# Lockport Group

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> Markdown URL: https://mediated.wiki/source/Lockport_Group.md
> Source: https://en.wikipedia.org/wiki/Lockport_Group
> Source revision: 1301117243
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{{Infobox rockunit
| name           = Lockport Group
| image          =
| caption        =
| type           = [Group](/source/Group_(stratigraphy))
| age            =  [Sheinwoodian](/source/Sheinwoodian)-[Homerian](/source/Homerian)<br />~{{Fossil range|433|427}}
| prilithology   =[Dolomite](/source/Dolomite_(rock))
| otherlithology =[Limestone](/source/Limestone), [Chert](/source/Chert)
| namedfor       =
| namedby        =
| region         = [New York](/source/New_York_(state)), [Ohio](/source/Ohio), [Pennsylvania](/source/Pennsylvania), [West Virginia](/source/West_Virginia), [Ontario](/source/Ontario)
| country        = [United States](/source/United_States), [Canada](/source/Canada)
| coordinates    =
| unitof         =[Cayugan Series](/source/Cayugan_Series)
| subunits       =*[Guelph Formation](/source/Guelph_Formation)
*[Eramosa Formation](/source/Eramosa_Formation)
*[Goat Island Formation](/source/Goat_Island_Formation)
*[Gasport Formation](/source/Gasport_Formation)
| underlies      =[Vernon Formation](/source/Vernon_Formation)
| overlies       =[Clinton Group](/source/Clinton_Group)
| thickness      =
| extent         =[Appalachian Basin](/source/Appalachian_Basin), [Michigan Basin](/source/Michigan_Basin)
| area           =
| map            =
| map_caption    =
|period=Upper Silurian}}

The '''Lockport Group''' is a [geologic group](/source/Group_(geology)) in the [Appalachian Basin](/source/Appalachian_Basin) and [Michigan Basin](/source/Michigan_Basin) in the northeastern [United States](/source/United_States) and [Canada](/source/Canada). This unit makes up the [Niagara Escarpment](/source/Niagara_Escarpment). Its most famous feature is [Niagara Falls](/source/Niagara_Falls). The unit [outcrops](/source/Outcrop) in [New York](/source/New_York_(state)), [Ontario](/source/Ontario), [Michigan](/source/Michigan), [Wisconsin](/source/Wisconsin), and [Illinois](/source/Illinois).<ref>{{Cite book |last=Kelly |first=Peter E. |title=The last stand : a journey through the ancient cliff-face forest of the Niagara Escarpment |date=2007 |publisher=Natural Heritage Books |others=Douglas W. Larson |isbn=978-1-55488-332-5 |location=Toronto |oclc=768163291}}</ref>

== Description ==
The Lockport Group is made up of four formations. From base to top: [Gasport Formation](/source/Gasport_Formation), [Goat Island Formation](/source/Goat_Island_Formation), [Eramosa Formation](/source/Eramosa_Formation) and [Guelph Formation](/source/Guelph_Formation). The entire unit is composed of [dolomite](/source/Dolomite_(rock)), with the exception of the Gasport which can be [limestone](/source/limestone), as well as occasional [chert](/source/chert) nodules.<ref>{{Cite web |last1=Tepper |first1=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}}</ref>

== Stratigraphy ==
{{inline citations needed|section|date=July 2024}}
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. Its base is delimited by a [stromatolite](/source/stromatolite) bed. 

Below the Guelph is the Eramosa Formation. This formation is typically a thinly laminated [packstone](/source/packstone) and [grainstone](/source/grainstone). There are stromatolite beds as well as corals preserved in this formation. Near the base the unit becomes [vuggy](/source/Vug). Again the top of this formation is marked by a sharp change between grainstone and a stromatolite bed.

== References ==<!-- Inline citations added to your article will automatically display here. See en.wikipedia.org/wiki/WP:REFB for instructions on how to add citations. -->
<references responsive="0" />

Category:Geologic groups of New York (state)
Category:Silurian New York
Category:Silurian Ohio
Category:Silurian West Virginia
Category:Silurian geology of Pennsylvania
Category:Geologic groups of Pennsylvania
Category:Geologic groups of Ohio
Category:Geologic groups of West Virginia
Category:Silurian Ontario
Category:Geologic groups of Ontario
Category:Limestone groups of the United States
Category:Limestone groups of Canada
Category:Dolomite groups
Category:Chert groups

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Adapted from the Wikipedia article [Lockport Group](https://en.wikipedia.org/wiki/Lockport_Group) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Lockport_Group?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.