Clinton Group

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Coordinates: 40°44′05″N 77°46′42″W / 40.73472°N 77.77833°W / 40.73472; -77.77833
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Clinton Group

Stratigraphic range: Early Silurian
Appalachian Basin of eastern North America
CountryUnited States
ExtentOhio, Pennsylvania, Maryland, New York, West Virginia
Type section
Named forClinton, New York
Named byLardner Vanuxem (1842)

The Clinton Group (also referred to as the Clinton Formation or the Clinton Shale) is a mapped unit of

Appalachian Foreland Basin, a major structural and depositional province extending from New York to Alabama.[1] The term has been employed in Kentucky, Maryland, Michigan, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia, though in many of these areas the same interval is referred to as the Rose Hill, Rockwood, or Red Mountain Formations.[1][5] Historically the term "Clinton" has also been assigned to several lower Silurian stratigraphic units in Ohio and Kentucky which are now known to be significantly older than the Clinton Group as it was originally defined.[6] Many parts of this succession are richly fossiliferous, making the Clinton Group an important record of marine life during the early Silurian.[4] Several economically valuable rock-types are found within this interval, though it is perhaps best known as a significant source of iron ore [7]

Stratigraphically, the Clinton Group overlies the coarse siliciclastics of the Medina Group in New York, The Albion Group in the Subsurface of Ohio, the Clinch Sandstone in Virginia and West Virginia, and the Tuscarora Sandstone in Pennsylvania.[1][5] It is overlain by the shales and carbonates of the Lockport Group in New York, the McKenzie Formation in Pennsylvania, and the Sneedville Limestone in Tennessee.[1][5] Owing to the great difference in resistivity between the relatively soft, readily weathering Clinton Group and the massive dolomites of the overlying Lockport, the former tends to erode preferentially out from underneath the latter. This has resulted in the formation of numerous cateracts such as Niagara Falls and the High Falls of Rochester, New York which are but local manifestations of a regional geographic feature called the Niagara Escarpment.[8]

Description

The Clinton Group (or Formation) is a widely traceable, lower Silurian lithostratigraphic unit composed primarily of shale and mudstone, though it encompasses a heterogeneous assemblage of sedimentary rock types, including conglomerate, sandstone, limestone, dolomite, and ironstone.[4] In its designated type area in Clinton, Oneida County, New York the unit is approximately 50 meters (180 feet) thick, and composed primarily of blue-grey mudstone, shale, and sandstone with several discrete ferruginous horizons, known colloquially as "Clinton Ironstones".[3][4] The lateral equivalent of these beds to the south is the Rose Hill Formation of Pennsylvania, and olive-gray to drab, thin-bedded sandstone.[9]

An outcrop of Clinton Group Strata exposed at Seth Greene Drive in Rochester New York. Pictured is the Reynales Limestone overlying the Maplewood Shale. The prominent bright red band is the Furnaceville (Ironstone) Member of the Reynales.
An outcrop of Clinton Group Strata exposed at Seth Greene Drive in Rochester, New York. Pictured is the Reynales Limestone overlying the Maplewood Shale. The prominent bright red band is the Furnaceville (Ironstone) Member of the Reynales.

Economic uses

In Maryland, the Rose Hill Formation contained the Cresaptown Iron Sandstone.[9]

Age

Relative age dating of the Clinton Group places it in the Lower

Tuscarora Formation and conformably below the Lower and Upper Silurian Lockport Group[10] and Bloomsburg Formation.[11]

References

  1. ^ a b c d e Brett, C.E.; Baarli, B.G.; Chowns, T.; Cotter, E.; Driese, S.; Goodman, W.; Johnson, M.E. (1998). "Early Silurian Condensed Intervals, Ironstones, and Sequence Stratigraphy in the Appalachian Foreland Basin". In Landing, E.; Johnson, M.E. (eds.). Silurian Cycles: Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic and Tectonic Changes. James Hall Centennial Volume. New York State Museum Bulletin. Vol. 491. pp. 89–143.
  2. ^ "Clinton Group, Group". National Geologic Map Database. Retrieved 2012-10-05.
  3. ^ a b Vanuxem, L. (1839). "Third Annual Report of the Geological Survey of the Third District". New York State Geological Survey Annual Report. Vol. 3. pp. 241–285.
  4. ^ a b c d Gillette, T. (1947). "The Clinton of Western and Central New York". New York State Museum Bulletin. Vol. 341. Albany, New York: The University of the State of New York. pp. 1–191.
  5. ^
    doi:10.1016/0037-0738(90)90051-T
    .
  6. ^ Rexroad, C.B.; Branson, E.R.; Smith, M.O.; Summerson, C.; Boucot, A.J. (1965). "The Silurian Formations of East-Central Kentucky and Adjacent Ohio". Kentucky Geological Survey, Series X. 2: 1–34.
  7. ^ "Iron Ore Mining and Manufacturing in the Town of Kirkland". Lecture at the Clinton Historical Society meeting on April 16, 1998 at the Society's Headquarters on Fountain Street, Clinton, New York. Retrieved 2012-10-05.
  8. ^ "The Niagara Escarpment". Archived from the original on 2010-06-04. Retrieved 2012-10-05.
  9. ^ a b "Geologic Maps of Maryland". Retrieved 2008-01-26.
  10. USGS
    . Retrieved 2008-01-26.
  11. ^ Jackson, Margaret S.; Hanley, Peter M.; Sak, Peter B. (2007). "Preliminary Bedrock Geologic Map of the Middle Portion of the Susquehanna River Valley, Cumberland, Dauphin, And Perry Counties, Pennsylvania" (PDF). Open File Report OFBM-07-05.0. Pennsylvania Geological Survey. Archived from the original (PDF) on June 9, 2011. Retrieved 2008-01-26.

See also

40°44′05″N 77°46′42″W / 40.73472°N 77.77833°W / 40.73472; -77.77833

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