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Artificial maturation of conifers by confined pyrolysis

Artificial maturation of conifers by confined pyrolysis Contribution to palaeofloral and palaeoclimatic reconstructions. HAUTEVELLE Yann, MICHELS Raymond, LANNUZEL Frédéric * , FARRE Bastien, MALARTRE Fabrice, TROUILLER Alain.

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Artificial maturation of conifers by confined pyrolysis

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  1. Artificial maturation of conifers by confined pyrolysis Contribution to palaeofloral and palaeoclimatic reconstructions HAUTEVELLE Yann, MICHELS Raymond, LANNUZEL Frédéric *, FARRE Bastien, MALARTRE Fabrice, TROUILLER Alain 17th International Symposium on Analytical & Applied Pyrolysis, Budapest, Hungary May 21-26, 2006

  2. Plant chemotaxonomy • Molecular composition : • lignin • carbohydrates • lipids like terpenoids abietic acid conifers lupeol Angio- sperms Many bioterpenoids have a chemotaxonomic value and are specific of certain plant taxa

  3. Transport and diagenesis of terpenoids transport conifers Angio- sperms Diagenetic transformations conifers Angio- sperms Geoterpenoids can keep the initial chemotaxonomic value Geoterpenoids or molecular biomarkers BIOSPHERE Sedimentary basins bioterpenoids sediment GEOSPHERE

  4. Plant biomarkers distribution as palaeofloristic proxy paleoflora reconstruction pines pines angiosperms cypress sequoia ferns The distribution of plant biomarkers in sediments & rocks is a proxy of the terrestrial palaeoflora at the time of the deposition Land plant biomarkers distribution in sediment Terrestrial flora at the time of the deposition

  5. Relations between floras and climates flora ↔ climate Temperate climate Desertic climate Tropical climate Polar climate

  6. Chemostratigraphy of vascular plant biomarkers    temperate climate    Geological times tropical climate   desertic climate palaeobiodiversity palaeoclimate T°, humidity paleoflora  Stratigraphic record Molecular facies

  7. Advantages & disadvantages of palaeochemotaxonomy PALEOBOTANY (fossil plants assemblages) classically used for the reconstruction of palaeofloras and palaeoclimates BUT macrofossil plants are rare PALYNOLOGY (spore & pollen assemblages) BUT spores and pollen are not easily related to plant taxa BOTANICAL PALEOCHEMOTAXONOMY(plant biomarkers assemblages) WHILE plant biomarkers are : - widespread in the stratigraphic record - related to plant taxa when they have a palaeochemotaxonomic value HOWEVER, presently molecular databases contain many gaps

  8. Aims of experimental palaeochemotaxonomy In order to fill these gaps : ➜ innovative experimental approach based on artificial maturation of extant plants by confined pyrolysis ➜ simulation of the diagenesis ➜ Aims 1 : determine the pyrolysis parameters for which the broadest distribution of plant biomarkers is obtained ➜ Aims 2 : verify the consistency with the plant biomarkers of the geological record ➜ Aims 3 : apply the procedure to a large set of extant plants in order to construct a palaeochemotaxonomic database

  9. Aims 1 and 2 Fresh Abiespinsapo Methylated total fraction Fresh Abies pinsapo contain large amounts of abietanoic acids Diagenetic evolution of abietanoic acids Retention time ➜ Pyrolysis of a Pinaceae(Abies pinsapo)

  10. Experimental procedure Fresh plant Sealed gold tubes Confined pyrolysis Aliphatics Aromatics Polar Extraction of terpenoids CH2Cl2 Fractionation Analysis by GC-MS

  11. Calibration of the pyrolysis temperature 280°C Presence of aromatic diterpanes Pyrolysed Abiespinsapo Total fraction m/z 219, 223, 237, 239, 241 150°C 200°C Diagenetic pathway of abietic acid Other pyrolysis parameters : duration: 24 h ; pressure :700 bar. 250°C 280°C 300°C

