Los Espejos Formation, Facies B1, Cerro del Fuerte section (Silurian of Argentina)

Where: Argentina (30.3° S, 68.8° W: paleocoordinates 45.6° S, 128.9° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Los Espejos Formation, Ludlow (427.4 - 423.0 Ma)

• Middle part of sequence, about 120 to 140 m thick.

• member-level stratigraphic resolution

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

• Increase in thickness and frequency of storm layers in facies B1 relative to facies A may indicate change from distal to proximal tempestites...internal structure of SSt beds indicates proximal storm layers..other signs indicate deposition in nearshore shallow water, slightly below average storm wave base...Associated traces (Cruziana ichnofacies) suggest shallow shelf, below fair weather wave base.
• Hummocky cross-stratifried sandstones and mudstones..fine- to -medium-grained green-gray sst..in beds averaging 20-30 cm thick...beds commonly lenticular..some beds with sharp erosional bases...some beds with tool and scour marks and trace fossil casts..meandering sinuous trals (Torrowangeo, Cosmoraphe, Planolites)...sst beds oftern underlain by shell lag...wave ripple cross-lamination...horizontal plane lamination...mudstones extrensively bioturbated (Planolites, Chondrites)...otherwise parallel to low-angle internal lamination preserved...

Collection methods: Coquina 9 in Table 2.

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 25054: authorized by Michael Foote, entered by Michael Foote on 27.08.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Bivalvia
 Nuculanida - Nuculanidae
Anthracoleda (Pseudoleda) minuta
Anthracoleda (Pseudoleda) minuta Sanchez et al. 1995 pointed nut clam
Rhynchonellata
 Orthida - Dalmanellidae
Isorthis (Protocortezorthis) cuyanum
 Rhynchonellida - Leptocoeliidae
"Harringtonina acutiplicata" = Anabaia
"Harringtonina acutiplicata" = Anabaia
Trilobita
 Phacopida - Phacopidae
"Phacops argentinus" = Paciphacops argentinus
"Phacops argentinus" = Paciphacops argentinus Thomas 1905 trilobite
 Phacopida - Dalmanitidae
Dalmanites cf. sudamericanus