Exceptional preservation of Carboniferous bryozoans in the Buckhorn Asphalt Quarry of Oklahoma, USA

Taylor P, Seuß B, Ernst A (2015)


Publication Type: Conference contribution, Abstract of lecture

Publication year: 2015

Event location: Thurso

Abstract

The Late Carboniferous Buckhorn Asphalt Quarry exposes an ‘Impregnation Fossil Lagerstätte’ (Seuss et al. 2009), famous for its high-quality preservation of molluscs and other fossils. Some of the fossils conserve pristine aragonite or high-Mg calcite, mineral phases seldom preserved in Palaeozoic deposits. Located 10 km south of Sulphur, Oklahoma, the Buckhorn Asphalt Quarry was worked commercially in the 1920s and 1930s for road-paving asphalt. The Buckhorn Asphalt Quarry deposit comprises mixed siliciclastic–carbonate, mostly shallow-water sediments belonging to the Boggy Formation (Deese Group). The impregnating asphalt was derived from hydrocarbons that migrated into the sediments during or shortly after deposition, infilling pore spaces, sealing the sediment and fossils from circulating pore waters and inhibiting diagenesis and cementation. Although bryozoans have been recorded previously from the Buckhorn Asphalt Quarry, they have never been studied in any detail. The fauna is dominated by rhabdomesine cryptostomes and trepostomes, with fewer fenestrates. Chambers of the zooids are largely empty of sediment or cement, which has enabled the observation of some enigmatic internal skeletal features under SEM. For instance, transverse rows of granules line the chambers of the rhabdomesine Streblotrypa, and the hemiphragms of a tabuliporid trepostome have peculiar spinose outgrowths on their proximal edges. Also puzzling is the occurrence in several species of submicron-sized pits on internal wall surfaces. Although superficially resembling microendoliths (Wisshak et al. 2008), the pits may be too small for such an origin to be correct (M. Wisshak, pers. comm.), and the laminae of the bryozoan skeletons appear to be deflected around them suggesting formation during the growth of the host bryozoan skeletons.

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APA:

Taylor, P., Seuß, B., & Ernst, A. (2015). Exceptional preservation of Carboniferous bryozoans in the Buckhorn Asphalt Quarry of Oklahoma, USA. Paper presentation at 13th Larwood Symposium, Thurso.

MLA:

Taylor, Paul, Barbara Seuß, and Andrej Ernst. "Exceptional preservation of Carboniferous bryozoans in the Buckhorn Asphalt Quarry of Oklahoma, USA." Presented at 13th Larwood Symposium, Thurso 2015.

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