Upper Decorah Shale Ostracodes in Minnesota (Ordovician to of the United States)

Where: Minnesota (44.0° N, 92.0° W: paleocoordinates 19.1° S, 62.9° W)

• coordinate estimated from map

• basin-level geographic resolution

When: Strictopora minima zone, Decorah Shale Formation, Rocklandian to Rocklandian (457.3 - 449.6 Ma)

• Correlates with the Ion Member of northeastern Iowa

• formation-level stratigraphic resolution

Environment/lithology: gray shale and limestone

• Environmental call by T. Hanson.
• "A few feet to 20 feet or more of greenishm-gray shale and blocky to thin-bedded fossiliferous limestone. The so-called fucoidal beds that contain many vermicular burrows and the goethitic "brassy oolites" beds are somewhat more common in the upper than the middle Decorah but that unit also contains these deposits locally."

Size class: microfossils

Collection methods: chemical,

Primary reference: F. M. Swain and J. R. Cornell. 1987. Ostracoda of the superfamilies Drepanellacea, Hollinacea, Leperditellacea, and Healdiacea from the Decorah Shale of Minnesota. In R. E. Sloan (ed.), Middle and Late Ordovician lithostratigraphy and biostratigraphy of the Upper Mississippi Valley: Minnesota Geological Survey Report of Investigations 35 102-130 [S. Holland/T. Hanson/S. Bruning]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 23148: authorized by Steven Holland, entered by Tori Hanson on 10.07.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Ostracoda
 Podocopida - Bairdiidae
 Podocopida - Bairdiocyprididae
 Palaeocopida - Tetradellidae
 Palaeocopida - Euprimitiidae
 Palaeocopida - Eurychilinidae
 Palaeocopida - Hollinidae
 Palaeocopida - Oepikellidae
 Palaeocopida - Bolliidae
Quasibollia persulcata Ulrich 1879 ostracod
Maratia mara ostracod
Maratia micula ostracod
 Palaeocopida - Aechminidae
 Palaeocopida - Drepanellidae
 Palaeocopida - Primitiidae