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