Dzhigiristan Formation

Dzhigiristan Fm

Period:

Jurassic

Age Interval:

upper Bathonian – Callovian, CK12

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along the Jigiristan River, left tributary of the Angren River, Tashkent area (district). Collective authors, 1959 (382, Table 13). Stratotype in the quarry of the Angren coal mine.

Synonym: Dzhigiristan Suite, Jigiristan sv., Джигиристанская св.

Lithology and Thickness

Variegated non-carbonate kaolinite clays, sandstones, siltstone (aleurolites), predominantly quartz, polymictic. Thickness up to 70m.

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

It lies conformably or with erosion on the Angren Fm

Upper contact

It is transgressively overlain by the Turonian

Regional extent

Tashkent area (district).

GeoJSON

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Fossils

In 1988, V.V. Kurbatov collected, and L.I. Savitskaya identified large plant remains from the D. suite (in burned rocks) - Lobifolia lobifolia (Phill.) Rassk. et Leb., Hausmannia luiana Szl., Dictyophyllum (?) sp., Coniopteris spectabilis Brick, Cladophlebis whitbiensis Brongn, Phoenicopsis angustifolia Heer., Pityophyllum sp., Elatocladus sp., Podozamites sp., typical for the Middle Jurassic Angren Fm.

Age

Considering the Aalenian - Bathonian age of the underlying Angren Fm and the position of the D. suite in the section, the age of the latter is dated to the upper Bathonian - Callovian. Before the Tashkent Conference of 1959 (382, Table 13), it was called the kaolinite suite and was attributed to the Lower - Middle Jurassic. At the Samarkand Conference (383, Table 5, p.2), it was dated to the Callovian.

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)”