IN SITU BIOMOLECULES AND ISOTOPIC SIGNALS FROM EXCEPTIONALLY PRESERVED CONIFER FOSSILS IN CENOZOIC ARCTIC DEPOSITS REVEALED UNIQUE INFORMATION ON PLANT PHYSIOLOGY AND PALEOCLIMATE
In the past, studies of exceptional preservation have focused on exquisitely preserved animal fossils, particularly soft-bodied organisms, such as those from the Cambrian Chengjiang deposit of Yunnan, China and the Burgess Shale of British Columbia in Canada. In contrast, plant fossil lagerstätten have been overlooked as a valuable material for molecular and in situ stable isotope analyses. Here, we demonstrate the value of three-dimensionally preserved plant fossils (Metasequoia dominated conifer assemblages) from several Cenozoic Arctic lagerstätten through a combined paleobotanical (morphological and anatomical) and geobiochemical (molecular and stable isotopic) approach.
Not only did we document the oldest preservation of labile biomolecules such as polysaccharides so far found in identifiable plant fossils, but also we characterized in situ molecular carbon and hydrogen isotope signals which have offered unique information on plant physiology and paleoclimate reconstruction. We are also able to link the preservation of labile biomolecules and isotopic signals to the preservation of three-dimensional morphology. The combined traditional paleobotanical and new organic geochemical approach along with experimental taphonomic method will enrich paleobiological information and shed light on our understanding of fossilization process that results in plant fossil lagerstätte preservation in terrestrial settings.