Elwood Atherton, Charles Collinson, and Jerry A. Lineback
The Valmeyeran Series (Weller and Sutton, in Moore, 1933, p. 261-262) is named for Valmeyer, Monroe County, near which much of the series is exposed.
The type area of the Valmeyeran Series is along the Mississippi River near St. Louis.
Extent and Thickness
The Valmeyeran Series underlies most of central and southern Illinois (fig. M-10) and includes strata from the top of the Chouteau Limestone upward to the base of the Shetlerville Member of the Renault Limestone (Swann, 1963) (figs. M-3, M-11, M-12, M-13). The series is thickest, over 1800 feet, in southeastern Illinois, and it thins to 600 feet or less before being truncated by erosion in northern Illinois (fig. M-10). It probably originally covered all of northern Illinois, as 200 feet of Valmeyeran strata are preserved in fault blocks in the Des Plaines Disturbance (Emrich and Bergstrom, 1962).
The Valmeyeran Series is the middle series of the Mississippian System and includes formations assigned to two series (Osagian and Meramecan) in other areas.
The Valmeyeran is characterized by lateral changes due to depositional pinchouts and lateral gradation. In the type area along the Mississippi River near St. Louis, the Valmeyeran is predominantly carbonate formations. In central Illinois the Burlington and Keokuk Limestones pinch out eastward and the lower part of the Valmeyeran consists of the thick Borden Siltstone (fig. M-14). Eastward, in southeastern Illinois, the Borden is replaced as the dominant unit by the very thick Ullin Limestone and then by thick siliceous limestone of the Fort Payne Formation. The sediment of the Borden Siltstone was transported from the northeast by a major river and deposited in the inland sea as a delta that spread to and overlapped the Keokuk and Burlington carbonates. The deep-water, sediment-starved basin adjacent to the delta was later filled with Fort Payne and Ullin sediments (Swann et al., 1965; Lineback, 1966, 1968a, 1968b).
The overlying Salem and St. Louis Limestones are more persistent across the basin than the underlying units, but they, too, show facies that reflect water depth. Massive biocalcarenitic Salem grades laterally northward into fine-grained evaporite-bearing carbonates of the St. Louis (Lineback, 1972). Near the top of the Valmeyeran Series, the members of the Ste. Genevieve Limestone show rapid facies changes and the contact with the underlying St. Louis Limestone is stepped up and down in response to local lithologic changes.
Because of the complex facies variations in the Valmeyeran Series, knowledge of the relations between the many units has grown slowly, and the classification has been repeatedly changed (fig. M-15).
EMRICH, G. H., and R. E. BERGSTROM, 1962, Des Plaines Disturbance, northeastern Illinois: Geological Society of America Bulletin, v. 73, p. 959-968; Illinois State Geological Survey Reprint 1962-T.
LINEBACK, J. A., 1966, Deep-water sediments adjacent to the Borden Siltstone (Mississippian) delta in southern Illinois: Illinois State Geological Survey Circular 401, 48 p.
LINEBACK, J. A., 1968a, Subdivisions and depositional environments of New Albany Shale (Devonian-Mississippian) in Indiana: American Association of Petroleum Geologists Bulletin, v. 52, p. 1291-1303.
LINEBACK, J. A., 1968b, Turbidites and other sandstone bodies in the Borden Siltstone (Mississippian) in Illinois: Illinois State Geological Survey Circular 425, 29 p.
LINEBACK, J. A., 1972, Lateral gradation of the Salem and St. Louis Limestones (Middle Mississippian) in Illinois: Illinois State Geological Survey Circular 474, 23 p.
MOORE, R. C., 1933, Historical geology: McGraw-Hill Book Co., Inc., New York, 673 p.
SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.
SWANN, D. H. , J. A. LINEBACK, and EUGENE FRUND, 1965, Borden Siltstone (Mississippian) delta in southwestern Illinois: Illinois State Geological Survey Circular 386, 20 p.
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