Wadsworth Formation

Lithostratigraphy: Wedron Group >>Wadsworth Formation
Chronostratigraphy: Cenozoic Erathem >>Quaternary System >>Pleistocene Series

Primary source

Hansel, Ardith K., and W. Hilton Johnson, 1996, Wedron and Mason Groups: Lithostratigraphic Reclassification of Deposits of the Wisconsin Episode, Lake Michigan Lobe Area: Illinois State Geological Survey Bulletin 104, 116 p.

Contributing author(s)

Ardith K. Hansel and W. Hilton Johnson

Name

Original description

Wadsworth Till Member (Willman and Frye 1970).

Derivation

Wadsworth, a village in Lake County.

History/background

The Wadsworth Till Member of the Wedron Formation was defined by Willman and Frye (1970) as clay-rich gray till of major moraines. It has since been elevated to formation rank as part of the Wedron Group.

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  Fig. 8 -- Lobe boundaries.

Type section

Type location

Roadcut at the intersection of Illinois Highway 131 and Wadsworth Road.

Type status

No longer exposed.

Reference section

Reference location

Fort Sheridan Lake Bluff Section; Land and Lakes Landfill Section; Cedarburg Lake Bluff Section.

Stratigraphic relationships

The Wadsworth Formation consists of gray, fine-grained diamicton that overlies the Lemont Formation and underlies the Kewaunee Formation.

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  Figure 13a -- Areal distribution of moraines and boundaries of formations and predominant members of the Wedron Group and the Trafalgar Formation in Illinois. (Names of formations and members are labeled on 13b.) Sublobe areas of the Lake Michigan Lobe and the Huron-Erie Lobe are shown on inset map: (1) Harvard; (2) Princeton, (3) Joliet; (4) Peoria; (5) Decatur; and (6) Huron-Erie (sublobe areas and moraines are modified from Willman and Frye 1970).
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  Figure 13b -- Names of Wedron Group formations and members in Illinois.
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  Figure 18 -- Clayey diamicton of the Wadsworth Formation above oxidized, silty, dolomitic diamicton of the undivided Lemont Formation at the Lemont Section.

Extent and thickness

The Wadsworth Formation forms a crescent-shaped wedge around the southern Lake Michigan basin and reaches significant thickness in moraine ridges.

Lithology

The formation consists of calcareous gray diamicton with lenses of clay, silt, and fine sand.

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  Figure 28 -- Silty clay diamicton of the Wadsworth Formation exposed in the Lake Michigan bluffs in Illinois.

Contacts

Lower boundary: contact with Lemont Formation or older units. Upper boundary: contact with Kewaunee Formation or younger deposits.

Age and correlation

Deposited during the Crown Point Phase of the Michigan Subepisode.

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  Figure 10 -- Geochronological units, chronostratigraphic units and diachronic units in the Lake Michigan Lobe in a transect from south of Peoria, Illinois, to north of the Straits of Mackinac in Michigan (geochronologic and chronostratigraphic units are after Frye et al. 1968, as modified by Follmer et al. 1979, Curry and Follmer 1992, and Evenson et al. 1976; upper part of time-distance diagram and phases of the Michigan Subepisode are after Hansel and Johnson 1992).
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  Figure 11 Correlation of the Wedron Group formations and members in the Lake Michigan Lobe area (units in Wisconsin from Mickelson et. al. 1984, Mickelson and Syverson, in press; units in Indiana from Bleuer et al. 1983, N.K. Bleuer, Indiana Geological Survey, personal communication, 1994; units in Michigan from Monaghan and Larson 1986, Monaghan et al. 1986, Taylor 1990).

Environments of deposition

Predominantly subglacial till with associated ice-marginal and subaqueous deposition.

Remarks

Revised unit.

References

BOGNER, J. E., 1975...
CLARK, P., and G. A. RUDLOFF, 1990...
COLMAN, S. M., and D. S. FOSTER, 1990...
COLMAN, S. M., D. S. FOSTER, and R. N. OLDALE, 1989...
GLASS, H. D., and M. M. KILLEY, 1987...
HANSEL, A. K., 1983...
HANSEL, A. K., and W. H. JOHNSON, 1992...
JUNG, D. J., and R. D. POWELL, 1985...
KILLEY, M. M., and C. B. TRASK, 1994...
LINEBACK, J. A., D. L. GROSS, and R. P. MEYER, 1974...
RONNERT, L., 1992...
WICKHAM, J. T., D. L. GROSS, J. A. LINEBACK, and R. L. THOMAS, 1978...
WILLMAN, H. B., and J. C. FRYE, 1970...

ISGS Codes

ISGS Code and Symbol

Stratigraphic Code	Geo Unit Designation
0410	w