A Case Study On Bioerosion In Fossil Cephalopods From The Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma, USA

Conference contribution


Publication Details

Author(s): Seuß B, Nützel A
Publication year: 2018
Language: English


Abstract

Cephalopod remains from the Desmoinesian (Pennsylvanian, Upper
Carboniferous) Buckhorn Asphalt Quarry (Oklahoma, USA) were studied intensively
over the past decades. However, this is the first study that focusses
exclusively on bioerosion affecting their shells. Research on bioerosion in
these fossils was possible due to soaking of sediments and shells with
hydrocarbons, during or shortly after time of deposition, that sealed open
space and prevented strong diagenesis. The shells derive from the ‘cephalopod
coquina’ that represents the deepest-water deposit within the single cycle of
trans- and regression in the outcrop. The cephalopod remains comprise fragments
of both, orthoconic and coiled nautiloid specimens as well as those from
ammonoids.



The shells were
cast and investigated with a scanning electron microscope. The study revealed a
diverse association of ichnotaxa and ichnoforms (twenty-two in total, eight of
them new – among them six ichnoforms could derive from foraminiferans - and
twelve with their oldest record in the Carboniferous) comprising chlorophyte,
cyanobacterial, and rhodophyte traces. Fungal and spongial traces as well as
those of so far unknown origin are also recorded. Most common are Ichnoreticulina
elegans
(a chlorophyte trace), a new morphotype of Scolecia isp.
(probably produced by cyanobacteria) as well as the fungal (Schizochytrium
sp.) trace Flagrichnus profundus, the ‘extremely thin form’ (likely the
Conchocelis-stage of Porphyra sp. or Bangia sp.), and the
‘superthin form’ that is produced by some unknown organotroph.



Straight
nautiloids are intensively bored by I. elegans and Scolecia n.
isp. while in the shells of coiled cephalopods F. profundus, the
‘extremely thin form’, and the ‘superthin form’ are most abundant. The ichnotaxon
associations in the shells indicate different modes of deposition: Shells of
coiled specimens seem to have drifted for a while and were therefore more prone
to bioerosion by autotrophs until they sank to the seafloor, while those of the
orthocones sank more rapidly with deposition in the deep euphotic to dysphotic
zone of the ichnobathymetrical scheme. A comparison with the studies on extant Nautilus
supports the idea that ichnotaxa present in Carboniferous cephalopods have gone
lost with the extinction of these.


FAU Authors / FAU Editors

Seuß, Barbara Dr.
Lehrstuhl für Paläoumwelt


External institutions with authors

Ludwig-Maximilians-Universität (LMU)


How to cite

APA:
Seuß, B., & Nützel, A. (2018). A Case Study On Bioerosion In Fossil Cephalopods From The Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma, USA. In Proceedings of the GSA. Indianapolis, US.

MLA:
Seuß, Barbara, and Alexander Nützel. "A Case Study On Bioerosion In Fossil Cephalopods From The Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma, USA." Proceedings of the GSA, Indianapolis 2018.

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Last updated on 2019-18-04 at 21:23