Coxville Sandstone Member
Nelson, W.J., 2020, Pennsylvanian Subsystem in Illinois: Illinois State Geological Survey Bulletin (in press).
Edited and figures drafted by Jennifer M. Obrad.
Coxville is the oldest of four names that have been used for sandstone that occupies the same stratigraphic position in different areas of the Illinois Basin. Ashley (1899, p. 300, 301, 384–387) named the Coxville Sandstone based on exposures along Raccoon Creek near Coxville in Parke County, Indiana. In these outcrops, the sandstone fills channels eroded down to and partially into what Ashley (1899) identified as Coal VI, now known as the Seelyville Coal. Friedman (1960) described the sandstone in greater detail, pinned down its stratigraphic position, described a type section and two reference sections, and designated the unit as the Coxville Sandstone Member (of the Linton Formation, Carbondale Group).
Also known as Roseville, Coxville was settled around 1820, making it one of the oldest communities in western Indiana. Its location is 15 mi (24 km) northeast of Terre Haute.
This unit has been called the Sebree Sandstone in western Kentucky, the Palzo Sandstone in southern Illinois, and the Browning Sandstone in western Illinois. Because the name Coxville has priority, it is accepted here, and the other three names are abandoned.
The type section is on the northeast side of Raccoon Creek opposite Coxville in the NE¼ of sec. 16, T 14 N, R 8 W.
Ashley (1899) indicated the locality and described the rocks briefly; Friedman (1960, p. 25) described the section in detail.
Abandoned quarry located in the SE¼ SW¼ sec. 15, T 14 N, R 8 W, Vigo County, Indiana. This section illustrates the channel phase of the Coxville.
Friedman (1960, p. 25–28).
Judging by Google Earth imagery, the quarry site has reverted to woodland.
Log of a coal-test borehole in NW¼ NW¼ SE¼ sec. 26, T 13 N, R 10 W, Vigo County, Indiana.
Friedman (1960, p. 25–28).
Friedman did not identify the borehole, and no record matching its location appears in the well-log database of the Indiana Geological Survey. Apparently, the only record is the drillers’ log, which Friedman published.
The Coxville is younger than the Abingdon, Dekoven, and Seelyville Coal Members and older than the Colchester Coal. In this report, the name Coxville is applied to strata that directly underlie the Colchester underclay and have distinct channel geometry, truncating older units. Having a channel profile, thickness of the Coxville corresponds to the depth of incision, less than 80 ft (24 m) in most places. The Coxville truncates the Abingdon, Dekoven, Davis, and Seelyville Coals. In western Illinois, Coxville channels locally are incised into Mississippian rocks (Wanless 1957). Thin sandstone or, more commonly, heterolithic clastics occupy the Dekoven-to-Colchester interval outside of channels. These rocks are considered older than the Coxville and they belong to a different member, as yet unnamed.
Extent and thickness
Potter (1962, 1963) mapped the thickness of sandstone between the Colchester and Davis Coals in the southern Illinois Basin. This is largely Coxville Sandstone, but in places it includes a thin, unnamed sandstone between the Davis and Dekoven Coals. As mapped by Potter, thick sandstone forms a series of “belt and dendroid” bodies up to 10 mi (16 km) wide. These have typical meander-belt geometry, both in profile and in map view. The manner in which some of the channels split, cross, and reunite indicates that not all formed at the same time. Larger valleys are mostly 40 to 80 ft (12 to 24 m) deep, and locally are deeper than 80 ft.
Wright (1965, plate 7) mapped interpretive lithofacies of the Coxville throughout the Illinois and Western Interior basins. Her map depicts a large delta complex entering the Fairfield Basin along the eastern margin. Meandering channel sandstone bodies bifurcate toward the west and south. Two more large channels join in northwestern Illinois, implying a source area to the north.
The Coxville is largely sandstone that is very fine to medium grained, poorly sorted lithic arenite or subgraywacke. It exhibits an upward-fining profile, grading to siltstone, shale, and mudstone in the upper part. In places, an entire channel is filled with siltstone and finer grained rocks. Archer et al. (1995) described tidal rhythmites in “Coxville Sandstone equivalent facies” but unfortunately did not clearly illustrate the stratigraphic relationships.
