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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Djamak Formation

Djamak Fm

Period:

Proterozoic

Age Interval:

Ediacaran (Rf? dz), V1

Province:
SE Tajik (Central W Pamir)

Type Locality and Naming

The Djamak Fm (Джамакская свита) - completes the section of the Vanch-Yazgulem Gr. This is the uppermost Fm in Vanch-Yazgulem Gr

Synonym: Djamakska formation, Джамакская свита

Reference section:

Lithology and Thickness

Composed of 80-90% gray, yellowish and pink, fine and medium-grained quartzites and quartz sandstones of incomplete thickness 1500 m. Among them, layers of quartz-mica shales, lenses of small-gravel conglomerates and greenstone-altered effusives are encountered.

Lithology Pattern:

Fine-grained sandstone

Relationships and Distribution

Lower contact

Yazgulem Fm

Upper contact

Contacts with overlying marbled limestones within the greater extent of the Cambrian Zorabat Fm, tectonic structures were observed by S. V. Ruzentsev (1970), as well as by Sh. Sh. Denikayev and V. F. Gorbatenko, noting cases of gradual transitions from the quartzites of the Djamak suite to the marbled limestones of the Zorabat Fm through a sequence of alternating quartzites and marbles up to 50 m thick. P. P. Chuenko also held a similar view. On the other hand, in the lower reaches of the Djaugas river, N. K. Sherbakov observed what seemed to be a transgressive, angular unconformable bedding of the marbled limestones of the Zorabat Fm over the sandstones and quartzites of the Djamak Fm with a conglomerate horizon at the base. This observation served as the basis for B. R. Pashkov (1962) to express the opinion that there was a break in sedimentation preceding the formation of the Cambrian? Zorabat Fm.

Regional extent

It is widespread in the western part of the Central Pamir.

GeoJSON

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Fossils

Age

Indicated as Riphean in the extracted literature, hence considered Neoproterozoic (Ediacaran) for schematic stratigraphic representation purpose.

Age Span:

Beginning stage:

Ediacaran

Fraction up in beginning stage:

0.0

Beginning date (Ma):

635.00

Ending stage:

Ediacaran

Fraction up in the ending stage:

1.0

Ending date (Ma):

538.80

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.