Willman, H. B., and John C. Frye, 1970, Pleistocene Stratigraphy of Illinois: Illinois State Geological Survey Bulletin 94, 204 p.
KILLEY, M.M., and J.A. LINEBACK, 1983, Stratigraphic reassignment of the Hagarstown Member in Illinois, in Geologic Notes: Illinois State Geological Survey, Circular 529, p. 13–16.
H. B. Willman and John C. Frye (1970); Kiley M. and Lineback J. (1983); Grimley D.A. (2010); Grimley and Walkowska (2017)
The Hagarstown Member of the Glasford Formation was informally named the Hagarstown beds by Jacobs and Lineback (1969, p. 12), for the south-central Illinois region.
It was named for Hagarstown, Fayette County, 5 miles west of the type section.
The Hagarstown Member was original introduced informally by Jacobs and Lineback (1969). It was formalized as the Hagarstown Member of the Glasford Formation by Willman and Frye (1970), and was originally noted to be stratigraphically above the Vandalia Member of the Glasford Formation. However, similar ice-contact deposits also occur above the Radnor Member of the Glasford Formation (notably mapped by Lineback, 1979). The Hagarstown Member is also associated with sand and gravel deposits of the Pearl Formation. To make its stratigraphic classification more analogous to that of the last glacial Wasco Member of the Henry Formation (now the Wasco facies), the Hagarstown Member was reclassified to be a member of the Pearl Formation (Killey and Lineback, 1983). Its use as a member of the Glasford Formation was also formally abandoned (Killey and Lineback, 1983). Since 2010, detailed mapping in the Kaskaskia River Basin has recognized two mappable facies (informal) of the Hagarstown Member, a sandy facies and a mixed facies (Grimley, 2010; Grimley and Walkowska, 2017). These facies were first used by Grimley (2010), but have been used on multiple 1:24,000 quadrangle maps in southwestern Illinois where differentiation of these facies seemed practical. The sandy facies would generally be more favorable for economic use of the aggregate.
The type section is the Hickory Ridge Section (Jacobs and Lineback, 1969, p. 20), SW NW Sec. 20, T. 6 N., R. 1 E., Fayette County. The original description on page 20 lists Section 30, but this is believed to be a typographical mistake. Based on the location of this section in Fig. 2 of Jacobs and Lineback (1969) and the location of the gravel pit on a topographic map of this era, the type section is believed to be in Section 20, T6N, R1E.
Jacobs and Lineback (1969) introduced informally; formalized by Willman and Frye (1970).
The sand and gravel pit of the type section (Hickory Ridge Section) was visited on a 2011 Midwest Friends of the Pleistocene field trip (Grimley and Phillips, 2015); the section studied in 2011 was probably within about 500 m (generally to the north) of the original type section of Jacobs and Lineback (1969).
The Hagarstown Member contains the Sangamon Geosol solum in the upper 2 m of the unit (if uneroded). The Hagarstown Member is generally overlain by the Roxana Silt and Peoria Silt (last glacial loess or resedimented loess). The Hagarstown may overlie the Glasford Formation, older Quaternary units, or bedrock.
Extent and thickness
It is probably more than 100 feet thick in some of the higher ridges. In surface expression the Hagarstown Member is the material of the elongate ridges, referred to as the "ridged drift," and of the sheet of dominantly water-laid sediments between the ridges. Its geographic distribution, origin, and composition have been described by Jacobs and Lineback (1969).
It consists of gravelly till, poorly sorted gravel, well sorted gravel, and sand.
Well log characteristics
Age and correlation
The Hagarstown Member is in either the early Jubileean or late Monican Substage of the Illinoian Stage.
Environments of deposition
Ice-contact sediments; in ice-walled channels, ice-walled fans; eskers, kames, crevasse-fills, reentrants or other ice-contact environments
In some areas, the Hagarstown Member is mined for sand and gravel; beds of fine sand to gravelly sands are typical in the sandy facies of this unit (generally eskers and ice-walled channels); the mixed facies of this unit is generally too variable to be used economically (with interbeds of diamicton, silt, and clay); sand and gravel pits are most notably found in the Kaskaskia River Basin (see Jacobs and Lineback, 1969; Grimley and Phillips, 2015), but also locally in northwestern, central and southeastern Illinois in ridges on the Illinois Episode till plain. Thick deposits of the Hagarstown Member in the subsurface are also of importance for groundwater use.
- GRIMLEY, D.A., 2010, Surficial Geology of Mascoutah Quadrangle, St. Clair County, Illinois: Illinois State Geological, Illinois Geologic Quadrangle Map, IGQ Mascoutah-SG, 2 sheets, 1:24,000; report, 9 p.
- GRIMLEY D.A . and A.C. PHILLIPS, editors. 2015, Ridges, Mounds, and Valleys: Glacial-Interglacial History of the Kaskaskia Basin, Southwestern Illinois, 55th Midwest Friends of the Pleistocene Field Conference (2011), Illinois State Geological Survey, Guidebook 41, 124 p.
- GRIMLEY, D.A., and K.A. WALKOWSKA, 2017, Surficial geology of Keyesport Quadrangle, Clinton, Bond, and Fayette Counties, Illinois: Illinois State Geological Survey, Illinois Geologic Quadrangle Map, IGQ Keyesport-SG, 2 sheets, 1:24,000; report, 10 p.
- JACOBS, A. M., and J. A. LINEBACK, 1969, Glacial geology of the Vandalia, Illinois, region: Illinois State Geological Survey Circular 442, 24 p.
- KILLEY, M.M., and J.A. LINEBACK, 1983, Stratigraphic reassignment of the Hagarstown Member in Illinois, in Geologic Notes: Illinois State Geological Survey, Circular 529, p. 13–16.
- LINEBACK, J.A., 1979, compiler, Quaternary deposits of Illinois. 1:500,000 scale map.
- WILLMAN, H.B. and J.C. FRYE, 1970, Pleistocene stratigraphy of Illinois: Illinois State Geological Survey Bulletin 94, 204 p.
|Stratigraphic Code||Geo Unit Designation|