McDonough Loess Member

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Lithostratigraphy: Roxana Silt >>McDonough Loess Member
Chronostratigraphy: Cenozoic Erathem >>Quaternary System >>Pleistocene Series

Primary source

Willman, H. B., and John C. Frye, 1970, Pleistocene Stratigraphy of Illinois: Illinois State Geological Survey Bulletin 94, 204 p.

Contributing author(s)

H. B. Willman and John C. Frye

Name

Original description

McDonough Loess Member (Willman and Frye 1970).

Derivation

The McDonough Loess Member of the Roxana Silt is named for McDonough Lake on the Mississippi River floodplain in Madison County.

Other names

History/background

Type section

Type location

Its type section is the Pleasant Grove School Section (table 6) 1 mile southeast of McDonough Lake, SW NE SE Sec. 20, T. 3 N., R. 8 W.

Table 6 -- Stratigraphic Sections (partial)
The following 21 stratigraphic sections describe exposures in Illinois and illustrate many of the aspects of Pleistocene stratigraphy. These sections contain the type localities for 21 rock-stratigraphic units, 4 soil-stratigraphic units, and 3 time-stratigraphic units and include paratypes for several other units. The sample numbers preceded by "P" are the numbers used in the Illinois State Geological Survey collections. Analytical data on many of these samples are on file at the Survey. The sections are arrange alphabetically by name.

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

The McDonough Member, designated Roxana zone-Ib in previous Illinois literature, overlies the Chapin Soil and is terminated at the top by the Pleasant Grove Soil and the overlying Meadow Loess Member of the Roxana Silt.

The spatial relations are shown diagrammatically by figure 8.

Extent and thickness

Lithology

The McDonough Loess is gray to tan, generally leached, but at a few places (e.g., Pleasant Grove School Section) it contains some etched fossil snail shells. The member is also described in the Chapin, Cottonwood School, and Gale Sections (table 6). Previously published sections that describe the McDonough Member (Roxana zone-Ib) include the De Pue, French Village, Fulton Quarry, Hillview, and Literberry Sections (table 7). Mineral compositions are listed in table 5.

Table 6 -- Stratigraphic Sections (partial)
The following 21 stratigraphic sections describe exposures in Illinois and illustrate many of the aspects of Pleistocene stratigraphy. These sections contain the type localities for 21 rock-stratigraphic units, 4 soil-stratigraphic units, and 3 time-stratigraphic units and include paratypes for several other units. The sample numbers preceded by "P" are the numbers used in the Illinois State Geological Survey collections. Analytical data on many of these samples are on file at the Survey. The sections are arrange alphabetically by name.

Core(s)

Photograph(s)

Contacts

Well log characteristics

Fossils

Age and correlation

Environments of deposition

Economic importance

Remarks

References

The McDonough Member is in the midpart of the Altonian Substage of the Wisconsinan Stage.

ISGS Codes

Stratigraphic Code Geo Unit Designation
0670
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