Kohlenstoffisotopendaten von tertiären Hölzern der Niederrheinischen Bucht (Carbon Isotope Data of Tertiary Wood Samples from the Lower Rhine Valley)

Abstract

Eight fossil tree trunks taken from various levels in the Tertiary deposits (Middle Miocene to Late Pliocene) of the Lower Rhine Valley were determined taxonomically and their annual rings measured. In addition, the carbon content of annual ring samples was examined by titration, cellulose was extracted and the carbon isotope ratio (¹³C/¹²C) was identified. Coalification experiments carried out in the laboratory showed that with degradation of the cellulose no notable differences could be observed in the δ¹³C values of wood or cellulose. Thus, the isotopic data from fossil wood in refer to those of recent ones are similar as long as the same taxa are considered. Within the strata, the δ¹³C values of the fossil tree trunks decreased considerably. This corresponds to the general course of temperature and eventual changes in atmospheric carbon dioxide content during the Neogene.

Key Words:

• Carbon 13
• carbon-content
• carbonisation experiment
• cellulose content
• diagenesis
• fossil trees
• Lower Rhine Valley
• neogene cooling
• paleoclimate