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Little evidence of macrofossil charcoal, a wildfire proxy, is recorded from upper Lower to lowermost Upper Devonian rocks. Coals of this age are few, and petrographic data indicate low volumes (<10% mineral-matter free) of charcoal. This paucity of data forms the basis of the “charcoal gap,” which is used to suggest an extended interval of abnormally low atmospheric oxygen (pO2). We reassess the current evidence for this hiatus using Emsian−Eifelian charcoal from the Trout Valley and St. Froid Lake Formations, Maine (northeastern United States), and integrate the microscopic charcoal record of dispersed organic matter. We conclude there is ample evidence of fire in the Middle Devonian. This interval is not innately of low pO2. Rather, it is one in which under-interpretation of available data has led to a perceived paucity of charcoal. This reconciliation indicates the Phanerozoic record of wildfire was substantially uninterrupted. Hence, we propose that pO2 achieved levels >16% and remained at such levels from the Silurian through the floral and faunal colonization of land and, from our current estimates, stayed as such until the present.
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This content will become publicly available on September 27, 2025
THROUGH FIRE, AND THROUGH WATER, AN ABUNDANCE OF MID-DEVONIAN CHARCOAL
Abstract Evidence of fire in the Middle Devonian remains globally scarce. Charcoalified mesofossils recovered from the Emsian–Eifelian Trout Valley and St. Froid Lake formations of Maine are direct evidence of wildfires proximal to the Acadian Orogen, formed as the Avalon terrane and the North American plate collided. These mesofossils include charred psilophytes, lycopsids, prototaxodioids, enigmatic taxa such as Spongiophyton, and coprolites. Here, fire combusted a senesced and partially decayed litter, and the intimately associated nematophytes, following a period of extended dryness. We envisage wildfires occurred during neap tide when exposure of the flora of this estuarine setting was prolonged. Herein we provide a reconstruction of this Middle Devonian landscape and its flora in which lightning generated by post-dry season storms ignited wildfires that propagated through an extensive psilophyte-dominated litter.
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- Award ID(s):
- 1828359
- PAR ID:
- 10544924
- Publisher / Repository:
- Society for Sedimentary Research
- Date Published:
- Journal Name:
- Palaios
- Volume:
- 39
- Issue:
- 9
- ISSN:
- 0883-1351
- Page Range / eLocation ID:
- 301 to 322
- Subject(s) / Keyword(s):
- Wildfire Devonian Maine Paleoecology Charcoal Paleobotany Atmospheric Oxygen
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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