Neogene

Paleogene

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Mesoproterozoic

Paleoproterozoic

Main source = Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian) Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

Predgorno-Nuratin Formation

Predgorno-Nuratin Fm

Period:

Carboniferous

Age Interval:

Tournaisian–Serpukhovian, N3

Province:
Nuratau

Type Locality and Naming

In the foothills of the Nuratau ridge. P.N. Podkopaev in 1956 (1961f). Stratotype - southern slope of the eastern part of Khanbandytay. Name translates as Foothill Nuratin Fm.

Synonym: Foothill Nuratainskaya Formation, Nuratau Foothill Fm, Предгорнонуратинская св. Predgornonuratinian Fm; Foothill Nuratin Fm

Lithology and Thickness

The suite is divided into three sub-suites.

Upper - micritic limestones, cherts, sandy clastic limestones, argillites, and sandstones.

Middle - sandstones with subordinate layers and lenses of claystone (argillites), sandy limestones, and cherts

Lower - sandstones, interbedded with greenish-gray argillites, gravelite horizons

The thickness of the suite is about 800-1000 m.

Lithology Pattern:

Siliceous limestone

Relationships and Distribution

Lower contact

The lower boundary of the suite is unclear.

Upper contact

According to V.S. Korsakov et al. (1993), it is tectonic with the Ust-Kuruksay Fm of the Upper Devonian. It is overlain with erosion, stratigraphic, and angular unconformity by the "conglomerate" layer of the Upper Carboniferous-Lower Permian (= Farishk Fm?).

Regional extent

North slope of the Nuratau Mountains, Uzunkuduk-Karamanskaya Plain, where the well is exposed, partially on the southern slope of the eastern end of Khanbandytay.

GeoJSON

null

Fossils

Upper – Contains conodonts - Gnathodus bilineatus (Round.), Lochriea nodosa (Bisch.), L. homopunctatus (Zieg.).

Middle – Conodonts - Neopolygnathus kylosjensis (Nigm.), Gnathodus typicus Soor.

Lower – Conodonts - Polygnathus sp., Siphonodella sp.

On the Uzunkuduk Plain, isolated biogenic mounds (thickness 60-100m) with a rich fauna complex of the Serpukhovian stage are found.

Age

It belongs to the Tournaisian and Serpukhovian stages of the Lower Carboniferous. The span and age of the suite are interpreted ambiguously. P.N. Podkopaev et al. (1961) attributed this suite to the Upper Visean; in the Stratigraphic Scheme of the Carboniferous of Central Asia (1961) - to the Lower Carboniferous (Namurian)-Middle Carboniferous (Lower Bashkirian); in Stratigraphy (457) - to the Middle Carboniferous-Lower Bashkirian; in the Stratigraphic Scheme of the Carboniferous of Central Asia (1969) - to the Middle Carboniferous, Lower Bashkirian; in the monograph (165) the age is accepted within the middle of the Visean stage of the Lower Carboniferous - early Bashkirian of the Middle Carboniferous; on the State Geological Map-500 of Uzbekistan (460) it is attributed to the Lower Carboniferous Visean-Serpukhovian stage.

Age Span:

Beginning stage:

Tournaisian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

359.30

Ending stage:

Serpukhovian

Fraction up in the ending stage:

1.0

Ending date (Ma):

323.40

Depositional setting

Depositional pattern:

Additional Information

Compiler:

I.M. Nigmadzhanov, F.S. Karimova – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”