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

Andreev Formation

Andreev Fm

Period:

Devonian, Carboniferous

Age Interval:

Famennian-Bashkirian, N4a

Province:
Nuratau

Type Locality and Naming

By the village of Andreevka, S. Nuratau Ridge. V.S. Korsakov in 1984 (Korsakov et al., 1993). Stratotype - southern outskirts of the village of Andreevka along the Ittyusay.

Synonym: Andreevskaya Suite, Андревская св.

Lithology and Thickness

The suite is divided into three parts.

Upper - spilites, diabases, interbedded with shales, claystone (argillites), cherts, and flaggy limestones.

Middle - limestones, shales, cherts, strongly cataclastically altered spilites, tuffaceous rocks (shalshteins).

Lower - siliceous-clayey (argillaceous) rocks, greenish-gray flaggy cherts, and strongly cataclastically altered amygdaloidal spilites.

Thickness 150-300 m.

Lithology Pattern:

Volcanics

Relationships and Distribution

Lower contact

Contacts with underlying and overlying deposits are tectonic.

Upper contact

Contacts with underlying and overlying deposits are tectonic.

Regional extent

Northern Nuratau Ridge, Bolosay, Sentab, Sop rivers basin, Darbazatau Mountains.

GeoJSON

null

Fossils

Upper – with ammonoids and early Bashkirian conodonts - Declinognathodus noduliferus (El. et Grav.), Idiognathoides asiaticus Nig, et Nem.

Middle – In limestones, conodonts - Gnathodus bilineatus (Roudy), Lochriea commutata (Branson et Mehl.) of the Visean and Serpukhovian ages.

Lower – In cherts, conodonts Polygnathus ex gr. semicostatus Br. et Mehl., Protognathodus cf. meishneri Zieg. of the Famennian age.

Age

The age is established within the Famennian age of the Middle Devonian - Bashkirian age of the Middle Carboniferous. P.N. Podkopaev et al. (1964) attributed (correlated?) it to the Chimkurgan Fm. of the lower Namurian of the Lower Carboniferous; R.R. Usmanov et al. (1984) considered it Ordovician-Silurian; A.K. Bukharin et al. (1990) - to the Bashkirian stage of the Middle Carboniferous; V.P. Vashchenko et al. (1992), V.S. Korsakov et al. (1993) - to the Lower Carboniferous; in the monograph (165) its age is considered to be Lower Carboniferous – Bashkirian of the Middle Carboniferous. V.V. Mikhaylov (460) dates the Andreev Fm to the Bashkirian of the Middle Carboniferous.

Age Span:

Beginning stage:

Famennian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

371.10

Ending stage:

Bashkirian

Fraction up in the ending stage:

1.0

Ending date (Ma):

315.15

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)”