Logan Formation
{{Short description|Lower Carboniferous sedimentary formation in West Virginia, United States}}
{{Infobox rockunit
| name = Logan Formation
| image = LoganFormationWooster.JPG
| caption = Logan Formation exposed in Wooster, Ohio.
| type = Sedimentary
| age = {{Fossil range|348|340|Lower Carboniferous (early Osagean)}}
| period = Mississippian
| prilithology = sandstone, siltstone, conglomerate
| otherlithology = shale
| namedfor = Logan, Ohio
| namedby = Andrews, 1870
| region = Appalachian Basin
| country = United States
| coordinates =
| unitof = Waverly Group
| subunits = Berne, Byer, Allenville, Vinton
| underlies = Maxville Limestone, Pottsville Group, and Rushville Shale
| overlies = Cuyahoga Formation; Black Hand Sandstone
| thickness = 0 to 40 m
| extent = Ohio, West Virginia
| area =
| map =
| map_caption =
}}
The Logan Formation is the name given to a Lower Carboniferous (early Osagean) siltstone, sandstone and conglomeratic unit exposed in east-central Ohio and parts of western West Virginia, USA.
Stratigraphy and paleoenvironment
The Logan Formation was named by Andrews (1870) and originally described as a "buff-colored, fine-grained sandstone" above the Waverly Formation and below the Maxville Limestone. Bork and Malcuit (1979) concluded that the Logan Formation was deposited on a shallow marine shelf in a generally transgressing sea. The age of the Logan Formation has been established as early Osagean (Tn3) by the occurrences of brachiopods, ammonoids, conodonts and miospores (Clayton et al., 1998; Matchen and Kammer, 2006).
References
- {{cite journal | last1 = Andrews | first1 = E.B. | year = 1870 | title = Report of progress in the second district, Part II, IN Report of progress in 1869 | journal = Ohio Division of Geological Survey Report of Progress |series=2nd Series | pages = 1091–1094 }}
- {{cite journal | last1 = Bork | first1 = K.B. | last2 = Malcuit | first2 = R.J. | year = 1979 | title = Paleoenvironments of the Cuyahoga and Logan Formations (Mississippian) of central Ohio | doi = 10.1130/0016-7606(1979)90<1091:potcal>2.0.co;2 | journal = Geological Society of America Bulletin | volume = 90 | pages = 89–113 }}
- {{cite journal | last1 = Clayton | first1 = G. | last2 = Manger | first2 = W.L. | last3 = Owens | first3 = B.| year = 1998 | title = Mississippian (Lower Carboniferous) miospores from the Cuyahoga and Logan Formations of northeastern Ohio, USA | journal = Journal of Micropalaeontology | volume = 17 | pages = 183–191 | doi=10.1144/jm.17.2.183| doi-access = free }}
- {{cite journal | last1 = Matchen | first1 = D.L. | last2 = Kammer | first2 = T.W. | year = 2006 | title = Incised valley fill interpretation for Mississippian Black Hand Sandstone, Appalachian Basin, USA: Implications for glacial eustacy at Kinderhookian-Osagean (Tn2-Tn3) boundary | journal = Sedimentary Geology | volume = 191 | pages = 89–113 |bibcode = 2006SedG..191...89M |doi = 10.1016/j.sedgeo.2006.02.002 }}
Image:LoganConglomerateWooster.jpg|Conglomerate in the Logan Formation exposed in Wooster, Ohio, USA.
Image:LoganBrachiopodsWooster.jpg|Brachiopod internal and external molds in the Logan Formation in Wooster, Ohio.
Image:Aviculopecten subcardiformis01.JPG|The bivalve Aviculopecten subcardiformis from the Logan Formation in Wooster, Ohio (external mold).
Image:LoganFauna011312.jpg|Bivalves (Aviculopecten) and brachiopods (Syringothyris) in the Logan Formation in Wooster, Ohio.
Image:Logan Formation Cross Bedding Scour.jpg|Cross-bedding and scour in the Logan Formation of Jackson County, Ohio.
Image:Schizodus_medinaensis.JPG|Schizodus medinaensis; a bivalve from the Logan Formation in Wooster, Ohio (internal mold).
Image:Syringothyris01.JPG|Syringothyris sp.; a spiriferinid brachiopod from the Logan Formation in Wooster, Ohio (internal mold).
Image:Syringothyris bored Wooster Carboniferous.jpg|Syringothyris external mold with borings; Logan Formation; Wooster, Ohio.
Image:Syringothyris texta Hall 1857 dorsal.jpg|Syringothyris texta (Hall 1857), dorsal view, internal mold. Lower Carboniferous of Wooster, Ohio.
Image:Helminthopsis01.JPG|Helminthopsis ichnosp.; a trace fossil from the Logan Formation in Wooster, Ohio.
Image:PlatyceratidMississippian.JPG|Crinoid calyx from the Logan Formation in Wooster, Ohio, with a conical platyceratid gastropod (Palaeocapulus acutirostre) attached.
{{Chronostratigraphy of Ohio}}
Category:Mississippian United States
Category:Carboniferous Indiana
Category:Carboniferous West Virginia
Category:Carboniferous southern paleotropical deposits
Category:Sandstone formations of the United States
Category:Siltstone formations of the United States
Category:Conglomerate formations
Category:Shale formations of the United States
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