Trace fossil zonation in regressive sequences in the lower Breathitt Formation (Pennsylvanian, Central Appalachian Basin)

Conference · Wed Jan 01 00:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5830138

Greb, S F; Chesnut, Jr, D R ^[1]

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1. Kentucky Geological Survey, Lexington, KY (United States)

Commonly, lithofacies of the lower Breathitt Formation occur in coarsening-upward regressive sequences, interpreted as coastal sedimentation in response to eustacy. Similar trace-fossil assemblages were noted within similar lithofacies of these coarsening-upward sequences at 25 locations. The bases of many regressive sequences are sharp and characterized by in situ productoids or transported productoids and crinoidal debris. Transported marine body fossils at the bases of shales are evidence for transgressive surfaces. Mixed sand and shale facies above the shales are interpreted as tidal flats, shoals, and intershoal areas, and exhibit high-abundance/moderate- to high-diversity trace-fossil assemblages. Vertical zoning of suspension- and deposit-feeding organisms were controlled by changes in sedimentation and salinity related to eustatic shallowing. Channel-fill sequences exhibit the widest range in ichnofossil diversity. Larger channels contain only low-abundance/low-diversity assemblages and arthropod locomotion traces. These channels may have been subjected to fresh-water influx and strong current reworking of sediment substrates. In contrast, small (> 150m width) tidal channels capping many regressive sequences contain high-abundance/low-to high-diversity trace-fossil assemblages similar to the intershoal/interflat facies but including different dwelling traces. These channels reworked the tops of the regressive sequences under intertidal conditions. Channels may be capped by coals or a subsequent regressive sequence.

• OSTI ID: 5830138
• Report Number(s): CONF-921058-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
58 GEOSCIENCES
APPALACHIAN BASIN
GEOLOGIC HISTORY
PALEONTOLOGY
CARBONIFEROUS PERIOD
COAL DEPOSITS
FOSSILS
SEA LEVEL
SEDIMENTATION
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
LEVELS
MINERAL RESOURCES
PALEOZOIC ERA
RESOURCES
SEDIMENTARY BASINS
011000* - Coal
Lignite
& Peat- Reserves
Geology
& Exploration
580000 - Geosciences