Palynologists and Plant Micropalaeontologists of Belgium (PPMB) Latest Developments in Palynology and Palaeobotany

volume Page 1 PROGRAM 10h00-10h20: E. Pétus, P. Gerrienne & C. Prestianni Physostoma cf. stellatum Holden : a Bashkirian spermatophyte from Bouxharmont (Belgium). 10h20-10h40: C. Prestianni, D. Fokan & P. Gerrienne Record of wildfires in the Famennian of Belgium. 10h40-11h00: P. Gonez & P. Gerrienne Comments on Cooksonia, a basal Eutracheophyte. 11h00-11h20: P. Gerrienne, C. Strullu-Derrien & P. Steemans A Lilliputian lignophyte from the Lower Devonian? 11h20-12h00: P. K. Strother The Cambro-Ordovician "Cryptospore" Record and its Significance for the Origin of Land Plants. 12h00-14h00: Dinner at University restaurant 14h00-14h20: T. Servais The Great Ordovician Biodiversification Event: linked to a (phyto-) plankton revolution? 14h20-14h40: J. Mortier The Upper Ordovician to Silurian Tihange section, Condroz Inlier: a lithoand biostratigraphical study. 14h40-15h00: J. Verniers Chitinozoans from the Ordovician-Silurian transition in the Röstanga borehole (Scania, Sweden). 15h00-15h20: C. Cornet, L. Fontaine & J. Dagnelie Miocene marine diatom biostratigraphy of Mem Moniz (Algarve, Portugal). 15h20-15h40: Coffee break 15h40-16h00: F. Damblon, M. Court-Picon, D. Bonjean & S. Pirson Current palaeobotanical research on the Scladina cave (Meuse basin, Belgium). 16h00-16h20: L. Vrydaghs Entre prairies et labours : l’analyse phytolitairenne des lames minces des terres noires bruxelloises (10 – 13 è siècles AD). 16h20-16h50 : E. Roche Palynologie du Quaternaire: distinguer les effets climatiques des effets anthropiques, mythe ou réalité ? Deux exemples: la Tunisie septentrionale et l'Afrique centrale. 16h50-17h10: F. De Vleeschouwer, C. Luthers, D. Mauquoy, C. Wastiaux, G. Le Roux, J. Pawlyta, A. Pazdur, J.Sikorski, & N. Piotrowska Multiproxy study in the Misten bog (East Belgium) during the last millenium. Palaeoclimatic vs. anthropogenic signals. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 2 Miocene marine diatom biostratigraphy of Mem Moniz (Algarve, Portugal)volume Page 2 Miocene marine diatom biostratigraphy of Mem Moniz (Algarve, Portugal) C. Cornet, L. Fontaine & J. Dagnelie University of Namur, Department of Geology The white marls of Mem Moniz (Algarve, south of Portugal) contain many microfossils : calcareous nannofossils, foraminifera, diatoms and siliceous spicules. The diatoms of the five samples studied are marine and characteristic of coastal regions. The most abundant are : Paralia sulcata, Pseudopodosira westii, Thalassionema nitzschioides and Thallassiothrix longissima. The following stratigraphically important species are also present : Actinocyclus ellipticus, Actinocyclus ingens, Denticulopsis punctata var. hustedtii, Hemidiscus cuneiformis, Nitzschia praereinholdi, Thalassiosira yabei and Andrewsiella fossilis. These allow to link the samples of Mem Moniz to the diatom unitary association U.A.5 defined by Monjanel (1987). This unitary association has been compared with the diatom zonation established for the low latitudes of the equatorial pacific ocean by Baldauf and Iwai (1995) and can be placed at the level of the Craspedodiscus coscinodiscus and Actinocyclus moronensis zones. The presence at Mem Moniz of Denticulopsis punctata var. hustedtii allows to locate the samples in the Craspedodiscus coscinodiscus zone. In this study, the diatom zonations are correlated with the geologic time scale of 2004. This allows to suggest the samples cover the late Serravallian early Tortonian. Calcareous nannoplanckton has been studied by Cachao (1995). It allows to locate the outcrop in the CN5a of Okada & Bukry (1980) of the Serravallian. On the other hand, planktonic foraminifera determine the N16 or even N17 zone, defined by Blow (1969), corresponding to Tortonian (Antunes et al.1981, 1990, 1992). An isotopic dating Sr/Sr performed on planktonic foraminifera shows an age of 12.5 (+0.7/-1.7) million years, i.e. Serravallian. The diatom biostratigraphy presented here agrees well with calcareous nannofossil biostratigraphy and the Sr/Sr dating. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 3 Current palaeobotanical research on the Scladina cave (Meuse basin, Belgium)volume Page 3 Current palaeobotanical research on the Scladina cave (Meuse basin, Belgium) F. Damblon*, M. Court-Picon*, D. Bonjean** & S. Pirson* * Royal Belgian Institute of Natural Sciences ** ASBL Archéologie Andennaise The palynological records from cave infillings in north west Europe are often deceiving due to complex taphonomic processes leading to corrosion, intrusion or reworking of pollen grains through the deposits. Moreover, the stratigraphic sequence which support any complementary palaeoenvironmental investigation generally appears as not enough precise and reliable. The excavation made at Scladina cave by the team of D. Bonjean was the opportunity to improve the geological approach of the