Pskem Formation

Pskem Fm

Period:

Carboniferous

Age Interval:

Lower Visean, CK3-5, CK6

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along the Pskem River, Chatkal Range. O.I. Sergun'kova, 1959 (382, p. 65), as a suite.

Synonym: Pskemskaya Series, Пскемская сер.

Lithology and Thickness

The series includes the Irisuy Fm, Kshikanidyan Fm, and Kibray-Carb Fm. Previously, the Kulusin Fm, Kuylyuk Fm, and Karatut Fm were mistakenly attributed to the series or its components. Overall, it consists of thin-bedded, organogenic-detrital, clayey limestones with frequent inclusions of cherts in the form of lenses, nodules, and layers (locally over 50%). Thickness from 300 to 1000 m.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

The lower boundary with the Chatkal Gr is conformable. They are defined by the disappearance and appearance of more massive limestones without cherts.

Upper contact

The upper boundary with the Ugam Gr is conformable. They are defined by the disappearance and appearance of more massive limestones without cherts.

Regional extent

Southwestern spurs of the Talassky Alatau, Chatkal, Pskem, Ugam, Sandalash, and Koksuy ranges.

GeoJSON

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Fossils

Contains representatives of brachiopod genera - Chonetes, Marginatia, Dictyoclostus, Verkhotomia; conodonts - Gnathodus, Paragnathodus, first Lochriea; numerous and diverse bryozoans - Fenestella, Polypora; corals - Siphonophyllia, "Nemistium".

Age

Lower Visean. Overall, the age range of the series corresponds to the Visean stage.

Age Span:

Beginning stage:

Visean

Fraction up in beginning stage:

0.1

Beginning date (Ma):

345.09

Ending stage:

Visean

Fraction up in the ending stage:

0.6

Ending date (Ma):

336.90

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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