Cenozoic

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Main source = Baratov, R.B., et al. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Publishing House "Donish", Dushanbe, 269 pp. plus tables. Provided by Dr. Jovid Aminov, Nazarbayev University, Astana, Kazakhstan Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

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Zortash Formation

Zortash Fm

Period:

Cretaceous

Age Interval:

Early Cretaceous (K_I), Ak-Ra1

Province:
East Tajik (NE Pamir)

Type Locality and Naming

Includes in Akbaital-Rangkul region

Synonym: Zortash Suite, зорташская свита, Zortaish Fm

Reference section:

Lithology and Thickness

The northern side of the Rangkul depression), the section of the Lower Cretaceous has a two-membered structure: Upper part (100-480 m) - alternating brown and gray claystones, sandstones, clays, marls, limestones with thin layers and lenses of gypsum, rock salt, and copper-bearing sandstones.

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

Being the upper part of two membered structure of Rangkul depression, the lower contact is Tuyum Fm

Upper contact

It is conformably overlain by the Upper Cretaceous Mergensky Fm (мергенская свита).

Regional extent

In the Sarykolsky district of the Northern Pamir (basin of the Kyzylzhiik River, the northern slope of the Zortashkol Range, the northern side of the Rangkul depression).

GeoJSON

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Fossils

The finds of bivalves Exogyra 'ex gr. lokalis Mordv., E. aff. tuberkulifera Koch. et Dunck., Anomia cf. laevigata Sow., Isognomon sp., Isoarca sp., Pinna sp.; gastropods Nerinea sp., Pseudomelania sp., Mathilda sp. (Kreydenkov, Raspopin, 1969).

Age

The Early Cretaceous age of the Zortash Fm is confirmed by the finds of bivalves. The presence in these layers of numerous remains of ostracods Cypridea ex gr. sangardakensis Andrv. testifies that this level corresponds to the upper Albian - the widest Early Cretaceous transgression. The described deposits were attributed by S. S. Karapetov and G. S. Voskonyants (1962) to the Paleogene. However, subsequent studies by G. P. Kreydenkov and V. A. Raspopin (1969), the results of which are presented here, allowed to refer the described thickness to the Lower Cretaceous.

Age Span:

Beginning stage:

Albian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

113.20

Ending stage:

Albian

Fraction up in the ending stage:

1.0

Ending date (Ma):

100.50

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Extracted from Baratov, R. B. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Donish, Lakhsh district, 276.