138-10 Evidence for the origins of soot emissions from the Refining Soot Emissions Associated with the Chicxulub Asteroid Impact at the Cretaceous-Paleogene Boundary

Session: The Cretaceous-Paleogene (K-Pg) Boundary Interval: From Large-Scale Geological Events to Mass Extinction Mechanisms

Presenting Author:

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Abstract:

Cretaceous-Paleogene Boundary (KPB) sites across the globe show anomalous deposition of elemental carbon particles coincident with the Chicxulub asteroid impact. Model simulations suggest that soot and charcoal particles emitted because of the impact were a major contributor to the climatic changes and extinctions at the KPB. However, there is debate about the sources of soot and charcoal particles deposited at the KPB. Some studies suggest soot and charcoal came primarily from near-global wildfires, while other studies suggest soot and charcoal came from the impact site itself. There are data on the soot and charcoal emission amounts in various locations, and their ratio.  An injection from the impact site might show diminishing masses with distance from the impact site. In contrast, local wildfires might produce heterogeneous distributions that correlate with regional fuel abundance. Here, we perform simulations for various soot and charcoal emission scenarios uncertainties using a state-of-the-art Earth System Model that simulates the evolution of both soot and charcoal particles. By comparing our simulations with KPB soot and charcoal records, we find that widespread fires triggered by the Chicxulub impact are necessary to match the geologic records, rather than emissions from the impact site. Irrespective of their source, the climate responses to the various soot emission scenarios are quite similar, supporting an important role for soot in the KPB extinction regardless of fire activity.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7242

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