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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Kamyshbashin Formation

Kamyshbashin Fm

Period:

Triassic

Age Interval:

Carnian – Rhaetian (T3 km), S2

Province:
North Tajik

Type Locality and Naming

Identified as a result of the work of V. N. Weber, M. I. Brik, and N. V. Shabarova (Geol. USSR, vol. 23, 1972).

Synonym: Kamyshbashinskaya Suite, Камышбашинская свита

Reference section:

Lithology and Thickness

Conglomerates, sandstones. Composed of colorful breccial conglomerates, sandstones, siltstones, and clays. Thickness 0-200 m. Divided into two sub-suites. The lower sub-suite is composed of alternating clays, sandstones, gravels, and conglomerates of thickness 0-100 m, colored in green, yellow, pink, and red-brown tones. The upper sub-suite is mainly composed of clays with interlayers of sandstones. Their thickness is 90-100 m, and they are colored in light gray, sometimes yellowish and green tones.

Lithology Pattern:

Aus Conglomerate

Relationships and Distribution

Lower contact

It is sporadically developed, located in ancient depressions of the terrain where it lies sharply discordant on different layers of the Silurian, Devonian, and Carboniferous.

Upper contact

It is generally overlain transgressively by carboniferous deposits of the Lower-Middle Jurassic. However, in the mentioned ancient depressions, the contact of the suite with the Lower-Middle Jurassic is conformable and is conditionally determined by the sole of clays containing massive accumulations of Jurassic ostracods (Geol. USSR, vol. 23, 1972).

Regional extent

Distributed in the northeast part of the Turkestan region

GeoJSON

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Fossils

In the lower sub-suite, remains of plants such as Schizoneura cf. gondwanensis Feist., Danaeopsis cf. Marântacea (Presl), Diplazites dentatus Sixt., and others have been found, which allow it to be classified as "lower layers of the upper Triassic" (Geol. USSR, vol. 23, 1972, book 1, p. 371). In the upper sub-suite of the Kamyshbashinskaya Suite, Clathropteris obovata Oishi, Neocalamites carrerei (Zeill.), Cycadocarpidium erdmanii Nath., and others have been found, which allow this sub-suite to be attributed to the upper layers of the upper Triassic (ibid).

Age

T.A. Sixtel (1960a) considered the lower sub-suite to belong to the Carnian stage, and the upper one - to the Norian and Rhaetian stages. At the Tashkent meeting (Decisions..., 1959), the lower sub-suite was equated with the lower Keuper (Carnian and Norian stages), and the upper one - with the upper Keuper (Rhaetian). Later, the division of the Upper Triassic of Central Asia according to plant remains into stages had to be abandoned due to the inconsistency of this division with the stratigraphic division, carried out by animal remains (Geol. USSR, vol. 23, 1972, book 1, p. 371).

Age Span:

Beginning stage:

Carnian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

232.15

Ending stage:

Rhaetian

Fraction up in the ending stage:

1.0

Ending date (Ma):

201.36

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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