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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Mayan stage Formation

Mayan stage Fm

Period:

Cambrian

Age Interval:

Middle Cambrian (Є2), S2

Province:
North Tajik

Type Locality and Naming

Mayan stage – Є2 is widespread in some points with the Lower Cambrian, identified by B.V. Yaskovich (Geol. USSR, vol. 23, 1972).

Synonym: Mayan stage

Reference section:

Lithology and Thickness

Clayey slates. Composed of interbedded dark gray clayey, calcareous clayey, and carbonaceous clayey slates, feldspar-quartz siltstones and sandstones, as well as limestones. Thickness is 1000 m.

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

It lies on the Lower Cambrian transgressively, with a horizon (up to 100 m) of basal calcareous conglomerates at the base.

Upper contact

It is overlain with a discordance.

Regional extent

GeoJSON

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Fossils

In the interlayers and lenses of limestones in the lower parts of the section, trilobites are found that characterize the lower parts of the Mayan stage (Geol. USSR, vol. 23, 1972), such as Dorypyge richthofeni Dames., Coniagnostus nathorsti (Brogger), Hypagnostus contortus Hajr., H. sublatus Hajr., Peronopsis Fallax (Linn.) var. sinopsis Ivchin, Phalacroma rabutensis Hajr., Ph. grandiforme (Ang.) and others. The middle and upper parts of the section are characterized by the following trilobites of the Mayan stage: Clavagnostus dentatus Hajr., Hypagnostus brevifrons (Ang.), H. cf. truncatus (Brogger), H. mirandus Hajr., Phalacroma glandiforme (Ang.), Ph. rabutensis Hajr., Linguagnostus (Brogger); L. tricuspis Lerm., Poronopsis quadrata (Tullb.), P. Fallax Linn.

Age

Middle Cambrian

Age Span:

Beginning stage:

Drumian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

504.50

Ending stage:

Guzhangian

Fraction up in the ending stage:

1.0

Ending date (Ma):

497.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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