View source for Black River Group

{{Short description|Geologic group in Eastern and Midwestern, USA}}
{{Infobox rockunit
| name           = Black River Group
| image          = Mudcracked limestone (Tyrone Limestone, Middle Ordovician, 454 Ma; Frankfort, Kentucky) 1.jpg
| caption        = Mudcracked limestone (Tyrone Limestone, Black River Group, Late [[Ordovician]]; [[Frankfort, Kentucky]])
| type           = [[Group (stratigraphy)|Group]]
| age            = [[Middle Ordovician]] to [[Late Ordovician]]<br>[[Whiterockian]]-[[Mohawkian]]<br />~{{Fossil range|460|450}}
| period         = Late Ordovician
| prilithology   = [[Limestone]]
| otherlithology = [[Dolomite (rock)|Dolomite]], [[Mudstone]]
| namedfor       =
| namedby        =
| region         = {{Flag|Indiana}}<br>{{Flag|Kentucky}}<br>{{Flag|Michigan}}<br>{{Flag|New York}}<br>{{Flag|Ohio}}<br>{{Flag|Pennsylvania}}<br>{{Flag|Tennessee}}<br>{{Flag|West Virginia}}<br><br>{{Flag|Ontario}}<br>{{Flag|Quebec}}
| country        = {{Flag|United States}}<br>{{Flag|Canada}}
| coordinates    =
| unitof         =
| subunits       =[[Coboconk Formation]]<BR>[[Deicke and Millbrig bentonite layers]]<BR>[[Gull River Formation]]<BR>Hatter Formation (PA)<BR>Isle La Motte Limestone (NY,VT)<BR>Linden Hall Limestone (PA)<BR>Pamelia Formation (NY)<BR>[[Pecatonica Formation]] (IN)<BR>Peery Limestone (VA,WV)<BR>Plattin Formation (IN)<BR>Selby Limestone (NY)<BR>Snyder Limestone (PA,VA,WV)<BR>Ward Cove Limestone (VA,WV)<BR>Wardell Formation (VA, WV)<BR>Witten Limestone (VA,WV)<BR>[[Shadow Lake Formation]].
; [[New York (state)|New York]]
: [[Amsterdam Limestone]]
: [[Waterton Limestone]]
: [[Lowville Formation]]
| underlies      = [[Lexington Limestone]] and [[Trenton Group]]
| overlies       = [[St. Paul Group]] and [[Wells Creek Formation]]
| thickness      =
| extent         =
| area           =
| map            =
| map_caption    =
}}

The '''Black River Group''' is a [[Group (geology)|geologic group]] that covers three sedimentary basins in the Eastern and Midwestern [[United States]]. These include the [[Appalachian Basin]], [[Illinois Basin]] and the [[Michigan Basin]]. It dates back to the Late [[Ordovician]] [[Period (geology)|period]]. It is roughly equivalent to the [[Platteville Group]] in [[Illinois]].<ref>{{Cite web |title=Black River Group |url=https://igws.indiana.edu/compendium/black-river-group |access-date=2023-09-14 |website=igws.indiana.edu |language=en}}</ref> In Kentucky and Tennessee it is also known as the High Bridge Group. In areas where this Geologic Unit thins it is also called the Black River Formation (undifferentiated). One example of this is over the [[Cincinnati Arch]] and Findley Arch.<ref>{{Cite web |title=NGMDB Product Description Page |url=https://ngmdb.usgs.gov/Prodesc/proddesc_93103.htm |access-date=2023-09-17 |website=ngmdb.usgs.gov}}</ref> Large parts of the Black River have been dolomized  (where the parent limestone CaCO<sub>3</sub> has been turned into [[Dolomite (rock)|dolomite]] CaMg(CO<sub>3</sub>)<sub>2.</sub>) This happed when there was interaction of hot saline brine and the limestone. This created hydrothermal dolomites that in some areas serve as [[petroleum]] reservoirs.<ref name=":2">{{Cite web |title=A Geologic Play Book for Trenton-Black River Appalachian Basin Exploration |url=http://www.wvgs.wvnet.edu/www/tbr/docs/41856R06.pdf |website=West Virginia Geological Survey}}</ref>

== Description ==
The Black River Group is characterized by [[Carbonate rock|carbonates]], primarily [[limestone]]. Some [[dolostone]]s can be found in localized areas.<ref name=":1">{{Cite web |last=SELLECK |first=BRUCE W. SELLECK |title=BLACK RIVER AND TRENTON GROUPS, NORTHWESTERN NEW YORK STATE |url=https://www.researchgate.net/publication/286256145 |website=Researchgate}}</ref> Due to fracturing and porosity naturally occurring with in the formation it servers as a gas reservoir throughout its reach.<ref name=":0">{{Cite web |last1=Patchen |first1=Douglas G. |last2=Hickman |first2=John B. |last3=Harris |first3=David |last4=Drahovzal |first4=James A |date=June 2006 |title=A Geologic Play Book for Trenton-Black River Appalachian Basin Exploration |url=https://www.researchgate.net/publication/292984149 |website=Researchgate}}</ref> It also serves as an oil reservoir in Michigan and North West Ohio.<ref name=":0" /><ref>{{Cite web |last1=Colquhoun |first1=Ian |last2=Vansickel |first2=Bill |title=TRENTON- BLACK RIVER HTD RESERVOIRS OF THE MICHIGAN BASIN |url=http://www.ogsrlibrary.com/downloads/OPI-2017_Trenton-Black-River-Hydrothermal-Reservoirs-of-the-Michigan-Basin_Colquhoun.pdf |website=Oil, Gas and Salt Resources Library}}</ref>

