Irondequoit Formation

Irondequoit Formation
Irondequoit Formation
Stratigraphic range: Sheinwoodian; ~
Type	Formation
Unit of	Clinton Group
Underlies	Rochester Formation
Overlies	Sodus Formation, Reynales Formation, Rockway Dolomite
Thickness	Up to 23'
Lithology
Primary	Limestone
Other	Dolomite, Shale
Location
Country	United States, Canada
Extent	New York, Pennsylvania, Ontario
Type section
Named for	Irondequoit, New York
Named by	Hartnagel (1907)

The Irondequoit Formation is a geologic formation in the Eastern United States and Canada.

Description

The Irondequoit is a mapped unit of Limestone with outcrops in western New York, and Ontario. It is a member of the Clinton Group. Subsurface it extends into northern Pennsylvania.^[1] The Irondequoit is described as a light gray-pinkish gray limestone-greenish gray carbonate. It tends to have abundant crinoids and brachiopods with some rugosa corals bound into a grainstone or packstone in the west.^[2]^[1] The beds are thick to massive. Toward the top of the formation as it nears the Rochester Formation thin greenish gray bed of shale maybe present. Reef knolls have been observed in the upper sections of the formation ranging from three to ten feet wide and up to six and a half feet tall. In the east it grades to packstones to wackestones.

Stratigraphy

The Irondequoit is overlain by the Rochester Formation. This contact is conformable in New York but in Ontario it is unconformable erosional contact.^[1] The lower contact in New York is the Rockway Dolomite marked by an unconformable contact.

Fossils

Conodont

Kockelella ranuliformis^[1]

Brachiopoda

Whitfieldella^[1]
Atrypa^[1]

Ostracods

Mastigobolbina typus^[1]

Rugose Coral

Enterolasma^[1]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Brett, Carlton E.; Tepper, Dorothy H.; Goodman, William M.; LoDuca, Steven T.; Eckert, Bea-Yeh (1995). "Revised Stratigraphy and Correlations of the Niagaran Provincial Series (Medina, Clinton, and Lockport Groups) in the Type Area of Western New York" (PDF). U.S. Geological Survey Bulletin. 2086: 39–40.
^ Grasso, Thomas X. "STRATIGRAPHY OF THE GENESEE GORGE AT ROCHESTER" (PDF). New York Geological Survey: 16.

[:0-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h Brett, Carlton E.; Tepper, Dorothy H.; Goodman, William M.; LoDuca, Steven T.; Eckert, Bea-Yeh (1995). "Revised Stratigraphy and Correlations of the Niagaran Provincial Series (Medina, Clinton, and Lockport Groups) in the Type Area of Western New York" (PDF). U.S. Geological Survey Bulletin. 2086: 39–40.

[2] Grasso, Thomas X. "STRATIGRAPHY OF THE GENESEE GORGE AT ROCHESTER" (PDF). New York Geological Survey: 16.

[1]

[2]