Thelodont biostratigraphy indicates the extension of the Lower-Middle Devonian palaeobasin in Sva... more Thelodont biostratigraphy indicates the extension of the Lower-Middle Devonian palaeobasin in Svalbard, Norvegian Arctics
Rare earth and trace elements of fossil bioapatite as palaeoenvironmental proxies : the Lower Dev... more Rare earth and trace elements of fossil bioapatite as palaeoenvironmental proxies : the Lower Devonian of the Andree Land, Svalbard
Biostratigraphy of Silurian vertebrates from Gotland, Sweden, revisited : understanding spatial a... more Biostratigraphy of Silurian vertebrates from Gotland, Sweden, revisited : understanding spatial and temporal distributions
Geological Society, London, Special Publications, 2010
The Late Devonian early tetrapods in East Greenland occur in the Celsius Bjerg Group. Key occurre... more The Late Devonian early tetrapods in East Greenland occur in the Celsius Bjerg Group. Key occurrences are located in a detailed stratigraphic section used here to interpret the sedimentary palaeoenvironments. The palaeoenvironment for the Britta Dal Formation (which contains bothIchthyostegaandAcanthostega) is reinterpreted. The Britta Dal Formation channels have flat bases, are poorly channelized, are of low sinuosity and are part of a very major distributory system that periodically experienced extreme flooding. The tetrapod fossils were recovered from an ephemeral system that was not permanently habitable in the immediate area. Plant megafossils are poorly preserved casts and impressions dominated by lycopsids and fern-like plants. The overbank siltstones are dominated by arid soil forming processes and comprise a spectacular sequence of vertisols. The 1174 min situ Ichthyostegalocality in Paralleldal was relocated and occurs just below the midpoint of the second megacycle in the Britta Dal Formation.
Affinity, classification and distribution of Silurian and lowermost Devonian birkeniid anaspid sc... more Affinity, classification and distribution of Silurian and lowermost Devonian birkeniid anaspid scales in the Circum-Arctic, Baltoscandia and Britain.
Late Devonian tetrapod-bearing localities:a review including new data and the need of accurate da... more Late Devonian tetrapod-bearing localities:a review including new data and the need of accurate dating.
Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Po... more Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Słupianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of ‘nostolepid’, poracanthodid and ‘gomphonchid’ types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Słupianka Member based on sequence stratigraphic...
Chemical and isotopic compositions of dental bioapatites have gained wide recognition as paleoenv... more Chemical and isotopic compositions of dental bioapatites have gained wide recognition as paleoenvironmental proxies, first demons trated on modern fish teeth (Longinelli & Nuti 1973a, 1973b; Kolodny et al. 1983) establishing a major link between bioapatite oxygen isotopic compositions and climate (e.g., Trotter et al. 2008; Joachimski et al. 2009; Zigaite et al. 2010; Barham et al. 2012). Advances in analytical techniques and methods (Dettman et al. 2011; Zigaite et al. 2012), as well as most recent experimental work on seabreams (Sparus aurata) by Pucéat et al. (2010) clearly defines the potential of aquatic vertebrate dental biomineral in palaeoenvironmental research. Plesiosaur teeth and lungfish tooth plates from the Lower Cretaceous high-latitude sequences of SE Australia, representing temperate to cold and seasonally freezing environment, were analysed for stable oxygen isotope compositions. Two methods for obtaining 18O/16O ratios have been applied: (1) in-situ 18O measurements of all the fluorapatite oxygen components within the enamel, enameloid and dentine have been carried out using a secondary ion microprobe, and (2) bulk 18O values of the separate phosphatic component of bioapatite have been measured through silver hosphate precipitation and high-temperature reduction mass-spectrometry. Dentine proved to be diagenetically susceptible, showing moderate variations in isotopic values, particularly those obtained by secondary ion microprobe. In contrast, both methods provided highly adequate and repeatable isotopic ratios within the enamel and enameloid in all the examined sequences, independently suggesting freezing climatic conditions, which confirm the existing sedimentological data for permafrost. The rare earth element (REE) abundances, analysed in situ using laser ablation inductively coupled plasma mass-spectrometry, supported the selective geochemical resilience of tissues, favouring enamel as the most reliable biomineral proxy for palaeoclimate research.