== Stratigraphy ==
The Black River Group is predominantly composed of carbonates. In addition clay minerals maybe found in differing amounts. Locally sand and silt maybe found in thin horizons especially in the eastern reaches of the unit. In addition there are [[Bentonite|K-bentonite]] beds. These were formed as a result of [[Types of volcanic eruptions|volcanic eruptions]] depositing layers of [[volcanic ash]].<ref>{{Cite web |last=Stith |first=David A. Stith |date=1979 |title=CHEMICAL COMPOSITIPN, STRATIGRAPHY, AND DEPOSITIONAL ENVIRONMENTS OF THE BLACK RIVER GROUP (MIDDLE ORDOVICIAN), SOUTHWESTERN OHIO |url=https://ohiodnr.gov/static/documents/geology/RI113_Stith_1979.pdf |website=Ohio Department of Natural Resources}}</ref> The Black River Group was deposited during a time when large parts of North America were a passive cratonic margin. North America at the time was near the equator and was a tropical environment. Large parts of what is now North America were covered by the [[Iapetus Ocean]]. The Black River Group was formed during a time of transition time where [[Laurentia]] was subject to the beginnings of the [[Taconic Orogeny]]. During the [[Cambrian]] the Iapetus began to slowly close. As Laurentia moved towards an [[island arc]] that it would eventually collide with the crust folded downward. As this happened the carbonate deposition of the [[continental shelf]] gradually gave way to clastic deposits of a deep marine environment.<ref name=":1" /><ref>{{Cite web |date=2011-07-22 |title=NYC Regional Geology |url=http://3dparks.wr.usgs.gov/nyc/highlands/highlands.html |access-date=2023-09-19 |archive-url=https://web.archive.org/web/20110722153634/http://3dparks.wr.usgs.gov/nyc/highlands/highlands.html |archive-date=2011-07-22 }}</ref> As a result, there are more siliceous deposits to the east.  The Taconic Orogeny occurred to the east and this formed a basin, but further west the crust buckled up into an arch. The result was the [[Cincinnati Arch]]. This arch was eroded back to late Ordovician aged rock. This split the basin of the Iapetus Ocean into three separate basins.<ref>{{Cite web |last=Prater |first=Jessica |date=2022-10-07 |title=The Cincinnati Arch |url=https://www.cincymuseum.org/2022/10/07/the-cincinnati-arch/ |access-date=2023-09-25 |website=Cincinnati Museum Center |language=en-US}}</ref>

== Subunits ==

===Black River Formation===
The '''Black River Formation''' is a [[Formation (geology)|geologic formation]] in [[Quebec]], [[Canada]] and [[Michigan]], [[United States]].<ref>{{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021|archive-date= 25 March 2022|archive-url= https://web.archive.org/web/20220325060448/http://www.fossilworks.org/cgi-bin/bridge.pl?action=home|url-status= live}}</ref> It preserves [[fossils]] dating back to the [[Ordovician]] [[Period (geology)|period]].

=== New York State ===

==== Amsterdam Limestone ====
The '''Amsterdam Limestone''' is a [[Formation (stratigraphy)|geologic formation]] in [[New York (state)|New York]]. It dates back to the [[Ordovician]] [[Period (geology)|period]]. It is a unit of the Black River Group in Eastern New York.

===== Fossils =====
''[[Cartersoceras]] noveboracense''

==== Waterton Limestone ====
The '''Waterton Limestone''' is a geologic formation in New York. It dates back to the Ordovician period. It is a unit of the Black River Group in Eastern New York.

==== Lowville Formation ====
The '''Lowville Formation''' is a geologic formation in New York and [[Ontario]]. It preserves fossils dating back to the Ordovician period.

== Energy production ==
The Black River Group acts as a reservoir for [[natural gas]] and [[petroleum]]. The reservoirs are associated with dolostones and. Gas and oil fields can be found in New York, Pennsylvania, Ohio, Indiana, Kentucky, Michigan, and Tennessee.<ref name=":2" /><ref>{{Cite web |title=UNDERGROUND STORAGE OF NATURAL GAS IN INDIANA |url=https://scholarworks.iu.edu/dspace/bitstream/handle/2022/27229/SR59_A1b.pdf?sequence=1&isAllowed=y |website=Scholar Works Indiana University}}</ref>

==See also==
{{Portal|Earth sciences|Canada|Paleontology}}
* [[List of fossiliferous stratigraphic units in Quebec]]
* [[List of fossiliferous stratigraphic units in Michigan]]

== References ==
{{reflist|30em}}

{{Chronostratigraphy of Indiana}}
{{Chronostratigraphy of Kentucky}}{{Stratigraphic column of Michigan}}
{{Chronostratigraphy of New York}}
{{Chronostratigraphy of Ohio}}
{{Chronostratigraphy of Pennsylvania}}
{{Stratigraphic column of West Virginia}}

[[Category:Ordovician Indiana]]
[[Category:Ordovician Michigan]]
[[Category:Ordovician Ohio]]
[[Category:Ordovician West Virginia]]