Los Espejos Formation, Facies B2, Cerro del Fuerte section (Silurian to of Argentina)

Where: Argentina (30.3° S, 68.8° W: paleocoordinates 57.2° S, 118.3° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Los Espejos Formation, Pridoli to Pridoli (423.0 - 393.3 Ma)

• Upper part of formation. Authors interpret age as Pridolian. Edgecombe et al. (1994, PBDB ref. 7141 think it is Lower Lochkovian on the basis of trilobites and presence of Pleurodictyum and typical Lower Lochkovian chitinozoans in immediately overlying beds.

• member-level stratigraphic resolution

Environment/lithology: marine; bioturbated, green, yellow mudstone and sandstone

• Interpretation similar to that for facies B1. Sed. structures in Sst suggests transition zone, i.e. below average storm wave base but above exceptional storm wave base. Increase in percentage of mudstones and decrease in frequencey per meter of storm layers towards top of facies could be related to increase of mud supply.
• Fossiliferous bioturbated mudstones and interbedded hummocky cross-stratified sandstones...higher proportion of mudstone than facies B1 (80-90%)...yellowish-green mudstones interbedded with fine-grained Sst 5 to 20 cm thick...some Sst beds exhibit low-angle hummocy CS and are capped by wave ripple. Basal concentration of shells almost invariably present. Bases of these beds sharp and erosive. Some gutter casts.

Collection methods: Coquinas 13, 15, 16, 32 in Table 2, and list of taxa in tables 3 and 4. One additional trilobite from PBDB ref. 7141.

Primary reference: T. M. Sanchez, B. G. Waisfeld, and J. L. Benedetto. 1991. Lithofacies, taphonomy, and brachiopod assemblages in the Silurian of western Argentina: A review of Malvinokaffric Realm communities. Journal of South American Earth Sciences 4(4):307-329 [M. Foote/M. Foote/O. Alfaro]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 25055: authorized by Michael Foote, entered by Michael Foote on 27.08.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Trilobita
 Odontopleurida - Odontopleuridae
Leonaspis sp. Richter and Richter 1917 trilobite
 Phacopida - Homalonotidae
 Phacopida - Calymenidae
 Phacopida - Calmoniidae
Andinacaste espejensis n. sp. trilobite
 Phacopida - Dalmanitidae
 Phacopida - Phacopidae
"Phacops argentinus" = Paciphacops argentinus
"Phacops argentinus" = Paciphacops argentinus Thomas 1905 trilobite
Deuteropoda
  -
Ostracoda indet. Latreille 1802 ostracod
 Lophophorata -
Tentaculitida indet. Ljaschenko 1955
Hyolitha
 Hyolithida -
Hyolithida indet. Mathew 1962
Rhynchonellata
 Athyridida - Anoplothecidae
 Atrypida - Lissatrypidae
 Orthida - Draboviidae
Salopina sp. Boucot 1960
 Orthida - Dalmanellidae
 Rhynchonellida - Leptocoeliidae
"Harringtonina acutiplicata" = Anabaia
"Harringtonina acutiplicata" = Anabaia
 Rhynchonellida - Eatoniidae
Strophomenata
 Strophomenida - Rafinesquinidae
Leptaena argentina Thomas 1905
 Strophomenida - Sowerbyellidae
Plectodonta (Plectodonta) minima Benedetto et al. 1992
 Strophomenida - Strophochonetidae
Lingulata
 Lingulida - Lingulidae
Gastropoda
 Bellerophontida -
"Bellerophontacea indet." = Bellerophontoidea
"Bellerophontacea indet." = Bellerophontoidea M'Coy 1851 snail
 Euomphalina - Platyceratidae
Platyostoma sp. Conrad 1842 snail
 Murchisoniina - Loxonematidae
Loxonema sp. Phillips 1841 snail
Cephalopoda
 Nautiloidea -
Nautiloidea indet. Agassiz 1847 nautiloid
Bivalvia
 Ostreida - Pterineidae
 Modiomorphida - Modiomorphidae
 Solemyida - Ctenodontidae
 Nuculanida - Cucullellidae
 Nuculanida - Malletiidae
? Palaeoneilo sp. Hall and Whitfield 1869 clam
 Nuculanida - Nuculanidae
Anthracoleda (Pseudoleda) minuta Sanchez et al. 1995 pointed nut clam
 Prionodesmacea -
Graptolithina
  -
Crinoidea
  -
Crinoidea indet. Miller 1821 Sea lily
Anthozoa
  -
Anthozoa indet. Ehrenberg 1834
solitary corals
 Favositida - Micheliniidae
Pleurodictyum sp. Goldfuss 1829 tabulate coral