Historical:Malden Till Member

Lithostratigraphy: Malden Till Member
Chronostratigraphy: Cenozoic Erathem >>Quaternary System >>Pleistocene Series

Authors

H. B. Willman and John C. Frye

Name origin

The Malden Till Member of the Wedron Formation is named for Malden, Bureau County.

Type section

The type section is the Malden South Section (table 6) in roadcuts 2 miles south of Malden, SW SE SE Sec. 5, T. 16 N., R. 10 E.

Stratigraphic relationships

It is bounded at the top by the darker gray, very clayey Yorkville Till and at the base by the pink Tiskilwa Till.

Extent and thickness

The geographic distribution is shown in figure 6.

Fig. 6 -- Areal distribution of the dominantly till formations and members of Illinois.

Lithology

The Malden Till Member consists of silty, locally sandy, yellow-gray to gray-tan till with discontinuous beds of sand and gravel. It differs from the Yorkville in having a higher ratio of garnet to epidote (table 4). Data on grain size, clay mineral composition, and color of the matrix of the till are given in table 3.

Table 3 -- Composition of Wedron Formation (X-ray analyses by H. D. Glass, Illinois State Geological Survey). Table 4 -- Averages of Analyses of Selected Heavy and Light Minerals (Analyses of size fraction 0.062-0.250 mm). (From Frye, Glass, and Willman, 1962; Frye, Willman, and Glass, 1964; Willman, Glass, and Frye, 1963).

Age and correlation

The Maiden Till is in the mid-part of the Woodfordian Substage of the Wisconsinan Stage. It was deposited by the Peoria, Princeton, and Harvard Sublobes of the Lake Michigan Lobe.

ISGS Codes

Stratigraphic Code	Geo Unit Designation
0440	--