Surkhat Formation

Surkhat Fm

Period:

Carboniferous

Age Interval:

Bashkirian, CK4

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along the Surhat Ridge, Pskem Ridge. A.S. Pitinova, 1965 (457, p.267). Stratotype in the Surhat Ridge on the Pskem River, tributary of the Isfay River.

Synonym: Surkhat Suite, Сурхатская св.

Lithology and Thickness

Suite is divided into two parts. Lower - layered organogenic-detrital, sandy limestones with interlayers of polymictic sandstones. Upper - interbedding of limestones, sandstones, tuff-gravels with inconsistent thickness interlayers of diabase and dacite porphyrites. Thickness 200-400m.

Lithology Pattern:

Limestone

Relationships and Distribution

Lower contact

Conformably overlies the Nauvalin Fm

Upper contact

Conformably overlain by the Upper Ugam Fm

Regional extent

Pskem Ridge, basin of the middle and upper reaches of the Pskem River (rivers Isfay, Oygaing), upper reaches of the Ugam River. Correlated with the Yakhak Fm (439; 457; 460).

GeoJSON

null

Fossils

Contains brachiopods - Choristites bisulcatiformis Sem.; foraminifers Pseudostaffella antiqua Dutk., P. grandis Schlyk.; ammonoids - Cancelloceras sp., Billinguites sp.

Age

Based on the findings of organic remains, it is attributed to the Lower Bashkirian substage.

Age Span:

Beginning stage:

Bashkirian

Fraction up in beginning stage:

0.3

Beginning date (Ma):

320.93

Ending stage:

Bashkirian

Fraction up in the ending stage:

0.6

Ending date (Ma):

318.45

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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