The lower contact is erosive. The upper contact is generally gradational to siltstone and mudstone underlying the Colchester Coal.
Well log characteristics
Log profiles are typical for sandstone that is either more or less uniform vertically or that becomes finer and more argillaceous upward. Although he did not label the Coxville, Jacobson (1987, 1993) published numerous examples of logs that show this unit.
Transported plant remains and peat (coal) stringers are the only forms noted.
Age and correlation
Sandstone at the Coxville position is part of the Croweburg Formation in Missouri (Gentile and Thompson 2004) and the Floris Formation in Iowa (Ravn et al. 1984). No formal names are used for such sandstone in the Appalachian Basin.
Environments of deposition
All indications are that the Coxville Member occupies valleys that were incised and filled during regression and early lowstand of a eustatic cycle, contemporaneous with the development of the Colchester underclay (paleosol). Earlier models (Potter 1963; Wright 1965) invoked deltaic sedimentation, with Coxville channels as distributaries. In counterpoint, no deltaic deposits are present in northwestern Illinois, where the interval between the Colchester and Abingdon Coals is commonly thinner than 10 ft (3 m). Coxville channels here are incised far below the Abingdon base level, in places truncating Mississippian rocks.
Sandstone from this unit was formerly quarried on a small scale for construction purposes.
- Archer, A.W., G.J. Kuecher, and E.P. Kvale, 1995, The role of tidal-velocity asymmetries in the deposition of silty tidal rhythmites (Carboniferous, Eastern Interior coal basin, USA): Journal of Sedimentary Research, v. A65, no. 2, p. 408–416.
- Ashley, G. H., 1899, The coal deposits of Indiana, in W.S. Blatchley, State Geologist, Indiana Department of Geology and Natural Resources, 23rd Annual Report [for 1898]: Bloomington, Indiana Department of Geology and Natural Resources, p. 1–1573.
- Friedman, S.A., 1960, Channel-fill sandstones in the Middle Pennsylvanian rocks of Indiana: Indiana Geological Survey, Report of Progress No. 23, 59 p.
- Gentile, R.J., and T.L. Thompson, 2004, Paleozoic succession in Missouri, Part 5, Pennsylvanian Subsystem, Volume A, Morrowan strata through Cherokee Group: Missouri Geological Survey, Report of Investigations 70, 241 p. and correlation chart.
- Jacobson, R.J., 1987, Stratigraphic correlations of the Seelyville, Dekoven, and Davis Coals of Illinois, Indiana, and western Kentucky: Illinois State Geological Survey, Circular 539, 27 p. and 2 pls.
- Jacobson, R.J., 1993, Coal resources of the Dekoven and Davis Members (Carbondale Formation) in Gallatin and Saline Counties, southeastern Illinois: Illinois State Geological Survey, Circular 551, 41 p., 5 pls.
- Potter, P.E., 1962, Shape and distribution patterns of Pennsylvanian sand bodies in Illinois: Illinois State Geological Survey, Circular 339, 36 p., 3 pls.
- Potter, P.E., 1963, Late Paleozoic sandstones of the Illinois Basin: Illinois State Geological Survey, Report of Investigations 217, 92 p., 1 pl.
- Ravn, R.L., J.W. Swade, M.R. Howes, J.L. Gregory, R.R. Anderson, and P.E. Van Dorpe, 1984, Stratigraphy of the Cherokee Group and revision of Pennsylvanian stratigraphic nomenclature in Iowa: Iowa Geological Survey, Technical Information Series No. 12, 76 p.
- Wanless, H.R., 1957, Geology and mineral resources of the Beardstown, Glasford, Havana, and Vermont Quadrangles: Illinois State Geological Survey, Bulletin 82, 233 p.
- Wright, C.R., 1965, Environmental mapping of the beds of the Liverpool cyclothem in the Illinois Basin and equivalent strata of the northern mid-continent region: Urbana, University of Illinois, Ph.D. thesis, 100 p.
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