SIDERITE CONCRETIONS IN THE COPAN CRINOID LAGERSTÄTTE (UPPER PENNSYLVANIAN, OKLAHOMA): IMPLICATIONS FOR INTERPRETING TAPHONOMIC AND DEPOSITIONAL PROCESSES IN MUDSTONE SUCCESSIONS

A thin interval of bioturbated, fossiliferous mudstone within the middle portion of the Upper Pennsylvanian Barnsdall Formation crops out near Copan, northeastern Oklahoma. Representing slow background sedimentation in an oxygenated distal shelf setting, this exposure has yielded an exceptionally di...

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Bibliographic Details
Published in:Palaios 2013-10, Vol.28 (10), p.697-709
Main Authors: THOMKA, JAMES R, LEWIS, RONALD D
Format: Article
Language:English
Subjects:
Barnsdall Formation
biogenic structures
burrows
carbonates
Carboniferous
clastic rocks
concretions
Copan Oklahoma
Crinoidea
Crinozoa
deposition
Echinodermata
Invertebrata
Lagerstatten
lebensspuren
lithostratigraphy
marine environment
mudstone
Oklahoma
paleoenvironment
Paleozoic
Pennsylvanian
preservation
secondary structures
sed rocks, sediments
Sedimentary petrology
sedimentary rocks
sedimentary structures
shelf environment
siderite
taphonomy
United States
Upper Pennsylvanian
Washington County Oklahoma
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Summary:A thin interval of bioturbated, fossiliferous mudstone within the middle portion of the Upper Pennsylvanian Barnsdall Formation crops out near Copan, northeastern Oklahoma. Representing slow background sedimentation in an oxygenated distal shelf setting, this exposure has yielded an exceptionally diverse and well-preserved crinoid fauna consisting of over 1200 articulated or partially articulated specimens. The interval is also characterized by abundant siderite concretions, present as four morphologies. Large concretions without a distinct skeletal nucleus are located in thin horizons containing abundant articulated crinoids; these indicate sediment starvation on the shelf. Also in these thin, crinoid-bearing units are extremely localized siderite concretions precipitated around sites where soft tissues would have been volumetrically more abundant within large macrofossils, notably tegmina and proximal arms of articulated crinoids, indicating extremely rapid burial events that episodically punctuated the sediment-starved conditions. Small concretions, generally
ISSN:0883-1351
1938-5323
DOI:10.2110/palo.2012.p12-130r