The Preservation of Cellulose in Fossil Wood – Implications from Organic Geochemical Study of Fossil and Modern Wood

Abstract

Fossil wood with well-preserved cellulose is detected in open-cast mines of the Miocene Lusatia lignite-mining district (eastern Germany). Aimed to explain the preservation of cellulose, an organic geochemical study was performed on the fossil wood samples and intact heartwood tissues of the respective modern woody species. The results of micro Fourier transform infrared (micro-FTIR) spectroscopy, biomarker distributions and δ13C values indicate that the preservation of cellulose in fossil wood samples was governed by reducing conditions. Furthermore, it can be also attributed to weathering of the surrounding tuff- and rhyolite-dominated acidic volcanic rock that might have caused lowering of pH. All fossil wood samples contain minor hopanoids, implying negligible post-depositional microbial degradation of OM. Limited microbial degradation of OM could be also caused by protection of the wood by conifer resins. For example, fossil Cupressaceae sensu lato, as confirmed by detection of hibaene, totarane, and cuparene, was more resinous than the modern forms. The absence of perylene in fossil wood indicates the limited degradation of wood by fungi.