Thelodont biostratigraphy indicates the extension of the Lower-Middle Devonian palaeobasin in Sva... more Thelodont biostratigraphy indicates the extension of the Lower-Middle Devonian palaeobasin in Svalbard, Norvegian Arctics
Rare earth and trace elements of fossil bioapatite as palaeoenvironmental proxies : the Lower Dev... more Rare earth and trace elements of fossil bioapatite as palaeoenvironmental proxies : the Lower Devonian of the Andree Land, Svalbard
Biostratigraphy of Silurian vertebrates from Gotland, Sweden, revisited : understanding spatial a... more Biostratigraphy of Silurian vertebrates from Gotland, Sweden, revisited : understanding spatial and temporal distributions
Geological Society, London, Special Publications, 2010
The Late Devonian early tetrapods in East Greenland occur in the Celsius Bjerg Group. Key occurre... more The Late Devonian early tetrapods in East Greenland occur in the Celsius Bjerg Group. Key occurrences are located in a detailed stratigraphic section used here to interpret the sedimentary palaeoenvironments. The palaeoenvironment for the Britta Dal Formation (which contains bothIchthyostegaandAcanthostega) is reinterpreted. The Britta Dal Formation channels have flat bases, are poorly channelized, are of low sinuosity and are part of a very major distributory system that periodically experienced extreme flooding. The tetrapod fossils were recovered from an ephemeral system that was not permanently habitable in the immediate area. Plant megafossils are poorly preserved casts and impressions dominated by lycopsids and fern-like plants. The overbank siltstones are dominated by arid soil forming processes and comprise a spectacular sequence of vertisols. The 1174 min situ Ichthyostegalocality in Paralleldal was relocated and occurs just below the midpoint of the second megacycle in the Britta Dal Formation.
Affinity, classification and distribution of Silurian and lowermost Devonian birkeniid anaspid sc... more Affinity, classification and distribution of Silurian and lowermost Devonian birkeniid anaspid scales in the Circum-Arctic, Baltoscandia and Britain.
Late Devonian tetrapod-bearing localities:a review including new data and the need of accurate da... more Late Devonian tetrapod-bearing localities:a review including new data and the need of accurate dating.
Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Po... more Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Słupianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of ‘nostolepid’, poracanthodid and ‘gomphonchid’ types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Słupianka Member based on sequence stratigraphic...
Chemical and isotopic compositions of dental bioapatites have gained wide recognition as paleoenv... more Chemical and isotopic compositions of dental bioapatites have gained wide recognition as paleoenvironmental proxies, first demons trated on modern fish teeth (Longinelli & Nuti 1973a, 1973b; Kolodny et al. 1983) establishing a major link between bioapatite oxygen isotopic compositions and climate (e.g., Trotter et al. 2008; Joachimski et al. 2009; Zigaite et al. 2010; Barham et al. 2012). Advances in analytical techniques and methods (Dettman et al. 2011; Zigaite et al. 2012), as well as most recent experimental work on seabreams (Sparus aurata) by Pucéat et al. (2010) clearly defines the potential of aquatic vertebrate dental biomineral in palaeoenvironmental research. Plesiosaur teeth and lungfish tooth plates from the Lower Cretaceous high-latitude sequences of SE Australia, representing temperate to cold and seasonally freezing environment, were analysed for stable oxygen isotope compositions. Two methods for obtaining 18O/16O ratios have been applied: (1) in-situ 18O measurements of all the fluorapatite oxygen components within the enamel, enameloid and dentine have been carried out using a secondary ion microprobe, and (2) bulk 18O values of the separate phosphatic component of bioapatite have been measured through silver hosphate precipitation and high-temperature reduction mass-spectrometry. Dentine proved to be diagenetically susceptible, showing moderate variations in isotopic values, particularly those obtained by secondary ion microprobe. In contrast, both methods provided highly adequate and repeatable isotopic ratios within the enamel and enameloid in all the examined sequences, independently suggesting freezing climatic conditions, which confirm the existing sedimentological data for permafrost. The rare earth element (REE) abundances, analysed in situ using laser ablation inductively coupled plasma mass-spectrometry, supported the selective geochemical resilience of tissues, favouring enamel as the most reliable biomineral proxy for palaeoclimate research.
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