  12. Generation of saturated diterpanes Unsaturated abietanes not satisfying Pyrolysed Abiespinsapo Aliphatic fraction TIC Pyrolysis with LiAlH4 280°C Saturated abietanes 280°C presence of diterpanes classically detected in the geosphere labdanes LiAlH4 phytene Pyrolysed Abiespinsapo Aliphatic fraction TIC 280°C Diterpane diagenesis

  13. Palaeochemotaxonomy of a virtual fossil Abies pinsapo 280°C with LiAlH4 280°C Without LiAlH4 Pyrolysed Abiespinsapo Aliphatic fraction TIC Pyrolysed Abiespinsapo Aromatic fraction TIC 280°C without LiAlH4 pyrolysedAbiespinsapo Polar fraction TIC

  14. Summary of the experimental procedure Determination/prediction of the fossil molecular signature of the pyrolysed plant The reproduction of this procedure on a great number of plant taxa will considerably increase our knowledge in palaeochemotaxonomy and contribute to the reconstruction of ancient flora Aliphatic fraction Time :24 h, pressure :700 bar,temperature :280°C,WITH LiAlH4 Aromatic fraction Time :24 h, pressure :700 bar, temperature:280°C,WITHOUT LiAlH4 Polar fraction Time :24 h, pressure :700 bar, temperature:280°C,WITHOUT LiAlH4

  15. Experimental palaeochemotaxonomy of conifers 17 conifer species were studied for experimental palaeochemotaxonomy ➜ Aim 3 : investigate the palaeochemotaxonomy of the conifers using our experimental procedure The conifers order is composed of 7 families : Araucariaceae 2 Araucaria Cupressaceae 1 Chamaecyparis &2 Juniperus Pinaceae 1 Abies (fir),1 Cedrus (cedar) &1 Picea (spruce) Podocarpaceae 2 Podocarpus Sciadopityaceae 1 Sciadopitys Taxaceae 1 Taxus (yew) Taxodiaceae 1 Sequoiadendron,1 Metasequoia,1 Cryptomeria &1 Taxodium

  16. Experimental palaeochemotaxonomy of conifers Relative abundance in chromatograms High: ++++ Low: + Each conifer family is characterized by its own molecular signature … Abietic acid derived abietanes Keto-phenolic abietanes Tetracyclic diterpanes cedrane Araucariaceae ++++ + Araucaria absent absent (ent-beyerane or kauranes) Cupressaceae + ++++ ++++ absent Chamaecyparis (ent-beyerane) ++++ ++++ ++ ++ Juniperus

  17. Conclusions Confined pyrolysis of extant land plants allows to significantly improve the paleochemotaxonomy of fossil plants Thank you for your attention 1) Our confined pyrolysis procedure of extant land plants allows to experimentally generate biomarkers consistent with those encountered in the fossil record 2) The reaction products are consistent with the diagenetic pathways of fossilization for biomarkers 3) Many biomarkers distributions obtained are of palaeochemotaxonomic value

  18. Conclusions Many compounds in the pyrolysates remain unidentified and may have a useful palaeochemotaxonomic value Thank you for your attention

  19. Experimental palaeochemotaxonomy of conifers - Pinaceae + Absence of tetracyclic diterpanes + High abundance of abietanes deriving from abietic acid and not from cétono-phenolic abietanes - Podocarpaceae + Absence of tetracyclic diterpanes + High abundance of abietanes deriving from cétono-phenolic abietanes and not from abietic acid - Sciadopityaceae + Abundance oflabdanes and tetracyclic diterpanes + Low abundance of abietanes deriving from abietic acid and not from cétono-phenolic abietanes The pyrolysis of these conifers show : 2)Each conifer family is characterized by its own molecular signature

  20. Experimental palaeochemotaxonomy of conifers 1)Many biomarkers are present in all pyrolysates : - Many sesquiterpenoids cadinanes dihydro-ar- curcumene many sesquiterpenoids e.g. eudesmanes, ionene - C29 steranes and steroids These biomarkers originate from all conifers families and are very frequent in sediments & sedimentary rocks The pyrolysis of these conifers show :

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