Early Paleogene wildfires in peat-forming environments at Schöningen, Germany

Abstract

Wildfire activity in early Paleogene greenhouse conditions can be used as an analogue to gauge the effect of future warming trends on wildfire in the current climate system. Inertinite (fossil charcoal in coal) from 11 autochthonous early Paleogene lignite seams from the Schöningen mine (Germany) was quantified using macerations, in situ pillars and industry standard crushed samples. A new three transect method was developed to quantify in situ charcoal. The combination of in situ pillars and crushed samples accounts for temporal and spatial variation in charcoal through a stratigraphically oriented pillar, whilst maintaining comparability with industry standards and previous work. Charcoal occurs as a range of randomly distributed particle sizes, indicating that fires were burning locally in the Schöningen peat-forming environment and in the surrounding areas, but according to petrological data, not in an episodic or periodic pattern. Although charcoal abundance is A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTRobson et al. Paleogene record of Wildfires 2 low (relative to previous high fire worlds such as the Cretaceous), three quantitative and semiquantitative methods show increased wildfire activity (relative to the modern world) in the warmest parts of the early Paleogene. As atmospheric oxygen levels stabilised to modern values and precipitation and humidity became the main control on wildfire, increased rainfall followed by drier intervals would have created an environment rich in dry fuel in which wildfires could easily propagate if humidity was low enough. In the later part of the Early Eocene (Ypresian) charcoal abundance fell to levels similar to those found in modern peats. This indicates that the transition to the modern low fire world occurred within the Early Eocene, earlier than previous records suggest.

Conceptual models for short‐eccentricity‐scale climate control on peat formation in a lower Palaeocene fluvial system, north‐eastern Montana (USA)

“…Scott & Glasspool, ; Scott, , and references cited therein). The average of 12% inertinite in coal seams of the Tullock Member is slightly lower than the 17% of inertinite in Palaeocene coals (Glasspool & Scott, ), but still significantly higher than inertinite percentages in coal seams of the early Eocene (Robson et al ., ). The inertinite percentages of the samples range from 1 to 31%, suggesting that wildfire activity significantly varied throughout the succession.…”

“…For in situ pillars, three transects were quantified with the same methodology as in Robson et al . ().…”

A 350‐million‐year legacy of fire adaptation among conifers

“…Robson et al . () have described the fluctuating, but overall, marked drop in fire‐derived inertinite records for mires in Germany during the early Eocene (40–55 M) compared with the Paleocene during one of the wettest periods known. This again raises the question of the fate of fire‐dependent species at such times.…”

Ecological and biogeochemical change in an early Paleogene peat-forming environment: Linking biomarkers and palynology

“…Non-gelified huminite macerals attrinite (cemented detrital material) and textinite (cell walls not gelified, open or open but infilled cell lumina) indicate drier conditions during peat formation (Sýkorová et al, 2005). Macerals were quantified following the method outlined in Robson et al (2015).…”