A comprehensive assessment of palaeowildfire activity across the Danian-C2 hyperthermal event by means of Raman spectroscopy-geothermometry

<p>Widespread intensification in wildfire activity within recent years suggests our future alongside flammable ecosystems is one of complexity and likely severity. Understanding changes to wildfire behaviour under a shifting climate state relies considerably upon determining key changes in palaeowildfire activity, particularly those occurring during ‘similar’ instances of prehistoric climate change i.e., hyperthermals. The application of palaeoclimatological and palynological study alongside palaeowildfire analyses, in particular charcoal geothermometry, allows for relationships between plants, climate and fire to be derived, in turn revealing the potential changes to wildfires we may come to experience. Implementation of multiple palaeoenvironmental proxies alongside assessments of relative palaeofire intensity change are becoming increasingly more common. However, very few consider assemblages ‘analogous’ to anthropogenic climate. Within this study, we have applied Raman spectroscopy-geothermometry to detrital charcoals, preserved within lacustrine sediments of the Boltysh Impact Crater sediment core – sampling from four distinct climatic states across the Danian-C2 hyperthermal event. Developing upon preliminary work, we present the most extensive assessment of wildfire activity during a hyperthermal period to date, including pre-, syn-, and post-negative carbon isotope excursion stages, as well as ecosystem recovery. We have corresponded established palaeoclimatological and palynological data to our assessments of relative intensity change, with significant implications for our understanding of wildfire activity under anthropogenic climate upheaval. Our data further highlight the effectivity and applicability of quantifying palaeowildfire behaviour in order to better understand our own future in flames.</p>