Pleistocene loessic deposits with a fine microstratigraphical study and gain new pollen data with regard to previous results obtained by Bastin (1992). Here we present a first set of pollen spectra distributed in the full sequence of deposits completed with charcoal found in some layers, both detritic and stalagmitic. The direct link between the detailed stratigraphy and the palaeobotanical results leads to a coherent interpretation of the sedimentary dynamics and the corresponding environment along the sequence. The largest part of the loessic sequence points to cold steppe environments while humic layers and soil horizons record climatic improvements favouring expansions of trees such as pine during the weakest ones. On the contrary, a clear development of mesophilous tree taxa (oak, ash, elm, ..) is recorded in the biggest stalagmitic floor CC4. Significant amounts of spruce (Picea) are also recorded in some humic layers. Such results confirm the data of Bastin in broad line but a fine connection between them is still in work notably due to the difference in precision of the previous and the new stratigraphical approaches. This needs further pollen and charcoal analyses, mainly on stalagmites but also on some loess layers, with the goal of improving the climatostratigraphical interpretation. A better knowledge of the chronostratigraphical framework is also absolutely necessary to position these climatic fluctuations in the Upper Pleistocene reference sequence. A major aspect standing out from all these results is the importance of a strong interdisciplinary approach in the study of cave entrance sedimentary sequences. Each discipline brings some information but only the confrontation of all the data allows a reliable interpretation. Excellent complementarities of geology and palaeobotany are worth mentioning. A direct consequence from these results in a next future is that they should lead to a better understanding of the climatic fluctuations and the palaeoenvironment in Belgium during the last glacial as well as a better knowledge of the context of the numerous archaeological and palaeoanthropological remains from cave entrance sequences. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 4 Multiproxy study in the Misten bog (East Belgium) during the last millenium. Palaeoclimatic vs. anthropogenic signals.volume Page 4 Multiproxy study in the Misten bog (East Belgium) during the last millenium. Palaeoclimatic vs. anthropogenic signals. F. De Vleeschouwer 1,2 , C. Luthers 3 , D. Mauquoy 4 , C. Wastiaux 5 , G. Le Roux 1 , J. Pawlyta 2 , A. Pazdur 2 , J.Sikorski 2 , and N. Piotrowska 2 1 U.R. Argiles, Géochimie et Environnements Sédimentaires, Géologie, ULg, Liège, Belgium. www2.ulg.ac.be/urap 2 GADAM Centre, Institute of Physics, Silesian University of Technology, Gliwice, Poland. www.carbon14.pl 3 U.R. Paléobotanique, Paléopalynologie et Micropaléontologie, Géologie, ULg, Liège, Belgium. www2.ulg.ac.be/palyno 4 Department of Geography and Environment, University of Aberdeen, Aberdeen, United Kingdom. www.abdn.ac.uk/geography 5 Station Scientifique des Hautes Fagnes, ULg, Robertville. www2.ulg.ac.be/sshf Strong pollution over East Belgium during the last two millennia has been characterised a few years ago using geochemical records in the Misten Bog, an ombrotrophic bog located in the Hautes-Fagnes Plateau (East Belgium). While the Roman period and the industrial revolution are evidenced by elevated concentration in lead and associated heavy metals, the Middle Ages display low heavy metal concentrations. Possible explanations are either a loss of knowledge in mining techniques, or an external factor causing reduced human activities. In February 2008, a new core was therefore taken, with the purpose of investigating proxies giving indication on climatic conditions over the past 1000 years. We present here a series of biological and geochemical proxies: pollen, macrofossils, humification and δ13C. These proxies are accompanied by 14 radiocarbon dates performed by accelerator mass spectrometry on carefully selected Sphagnum macrofossils. Preliminary interpretations indicate that a series of proxies show similar trends between 1200 and 1800 AD. These similar trends mirror hydrological changes in the bog, possibly triggered by the Little Ice Age cold events. The Little Ice Age may therefore be a plausible explanation to reduced human activities in East Belgium during this time span. This study also emphasizes the fact that, conversely to studies dealing with pollution using geochemical proxies, palaeoclimatic studies in peat bogs need as much proxies as possible, together with highly accurate age-model. Therefore, in a near future, these different analyses will be undertaken on two more short cores, in order to test the reproducibility of the various proxies and their interpretation. