Hardground assemblage: Anisian, Poland

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Bivalvia - Pectinida - Limidae
Plagiostoma sp. Sowerby 1814
1 %-specimens
Pseudolimea sp. Douglas and Arkell 1932
1 %-specimens
Bivalvia - Pterioida - Prospondylidea
Enantiostreon difforme (Schlotheim 1820)
2 %-specimens
recombined as Terquemia difformis
Rhynchonellata - Rhynchonellida - Austrirhynchidae
Decurtella decurtata (Girard 1843)
2 %-specimens
Rhynchonellata - Athyridida - Diplospirellidae
Tetractinella trigonella (Schlotheim 1820)
70 %-specimens
Rhynchonellata - Terebratulida - Dielasmatidae
Coenothyris vulgaris (Schlotheim 1820)
20 %-specimens
see common names

Geography
Country:Poland
Coordinates: 50.0° North, 19.0° East (view map)
Paleocoordinates:18.2° North, 24.6° East
Basis of coordinate:based on nearby landmark
Geographic resolution:small collection
Time
Period:Triassic Epoch:Middle Triassic
Stage:Anisian 10 m.y. bin:Triassic 2
Key time interval:Anisian
Age range of interval:247.20000 - 242.00000 m.y. ago
Stratigraphy
Formation:Karchowice
Regional section:Upper Silesian Region
Stratigraphic resolution:group of beds
Stratigraphy comments: The paleoecologic analysis is based on five sections from the Strzelc Opolskie Quarry. The five sections cover the entire span of the Terebratula Beds and the lowermost part of the Karchowice Beds. The Terebratula Beds are subdivided into three units: Lower marls, Crinoid limestones, and Coquina and wavy limestones (See description below for details)
Lithology and environment
Primary lithology: lithified "limestone"
Includes fossils?Y
Lithology description: Lower marls - Crumpled and wavy limestones dominate in this unit. Shelly fossils are practically absent. Only in one place badly preserved tiny bivalves have been observed. Crinoid Limestone - Two firmgrounds occur in the lower part of this unit. the middle and upper parts are composed of thick calcarenitic beds. Dominant skeletal components change upward from mixed skeletal debris in the lower part, through crinoid columnals in the middle part, to terebratulid shell debis in the upper part. Coquinas and wavy limestone - Four lithological types have been distinguished: a) brachiopod coqunia. Up to 30 cm thick coquina layers, separated by crumpled and wavy limestone, occur in the whole unit. b) Crumpled and wavy limestone. Limestone beds which exhibit deformational structures varying from wavy bedding and gentle undulation, to structures intricately crumpled and fragmented. Fossils uncommon but their number increase upward. c) Bivalve coquina. This lithology appears in the uppermost part if the unit as thin shell beds composed of closely packed internal molds of small articulated bivalves. d) Organodetrial limestone with foraminifers. Numerous benthic forams are the main component of this limestone. Karchowice Beds - Crinoid and micritic limestones dominate in this unit. Sponges as well as brachiopods are identified. Very numerous are columnals of crinoids and in places, shells of unidentified bivalves. Hardgrounds with a rich assemblages of trace fossiles are well developed on the micritic limestone bedding planes
Environment:marine indet.
Geology comments: the assemblage representing this type have been found only in the loose blocks scatterted on the quarry floor. T. trogonella occurs abundantly, usually exceeding 50 individuals per square meter, in thin layers of fine and well-sorted organodetrital limestone that cap the hardground surfaces.
Taphonomy
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:paleoecologic analysis
Metadata
Database number:33425
Authorizer:D. Bottjer Enterer:N. Bonuso
Modifier:N. Bonuso Research group:marine invertebrate
Created:2003-07-29 16:01:36 Last modified:2004-08-19 22:47:44
Access level:the public Released:2003-07-29 16:01:36
Creative Commons license:CC BY
Reference information

Primary reference:
8874. A. Kaim. 1997. Brachiopod-bivalve assemblages of the middle Triassic Terebratula Beds, Upper Siesia, Poland. Acta Palaeontologica Polonica 42(2):333-359 [D. Bottjer/N. Bonuso/M. Uhen]