Fossil wood cells recorded 300 million years of Europe’s tectonic history

Abstract

Abstract Woody debris undergoes the same processes of deposition and diagenesis as its embedding sediments, making its fossilized products potentially good archives of basin evolution. We review this hypothesis by reconstructing the timelines, source and physicochemical conditions of mineralization in silicified Pennsylvanian wood from the Kyffhäuser, central Germany. Five stages of silicification are evidenced from quartz cathodoluminescence, fluid inclusions, triple-O and Si isotopes, Raman thermometry, electron-microprobe and scanning-electron analyses, and in situ U–Pb radiogenic isotope dating. (1) 304–299 Ma: permineralization of fluvial woody debris at near-surface conditions sourced from pedogenically altered pyroclasts; (2) 299–290 Ma: opal-quartz transformation during initial burial; (3) 257–260 Ma: quartz-hematite mineralization at 1 km depth related to thermal crustal relaxation; (4) c. 180 Ma: quartz formation from basinal brines upon maximum burial at 170–240°C and 3.5–5 km; and (5) 100 Ma: regional quartz-baryte mineralization following basin inversion before final exhumation in the Quaternary. The results expand the hitherto known timescales of wood mineralization, and reveal that fossil wood can record a basin’s burial history and disclose the tectonic events on the hundred-million-year timescale.