Lombard Dolomite Member
Lithostratigraphy: Knox Dolomite Megagroup >>Eau Claire Formation >>Lombard Dolomite Member
Chronostratigraphy: Paleozoic Erathem >>Cambrian System >>Croixan Series >>Dresbachian Stage
Allostratigraphy: Sauk Sequence
Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.
T. C. Buschbach
The Lombard Dolomite Member of the Eau Claire Formation (Buschbach, 1964, p. 32).
Named for Lombard, Du Page County.
The type section of the Lombard Dolomite Member is located 2 miles east of Lombard, DuPage County, and is at a depth of 1535-1640 feet (sample set 15,336) in the same boring as the Elmhurst Member.
The Lombard Dolomite Member overlies the Elmhurst Member of the Eau Claire Formation.
Extent and thickness
The Lombard Member is recognized in northeastern Illinois, where it ranges from a few to 150 feet thick.
The Lombard consists chiefly of grayish brown, glauconitic, partly sandy dolomite containing beds of greenish gray shale. It contains beds of limestone in Kane and DuPage Counties. Northward and westward it grades to sandstone, and southward it becomes more shaly.
Well log characteristics
Age and correlation
Environments of deposition
BUSCHBACH, T. C., 1964, Cambrian and Ordovician strata of northeastern Illinois: Illinois State Geological Survey Report of Investigations 218, 90 p.
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