A Middle Devonian (Edgecliff Member, Onondaga Formation) temperate water limestone--Paleontological and isotopic evidence

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

OSTI ID:5936705

Wolosz, T H ^[1]

---

1. State Univ. of New York, Plattsburgh, NY (United States)

The Edgecliff Member of the Onondaga Formation is a reefy'' and biostromal unit which extends westward from just south of Albany, across New York and into Ontario, Canada. The presence of reefs with abundant rugose and tabulate corals has long led to the interpretation of the Edgecliff as a tropical to sub-tropical limestone, despite the absence of stromatoporoids, calcareous algae and typical peritidal carbonate facies. Recent investigation of Edgecliff reefs has revealed that stromatoporoids are present in grainstones which cap some eastern reefs, but are for the most part very small, averaging only a few cm. in diameter and only a few mm. thick. In western New York they are still rare, but attain diameters of up to 10cm. and thicknesses of over a cm. This trend continues into Ontario where colonies become more common and reach diameters of up to 1.5 m. To test the hypothesis that cool water conditions hindered stromatoporoid growth, carbon and oxygen isotope analyses were performed on 29 samples from non-luminescent portions of 15 brachiopods with prismatic ultrastructure. delta O-18 values range from [minus]1.18 to [minus]4.38 [per thousand] (PDB) with 19 analyses ranging from [minus]3.00 to [minus]3.93 [per thousand], 7 analyses from [minus]3.00 to [minus]3.93[per thousand], and only 3 analyses lighter than [minus]4.00[per thousand]. delta C-13 values range from 1.35 to 3.18 [per thousand]. These delta O-18 values are isotopically heavier than accepted values for Devonian sea-water, and in conjunction with the stromatoporoid distribution data lend support to the hypothesis of Edgecliff deposition under temperate water conditions.

• OSTI ID: 5936705
• 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
ONTARIO
PALEONTOLOGY
PALEOTEMPERATURE
ALGAE
DEVONIAN PERIOD
GROWTH
ISOTOPE RATIO
LIMESTONE
REEFS
CANADA
CARBONATE ROCKS
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
NORTH AMERICA
PALEOZOIC ERA
PLANTS
ROCKS
SEDIMENTARY ROCKS
USA
580000* - Geosciences