Historical:Nokomis Sandstone Member
Lithostratigraphy: Ottawa Limestone Megagroup >>Ancell Group >>Glenwood Formation >>Nokomis Sandstone Member
Chronostratigraphy: Paleozoic Erathem >>Ordovician System >>Champlainian Series >>Blackriveran Stage
Allostratigraphy: Tippecanoe Sequence
Authors
H. B. Willman and T. C. Buschbach
Name Origin
The Nokomis Sandstone Member of the Glenwood Formation (Templeton and Willman, 1963, p. 51), which commonly includes all the sandstone of the formation in extreme northern Illinois and farther north, is named for Lake Nokomis.
Type Section
The type section of the Nokomis Sandstone Member is located 1.5 miles east of Lake Nokomis in the bluff on the west side of the Mississippi River at Lock and Dam No. 1 in Minneapolis, Minnesota, where the member is 10.8 feet thick.
Extent and Thickness
The Nokomis Sandstone Member has a maximum thickness of 11 feet in Illinois but is generally less than 5 feet and is absent in places.
Stratigraphic Position
The Nokomis Sandstone Member rests on the St. Peter Sandstone and is overlain by the Harmony Hill Shale Member.
Description
The Nokomis Member results from the merger northward of the Kingdom and Loughridge Sandstone Members beyond the margin of the intervening Daysville Dolomite Member. It has the typical Glenwood texture and generally rests sharply on the underlying St. Peter Sandstone.
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
| Stratigraphic Code | Geo Unit Designation |
|---|---|