Dastar Formation

Dastar Fm

Period:

Carboniferous

Age Interval:

Upper Carboniferous (Gzhelian), F9c

Province:
Fergana

Type Locality and Naming

Along Dastar, Karachatyr Ridge, South Fergana. A. D. Miklukho-Maklai, 1956 (293, p.1153). Stratotype on Dastar, northern wing of the Karachatyr syncline.

Synonym: Dastarskaya Svita, Дастарская св.

Lithology and Thickness

Divided into three sub-stages (members). Lower (thickness 230-336m) - frequently alternating sandstones and siltstone (aleurolites), packets of thick-bedded sandstones with lenticular interlayers of conglomerates, terrigenous-carbonate turbidite horizons, and interlayers of limestones. Middle (thickness 160-175m) - thin-bedded sandstones and aleuropelites, interlayers of calcareous silty-claystone (aleuropelites) and clayey limestones. Upper sub-stage is divided into two parts. Lower (thickness 600-650m) - thin interbedding of sandstones, siltstone (aleurolites), argillites with interlayers of organogenic, sandy and detrital limestones, and near the base (Dastar) biogenic limestones. Upper (thickness 175-200m) - sandstones and limestones with subordinate aleuropelites, often pinching out along the strike.

Lithology Pattern:

Sandy limestone

Relationships and Distribution

Lower contact

Conformably overlies the Uchbulak Fm

Upper contact

It is conformably overlain by the Kerkidon Fm

Regional extent

South Fergana, Karachatyr Ridge, Tokuzbulaksai, Bulaksai.

GeoJSON

null

Fossils

In the Lower substage - foraminifers Schwageriniformis schwageriniformis subsp. parallelos (Scherb.), Triticites orysiformis Newell, T. (?) rossicus (Schellw.), Rauserites aff. fortissimus (Raus.), R. erraticus (Ros.), Rugosofusulina cylindrica Sosn. and others. In the Middle substage – contains Goniatites - Schistoceras uralensis Ruzh., Paraschistoceras optatum Ruzh., Prouddenites ferganensis (Ruzh.); conodonts - Streptognathodus elegantulus Stauf. et Plum., S. ruzhencevi Kozur. and others, and overlying biomorphic limestones with foraminifers - Rauserites karlensis Ros., Jigulites turanicus Bensh, J. corpulentus Bensh, J. major (Ros.), Daixina minima Bensh, D. asiatica Bensh, Rugosofusulina procera Bensh and others. In the Upper sub-stage, lower part contains foraminifers - Dutkevitchia dastarensis (Bensh), D. lancetiformis (M.-Macl.), massive Eoparafusulina ferganensis (Dutk.) and others. The upper part of Upper sub-stage contains foraminifers Eoparafusulina ferganensis (Dutk.) - many, Triticites pseudorhodesi Bensh, T. ex gr. ventricosus (Meek et Hayden), Daixina (Bosbytauella) bosbytauensis Bensh and others; conodonts - Streptognathodus elongatus Gunn., S. simplex Gunn., S. wabaunsensis Gunn.

Age

Late Carboniferous, Gzhelian epoch. (110; 209; 382; 439).

Age Span:

Beginning stage:

Gzhelian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

303.68

Ending stage:

Gzhelian

Fraction up in the ending stage:

1.0

Ending date (Ma):

298.89

Depositional setting

Depositional pattern:

Additional Information

Compiler:

F.R. Beni – In: GeoGPT translation of: ”Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)"