Hazelwood Member
Lithostratigraphy: Ottawa Limestone Megagroup >>Platteville Group >>Plattin Subgroup >>Mifflin Formation >>Hazelwood Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Blackriveran Stage
Allostratigraphy: Tippecanoe Sequence
Primary source
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.
Contributing author(s)
H. B. Willman and T. C. Buschbach
Name
Original description
The Hazelwood Member of the Mifflin Formation (Templeton and Willman, 1963, p. 82).
Derivation
Named for Hazelwood School, Lee County, 2 miles west of the type section.
Other names
History/background
Type section
Type location
The type section of the Hazelwood Member is located in a quarry on the east side of the Rock River Valley 3.5 miles north of Dixon (SW SW NW 22, 22N-9E), where it is 5.7 feet thick.
Type author(s)
Type status
Reference section
Reference location
Reference author(s)
Reference status
Stratigraphic relationships
Extent and thickness
The Hazelwood Member is widespread, but it is missing in Calhoun County. It is commonly 4-6 feet thick in the northern outcrop area, but it thickens southward and, judging from exposures near Cape Girardeau, Missouri, is probably as much as 50 feet thick in subsurface in southern Illinois.
Lithology
In the northern outcrop area, the Hazelwood is relatively pure, gray, thick-bedded to massive, lithographic limestone generally dolomite mottled, fucoidal, and with few fossils. A ferruginous corrosion surface occurs on the top. In the southern area, the Hazelwood is relatively pure, brown, fucoidal, fine-grained limestone, thicker bedded than the members above and below.
Core(s)
Photograph(s)
Contacts
Well log characteristics
Fossils
Age and correlation
Environments of deposition
Economic importance
Remarks
References
TEMPLETON, J. S., and H. B. WILLMAN, 1963, Champlainian Series (Middle Ordovician) in Illinois: Illinois State Geological Survey Bulletin 89, 260 p.
ISGS Codes
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