Aktashkan Formation

Aktashkan Fm

Period:

Devonian, Carboniferous

Age Interval:

Upper Devonian-Lower Carboniferous (Famennian-Tournaisian), CK9b

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along g. Aktashkan, Kuraminsky hr. I.A. Bardashev et al. in 1990.

Synonym: Aktashkanskaya Svita, Акташканская св.

Lithology and Thickness

Sparite limestones with rare layers of cherts. Rocks are layered with a predominance of medium-layered. Thickness 180-400m.

Lithology Pattern:

Limestone

Relationships and Distribution

Lower contact

Lies conformably on the dolomites of the Baraktyn Fm

Upper contact

It is conformably overlain by the Sallyatash Fm

Regional extent

Southwestern part of the Kuraminsky range. (Mountains of Baraktyntau, ridges of Altyn-Topkan, Takeli).

GeoJSON

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Fossils

In the lower part, conodonts of the Marginifera zone (middle part of the Famennian stage of the Upper Devonian), and in the middle and upper parts, Tournaisian conodonts Bispathodus aculeatus plumulus R.A. et D. brachiopods - Mesoplica kassini Nal., Rhytiophora temirensis (Serg.), Palaeochoristites čatkalicus (Dik.).

Age

Previously, O.I. Sergunkova (457) attributed these deposits to the upper substage of the Tournaisian stage, and I.A. Bardashev et al. in 1990 identified the Aktashkan Fm in the interval from the middle part of the Famennian stage (marginifera zone) of the Upper Devonian to the upper part of the Tournaisian stage in the Altyn-Topkan ridge.

Age Span:

Beginning stage:

Famennian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

365.20

Ending stage:

Tournaisian

Fraction up in the ending stage:

1.0

Ending date (Ma):

346.73

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)”