Middlesex Formation

{{Short description|Geologic formation in the United States}} {{Infobox rockunit | name = Middlesex Formation | image = | caption = | type = [[Formation (stratigraphy)|Formation]] | age = [[Frasnian]] | prilithology =[[Black Shale]] | otherlithology = | namedfor =Town of Middlesex, NY | namedby = | region = [[Maryland]], [[New York (state)|New York]], [[Ohio]], [[Pennsylvania]], [[West Virginia]] | country = United States | coordinates = | unitof = [[Sonyea Group]] | subunits = | underlies = [[Cashaqua Shale]] or [[Pulteney shale]] | overlies =[[Genesee Group]] | thickness =6–{{convert|75|ft|m}} | extent = | area = | map = | map_caption = }}

The '''Middlesex Formation''' is a carbon rich black shale [[Formation (stratigraphy)|geologic formation]] found in the [[Appalachian Basin]]. It represents one of several transgressive events (rising sea levels) during the [[Late Devonian]].<ref>{{Cite web |last1=KIRCHGASSER |first1=WILLIAM T. |last2=OVER |first2=D. JEFFREY |date=9 December 2023 |title=FRASNIAN (UPPER DEVONIAN) STRATA OF THE GENESEE RIVER VALLEY, WESTERN NEW YORK STATE |url=https://ottohmuller.com/nysga2ge/Files/1994/NYSGA%201994%20A5%20-%20Frasnian%20(Upper%20Devonian)%20Strata%20of%20the%20Genesee%20River%20Valley,.pdf |access-date=9 December 2023 |website=Otto's Website}}</ref>

== Description == The Middlesex is a laminated, dark grey to black formation comprising [[mudstone]] and [[siltstone]]. It developed in an [[Anoxic waters|anoxic]] environment. Further evidence of this is the lack of [[bioturbation]]. There are also sparse sand and silt layers, suggesting that they were single event deposits.<ref>{{Cite journal |last=Schieber |first=J. |date=1999-07-01 |title=Distribution and deposition of mudstone facies in the Upper Devonian Sonyea Group of New York |url=http://dx.doi.org/10.2110/jsr.69.909 |journal=Journal of Sedimentary Research |volume=69 |issue=4 |pages=909–925 |doi=10.2110/jsr.69.909 |issn=1527-1404|url-access=subscription }}</ref>

==References== {{Reflist}}

* {{cite web |url=http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=NYDs%3B4 |title=Cashaqua and Middlesex Shales |publisher=USGS |access-date=2015-09-17 }} * {{cite journal |last=Bergin |first= M. J. |date=1964 |title=Bedrock Geology of the Penn Yan and Keuka Park Quadrangles New York |url=https://pubs.er.usgs.gov/publication/b1161G |journal=Geological Survey Bulletin |publisher=USGS |issue=1161-G |access-date=22 September 2015}} * {{cite web |url = https://macrostrat.org/unit_info.php?name_id=4156 |title = Middlesex Shale Formation – Sonyea Group |publisher = Shanan E. Peters & Noel A. Heim |access-date = 2015-09-17 |url-status = dead |archiveurl = https://web.archive.org/web/20150923144159/https://macrostrat.org/unit_info.php?name_id=4156 |archivedate = 2015-09-23 }} * {{cite journal |last=Schieber |first=J. |date=1999 |title=Distribution and deposition of mudstone facies in the Upper Devonian Sonyea Group of New York |url=http://www.shale-mudstone-research-schieber.indiana.edu/sonyea-shales.htm |journal=Journal of Sedimentary Research |publisher=SEPM Society for Sedimentary Geology |volume=69 |issue=4 |pages=909–925 |access-date=22 September 2015 |doi=10.2110/jsr.69.909|url-access=subscription }}

[[Category:Devonian geology of New York (state)]] [[Category:Devonian Pennsylvania]] [[Category:Shale formations of the United States]] [[Category:Devonian Maryland]] [[Category:Devonian Ohio]] [[Category:Devonian West Virginia]] [[Category:Geologic formations of New York (state)]] [[Category:Geologic formations of Pennsylvania]] [[Category:Geologic formations of Maryland]] [[Category:Geologic formations of Ohio]] [[Category:Geologic formations of West Virginia]]