Fossil wood from the Miocene and Oligocene epoch: chemistry and morphology

Abstract

Fossil wood is the naturally preserved remain of the secondary xylem of plants that lived before the Holocene epoch. Typically, fossil wood is preserved as coalified or petrified and rarely as mummified tissue. The process of fossilization is very complex and it is still unknown why in the same fossil record, wood can be found in different fossilisation forms. In 2007, a fossil forest was found in the Bükkábrány open-pit coal mine in Hungary. The non-petrified forest is estimated to be 7 million years old (Miocene epoch) and its trees were found standing in an upright position. This fossil assemblage is exceptionally rare because wood has been preserved as soft waterlogged tissue. This study aimed to investigate this remarkable way of fossil wood preservation, by examining its chemistry with (13)C CPMAS NMR and its morphology with light and electron microscopy. For comparison reasons, a petrified wood trunk from the Oligocene epoch (30 Myr) found in 2001 at Porrentruy region in Switzerland and two fresh wood samples of the modern equivalents of the Miocene sample were also examined. The results obtained showed that the outstanding preservation state of the Miocene fossil is not owed to petrification or coalification. Mummification is a potential mechanism that could explain Bükkábrány trunks' condition, however this fossilisation process is not well studied and therefore this hypothesis needs to be further investigated.

Three new Miocene fungal palynomorphs from the Brassington Formation, Derbyshire, UK

“…Additionally, as we are able to recognize both anamorphs and teleomorphs, we are able to define fossil holomorphs of fungi, a practice key to providing fossil evidence supporting molecular phylogenies. wood from the Bükkábrány fossil forest in Hungary (Erdei et al 2009;Bardet & Pournou 2015;Nikolouli et al 2016) and biomarkers (that may be indicative of fungi) have been extracted from North Alpine Foreland Basin and Lubstów deposit woods (Bechtel et al 2007;2008). Like initial research on the Brassington Formation, palynological studies of these sites have typically been focussed on the pollen and spore content to reconstruct vegetation, with fungal remains either left unidentified or subject to ongoing research (Boulter 1971;Erdei et al 2009;Worobiec 2009;Worobiec et al 2009;Pound & Riding 2016;Worobiec & Worobiec 2017).…”

Late Tertiary Petrified Wood from Nevada, USA: Evidence of Multiple Silicification Pathways

“…Wood buried in an anaerobic environment (e.g., impervious clay) may be protected from microbial degradation, preserved in an unmineralized state [42,43]. Carbonized wood specimens were observed at only one locality, the Royal Peacock opal mine at Virgin Valley (locality 2).…”

Analysis of water content in wood material through 1D and 2D 1H NMR relaxometry: Application to the determination of the dry mass of wood

“…This makes NMR relaxometry an excellent tool due to its short experimental time and noninvasive and nondestructive nature. It should be noted that these NMR relaxometry experiments are carried out on low-field NMR permanent magnets, contrary to high-field NMR used to quantify and characterise wood polymers in solution [33] and solid state [34]. As experiments were performed over several months, the performance of the NMR instrument was verified by running a standard reference.…”