Tissue decay tested in modern Metasequoia leaves: Implications for early diagenesis of leaves in fossil Lagerstätten

Sedimentary deposits yielding extraordinarily-preserved fossils (known as Lagerstätten) may provide significant insights into the physiology and environments of ancient plants, particularly when represent their original characteristics with limited diagenetic modifications. To better understand molecular, isotopic, morphological changes during early stages diagenesis, degradation experiments were conducted in two time series: 1) a laboratory decay series using fungi on leaves over course month 2) natural collected from different leaf senescence diagenesis. Both used modern dawn redwood Metasequoia glyptostroboides, referred to “living fossil” due stability genus past 100 million years. demonstrate that microbial polysaccharides occurs extremely short timescales results cell collapse, first exclusively cellulose-based primary walls then much later lignin-strengthened secondary walls. Despite molecular changes, stable carbon isotopic composition bulk n-alkanes remained virtually unchanged. Together, these findings suggest that: rapid burial tissue stabilization is essential formation Lagerstätte fossils, play key role maintaining three-dimensional fossil structures thus polysaccharide preservation implies minimal degradation, 3) isotope signals, including at level, altered little Thus, interpretations physiological environmental signals conifer Lagerstätten are not likely impacted by