Isfara Stage, units 18-21, Isfara River S-D section (Silurian of Tajikistan)

Where: Tajikistan (40.0° N, 70.5° E: paleocoordinates 10.5° S, 74.8° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Isfara Formation, Pridoli (423.0 - 419.2 Ma)

• Correlation with Czech Pridolian based mainly on brachiopods, according to authors. PJW: Pridoli here is now called Isfara formation.

• formation-level stratigraphic resolution

Environment/lithology: marine; shelly/skeletal, gray limestone and argillaceous shale

• "The investigated sections are found at the southern margin of the basin where limestones continuously accumulated during Upper Silurian and Devonian time.."
• "...(18) dark grey, knotty, platy, pelitomorphic limestones [containing] rare beds of organogenous-detrital limestones...(19) limestones interstratified with aleurolites and clay shales...algal limestones...(20)...massive...limestones, conglomerate-lie and breccia-like texture...(21) alternating limestones and aleurolites..."

Size class: macrofossils

Primary reference: J. S. Biske, V. B. Gorianov, and M. A. Rzonsnickaja. 1977. Tien-Shan. In A. Martinsson (ed.), The Silurian-Devonian boundary IUGS Serie(5):227-237 [M. Foote/M. Foote/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 13977: authorized by Michael Foote, entered by Michael Foote on 06.05.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

 Phacopida - Encrinuridae
Encrinurus sp. Emmrich 1844 trilobite
 Proetida - Proetidae
Unguliproetus sp. Erben 1951 trilobite
 Athyridida - Dayiidae
? Dayia sp. Davidson 1881
Dayia ex gr. navicula Sowerby 1839
 Spiriferida - Cyrtiidae
 Spiriferida - Reticulariidae
"Proreticularia carens" = Alaskospira, "Proreticularia sp." = Alaskospira
"Proreticularia carens" = Alaskospira
"Proreticularia sp." = Alaskospira Kirk and Amsden 1952
 Pentamerida - Gypidulidae
 Atrypida - Atrypidae
 Atrypida - Atrypinidae
 Atrypida - Lissatrypidae
"Atrypella cf. columebella" = Atrypoidea, "Atrypella linguata" = Atrypoidea, Atrypella aff. scheii
"Atrypella cf. columebella" = Atrypoidea
"Atrypella linguata" = Atrypoidea
Atrypella aff. scheii Holtedahl 1914
 Ozarkodinida -
Ozarkodina steinhornensis Ziegler 1956 conodont
 Favositida - Favositidae
Emmonsiella saaminica tabulate coral
Favosites interstinctus tabulate coral
Favosites difformis tabulate coral
Favosites vicinalis tabulate coral
Favosites cf. nitidus tabulate coral
 Favositida - Cleistoporidae
 Favositida - Micheliniidae
Pleurodictyum sp. Goldfuss 1829 tabulate coral
 Favositida - Parastriatoporidae
 Heliolitida - Heliolitidae
Helioplasma distans tabulate coral
 Cystiphyllida - Holmophyllidae
Holmophyllum sp. Wedekind 1927 horn coral
 Cystiphyllida - Goniophyllidae
 Rugosa - Chonophyllidae
 Stauriida - Pycnostylidae
 Stauriida - Lykophyllidae
Phaulactis sp. Ryder 1926 horn coral
 Stauriida - Entelophyllidae
"Entelophyllum articulatum" = Entelophyllum, "Stereoxylodes argutus" = Entelophyllum
"Entelophyllum articulatum" = Entelophyllum horn coral
"Stereoxylodes argutus" = Entelophyllum horn coral