Response of infaunal organisms represented by trace fossils to sea-level changes in the Ordovician Black River and Trenton Group limestones, upstate New York

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

OSTI ID:5769329

Tegan, J R ^[1]; Curran, H A ^[2]

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1. Univ. of Cincinnati, OH (United States). Dept. of Geology
2. Smith Coll., Northampton, MA (United States)

Small-scale fluctuations in sea level were revealed by detailed analysis of trace fossil assemblages formed by infaunal organisms within the Lowville (Black River Grp.), Napanee, and Kings Falls limestones (Trenton Grp.) at Ingham Mills. The paleodepositional environment of the Lowville Limestone (LL) is interpreted as peritidal, representing the high intertidal to shallow subtidal zones. The trace fossil assemblages define clearly several fluctuations within this environment. Large, well-formed specimens of the trace fossil Beaconites barretti occur within tidal channel and levee beds of the LL. In other regions this trace fossil has consistently been associated with channel and levee beds, most commonly in fluvial settings. The occurrence of Beaconites in the LL extends the age range of this ichnogenus to Ordovician time (oldest previous record is Silurian) and broadens its paleoenvironment range. The Napanee (Np) and lower Kings Falls (KF), limestones have most commonly been described as being deposited in a lagoonal setting. Both formations contain well-preserved trace fossils; the primary difference being that the Np exhibits much lower trace and body fossil diversities than the KF. The low diversity of trace fossils in the Np was most likely the result of limiting environmental conditions such as low oxygen and/or hypersalinity. The higher diversity of trace fossils in the KF indicates that the ancient lagoon became increasingly controlled by normal marine conditions, and, therefore, hospitable to a more diverse group of organisms. The trace fossil assemblages of the Black River and Trenton Group limestones indicate that the infaunal organisms of these Ordovician communities were highly sensitive to small-scale sea-level fluctuations.

• OSTI ID: 5769329
• 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

58 GEOSCIENCES
NEW YORK
SEDIMENTARY BASINS
ORDOVICIAN PERIOD
SEA LEVEL
PALEONTOLOGY
AQUATIC ORGANISMS
DEPOSITION
FLUCTUATIONS
FOSSILS
GEOLOGIC HISTORY
LIMESTONE
RESPONSE FUNCTIONS
CARBONATE ROCKS
DEVELOPED COUNTRIES
FUNCTIONS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
LEVELS
NORTH AMERICA
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
USA
VARIATIONS
580000* - Geosciences