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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
May 21-26, 200617th International Symposium on
Analytical & Applied Pyrolysis, Budapest, Hungary
Plant chemotaxonomy
Many bioterpenoids have a chemotaxonomic value and are
specific of certain plant taxa
Molecular composition :- lignin- carbohydrates- lipids like terpenoids
conifers
abietic acid
Angio-sperms
lupeol
Transport and diagenesis of terpenoids
BIOSPHERE
GEOSPHERE
Sedimentary basins
transport
sedimentbioterpenoids
Geoterpenoids ormolecular biomarkers
Diagenetic
transformations
Geoterpenoids can keep the initial chemotaxonomic value
conifers
Angio-sperms
conifers
Angio-sperms
Plant biomarkers distribution as palaeofloristic proxy
Terrestrial floraat the time
of the deposition
angiospermspines pines
cypress
sequoia
Land plant biomarkers
distribution in sediment
ferns
paleoflora reconstruction
The distribution of plant biomarkers in sediments & rocks is a proxy of the terrestrial palaeoflora at the time
of the deposition
Relations between floras and climates
Desertic climate
Temperate climate
Tropical climate
Polar climate
flora ↔ climate
Chemostratigraphy of vascular plant biomarkers
Stratigraphicrecord
palaeobiodiversity
paleoflora
palaeoclimate
T°, humidity
desertic climate
Geolo
gic
al ti
mes
tropical climate
temperate climate
Molecularfacies
Advantages & disadvantages of palaeochemotaxonomy
BOTANICAL PALEOCHEMOTAXONOMY (plant biomarkers assemblages)
BUT macrofossil plants are rare
classically used for the
reconstruction of
palaeofloras and
palaeoclimates
PALEOBOTANY(fossil plants assemblages)
PALYNOLOGY(spore & pollen assemblages)
BUT spores and pollen are noteasily related to plant taxa
- widespread in the stratigraphic record
- related to plant taxa when they have a palaeochemotaxonomic value
WHILE plant biomarkers are :
HOWEVER, presently molecular databases contain many gaps
Aims of experimental palaeochemotaxonomy
➜ 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
In order to fill these gaps :
➜ 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
Aims 1 and 2
➜ Pyrolysis of a Pinaceae (Abies pinsapo)
Fresh Abies pinsapoMethylated total fraction
Retention time
Diagenetic evolution of abietanoic acids
Fresh Abies pinsapo contain large amountsof abietanoic acids
Experimental procedure
Fresh plant Sealed gold tubes Confined pyrolysis
Extraction of terpenoidsCH2Cl2
Analysis by GC-MS
Aliphatics
Aromatics
Polar
Fractionation
Calibration of the pyrolysis temperature
150°C
200°C
250°C
280°C
300°C
Other pyrolysis parameters :duration : 24 h ;pressure : 700 bar.
Diagenetic pathway of abietic acid
280°C Presence ofaromatic diterpanes
Pyrolysed Abies pinsapoTotal fractionm/z 219, 223, 237, 239, 241
Generation of saturated diterpanes
phytene
280°C
280°C presence of diterpanesclassically detected
in the geosphereLiAlH4
Unsaturated abietanes
not satisfying
Pyrolysis with LiAlH4
Pyrolysed Abies pinsapoAliphatic fraction TIC
280°CSaturatedabietanes
labdanes
Diterpane diagenesis
Pyrolysed Abies pinsapoAliphatic fraction TIC
Palaeochemotaxonomy of a virtual fossil Abies pinsapo
Pyrolysed Abies pinsapoAliphatic fraction TIC
Pyrolysed Abies pinsapoAromatic fraction TIC
pyrolysed Abies pinsapoPolar fraction TIC
with LiAlH4
280°C
WithoutLiAlH4
280°C
withoutLiAlH4
280°C
Summary of the experimental procedure
Aliphatic fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITH LiAlH4
Aromatic fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITHOUT LiAlH4
Polar fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITHOUT LiAlH4
Determination/prediction of the fossil molecular signatureof 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
Experimental palaeochemotaxonomy of conifers
➜ Aim 3 : investigate the palaeochemotaxonomy of the conifers using our experimental procedure
The conifers order is composed of 7 families :Araucariaceae
2 Araucaria
Cupressaceae1 Chamaecyparis & 2 Juniperus
Pinaceae 1 Abies (fir), 1 Cedrus (cedar) & 1 Picea (spruce)
Podocarpaceae2 Podocarpus
Sciadopityaceae1 Sciadopitys
Taxaceae1 Taxus (yew)
Taxodiaceae1 Sequoiadendron, 1 Metasequoia, 1 Cryptomeria & 1 Taxodium
17 conifer species were studied forexperimental palaeochemotaxonomy
Experimental palaeochemotaxonomy of conifers
Each conifer family is characterized by its own molecular signature
Araucariaceae
Cupressaceae
Chamaecyparis
Juniperus
Araucaria
Tetracyclic diterpanes
Abietic acid derived abietanes
Keto-phenolic abietanes
cedrane
+++++ absent
…
absent(ent-beyeraneor kauranes)
++++(ent-beyerane)
+ ++++
++
Relative abundance in chromatograms
High: ++++ Low: +
++++++ ++++
absent
1) Our confined pyrolysis procedure of extant land plants
allowsto experimentally generate biomarkers consistent with those encountered in the fossil record
Confined pyrolysis of extant land plants
allows to significantly improve the paleochemotaxonomy
of fossil plants
Conclusions
Thank you for your attention
2) The reaction products are consistent with the
diagenetic pathways of fossilization for biomarkers
3) Many biomarkers distributions obtained are of
palaeochemotaxonomic value
Conclusions
Thank you for your attention
Many compounds in the pyrolysates remain unidentified and may have a useful
palaeochemotaxonomic value
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 of labdanes 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
The pyrolysis of these conifers show :
These biomarkers originate from all conifers familiesand are very frequent in sediments & sedimentary rocks
1) Many biomarkers are present in all pyrolysates :- Many sesquiterpenoids
cadinanes dihydro-ar-curcumene
many sesquiterpenoidse.g. eudesmanes, ionene
- C29 steranes and steroids
Experimental palaeochemotaxonomy of conifers
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