Seccion de la Loma de Los Piojos. Layer 2: Rhuddanian, Argentina

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Strophomenata - Strophomenida - Leptostrophiidae
Aphanomena chilcaensis Benedetto 1995
recombined as Eostropheodonta chilcaensis
Rhynchonellata - Orthida - Dalmanellidae
? Dedzetina sp.
Rhynchonellata - Orthida - Proschizophoriidae
Cordatomyonia umangoensis Benedetto 1995
Rhynchonellata - Athyridida - Rhynchospirinidae
Homoeospira antiqua
Rhynchonellata - Rhynchonellida - Leptocoeliidae
? Anabaia informal n. sp.
Rhynchonellata - Rhynchonellida - Trigonirhynchiidae
Rostricellula sp. Ulrich and Cooper 1942
see common names

Geography
Country:Argentina State/province:San Juan
Coordinates: 30.3° South, 68.8° West (view map)
Paleocoordinates:34.2° South, 135.1° West
Basis of coordinate:based on nearby landmark
Geographic resolution:local area
Time
Period:Silurian Epoch:Llandovery
Stage:Rhuddanian 10 m.y. bin:Silurian 1
Key time interval:Rhuddanian Graptolite zone: Atavograptus atavus
Age range of interval:443.80000 - 440.80000 m.y. ago
Stratigraphy
Formation:La Chilca
Local section:Loma de Los Piojos Local bed:30 m
Local order:bottom to top
Stratigraphic resolution:group of beds
Stratigraphy comments: Age based on fact that beds containing the brachiopods are interbedded with or above beds of Atovograptus atavus Biozone.
Lithology and environment
Primary lithology:hummocky CS,"cross stratification",shelly/skeletal sandstone
Secondary lithology: "shale"
Lithology description: Lower part of shale and Sst...Upper part of fine-grained Sst [the part with fossils]...high-angle cross beds...hummocky cross beds...
Environment:marine indet.
Geology comments: Precordillera. Occurrences generally in dense shell accumulations; valves generally fragmented and disarticulated, indicating turbulence, possibly due to storms. In other instances the valves are articulated, less fragmented. Some cases of partial or total silicification.
Taphonomy
Modes of preservation:body,replaced with silica
Size of fossils:macrofossils
Collection methods and comments
Collection excludes:some macrofossils
Reason for describing collection:biostratigraphic analysis
Collection method comments: Brachiopods studied and listed; other higher taxa simply mentioned; graptolites listed for two of the sections that contain them. See location details.
Metadata
Database number:185895
Authorizer:P. Wagner Enterer:P. Wagner
Modifier:P. Wagner Research group:marine invertebrate
Created:2017-05-23 22:37:10 Last modified:2019-09-18 23:17:00
Access level:the public Released:2017-05-23 22:37:10
Creative Commons license:CC BY
Reference information

Primary reference:
7045. J. L. Benedetto. 1995. Braquiopodos del Silurica temprano malvinocafrico (Formacion La Chilca), Precordillera Argentina. Géobios 28(4):425-457 [M. Foote/M. Foote/J. Alroy]