Koksuy Formation

Koksuy Fm

Period:

Carboniferous

Age Interval:

Tournaisian, CK3, CK4

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along the Koksu River, Chatkal River basin, Chatkal Ridge. O.I. Sergun'kova, 1959 (382, p. 63). Stratotype on the Kulosey River, left tributary of the Koksu River, near the village of Burchmulla.

Synonym: Koksu Suite, Коксуйская св.

Lithology and Thickness

The suite is divided into two parts. Lower - gray layered, nodular, nodular, aphanitic limestones with characteristic small "eyes" of transparent calcite. Thickness up to 200m. Upper - thick- to medium-bedded dark gray to black limestones, predominantly organogenic-detrital. Thickness 40-80m.

Lithology Pattern:

Limestone

Relationships and Distribution

Lower contact

Along V.V. Mikhailov (460), it lies conformably on the Temirbastau Fm, and when this suite is completely absent from the section, it lies conformably on Devonian deposits

Upper contact

It is conformably overlain by the Taldybulak Fm or its analogue - the Kulosey Fm

Regional extent

Ugam, Pskem, and Koksu Ridges. Laterally, on the left bank of the Chatkal River (Chatkal River basin), it is replaced by massive limestones of the Akbulak Fm and reefoid masses of the "Akbulak" type.

GeoJSON

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Fossils

Contains numerous crinoid remains; brachiopods - Palaeochoristites čatkalicus Dik., foraminifera - Septabrunsiina donica Lip., Endothyra parakosvensis Lip.; conodonts - Siphonodella crenulata Coop., S. isosticha (Coop.), S. obsoleta Hass.

Age

Based on the fossil data, the age of the suite is determined in the interval of the middle part of the early Tournaisian - middle part of the late Tournaisian. By age, the suite belongs to the Tournaisian period.

Age Span:

Beginning stage:

Tournaisian

Fraction up in beginning stage:

0.4

Beginning date (Ma):

354.27

Ending stage:

Tournaisian

Fraction up in the ending stage:

0.8

Ending date (Ma):

349.24

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)”