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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Lokzun Formation

Lokzun Fm

Period:

Triassic

Age Interval:

Norian-Rhaetian (T₃ n-r), M3c

Province:
SE Tajik (SE Pamir)

Type Locality and Naming

Includes in SE Murghab district (Gurdumdin type section Shin and Igrymiyu rivers)

Synonym: Lokzun suite, Локзунская свита

Reference section:

Lithology and Thickness

The thickness is 300 m. It consists of two conformably lying members: the Jilgakochusuy and Gudar.

The Jilgakochusuy member (100-150 m) is made up of greenish-gray calcareous sandstones and calcareous marls with interlayers of organogenic limestones.

The Gudar member (100-150 m) consists of dark siltstones with layers of sandstones.

Lithology Pattern:

Sandy limestone

Relationships and Distribution

Lower contact

It conformably overlies the Ladinian-Norian Aktash Fm (акташской свите)

Upper contact

It is unconformably overlain by the Toarcian-Bajocian layers.

Regional extent

It is widespread in the basin of the Shin and Igrymiyu rivers.

GeoJSON

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Fossils

In Jilgakochusuy member, it includes abundant remains of Middle-Late Norian pteriopods Astarte triassina Roem., Monotis sp. and others; brachiopods Halorella amphitoma Bronn., H. stoliczkai Suess, H. rosittana Bitt., H. rarecostata Bitt., H. pamirensis Moiss., Spiriferina akdjilgaensis Moiss., Koninckina cf. telleri Bitt., Zeilleria cf. bukowskii Bitt., Aulacothyris reflexa Bitt., Athyris ex gr. manzavini Bitt.; corals Phyllocoenia decussata (Reuss), Palaeastraea grandissima (Frech), Elysastraea profunda (Reuss).

No organic remains have been found in Gudar member

Age

Norian-Rhaetian. No organic remains have been found in it; by its position in the section, it is conditionally attributed to the upper part of the Norian stage and partially to the Rhaetian stage.

Age Span:

Beginning stage:

Norian

Fraction up in beginning stage:

0.2

Beginning date (Ma):

222.99

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.