Fossil samples of Pinus sylvestris found near Siena (Tuscany, Italy) in geological formations 2-3 million years old were chemically examined in order to solve the problem of the contrast between the age of geological formations and their good degree of preservation.Comparison with a living Pinus sylvestris was carried out on standard wood component analyses, cation exchange capacity and residual terpene content. The analyses of wood components were close to those of the reference pine, whilst the cation exchange capacity values showed remarkable changes. The increase of salt carboxyls suggested the hydrolysis of ester carboxyls originally present, whilst the reduction of total carboxyls revealed a partial loss of hemicelluloses. Both changes were attributed to the percolation of salt-bearing water through the wood, thus causing ester hydrolysis, carboxyl salification and hemicellulose solubilisation. Residual terpene analysis showed, for the first time in a
Barks from the litters of a multiple level Tertiary fossil forest from the Canadian Arctic were chemically examined and compared with coeval Arctic fossil woods. Degradation and diagenesis of the polysaccharides similarly occurred in barks and woods. However, unlike the fossil woods, the loss of polysaccharides led to materials exhibiting a marked cation exchange capacity, which is comparable to what is found for humus, the final product of diagenesis of the forest litter. Dichloromethane extracts from the barks invariably showed the presence of n-alkanes from C14 to C30, and terpenes such as cadalene, calamenene, fichtelite, sandaracopimarane, abietatriene, simonellite, diaromatic totarane, ferruginol, dehydroferruginol, and sugiol. The presence of phenol-diterpenes and/or diaromatic totarane was related to species belonging to Cupressaceae, Taxodiaceae and Podocarpaceae, in agreement with the recovery of trunks of metasequoia in some forest levels.
KeywordsFossil bark Fossil woods Wood extractives Terpenes GC/MS Brought to you by | University of Georgia Libraries Authenticated Download Date | 6/2/15 5:59 AM
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