Balabansay Formation

Balabansay Fm

Period:

Jurassic

Age Interval:

Middle Jurassic (upper Bathonian- Callovian), F9a

Province:
Fergana

Type Locality and Naming

Along the Balabansay valley in the area of the Tashkumyr mine, Northern Fergana.

Collective authors, 1959 (382, Table 13). Stratotype Along the Tashkumyr section.

Synonym: Balabansai Formation, Балабансайская св.

Lithology and Thickness

Variegated sandstones, sandy clays, siltstone (aleurolites), conglomerates, gravellites. Thickness 50-380m.

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

Transgressively overlies the Samarkandek Fm and with erosion on the Zindan Fm,

Upper contact

with erosion overlain by Cretaceous deposits

Regional extent

Fergana region (Shurab, Shorsu, Abshir, Khodzhakelen).

GeoJSON

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Fossils

Contains freshwater bivalve mollusks - Jeniella sculpturata Mart. and others; large plant remains Coniopteris hymenophylloides (Brongn.) Sew. and others; freshwater ostracods - Darwinula oblonga (Roemer); fossil wood - Araucaripitys transiens (Goth.), Ptyllocladoxylon eboracense (Hold.), Protopodocarpoxylon blevillonse (Ling.), Xenolylon hoplinsis Chang., X. latiporosum (Gramer.); sharks - Polyacrodus cf. polyprion (Ag.), P. cf. prodigialis Ness. et Kazn., Palaeobates versilini Ness. et Kazn., Ptycholepididae; sturgeon-like - Chondrosteidea; turtles - Xinjiangchelys; tailless amphibian bones - Kokartus honorarius Ness.; dinosaur bones - (cf. Oznithopoda); crocodile vertebrae - Mesosuchia; crocodile teeth - cf. Goniopholidae; predatory dinosaur vertebrae - Coeluroidea; charophyte algae - Jurella abshirika KyansepRom. Gen. et sp. n. and others; complex of spores and pollen (383, Table 5, p.2,3).

Age

Middle Jurassic (upper Bathonian- Callovian). Organic remains do not contradict the Callovian. P.A. Shekhtman in 1941 (507) called it the variegated suite and assigned it to the Middle and Late Jurassic, while the collective authors in 1959 (382, Table 13) called it the Shurabsay suite and correlated it with the Upper Jurassic.

Age Span:

Beginning stage:

Bathonian

Fraction up in beginning stage:

0.8

Beginning date (Ma):

165.87

Ending stage:

Callovian

Fraction up in the ending stage:

1.0

Ending date (Ma):

161.53

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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