos specimens, including 90 specimens studied in detail, have been analysed in the continuous Upper Cretaceous–Lower Miocene pelagic sedimentary type sections of the Gubbio area (the Contessa Highway, Contessa Quarry and Bottac- cione sections, Northern Apennines). The sediments are reddish to grey limestones and marls of the Scaglia Group and marls with volcaniclastic deposits of the Bisciaro Formation. The aim was to examine the evolutionary trend of what is probably the most debated trace fossil of all time, from the Upper Cretaceous to Lower Miocene. Despite having been found in beds ranging from the Cambrian to the present, no con- sensus has been reached regarding mode of construction, tracemaker or ethological explanation for Zoophycos. Four Zoophycos morphotypes are recognized at Gubbio showing variations of major and minor lamellae, apex, lobes and whorls: the Cretaceous–Eocene cone-shaped type 1, the Upper Eocene–Middle Oligocene helicoidal type 2, the Oligocene lobate type 3 and the Upper Oligocene–Lower Miocene flat type 4. The very high ichnodensity in some beds (hundreds of specimens in discrete levels of the Bisciaro Formation, now destroyed by quarrying) seems to find explanation in abnormal concentrations of phytodetritus and organic matter on the seafloor in some periods. This very high abundance in discrete levels reflects a change in sedimentation and seafloor conditions at pre-flysch deposition. Due to such high ichnodensity, many adjacent specimens display deformed outer margins. Taphonomic analysis shows a variation of whorls, laminae and U-shaped lobes, reflecting ontoge- netic development of the tracemaker(s) (?sipunculid worms)
The invertebrate trace fossil Labyrintichnus in the Late Triassic red beds of the Argana Basin (Western High Atlas Mountains, Morocco)
No full textLabyrintichnus terrerensis Uchman and Álvaro, 2000, a cylindrical, intrastratal, passively filled trace fossil composed of irregular nets and branched galleries, so far known from Miocene marginal lacustrine clastic sediments, was found in Carnian alluvial-plain sediments of the Argana Basin, Morocco. This is the oldest occurrence of this rarely reported trace fossil. Associated tetrapod footprints and invertebrate trace fossils (Diplopodichnus, Scoyenia, Spongeliomorpha, Taenidium, cf. Helminthoidichnites, and others) point to the Scoyenia ichnofacies typical of inundated and desiccating sediments. Co-occurring current-ripples, mudcracks and raindrop imprints confirm this interpretation. The trace fossils reflect changing consistency from softground (cf. Helminthoidichnites; Diplopodichnus) to firm ground (e.g., Spongeliomorpha). Beside beetles and their larvae, fly larvae are considered as possible tracemakers of shallow Labyrintichnus terrerensis on the basis of similarities to recent burrows
The record of Avetoichnus luisae Uchman & Ratazzi, 2011 in the Iberian Peninsula : facies relations and palaeoenvironmental implications
No full textAvian diversity and behavior in an Eocene coastal plain, Svalbard: the ichnological evidence
No full textThis study presents an ichnotaxonomical assessment of bird footprints from a coastal plain setting in the Eocene lower to middle Aspelintoppen Formation in Brongniartfjellet and Storvola, Svalbard. These footprints are unique evidence for Paleogene birds from Svalbard and the second evidence of Paleogene avifauna of the Arctic (along with scarce fossil remains from Ellesmere Island). The analyzed footprints are assigned to six ichnotaxa belonging to three ichnofamilies: Aquatilavipes isp., avian footprint morphotype A and B (ichnofamily Avipedidae); Gruipeda cf. G. abeli, Gruipeda cf. G. dominguensis (ichnofamily Gruipedidae); and Gyeongsangornipes isp. (ichnofamily unknown). Associated invertebrate ichnofossils include Helminthoidichnites tenuis, Cochlichnus anguineus, and Helminthopsis isp. The avian footprints reflect small, medium-sized and rare large birds that can be morphologically compared to those of modern relatives including crane, heron, plover, moorhen, gallinule, oystercatcher and curlew. It is also proposed that in situ sets of shorebird footprints showing a preferred orientation, not composing trackways and showing overprinting, can be used as an indicator of the position and orientation of the shoreline.Fil: Melchor, Ricardo Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Uchman, Alfred. Jagiellonian University; PoloniaFil: Steel, Ronald J.. University of Texas at Austin; Estados Unido
Comments on the paper "Reconnaissance of Upper Jurassic Morrison Formation ichnofossils, Rocky Mountain Region, USA : paleoenvironmental, stratigraphic, and paleoclimatic significance of terrestrial and freshwater ichnocoenoses" by Stephen T. Hasiotis
No full textHasiotis (2004) has described and interpreted a relatively diverse and potentially very interesting ichnofauna from the Upper Jurassic Morrison Formation of the western United States. An effort was made by the author to bring the data to the reader, but, in our opinion, his analysis is seriously flawed and the resulting discussion and conclusions are not sufficiently supported by data...Fil: Bromley, Richard G.. Geological Institute; DinamarcaFil: Buatois, Luis Alberto. University of Saskatchewan; CanadáFil: Genise, Jorge Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Conrad Labandeira. National Museum of Natural History; Estados UnidosFil: Mángano, M Gabriela. University of Saskatchewan; CanadáFil: Melchor, Ricardo Nestor. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schlirf, Michael. Institut für Paläontologie der Universität; AlemaniaFil: Uchman, Alfred. Jagiellonian University. Institute of Geological Sciences; Poloni
- …
