The Lockport Group is a
geologic group
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Eart ...
in the
Appalachian Basin and
Michigan Basin
The Michigan Basin is a geologic basin centered on the Lower Peninsula of the U.S. state of Michigan. The feature is represented by a nearly circular pattern of geologic sedimentary strata in the area with a nearly uniform structural dip toward ...
in the northeastern
United States and
Canada. This unit makes up the
Niagara Escarpment
The Niagara Escarpment is a long escarpment, or cuesta, in Canada and the United States that runs predominantly east–west from New York through Ontario, Michigan, Wisconsin, and into Illinois. The escarpment is most famous as the cliff over ...
. Its most famous feature is
Niagara Falls. The unit
outcrops in
New York
New York most commonly refers to:
* New York City, the most populous city in the United States, located in the state of New York
* New York (state), a state in the northeastern United States
New York may also refer to:
Film and television
* '' ...
,
Ontario,
Michigan,
Wisconsin, and
Illinois.
Description
The Lockport Group is made up of four formations. From base to top:
Gasport Formation
The Gasport Formation is a geologic formation in Ontario. It preserves fossils dating back to the Silurian period.
See also
* List of fossiliferous stratigraphic units in Ontario
This is a list of stratigraphic units in Ontario bearing fossils ...
,
Goat Island Formation
The Goat Island Formation is a geologic formation in Ontario. It preserves fossils dating back to the Silurian period.
See also
* List of fossiliferous stratigraphic units in Ontario
This is a list of stratigraphic units in Ontario bearing fo ...
,
Eramosa Formation
The Eramosa Formation is a geologic formation in New York. It preserves fossils dating back to the Silurian period.
See also
* List of fossiliferous stratigraphic units in New York
This article contains a list of fossil-bearing stratigraph ...
and
Guelph Formation
The Guelph Formation is a geologic formation in New York. It preserves fossils dating back to the Silurian period.
See also
* List of fossiliferous stratigraphic units in New York
This article contains a list of fossil-bearing stratigraphic un ...
. The entire unit is composed of
dolomite Dolomite may refer to:
*Dolomite (mineral), a carbonate mineral
*Dolomite (rock), also known as dolostone, a sedimentary carbonate rock
*Dolomite, Alabama, United States, an unincorporated community
*Dolomite, California, United States, an unincor ...
, with the exception of the Gasport which can be
limestone, as well as occasional
chert nodules.
[{{Cite web , last=Tepper , first=Dorothy H. , last2=Goodman , first2=William M. , last3=Gross , first3=Michael R. , last4=Kappel , first4=William M. , last5=Yager , first5=Richard M. , title=Stratigraphy, Structural Geology, and Hydrogeology of the Lockport Group: Niagara Falls Area, New York , url=https://www.nysga-online.org/wp-content/uploads/2019/06/NYSGA-1990-SunB-Stratigraphy-Structure-And-Hydrogeology-Of-The-Lockport-Group-Niagara-Falls-Area-New-York.pdf , access-date=9 April 2023 , website=New York State Geological Association Online]
Stratigraphy
The Guelph Formation is at the top of the Lockport Group. It has been called the "Vernon Transition Zone" due to thin beds and laminations between carbonates, claystones and evaporates. At its base is a
stromatolite bed, marking its base.
Below the Guelph is the Eramosa Formation. This formation is typically a thinly laminated
packstone and
grainstone. There are stromatolite beds as well as corals preserved in this formation. Near the base the unit becomes
vuggy. Again the top of this formation is marked by a sharp change between grainstone and a stromatolite bed.
References
Geologic groups of New York (state)
Silurian New York
Silurian Ohio
Silurian West Virginia
Silurian geology of Pennsylvania
Geologic groups of Pennsylvania
Geologic groups of Ohio
Geologic groups of West Virginia