The Traverse Group is a geologic group in Michigan, Indiana and Ohio comprising middle Devonian limestones with calcareous shale components.[1][2] Its marine fossils notably include Michigan's state stone, the Petoskey stone (the extinct coral Hexagonaria percarinata), among other corals and records of ancient marine life. A range of trilobites has also been found in the Traverse Group.[3]
| Traverse Group | |
|---|---|
| Stratigraphic range: Devonian | |
| Type | Group |
| Sub-units | Bell Shale, Rockport Quarry Limestone, Ferron Point Fm, Koehler Limestone, Gravel Point Fm, Charlevoix Limestone, Petoskey Fm, Whiskey Creek Fm, Ten Mile Creek Dolomite |
| Underlies | Antrim Shale and Jordan River Formation |
| Overlies | Dundee Formation and Rogers City Limestone |
| Thickness | 183 meters |
| Lithology | |
| Other | Limestone |
| Location | |
| Region | |
| Country |  United States |
The Traverse Group outcrops in Emmet and Charlevoix counties along the northwestern shore of Michigan's lower peninsula. Its formations are Gravel Point, Charlevoix Limestone, Petoskey, and Whiskey Creek.[4] The Gravel Point Formation consists of a lithographic gray to brown limestone with shale beds up to 0.5 meters thick; it also includes chert nodules and bioherms (fossilized reef mounds). The Charlevoix Limestone is a mildly argillaceous limestone with interbedded coquina. The Petoskey Formation is an arenaceous limestone named for its locale (Petoskey, Michigan), and contains the eponymous Petoskey stones. The Whiskey Creek Formation is a limestone.
The Traverse Group formed as a shallow carbonate shelf during the Devonian period (~419 to 359 Ma), when the most recent supercontinent, Pangea, was just beginning to take shape.
See also edit
References edit
- ^ "Traverse Group (MIDt;0)". mrdata.usgs.gov. Retrieved 2016-06-29.
- ^ John., Imbrie (1959-01-01). "Brachiopods of the Traverse group (Devonian) of Michigan. Part 1, Dalmanellacea, Pentameracea, Strophomenacea, Orthotetacea, Chonetacea, and Productacea. Bulletin of the AMNH ; v. 116, article 4". hdl:2246/1258.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Stumm, Erwin (1953). "Trilobites of the Devonian Traverse Group of Michigan" (PDF). University of Michigan Press - Museum of Paleontology.
- ^ Milstein, Randall (1987). "Middle Devonian Traverse Group in Emmet and Charlevoix Counties, Michigan" (PDF). Geological Society of America Centennial Field Guide - North-Central Section. doi:10.1130/0-8137-5403-8.293.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
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