Øvre Øren, Vikersund (Ordovician of Sweden)

Where: Sweden (60.0° N, 10.0° E: paleocoordinates 37.9° S, 16.5° W)

When: Apatokephalus serratus conodont zone, Bjørkåsholmen Formation, Varangu (485.4 - 484.5 Ma)

• = Ceratopyge Limestone (3ay) of older literature.

•Paltodus deltifer conodont zone

•Kiaerograptus supremus graptolite zone

• group of beds-level stratigraphic resolution

Environment/lithology: open shallow subtidal; gray limestone and nodular limestone

• A basic facies pattern of a carbonate unit like the Bjørkåsholmen Formation is that of a shallow and tectonic stable shelf environment (Wilson 1 975, pp. 2 5 , 3 5 5- 3 5 6 ) . The water depth would reach below normal wave base and even below storm wave base. The sea water would be oxygenated, with normal salinity and good current circulation. The sediments would generally be uniform and widespread, well-homogenized, very fossiliferous with diverse shelly fauna, and have wavy and nodular beds and load cast structures. These features match well with the setting of the Bjørkåsholmen Formation, at least for the post-Bienvillia beds.
• light and dark shale of varying thickness ( 5- 1 5 cm) , with distinet dark limestone nodules ( 2-5 cm thick), containing a fauna dominated by the olenid Bienvillia angelini

Size class: macrofossils

Primary reference: J.O.R. Ebbestad. 1999. Trilobites of the Tremadoc Bjørkåsholmen Formation in the Oslo Region, Norway. Fossils and Strata 47:1-118 [P. Novack-Gottshall/P. Hearn]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 172663: authorized by Pete Wagner, entered by Pete Wagner on 15.08.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Artiopoda
 Agnostida - Metagnostidae
Arthrorhachis mobergi, Geragnostus sidenbladhi
Arthrorhachis mobergi Tjernvik 1956
32-40 cm above base
Geragnostus sidenbladhi
32-40 cm above base
Trilobita
 Olenida - Olenidae
Bienvillia angelini
Bienvillia angelini Linnarsson 1869 trilobite
 Olenida - Eulomidae
Euloma ornatum
Euloma ornatum trilobite
 Harpetida - Harpididae
Harpides rugosus
 Trinucleida - Alsataspididae
Falanaspis aliena, Pagometopus gibbus
Falanaspis aliena Tjernvik 1956 trilobite
upper
 Asaphida - Nileidae
Symphysurus angustatus
Symphysurus angustatus Sars and Boeck 1838 trilobite
 Asaphida - Ceratopygidae
Ceratopyge acicularis
 Asaphida - Remopleurididae
Apatokephalus serratus
Apatokephalus serratus Boeck 1838 trilobite
40-80 cm
 Asaphida - Asaphidae
Niobe spp., Promegalaspides intactus
Niobe spp. Angelin 1851 trilobite
Promegalaspides intactus Moberg and Segerberg 1906 trilobite