Neogene

Paleogene

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Mesoproterozoic

Paleoproterozoic

Main source = Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian) Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

Bilfurak Beds Formation

Bilfurak Beds Fm

Period:

Silurian

Age Interval:

Middle Llandovery, Z1

Province:
Zarafshan-N.Gissar

Type Locality and Naming

Along the Bilfurak stream, Shing River basin, Zarafshan-Gissar mountain region. A.I. Lavrushevich, G.N. Menakova, 1966 (368, p. 19). Stratotype in the section of the Daurch mountain as part of the Shing suite.

Synonym: Bilfurak Layers, Бильфуракские сл.

Lithology and Thickness

Thin-bedded clayey or sandy dolomitized sludge-detrital limestones. Sometimes in the lower part, clayey-calcareous dolomitized shales, strongly ferruginous sericite-quartz shales with lenses and interlayers of quartz siltstone (aleurolites) or quartz sandstones and conglomerates are observed. Thickness 35-37m.

Lithology Pattern:

Sandy limestone

Relationships and Distribution

Lower contact

Lies conformably on the Raz Member (Ra Beds Fm)

Upper contact

Conformably overlain by the Daurich Beds Fm.

Regional extent

Zarafshan-Gissar mountain region, section of the Daurch mountain, mouths of the Bilfurak and Arg rivers, Muhkak mountain, Ispena locality, Chakyly-Kalyan ridge.

GeoJSON

null

Fossils

Contains stromatoporoids Clathrodictyon">Clathrodictyon regulare (Rosen.); tabulates - Palaeofavosites balticus (Rukhin), P. multitabulatus Sok., P. paulus Sok., Catenipora gotlandica (Gabe); rugosans - Calostylis denticulata (Kjerulf); brachiopods - Dalmanella neocrassa (Nikif.), Eospirifer cf radiatus (Sow.).

Age

Bilfurak Member, according to A.A., correspond to the middle Llandovery of the Lower Silurian.

Age Span:

Beginning stage:

Aeronian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

440.49

Ending stage:

Aeronian

Fraction up in the ending stage:

0.5

Ending date (Ma):

439.54

Depositional setting

Depositional pattern:

Additional Information

Compiler:

A.I. Kim – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”