Exceptional Preservation of Molluscs in the Buckhorn Asphalt

Conference contribution
(Abstract of a poster)


Publication Details

Author(s): Seuß B, Nützel A, Schulbert C
Publication year: 2007
Language: English


Abstract

The Late Carboniferous (Desmoinesian, approx. 306 m years) sediments of
the Buckhorn Asphalt Quarry (Oklahoma, USA) contain the best preserved
Palaeozoic mollusc fauna world wide. Molluscs are commonly preserved in
original aragonite including shell microstructures, though aragonite is
normally dissolved or recrystallised shortly after deposition. Even
larval shells and colour patterns are preserved. The good preservation
of fossils was caused by Ordovician oil which intruded into the
sediments simultaneously to or shortly after deposition, sealing pore
space and preventing recrystallisation via circulating pore waters. The
oil then transformed into asphalt loosing its volatiles.

The fauna of the Buckhorn Asphalt is dominated by mollusc species,
especially by cephalopods and small gastropods. For the purpose of
inferring the depositional environment and Palaeoecology, thin sections
were prepared from samples of all main lithologies. Asphaltic rocks were
dissolved in a Soxhlet apparatus using methylene chloride as solvent
(asphalt content is up to 20%). The dissolved samples were sieved (2 mm,
500 µm, 125 µm) and picked. Fossils, especially small gastropods were
documented with SEM- and light microscope pictures. Bioerosion in the
Buckhorn fossils is common and could be proved using SEM-photographs of
fossils and casts, as well as with thin sections. At least 50 gastropod
species, two coiled and three orthocone nautiloids have been documented,
however brachiopods and bivalves are rare. The rich marine fauna is
furthermore represented by ostracods, foraminifers, echinoderms, and
bryozoans. Vertebrate remains like fish teeth are rare. First results
suggest that most fossils lived in shallow water as is indicated by a
diverse assemblage of bioeroders within the mollusc shells as well as by
the presence of large land plant remains. The fossil material is mixed
with siliciclastic sediment which is conglomeratic sometimes, and was
transported over a relatively steep slope or in channels.


FAU Authors / FAU Editors

Schulbert, Christian
Lehrstuhl für Paläoumwelt
Seuß, Barbara Dr.
Lehrstuhl für Paläoumwelt


External institutions with authors

Ludwig-Maximilians-Universität (LMU)


How to cite

APA:
Seuß, B., Nützel, A., & Schulbert, C. (2007). Exceptional Preservation of Molluscs in the Buckhorn Asphalt. Poster presentation at World Congress of Malacology, Antwerpen.

MLA:
Seuß, Barbara, Alexander Nützel, and Christian Schulbert. "Exceptional Preservation of Molluscs in the Buckhorn Asphalt." Presented at World Congress of Malacology, Antwerpen 2007.

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Last updated on 2018-06-12 at 09:08