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 5 A Lilliputian lignophyte from the Lower Devonian?volume Page 5 A Lilliputian lignophyte from the Lower Devonian? P. Gerrienne, C. Strullu-Derrien & P. Steemans PPM, Dept of Geology, Liège University The lignophytes are the plants that possess a bifacial vascular cambium, producing secondary phloem (inner bark) towards the outside and secondary xylem (wood) towards the inside. Thanks to this innovation, lignophytes evolved the tree habit which allowed those plants reaching much greater heights, increasing mechanical stability, propagule dispersion and light interception efficiency. Lignophytes have the ability to achieve the largest and most complex bodies in the plant kingdom. Their advent during the Devonian is therefore a major event in the history of life. It had a profound impact on terrestrial environments, as lignophytes also evolved long-lived roots which had major implications on the elaboration of early soils and complex microbial communities. To date, the earliest remains of lignophytes are included in the Aneurophytales (Middle to Upper Devonian) and possibly in the Stenokoleales (Middle Devonian to Lower Carboniferous). Members of both orders were medium-sized plants or shrubs. The earliest truly arborescent lignophytes belong to the Archaeopteridales, which had a cosmopolitan distribution at the end of the Devonian. The present work is the description of a possible early representative of the lignophytes from Châteaupanne quarry (Montjean-sur-Loire, Armorican Massif, France). Based on spores, the locality is attributed to the Lower Devonian (Pragian or less probably early Emsian). During a recent re-investigation of the flora from the quarry, we have found a new fossiliferous layer which yielded a large collection of a pyritised tiny plant. Nothing is known on the external morphology of the plant, but its anatomical structure is partly preserved. Axes are 1-3 mm in diameter. In transverse section, a massive circular xylem strand is visible, with an elongated centrarch protoxylem area. Metaxylem is comprised of P-type tracheids with scalariform pitting. In many specimens, the central part of the strand with randomly arranged tracheids is surrounded by a zone of tracheids placed in radial rows. Up to now, it has not been possible to decide if those radially disposed tracheids were aligned primary xylem (produced by the procambium) or secondary xylem (produced by the cambium). Nevertheless, such an internal organization had never been observed in any Lower Devonian plant and locates the plant from Châteaupanne at the very base of the lignophyte clade. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 6 Comments on Cooksonia, a basal Eutracheophytevolume Page 6 Comments on Cooksonia, a basal Eutracheophyte P. Gonez & P. Gerrienne PPM, Dept of Geology, Liège University The genus Cooksonia Lang, 1937 is currently considered as including the earliest vascular plants and central to the definition of Eutracheophytes. The circumscription of the genus is however problematical: the original diagnosis is not restrictive enough, and most of the few characters are plesiomorphic. The typespecies, Cooksonia pertoni Lang 1937, is comprised of specimens with slender leafless axes isotomously branched, and terminal trumpet-like sporangia wider than high. Cooksonia paranensis Gerrienne et al., 2001 and C. banksii Habgood et al., 2002 appear morphologically very close to C. pertoni. The only perceptible differences are the following: the axes of C. paranensis and C. banksii are more slender and their sporangium seems to be sunken into the axis. The conspecificity of C. paranensis and C. banksii, respectively described from compression fossils and three-dimensionally preserved specimens, is also discussed. An allometric study on more than one hundred specimens of C. paranensis was performed. It allows discriminating between true morphological variation and ontogenetic stages. This allometric study of specimens which are indisputable members of the genus and the re-examination of the type-material itself allow us to suggest more precise diagnostic characters. The latter should be included in an emended diagnosis of the genus. The type-material of another species of Cooksonia, C. caledonica Edwards, 1970, as well as new large specimens, was also studied. The sporangium of that species is clearly different from that of the type-species as it is bivalved and possesses a complex distal structure for dehiscence. The specimens of C. caledonica are compared with those of Sporathylacium salopense Edwards et al., 2001, which show the same sporangial organisation. Our observations should lead to a better circumscription of the genus Cooksonia that may help to produce more accurate phylogenies of early vascular plants. MVP-PPMB meeting Liège, November 27, 2008 Abstract volume Page 7 The Upper Ordovician to Silurian Tihange section, Condroz Inlier: a lithoandvolume Page 7 The Upper Ordovician to Silurian Tihange section, Condroz Inlier: a lithoand biostratigraphical study