Historical:Esmond Till Member

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Pleistocene stratigraphy of Illinois
Series Bulletin 94
Author H. B. Willman and John C. Frye
Date 1970
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Lithostratigraphy: Esmond Till Member
Chronostratigraphy: Cenozoic Erathem >>Quaternary System >>Pleistocene Series

Authors

H. B. Willman and John C. Frye

Name origin

The Esmond Till Member of the Wedron Formation was informally named the Esmond till (Frye et al., 1969, p. 26) from the village of Esmond, De Kalb County.

Type section

The type section is in roadcuts, NW SW NW Sec. 27, T. 43 N., R. 2 E., Winnebago County, 10 miles north of Esmond, but the till has been studied in detail in the Greenway School cores near Esmond (Frye et al., 1969). The type section exposes about 10 feet of brownish gray, calcareous, clayey till of the Esmond Member overlain by 2 feet of Richland Loess. The underlying pink sandy till of the Winnebago Formation is exposed down the hill 100 yards to the north. The Esmond is also well exposed in the Dixon Northwest and the Grand Detour Sections (table 7).

Stratigraphic relationships

The upper boundary of the member is the pink-tan Tiskilwa Member or equivalent deposits, and the lower boundary is on Morton Loess or deposits of the Robein Silt or Winnebago Formation.

Extent and thickness

It is a thin drift, generally not more than 20 to 30 feet thick. Its geographic distribution is shown in figure 6.

Lithology

The Esmond Till has two phases, an upper silty phase and a lower silty clay phase, both of which are characterized by a high illite content (tables 2 and 3). It is gray and contains relatively few cobbles and pebbles.

Age and correlation

The Esmond Till is in the early part of the Woodfordian Substage of the Wisconsinan Stage. It was deposited by the Dixon Sublobe of the Lake Michigan Lobe.

References

FRYE, J. C. (et al.), H. D. GLASS, J. P. KEMPTON, and H. B. WILLMAN, 1969, Glacial tills of northwestern Illinois: Illinois State Geological Survey Circular 437, 47 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation
0530
g-le