2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)

Paper No. 198-10
Presentation Time: 10:20 AM

LATEST PERMIAN CHARS MAY DERIVE FROM WILDFIRES, NOT COAL COMBUSTION


HUDSPITH, Victoria, Department of Geography, University of Exeter, Exeter, EX4 4QE, United Kingdom, RIMMER, Susan M., Department of Geology, Southern Illinois University, Mailcode 4324, Carbondale, IL 62901 and BELCHER, Claire M., Department of Geography, University of Exeter, Exeter, EX4 4PS, United Kingdom, v.a.hudspith@exeter.ac.uk

The Permian-Triassic boundary extinction event was the largest biological crisis of the Phanerozoic. One of the principle triggers for the mass extinction is thought to be greenhouse warming resulting from the release of CH4 from basalt-coal interaction during the extensive Siberian Traps (Russia) eruptions. Observations of organic matter interpreted to be coal combustion products (fly ash) in latest Permian marine sediments have been used to support this hypothesis. However, this interpretation is dependent upon vesicular chars being fly ash (coal combustion derived) and not formed by alternative mechanisms. Here we present reflectance microscopy images of vesicular chars from Russian Permian coals, and chars from modern tundra, peatland, and boreal forest fires, to demonstrate that despite a difference in precursor fuels, wildfires are capable of generating vesicular chars that are morphologically comparable to end-Permian fly ash. These observations, coupled with extensive global evidence of wildfires during this time interval, call into question the contribution of coal combustion to the end-Permian extinction event.