“Big Clifty Sandstone”的意思、由来-开放百科全书

The Big Clifty Sandstone is a geologic formation in Indiana,^[1] and is a member of the Golconda Formation^[2] in Kentucky and is correlative with the Fraileys Shale ^[3] to which it grades to in southern Illinois.^[4] The Big Clifty and Golconda are part of the Chesterian Series^[5] of late Mississippian age. The Big Clifty Sandstone was deposited in deltaic to marginal marine environment by the paleo Michigan River which in modern directions flowed south from the Canadian shield, the sediment source, and then westward depositing sediment across Illinois, Indiana and Kentucky.^[6]^[7] At Mammoth Cave National Park the Big Clifty overlies the Girkin Formation, the uppermost of three cave forming carbonate formations which the Mammoth-Flint Ridge cave system spans.^[8] Below the Girkin Formation are the Ste. Genevieve Limestone, and the St. Louis Limestone respectively. The chemically resistant sediments comprising the Big Clifty, and similar siliciclastics, act as a caprock over the dissolving carbonates. The presence of the Big Clifty is one of several contributory factors that create favorable conditions for the formation, and subsequent preservation, of connected cavernous porosity in the Mammoth-Flint Ridge cave system.

The Big Clifty Sandstone also appears as sandstone knobs throughout south-central Kentucky, including the {{convert|200|ft|m|adj=mid|-tall}} Pilot Rock on the border of Todd County.

References

1. ^{{cite web|url=http://igs.indiana.edu/compendium/comp6dus.cfm|title=Big Clifty Formation|website=Igs.indiana.edu|accessdate=30 June 2018}}
2. ^{{cite web|url=http://ngmdb.usgs.gov/Geolex/NewRefsmry/sumry_1823.html|title=Geolex — Golconda publications|website=Ngmdb.usgs.gov|accessdate=30 June 2018}}
3. ^{{cite web|url=http://ngmdb.usgs.gov/Geolex/NewRefsmry/sumry_1722.html|title=Geolex — Fraileys publications|website=Ngmdb.usgs.gov|accessdate=30 June 2018}}
4. ^Treworgy, J.D., 1990, Kaskaskia Sequence: Valmeyeran and Chesterian Series, in M.W. Leighton, D.R. Kolata, D.T. Oltz, J.J. Eidel, eds., Interior Cratonic Basins: AAPG Memoir 51, p. 125-142
5. ^Treworgy, J.D., and Devera, J.A., 1990, Kaskaskia Sequence Overview: Middle Devonian Series through Chesterian Series, in M.W. Leighton, D.R. Kolata, D.T. Oltz, J.J. Eidel, eds., Interior Cratonic Basins: AAPG Memoir 51, p.109-112
6. ^Swann, D.H., 1963, Classification of Genevivian and Chesterian (Late Mississippian) Rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
7. ^Treworgy, J.D., 1998, The Illinois Basin-a Tidally and Tectonically influenced Ramp During the Mid-Chesterian Time, Illinois State Geological Survey, Circular 544, 20 p.
8. ^Palmer, A.N., 1981, Geologic Guide to Mammoth Cave National Park: Teaneck, N.J., Zephyrus Press, 210 p.