An exceptionally preserved Carboniferous faunal assemblage from the Buckhorn Asphalt Lagerstätte (Oklahoma, USA)

Seuß B, Wisshak M, Nützel A, Schulbert C (2008)


Publication Language: English

Publication Type: Conference contribution, Abstract of lecture

Publication year: 2008

Event location: Erlangen

Abstract

The Pennsylvanian Buckhorn Asphalt Quarry in Oklahoma (USA) is an Impregnation Lagerstätte containing the best-preserved Palaeozoic mollusc fauna in the world. Besides preserved Mg-calcite, microstructures, and early ontogenetic shells, it is the only Late Palaeozoic Lagerstätte with conservation of original aragonite known to date. The outstanding preservation is due to an early impregnation by migrating hydrocarbons intruding the mixed siliciclastic-carbonatic sediments of the Buckhorn Asphalt. Deposition took place during a transgressive-regressive cycle near the coast – indicated by landplant remains and high siliciclastic input. The sediments comprise coarse conglomerates to mudstones, and shell beds. Some sediments in the quarry were probably deposited by mass flows, while others are more or less autochthounous. In total the shelly invertebrate fauna comprises more than 155 species and about 120 genera which is unusual for Late Palaeozoic deposits. This corroborates that aragonite dissolution produces a major bias in the fossil record. However, most mollusc genera in the Buckhorn Asphalt Lagerstätte are known as replaced shells from other Pennsylvanian deposits. According to this the preservation bias via dissolution might be overestimated. The fauna is dominated by molluscs, especially gastropods with more than 50 genera, cephalopods, and bivalves. The faunal assemblage is complemented by foraminiferans, ostracodes, bryozoans, brachiopods, and further fossils in smaller amounts like vertebrate and echinoderm remains. Chaetetids represent the largest benthic macro-organisms at the top of the regressive intervals. The preservation of planktotrophic larval shells indicates a high primary production in the ocean waters of the Buckhorn area - an important information, as remains of producer organisms are generally scarce in Late Palaeozoic deposits. The biodiversity of endolithic biota, as indirectly recorded by bioerosion ichnotaxa in the shells, reveals a total of 18 known ichnospecies and the new ichnotaxon Aurimorpha varia, reflecting the most diverse Palaeozoic microboring assemblage known to date. The ichnocoenosis is dominated by Eurygonum nodosum, Scolecia filosa, and Fascichnus dactylus (all of them are cyanobacterial traces). Further traces are e.g. Fascichnus frutex, Planobola macrogata, and Cavernula coccidia. 17 out of 19 reported ichnospecies are known to neoichnology and are present in similar ichnocoenosis of Recent shallow-euphotic seas showing the longevity of microedolithic taxa and therefore their value as palaeoenvironmental indicators. 2/3 of the recorded ichnotaxa were reported for the first time from the Carboniferous.

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APA:

Seuß, B., Wisshak, M., Nützel, A., & Schulbert, C. (2008). An exceptionally preserved Carboniferous faunal assemblage from the Buckhorn Asphalt Lagerstätte (Oklahoma, USA). Paper presentation at Annual Meeting of the Paläontologische Gesellschaft,, Erlangen.

MLA:

Seuß, Barbara, et al. "An exceptionally preserved Carboniferous faunal assemblage from the Buckhorn Asphalt Lagerstätte (Oklahoma, USA)." Presented at Annual Meeting of the Paläontologische Gesellschaft,, Erlangen 2008.

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