1 Paleontology

Thursday, 10 April 2014
10:15 AM - 12:15 PM
Duck Pond

PRESERVATION OF CHARRED WOOD NEAR ELKINS, WEST VIRGINIA: EVIDENCE OF A DEVONIAN FOREST FIRE?

Paper number: 1-4
Program: Technical Sessions
Time: 11:15 AM – 11:35 AM

Authors

Abstract

Plant fossils preserved as three-dimensional pieces of charred wood were recovered from a roadcut 4.5 kilometers northwest of Elkins, West Virginia. The plants were found in a one meter thick yellowish silty bed in association with non-marine red shales and quartz pebble conglomerates. The largest recovered fragments are 34 centimeters long, 8 centimeters wide, and 6 centimeters thick. The charred pieces themselves are not identifiable, but occasional exterior molds indicate a series of longitudinal parallel lines that most closely resemble the exterior of the progymnosperm Archaeopteris or a closely related genus. There are no apparent microphyll attachment scars as in a lycopod, or any transverse lines as in equisetopsids. As the wood fragments indicate charring rather than being preserved as coal or as carbon films, the interpreted scenario is that wood fragments from a forest fire were carried and deposited by a stream which is consistent with the local lithology.

The bed containing the charred wood lies 158 stratigraphic meters above the dark marine siltstones of the Late Devonian Foreknobs Formation. The red shales in association with charred wood are deep red and chippy with occasional mudcracks, and the conglomerates contain well-rounded quartz pebbles up to 18 millimeters across. Lithologically the shales and conglomerates resemble the Late Devonian Hampshire Formation which would be consistent in age with fossils of Archaeopteris. Forest fires have been associated with the Late Devonian Frasnian-Famennian extinction event, but the charred fragments near Elkins occur well above the F-F boundary found within the Foreknobs Formation and therefore suggest a discrete event after the F-F extinction.